Wheel with window and method for viewing the interior of a tire wheel assembly under dynamic conditions

This application claims the benefit of U.S. Provisional Application No.: APPLICATION NO. 60/302,444 FILING DATE Jul. 02, 2001

FIELD OF THE INVENTION

This invention relates to method and apparatus allowing visual access to the interior of a tire wheel assembly under dynamic conditions. More particularly, the present invention relates to a wheel rim having at least one window such that the interior of a tire mounted on the wheel rim may be viewed under dynamic conditions such as those provided by a dynamometer test machine.

BACKGROUND OF THE INVENTION

Vibration felt by a vehicle driver through the vehicle seat, steering wheel, and acceleration pedal are typically directly related to force variations encountered at the tire footprint which may be caused by a variety of sources. These sources include, but are not limited to, imbalance of the tire wheel assembly, runout of the wheel and/or tire, irregularities in the structure of the tire (non-uniformity), brake drag, wheel misalignment, road disturbances, worn linkages, etc. In recent years, automobile vehicles weights have been generally declining in order to improve gas mileage. A result of the weight loss is that the suspensions and wheel support parts have become lighter and more susceptible to vibration. Vibration, especially vibration due to non-uniformity of the tire and imbalance due to tire and/or wheel runout, is now a prominent issue for tire manufactures who are also under economic pressure to do more with less. In addition, lead balance weights used to correct tire wheel assembly imbalance, long considered a health concern, will likely be banned and a replacement for lead will need to be used to manufacture the weights.

It has long been known that inserting various materials into the interior of a tire wheel assembly could provide a benefit of balancing the tire wheel assembly. Internal flowable materials have long been used as a staple for many fleet managers in the trucking industry to help combat vibration, promote even tire wear, and extend tire life. The cause behind this benefit has been described in a variety of manners, the most common being the principle of mass balancing. Based on this theory, during tire rotation, free flowing materials contained the tire wheel assembly will seek a distribution in balance about the center of rotation and will tend to offset any imbalance inherent in the tire wheel assembly. However, while the performance of the internal materials could be verified both subjectively and by objectively by testing, none of the theories on the way the internal materials worked could be substantiated because it was impossible to see into the interior of the tire wheel assembly to see how the materials acted under operating conditions. Furthermore, without proving the mechanics of how the internal flowable material works, it has been recognized that at least some internally flowable materials not only work to reduce the vibratory effects of imbalance, but also work to reduce force variations due to non-uniformity of the tire as well as dampening other sources of vibration and noise.

Accordingly, internal flowable materials are positioned to help the tire and vehicle manufactures provide a better ride for their customers. However, testing variations of different materials may be necessary to optimize the make-up and/or amount of internal flowable material for a particular tire/vehicle application. This testing could be facilitated by a definite knowledge and comparison of how the internal flowable materials react to forces within the tire under dynamic conditions.

Other problems with the state of the prior art is with unsubstantiated and competing claims by some internal flowable material manufacturers which may confuse potential consumers as to how a product actually performs within a tire. With the introduction of various competing internally flowable materials, additional theories have been forwarded by these manufacturer in order to substantiate claims of superior performance of a particular material. As an example, one such manufacture using a material comprising glass beads has claimed that their glass beads, once properly positioned by the rotation of the tire wheel assembly to a position causing balance of the tire wheel assembly, will remain in this balancing position along the innerliner of the tire due to electrostatic cling produced by the tribological forces generated by the glass beads rubbing against the innerliner of the tire and against each other. The manufacturer has claimed that the glass beads remaining in position provided a benefit in that the internal balancing compound did not become displaced when the vehicle stopped, thus the tire wheel assembly remained in a dynamically balanced condition. As with the theories as to how these internal flowable materials worked, the electrostatic cling theory could not be substantiated or disproved because it was impossible to see into the interior of the tire wheel assembly to see how the materials acted under operating conditions.

There are a multitude of additional problems related to the inability to view the interior of a tire wheel assembly. Improved performance tests could be developed such as monitoring the development of innerliner cracking or monitoring specific interior areas of the tires under specialized test conditions.

Therefore, there remains a need in the art for a wheel and method that will enable the interior of the tire wheel assembly to be viewed under operating conditions.

SUMMARY OF THE INVENTION

An object of the present invention is to allow the interior of a tire to be viewed when the tire is mounted on a wheel rim as part of a tire wheel assembly. These and other advantages are provided by a wheel rim having at least one aperture formed therein. A transparent material is attached to the tubewell in a position covering the aperture in a manner preventing air loss and forming a window through the wheel rim.

These and other advantages are also provided by a tire wheel assembly comprising a tire mounted on a wheel rim having at least one aperture formed in a tubewell portion of the rim and a transparent material attached to the wheel rim and positioned over the aperture forming a window through which an interior surface of the tire is visible.

These and other advantages are also provided by a method of viewing the interior of a tire of a tire wheel assembly undergoing dynamic operations comprising the steps of providing at least one window in a tubewell portion of a tire wheel assembly; causing the tire wheel assembly to rotate against a test surface; and directing a camera toward a predetermined position where the window will occupy during at least a portion of its rotational path.

