Run-flat support for pneumatic tired wheel

A tire is supported in a deflated or run-flat condition by curved, tubular support segments. End portions of adjacent support segments include complementary male and female portions disposed in mating engagement when installed on a wheel in the run-flat operative position. The mating end portions maintain alignment of the support segments during installation and oppose lateral deflection of the segments relative to the wheel in response to side impact forces imposed on the tire during run-flat operation. Each support segment includes a smooth crown portion centered between two shoulder portions and separated from the shoulder portions by a pair of annular grooves or pockets. During run-flat turning and cornering movement, tire tread material is pressed into one of the annular grooves, thus centering the tire on the support segment, thereby opposing lateral shifting movement of the tire tread relative to the support segment and distributing load forces uniformly across the tire tread. The curved support segments include transverse sidewalls arranged generally in a tubular structure having the form of a pentagon in cross-section profile for reacting load forces during run-flat operation.

This invention is generally related to pneumatic tires for motor vehicles, 
and in particular to an internal rim support assembly for supporting a 
tire in a deflated and run-flat condition. 
Pneumatic tired wheels are widely used on virtually all types of land 
vehicles, including automobiles, trucks, trailers, tractors, other 
self-propelled and unpowered vehicles and aircraft landing gear. Intensive 
development activities involving pneumatic tired wheels and tires have 
resulted in a highly developed state of the art with respect to tire 
design, including the development of tubeless tires and radial tires which 
allow substantial deflection of the tire sidewall during normal operation 
to improve vehicle handling performance, cushion the vehicle against road 
imperfections, improve vehicle operating efficiency and lengthen tire life 
by reducing friction caused by tire deflection. 
A substantial limitation on the performance of pneumatic or gas medium 
charged tires is directly caused by the loss of inflation pressure. 
Various attempts have been made to eliminate loss of tire pressure due to 
tire wall puncture and provide tire designs that will enable the tire to 
continue to operate in a deflated or "run-flat" condition. Of course, 
conventional pneumatic tires, if deflated, cause substantial loss of 
vehicle control and both tire and wheel damage quickly result from 
continued operation. 
Efforts have been directed at developing tires with sidewall and tread 
reinforcements and wheel rim configurations which permit tires to operate 
in the run-flat condition. These efforts have only been partially 
successful and still result in reduced vehicle stability and control and 
undesirable changes in traction and handling due to changes in effective 
wheel diameter and tire deflection. Moreover, run-flat tires have been 
developed for the purpose of eliminating the need for a spare tire on 
board the vehicle and the problems associated with changing flat tires 
under hazardous on-the-road conditions as well as the desire to eliminate 
the problems associated with the space required in the vehicle for storing 
a spare tire and the associated tire changing tools. 
Accordingly, considering the problems associated with providing 
conventional spare tires and tools and the limitations imposed by 
self-sealing and conventional run-flat tire designs, there is considerable 
interest in providing vehicle wheels with improved run-flat support 
devices that may be installed within the wheel-tire pressure chamber and 
which support the tire in a seriously under-inflated, deflated or run-flat 
condition. 
The problems associated with self-sealing tires to minimize pressure loss 
and efforts to design tires which will operate in a deflated or run-flat 
condition have prompted the development of support devices which may be 
installed on a pneumatic tired wheel within the tire pressure chamber to 
support the tire when it is partially or completely deflated without 
substantially reducing the wheel effective diameter so that vehicle 
stability and control are not compromised and the vehicle can be operated 
for an extended period of time in the run-flat condition. Devices have 
been developed that include single and multi-part cushion members which 
are disposed on the wheel rim between the tire bead flanges and extend 
radially outward from the wheel axis of rotation to support the tire in a 
deflated condition. 
Some of these conventional run-flat devices have been fabricated of 
resilient elastomeric materials of relatively complex construction and may 
be stretched over the wheel rim to mount on unitary rims. These devices, 
if stiff enough to support a tire in a run-flat condition, are difficult 
to mount on one piece rims due to the difference in diameter between the 
tire bead flanges and the interconnecting rim center portion or web. On 
the other hand, if these devices are made resilient enough to be slipped 
over the bead flanges and engaged with the wheel rim in a static 
condition, they tend to lose their support position during high wheel 
speed due to centrifugal forces acting thereon. 
