TECHNICAL FIELD

The present disclosure relates to pneumatic tires having a magnetic tire sealant material for sealing a puncture, and more particularly, pneumatic tires having sealed tire area formed from the magnetic tire sealant material and a portion of the sealed tire area being present at the outer surface of the tire for using an apparatus to detect the sealed puncture.

BACKGROUND

Tires are generally still operable after a puncture because an object that passes through a tire often does not easily come out and air does not leak rapidly from the tire. However, over a long period of run time, the object is exposed to centrifugal forces caused by the rotation of the tire that can dislodge the object. When the object comes out, air quickly leaks from the tire and operation of a vehicle can become dangerous. To combat punctures, modern puncture-sealing pneumatic tires provide a sealant material that prevents the leakage of air when a foreign object, for example, a nail on a roadway surface, penetrates through the tire during operation.

The sealant layer is often formed of a thin viscous rubber layer adhered integrally to an inner peripheral surface of the tire at the backside of the tread portion. When a foreign object falls out of a puncture and forms an opening, the same centrifugal forces caused by the rotation of the tire that dislodged the object result in the viscous sealant layer to flow into the puncture opening. The sealant layer fills and preferably closes the puncture opening to result in the tire being air-tight for continued use.

A tire having a sealed puncture can continue to be used without the puncture area being noticed by a driver. There is an interest, however, that a sealed puncture be detected to notify the driver of a possible defect. It is an objective of the present disclosure to overcome one or more difficulties related to the prior art. It has been found that a magnetic tire sealant material can be used to detect a sealed puncture on the outer surface of the tire and that an external apparatus can be used to indicate such a sealed puncture.

SUMMARY

In a first aspect, there is a pneumatic tire that includes an outer surface; a magnetic tire sealing material arranged in an interior portion of the tire, the sealing material underlying the outer surface of the tire and the sealing material containing magnetic particles; wherein a puncture of the outer surface of the tire that contacts the sealing material is sealed by the sealing material flowing in the puncture to form a sealed tire area that includes a portion the sealing material, the sealed tire area is present at the outer surface of the tire, and a portion of the magnetic particles of the sealing material is present in the sealed tire area at the outer surface of the tire.

In an example of aspect 1, the magnetic particles are present up to 5 weight percent of the total weight of the sealing material in the tire.

In another example of aspect 1, the magnetic particles are present in the range of 0.1 to 5 weight percent of the total weight of the sealing material in the tire.

In another example of aspect 1, the magnetic particles are a ferrite, metal oxide or a combination thereof.

In another example of aspect 1, the magnetic particles are selected from the group consisting of Fe2O3, CoOFe2O3, Fe3O4, γ-Fe2O3, strontium ferrite, barium ferrite, and combinations thereof.

In another example of aspect 1, the magnetic particles are nanoparticles.

In another example of aspect 1, the magnetic particles have an average particle diameter in the range of 5 nanometers to 100 nanometers.

In another example of aspect 1, the sealed tire area is substantially air tight to prevent leakage of air from inside the pneumatic tire through or around the sealed tire area present at the outer surface of the tire.

In another example of aspect 1, the sealed tire area at the outer surface of the tire has a greater average concentration of magnetic particles than the average concentration of magnetic particles over the remaining outer surface of the tire.

In another example of aspect 1, the sealed tire area at the outer surface of the tire has a stronger average magnetic field than the average magnetic field over the remaining outer surface of the tire.

In another example of aspect 1, the sealing material forms two or more sealed tire areas at the outer surface of the tire.

In another example of aspect 1, the sealing material is located under a tread area in a crown portion of the tire.

The first aspect may be provided alone or in combination with any one or more of the examples of the first aspect discussed above.

In a second aspect, there is a method of detecting the presence of a sealed puncture in a pneumatic tire, the method includes positioning the tire within a detection zone of an apparatus for detecting magnetic particles, the tire includes an outer surface and a magnetic tire sealing material containing magnetic particles, the sealing material arranged in an interior portion of the tire, a portion of the sealing material underlying the outer surface of the tire and a portion of the sealing material forming a sealed tire area at the outer surface of the tire; operating the apparatus to detect the presence of the magnetic particles in the sealed tire area at the outer surface of the tire, the detection of the magnetic particles of the sealing material at the outer surface of the tire indicating that the tire contains a sealed puncture.

In an example of aspect 2, the detection zone is a magnetic field detection zone.

In another example of aspect 2, the apparatus is capable of measuring a magnetic field.

In another example of aspect 2, the sealed tire area is formed by the sealing material flowing in an open puncture, and the open puncture extends from the outer surface of the tire to the sealing material underlying the outer surface of the tire, the sealing material flows and fills the open puncture to create a sealed puncture and a sealed tire area at the outer surface of the tire.

In another example of aspect 2, the sealed tire area at the outer surface of the tire has a greater average concentration of magnetic particles than the average concentration of magnetic particles over the remaining outer surface of the tire.

In another example of aspect 2, the sealed tire area at the outer surface of the tire has a stronger average magnetic field than the average magnetic field over the remaining outer surface of the tire.

In another example of aspect 2, the sealed tire area at the outer surface of the tire is in a tread portion of the tire.

In another example of aspect 2, the magnetic particles are present up to 5 weight percent of the total weight of the sealing material in the tire.

The second aspect may be provided alone or in combination with any one or more of the examples of the second aspect discussed above, or with any one or more of the examples of the first aspect.

The accompanying drawings are included to provide a further understanding of principles of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain, by way of example, principles and operation of the invention. It is to be understood that various features disclosed in this specification and in the drawings can be used in any and all combinations. By way of non-limiting example the various features may be combined with one another as set forth in the specification as aspects.