With the above, and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description and the several views illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

shows a perspective view of a wheel rim having at least one see-through window in an embodiment of the present invention;

FIG. 2A

shows a cross-sectional view of a tire wheel assembly of the present invention wherein an internal flowable material on the innerliner of the tire opposite the tire footprint is positioned below the window;

FIG. 2B

shows a cross-sectional view of an alternate embodiment of the present invention wherein the window forms a door providing access to the interior of the tire wheel assembly under uninflated conditions;

FIG. 3

shows a view of a tire wheel assembly of the present invention wherein the innerliner of the tire opposite the tire footprint is visible through the window;

FIG. 4

shows a portion of a test set up of the present invention to see the interior of the tire under dynamic conditions; and

FIG. 5

shows a flowchart of the method of the present invention to see the interior of the tire under dynamic conditions.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is first made to

FIG. 1

of the drawings which shows the wheel rim

10

of the present invention having at least one window

12

positioned in the tubewell section

14

of the wheel rim

10

. The window

12

can be made of any appropriate transparent material which has sufficient strength such as various known plastic materials. The window

12

can be fastened to the wheel rim

10

using appropriate fasteners

16

and a gasket or sealant

18

around the perimeter to prevent loss of air pressure. Alternatively, the window

12

can also be bonded to the tubewell

14

with an adhesive, or attached in any appropriate manner. Still another alternative would be a hinged window that would allow access into the interior of the wheel rim

10

when an attached tire in unpressurized. This would prevent the need to dismount the tire from the wheel rim when inserting or removing an object from the tire wheel assembly.

Referring now to

FIG. 2A

, window

12

is preferably positioned and of sufficient width and length to view a substantial portion of the interior surface or innerliner

22

of a tire

20

mounted on the wheel rim

10

to form a tire wheel assembly

30

. As shown, window

12

is positioned on the tubewell

14

portion of wheel

10

and is large enough to allow viewing of the entire innerliner

22

at the tire footprint

24

when the tire wheel assembly

30

is under loaded conditions.

Referring now to

FIG. 2B

, an alternate embodiment of window

12

′ comprise a hinge

13

which enables window

12

′ to be opened when tire wheel assembly

30

in unpressurized. The window

12

′ is sealed by releasable seal or gasket

18

. When the tire wheel assembly is unpressurized, the gasket

18

holds the window

12

′ in place. Although not shown, it is also contemplated that the window

12

′ could be held shut by a rotatable bar, a releasable snap, latch, or other holding mechanism which can be relatively quickly opened to allow access to the interior of the tire wheel assembly

30

. When inflated, the window

12

′ is preferably shaped and positioned such that the air pressure will help seal and retain the window

12

′ in position, such as by flange

19

.

Referring now to

FIG. 3

, a flowable material

40

has been inserted into the tire wheel assembly

30

and is visible on the innerliner

22

of the tire

20

through window

12

. Under dynamic conditions, the reaction of the flowable material

40

to dynamic loads at the tire footprint (as well as any location around the tire) can be studied.

In

FIG. 4

, the visual set-up is shown. A camera

54

is positioned on the inboard side of the wheel rim

10

and directed toward window

12

. Window

12

is shown positioned over the tire footprint

24

which is adjacent dynamometer wheel

52

. Flowable material

40

inserted into the tire wheel assembly

30

is visible through window

12

and camera

54

. A strobe light

56

is also directed toward window

12

, shown positioned over the tire footprint

24

against dynamometer wheel

52

. The tire wheel assembly

30

is attached to a dynamometer carriage

51

which forces the tire wheel assembly

30

against dynamometer wheel

52

. The strobe light

56

provides sufficient illumination of the innerliner

22

of the tire

20

. During dynamic conditions, the strobe light

56

is coordinated with the rotational speed of the tire wheel assembly

30

such that the strobe light only flashes when the window

12

is directly in the frame of camera

54

such as when it is overtop footprint

24

or at any other predetermined location. This enables video or still from camera

54

to provide a frame by frame shot of the tire innerliner

22

for each rotation of the tire wheel assembly

30

. When directed at the tire footprint

24

, the reaction of the inserted flowable material

40

to dynamic loads can be studied. By rotating the camera

54

and strobe light

56

to different radial positions of the tire wheel assembly

30

, the reaction of the inserted flowable material

40

positioned away from the footprint

24

can be studied.

Referring now to

FIG. 5

, the method

110

for viewing the interior of the tire

20

under dynamic conditions is depicted. The method

110

comprises the steps of providing a tire wheel assembly comprising a tire mounted on a wheel rim having at least one window positioned to allow the interior of tire to be viewed

112

; positioning a camera at a predetermined location with respect to the tire wheel assembly where the camera is directed toward the window wherein the camera can provide an image of the interior of the tire wheel assembly

114

; and causing the tire wheel assembly to rotate

116

. In addition, other steps may be included to help view the interior of the tire wheel assembly such as positioning a strobe light at a predetermined location with respect to the tire wheel assembly where the strobe light is directed toward the window

118

and coordinating a light flash from the strobe light to correspond with the rotational position and rotational speed of the window

120

. When using the method with flowable materials the method may include the steps of inserting a flowable material into the tire wheel assembly

122

and recording the movement of the flowable materials in the rotating tire wheel assembly

124

. The method may also include the steps of applying a load force upon the tire wheel assembly against a test surface

126

and recording the force variations in the rotating tire wheel assembly

128

.

In addition to providing a method and apparatus for viewing the interior of the tire

20

under dynamic conditions, the window

12

allows the interior tire surface

22

to be checked after the tire wheel assembly

30

stops rotating.

While the present invention is especially effective for viewing flowable materials inserted into the pressure chamber of tire wheel assembly under dynamic conditions, it is contemplated that the tire wheel assembly window can be used for other tests related to tire performance such as monitoring the development of innerliner cracking or monitoring specific interior areas of the tires under specialized test conditions. It is also contemplated that different types of cameras such as infrared or other types may be used to provide useful information regarding the interior of the tire. Although not specifically shown it is contemplated that the present invention could be used on any dynamometer or Flat-Trac® type testing machine, as well as used in conjunction with an on-vehicle set up.

Although the present invention has been described above in detail, the same is by way of illustration and example only and is not to be taken as a limitation on the present invention. Accordingly, the scope and content of the present invention are to be defined only by the terms of the appended claims.