Additionally, single and multi-part, substantially rigid, annular or 
toroidal support devices have been developed for mounting on pneumatic 
tired wheel rims, particularly multi-part rims wherein there is no 
requirement that the diameter of the support device change during the 
mounting procedure since it is not necessary to provide for slipping the 
device over the larger diameter tire bead flange and then be adapted to 
engage the smaller diameter rim web. 
A substantial number of relatively light duty vehicle wheel configurations 
are characterized by one piece or welded multi-part wheel structures that 
cannot be disassembled to provide access to the smaller diameter rim web 
or center portion for mounting a conventional run-flat support device. 
Conventional devices for supporting pneumatic tires in a run-flat 
condition have not been properly adapted for mounting on a rim which has a 
tire bead flange of a larger diameter than the rim web portion between the 
bead flanges. 
The present invention has been developed for providing a support device for 
use in combination with a pneumatic tired wheel to permit safe operation 
of the wheel in a run-flat condition of the tire without significant loss 
of vehicle stability or control, while providing adequate tractive effort 
of the wheel with the tire in the run-flat condition and to substantially 
avoid tire destruction or damage while being operated in the 
under-inflated or run-flat condition for extended periods. 
BRIEF SUMMARY OF THE INVENTION 
The present invention provides an improved support device for a pneumatic 
tired wheel for supporting a pneumatic tire in an under-inflated, deflated 
or run-flat condition. The run-flat assembly is particularly adapted for 
installation on a substantially one piece or fixed wheel having a circular 
rim or web portion interposed between opposed tire bead flanges. 
In accordance with one aspect of the present invention, a multi-segment 
run-flat support assembly is provided for mounting on a pneumatic tired 
wheel and adapted to be installed between flanges of the wheel which 
support the circular pneumatic tire beads. In the preferred embodiment, 
the support assembly includes two or more curved support segments each 
including transverse sidewalls for engaging the wheel and a crown sidewall 
for engaging the tire tread inner wall to support the tire in an 
under-inflated, deflated, or partially reduced diameter operating 
condition, which will provide suitable vehicle stability and control and 
suitable tractive capability under run-flat conditions. 
End portions of adjacent support segments include complementary male and 
female portions disposed in mating engagement when installed in the 
run-flat operative position on the wheel. The mating end portions assist 
in proper location and alignment of the support segments during 
installation, and also stabilize and help maintain alignment of the 
support segments in response to side impact forces directed against the 
tire during run-flat operation. The mating end portions further provide 
uniform load distribution against the tire and smooth running response 
during run-flat operation. 
The present invention further provides a multi-segment run-flat support 
assembly for mounting on a pneumatic tired vehicle wheel which includes a 
unique crown configuration for preventing lateral shifting movement of the 
tire relative to the wheel during turning and cornering maneuvers under 
run-flat conditions. Each run-flat support segment includes a smooth crown 
portion disposed between two shoulder portions, with the crown portion 
being separated from the shoulder portions by circumferential grooves or 
recesses. During run-flat turning and cornering movement, tire tread 
material is pressed into one of the grooves, thus preventing lateral 
shifting movement of the tire tread relative to the support segment. 
Still further, the support segments of the tire support device are 
substantially tubular in form and include transverse sidewalls that can be 
mounted on various types of conventional one piece, fixed or multi-part 
wheel rims and suitably secured thereto by threaded bolt fasteners as OEM 
equipment or by add-on retrofit installation. Each transverse sidewall is 
arranged generally in the form of a five-sided tubular segment that is 
curved and open-ended. The tubular, transverse sidewall arrangement reacts 
run-flat load forces uniformly and substantially without deforming the 
tubular segment. 
The foregoing features and advantages of the run-flat tire support device 
of the present invention will be understood by those skilled in the art 
upon reading the detailed description which follows with reference to the 
drawings, wherein:

DETAILED DESCRIPTION OF THE INVENTION 
In the description which follows, like parts are marked throughout the 
specification and drawing with the same reference numerals, respectively. 
