Tire comprising bead core material having characteristics of superelasticity and shape memory

• US 6,554,039 B1
• Filed: 10/27/1999
• Issued: 04/29/2003
• Est. Priority Date: 10/28/1998
• Status: Expired due to Fees

• Current Assignee: Pirelli Pneumatici S.P.A. (Pirelli & C SPA)
• Original Assignee: Pirelli Pneumatici S.P.A. (Pirelli & C SPA)
• Inventors: Volpi, Alessandro, Villani, Claudio, Riva, Guido, Orjela, Gurdev, Mowdood, Syed Khawja
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Fischer, Justin
• Application Number:
  US09/427,708
• Time in Patent Office: 1,280 Days
• Field of Search: 152/539, 152/540, 152/451, 148/402, 148/563, 579/02, 156/136
• US Class Current: 152/540
• CPC Class Codes: B60C 15/028 Spacers between beads emergency load-supporting means B60C17/00
• CPC Class Codes: B60C 15/04 Bead cores
• CPC Class Codes: B60C 17/00 Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
• CPC Class Codes: Y10T 29/49494 Assembling tire to wheel body

Abstract

A tire includes a toroidal carcass and a tread band. The toroidal carcass includes a central crown and two sidewalls terminating in a pair of annular beads. Each annular bead includes a metallic bead core for anchoring to corresponding bead seats of a wheel rim. The metallic bead cores include at least one annular portion made of a material having characteristics of superelasticity and shape memory. The material having characteristics of superelasticity and shape memory is deformable at ambient temperature in response to a constant force and recovers to an original shape upon removal of the constant force to facilitate mounting the tire on the wheel rim. The wheel rim includes a central cylindrical channel from which branches off, axially and outwardly, from opposite sides, diverging surfaces each terminating in a peripheral flange. The diverging surfaces form the bead seats for respective annular beads of the tire.

Claims

1. A tire, comprising:

a toroidal carcass; and

a tread band;

wherein the toroidal carcass comprises a central crown and two sidewalls,

wherein each sidewall terminates in an annular bead,

wherein each annular bead comprises a metallic bead core for anchoring the bead to a corresponding bead seat of a wheel rim,

wherein at least one bead core comprises one or more annular portions made of a material having characteristics of superelasticity and shape memory,

wherein the material is deformable at ambient temperature in response to a constant force and recovers to an original shape upon removal of the constant force to facilitate mounting the tire on the rim,

wherein the rim comprises a central channel from which branches off, axially and outwardly, from opposite sides, diverging surfaces each terminating in a peripheral flange,

wherein the diverging surfaces form the bead seats for respective annular beads of the tire, and

wherein, for a flat tire, heating of the one or more annular portions results in tighter gripping of a respective bead to a respective bead seat to prevent the tire from separating from the rim.

2. A tire, comprising:

a toroidal carcass; and

a tread band;

wherein the toroidal carcass comprises a central crown and two sidewalls,

wherein each sidewall terminates in an annular bead,

wherein each annular bead comprises a metallic bead core for anchoring the bead to a corresponding bead seat of a wheel rim,

wherein at least one bead core comprises one or more annular portions made of a material having characteristics of superelasticity and shape memory,

wherein the one or more annular portions are progressively heated when the tire is operated in a deflated condition and develop increasing forces of contraction up to a maximum value corresponding to a temperature at which formation of an austenitic structure of the material is complete, and

wherein the forces of contraction result in tighter gripping of a respective bead to a respective bead seat to prevent the tire from separating from the rim.

3. A tire, comprising:

a toroidal carcass; and

a tread band;

wherein the toroidal carcass comprises a central crown and two sidewalls,

wherein each sidewall terminates in an annular bead,

wherein each annular bead comprises a metallic bead core for anchoring the bead to a corresponding bead seat of a wheel rim,

wherein at least one bead core comprises one or more annular portions made of a material having characteristics of superelasticity and shape memory,

wherein the material is deformable at ambient temperature in response to a constant force and recovers to an original shape upon removal of the constant force to facilitate mounting the tire on the rim,

wherein the rim comprises a central channel from which branches off, axially and outwardly, from opposite sides, diverging surfaces each terminating in a peripheral flange,

wherein the diverging surfaces form the bead seats for respective annular beads of the tire, and

wherein the one or more annular portions impart to a respective bead core lengthwise contraction stresses when a predetermined temperature of the one or more annular portions is reached during operation of the tire.

4. The tire of claim 3, wherein, if a first temperature of the one or more annular portions continues to rise above the predetermined temperature, then the lengthwise contraction stresses progressively increase to a maximum value corresponding to a second temperature at which formation of an austenitic structure of the material is complete.

5. The tire of claim 3, wherein the one or more annular portions are progressively heated when the tire is operated in a deflated condition and develop increasing forces of contraction up to a maximum value corresponding to a temperature at which formation of an austenitic structure of the material is complete, and

wherein the forces of contraction result in tighter gripping of a respective bead to a respective bead seat to prevent the tire from separating from the rim.