The drawing figures are not necessarily to scale in the interest of 
clarity and conciseness. 
Referring to FIGS. 1, 7 and 9, there is shown a conventional pneumatic 
tired wheel assembly, generally designated by the numeral 10, which has 
been modified to include the unique run-flat tire support assembly of the 
present invention. The wheel assembly 10 includes a conventional pneumatic 
tire 12 supported on a substantially rigid wheel 14 and forming an annular 
inflation space or chamber 16. In FIG. 7 and FIG. 9, the tire 12 is shown 
in a condition wherein the gas pressure in the wheel tire pressure chamber 
16 is reduced enough to permit the tire to operate in the run-flat 
condition. The tire 12 is of conventional design and may be either a bias 
ply or radial type. The tire 12 includes a circular, circumferential tread 
part 18, opposed sidewalls 20 and 22 integrally formed with the tread part 
18 and delimited by radially inwardly disposed circumferential bead 
portions 24 and 26, respectively. 
The wheel 14 is of substantially conventional construction and includes a 
central, circular disk hub portion 28 adapted to be mounted on a 
conventional vehicle rotatable wheel hub, not shown. A circumferential 
circular rim 30 of wheel 14 includes opposed generally laterally extending 
webs 32 and 34 on opposite sides of the hub 28 and each being delimited by 
radially outwardly disposed circumferential tire bead flanges 36 and 38, 
respectively. The flanges 36 and 38 include curved surfaces 36A and 38A 
configured to be in sealing and supportive engagement with the tire bead 
portions 24 and 26, respectively, to prevent loss of pressurized air from 
the inflation chamber 16. 
Those skilled in the art will recognize that the center rim 30 may take 
different cross-sectional configurations. However, typically the rim 30, 
including the web portions 32 and 34, is of a smaller diameter with 
respect to the wheel central axis of rotation 40, FIG. 9, than the flanges 
36 and 38, and smaller in particular than the outermost edges of the 
flange 36 and 38. 
Although the wheel 14 is shown having integral hub and rim portions 28 and 
30, those skilled in the art will recognize that the present invention may 
be used in conjunction with fixed multiple-piece welded or riveted rims or 
separable wheel rims of various designs. The run-flat support assembly of 
the invention is particularly advantageous in that it may be mounted on 
fixed or integral rims of the type including bead flanges 36 and 38 that 
are not separable from each other or from the rim 30. 
Referring now to FIG. 1, FIG. 2 and FIG. 3, the run-flat support assembly 
of the invention is illustrated and generally designated by the numeral 
42. The support assembly 42 includes opposed, end coupled, semi-circular 
support segments 44 of substantially identical construction. Each segment 
44 is characterized by a substantially semi-cylindrical tire support crown 
web portion 46, opposed radially inwardly extending generally parallel 
sidewall flanges 48 and 50, a first coupling web 52 for attachment to the 
rim 30 in the run-flat operative position as shown in FIG. 7 and FIG. 9, 
and a second coupling web 54 attached to the first coupling web and 
extending transversely with respect thereto, and engaging the lateral rim 
web 34. 
Preferably, each segment 44 includes first and second body portions 44A, 
44B that are welded together along weld lines W as shown in FIG. 3 and 
FIG. 6, thereby forming an open-ended, tubular support structure. The 
segments 44 may be formed of a suitable engineering material such as 
steel, aluminum or a high strength reinforced plastic. In the preferred 
embodiment, the crown web 46, the sidewall flanges 48, 50 and the coupling 
webs 52, 54 are interconnected and arranged generally in a tubular 
structure having the form of a pentagon in cross-section profile for 
reacting load forces during run-flat operation. The body sections 44A, 44B 
are prefabricated and are conformed for concave nesting engagement within 
the curvature of the rim 30. When the body sections 44A and 44B are welded 
together along the weld lines W, the webs and sidewalls define a 
mechanical box section with all peripheral surfaces being connected 
without a break. 
Referring now to FIG. 6, FIG. 8 and FIG. 9, the coupling web 52 of body 
section 44B is intersected by a coupling aperture 56, and a threaded 
fastener nut 58 is welded to the underside of the coupling web 52 in 
registration with the aperture 56. The rim 30 is also intersected by a 
threaded coupling aperture 60 and receives a support bushing 62. A 
threaded bolt fastener 64 extends through the support bushing and is 
torqued into engagement with the nut fastener 58. 
The wheel 14 is further modified to receive additional segments 44 of the 
run-flat support assembly 42 by the installation of plural support 
bushings 62 projecting radially through the rim 30 on the web portion 32, 
for example, as shown in FIG. 7. A suitable radial hole 56 may be bored in 
the web 34 and the bushing 62 welded in place by suitable airtight welds 
on the both the inner and outer surfaces of the web 34, as shown. The 
bushing 62 is preferably centered between the flanges 36 and 38 and is 
adapted to form a support for an elongated threaded bolt 64 having a 
socket head portion 64H and a threaded shank portion 64S. 
A non-threaded cylindrical shank portion 64N extends between the head 64H 
and the threaded shank portion 64S. The non-threaded shank portion 64N is 
adapted for a close sliding fit in a bore formed through the bushing 62. A 
suitable elastomeric seal ring 68 is supported on the bushing 62 for 
engagement with a beveled edge portion of the head 64H to prevent leakage 
of pressurized air from the inflation space 16. As shown in FIG. 1, three 
sets of diametrically opposed bolts 64 and support bushings 62 are 
provided in the rim 30 for attaching three run-flat support segments 44 in 
the operative position. Opposed holes are drilled or otherwise formed in 
the rim web 32 to receive the bushings 62 and the bushings are welded in 
place in the positions shown in FIG. 1 for receiving the bolts 64. 
FIG. 7 and FIG. 9 show the run-flat support assembly 42 disposed on the 
wheel 14 and in an operative run-flat working position wherein the tire 12 
has been deflated. The portion of the tire tread 18 in contact with a 
roadway 66 forces the tread inner wall into engagement with the support 
crown 46 as the wheel rotates. 
In the inflated condition of the tire 12 on the wheel 14 and without any 
load weight applied thereto the tire assumes a nominal radius with respect 
to the axis 40, as shown in FIG. 1. When the tire 12 is under a rated 
vehicle weight load, it assumes a position wherein the sidewalls deflect 
some and the tread 18 assumes a position at an intermediate reduced radius 
with respect to the axis 40. Finally, as shown in FIG. 9, when the tire 12 
is substantially deflated, the sidewalls 20 and 22 deflect to a position 
wherein the tread 18 is at a further reduced radius with respect to the 
axis 40 and the crown 46 is engaged with the inner tread 18. Preferably, 
the run-flat working position diameter of the support assembly crown 
surface 46 should be about 80%-85% of the nominal diameter of an inflated 
but unloaded tire. 
It will be appreciated that the tire 12, when operated under-inflated or 
during run-flat conditions, is subjected to loading forces that tend to 
deflect the support segments relative to the wheel. In order to maintain 
true alignment of the support segments 44, the crown member of each 
support segment includes first and second end portions 44E, 44F, with the 
end portions including complementary male coupling members 70 and female 
coupling members 72. In the preferred embodiment, the male and female 
coupling members are arranged in a sawtooth coupling structure in which 
the male coupling member consists of a triangular tooth member projecting 
circumferentially from the first end portion of the crown member, and each 
female coupling member including a V-shaped notch or pocket extending 
circumferentially into the second end portion of each crown member. 
According to this arrangement, the notches or pockets of one support 
segment are disposed in mating engagement with the teeth of an adjacent 
support segment when the support segments are mounted on the rim in the 
end-to-end circumferentially arranged, operative position as shown in FIG. 
1 and FIG. 4. 
Alternative end mating arrangements are shown in FIG. 10 in which the male 
and female coupling members 70R, 72R have a rectangular form, and in FIG. 
11 in which the male and female coupling members 70C, 72C have a 
cloverleaf profile. Preferably, the male and female coupling members 
alternate with each other on each end portion of the support segments. 
Upon loss of inflation pressure within the wheel-tire pressure chamber 16, 
the sidewalls of the tire 12 undergo simultaneous compression and 
deformation due to side loading forces. These side loading forces cause 
lateral shifting movement of the tire relative to the wheel during turning 
and cornering maneuvers under run-flat conditions. To maintain alignment 
of the tire tread 18 with the support segment crown 46, each run-flat 
support segment includes a smooth crown web portion 46W disposed between 
two shoulder portions 46L and 46R. The crown portion 46W is separated from 
the shoulder portions 46L, 46R by circumferential grooves or recesses 74, 
76, respectively. 
During run-flat turning and cornering movement, tire tread material 18T, as 
shown in FIG. 8, is pressed into grooves 74, thus preventing lateral 
shifting movement of the tire tread relative to the support segment crown 
member 46. The grooves or pockets 74, 76 are laterally spaced apart on 
opposite sides of the crown member 46, and extend circumferentially along 
the support segment 44 between the crown web and the laterally opposite 
shoulders 46L, 46R, respectively. 
Preferably, the circumferential grooves are formed by first and second 
intermediate web portions 78, 80 that are radially inset with respect to 
the crown web 46, thereby defining the first and second grooves or pockets 
74, 76, respectively. When the support segments are assembled in 
end-to-end mating engagement with each other, they collectively form a 
substantially continuous circumferential crown support surface, with the 
circumferential grooves extending completely around the assembled support 
segments 44, for supporting and stabilizing the tire tread during run-flat 
operation. 
The crown, shoulder portions and grooves form gripping means 52 that engage 
the inner wall 18A of the tire tread to prevent lateral or circumferential 
slippage of the tread with respect to the support segment 42 under either 
lateral forces exerted on the wheel 14 or tractive effort exerted by 
rotation of the wheel 14. 
Fitting the support assembly 42 to a wheel is carried out with the tire 12 
removed from the wheel. The support segments 44 are then inserted into the 
wheel-tire pressure space 16, as shown in FIG. 6, with three support 
segments 44 being arranged in end-to-end mating relation. The wheel 14 is 
then placed onto the tire and the tire sidewall bead 26 is inserted into 
the flange pocket 38A. The support segments 44 are then shifted 
circumferentially until the coupling apertures are in alignment and so 
that the bolts 64 may be threadedly engaged therewith upon sliding the 
bolts through the bushings 62. Upon tightening the bolts 64 against the 
fastener nuts 58, the coupling web 52 of the support segment 44 is brought 
into compression engagement with the rim web 32, as shown in FIG. 1 and 
FIG. 4. 
After positioning the support segments 42 as described above and securing 
the support segment to the wheel, the tire 12 may be fully mounted on the 
wheel by forcing the tire bead 24 over the flange 36 so that it is 
disposed in the pocket 36A between the flanges 34 and 36. After the beads 
24 and 26 are fully inserted into the pockets 36A, 38A, respectively, the 
tire is inflated to its rated pressure. The wheel assembly 10 is then 
ready to be mounted on a vehicle for normal use. Thanks to the 
construction of the run-flat support assembly 42, including the gripping 
means provided by the crown 46, the shoulders 46L, 46R and grooves 74, 76 
formed thereby the tire 12 may be operated in a run-flat condition for an 
extended period of time. The run-flat support assembly 42 does not add a 
substantial amount of weight to the wheel assembly and may be constructed 
of conventional engineering materials as mentioned above. 
Those skilled in the art will appreciate that the run-flat support assembly 
42 may be advantageously retrofitted to existing one-piece or fixed 
multi-part wheels having opposed bead flanges and center rim portions 
arranged such that the rim portion has an effective outer diameter less 
than the diameter of the bead flanges, thereby precluding assembly of a 
one-piece as well as prior art multi-piece run-flat support devices to a 
conventional fixed or one-piece wheel. Additionally, the support assembly 
42 may also be mounted on separable multi-part wheels if desired. 
Although preferred embodiments of the invention have been described in 
detail herein, those skilled in the art will recognize that various 
substitutions and modifications may be made to the support segments and 
equivalents thereof without departing from the scope and spirit of the 
invention as recited in the appended claims.