Non-pneumatic tire having curved spokes and method of making same
AssigneeBridgestone Americas Tire Operations, LLC
InventorJonathan W. Fisk
Life of this patent
Estimating the term…
Abstract
A non-pneumatic tire includes a lower ring having a first diameter and an upper ring having a second diameter greater than the first diameter. The upper ring is substantially coaxial with the lower ring. The non-pneumatic tire further includes a plurality of curved, steel spokes extending between the lower ring and the upper ring. Each of the plurality of curved, steel spokes has a 0.2% yield strength of at least 1300 MPA, a tensile strength of at least 1400 MPa, and a hardness of at least 50 HRC.
Claims20
A method of making a nonpneumatic tire, the method comprising:
- providing a rolled sheet of steel having a carbon content between 0.20% and 0.60%, the sheet having a thickness between 1.5 mm and 7 mm;
- unwinding the rolled sheet of steel;
- tailor rolling the sheet of steel, such that the thickness of the sheet varies periodically along its length between a minimum thickness and a maximum thickness,
- wherein the minimum thickness is at least 1.2 mm, and
- wherein the maximum thickness is no more than 4.5 mm;
- cutting the sheet into blanks containing one or more thick section and one or more thin section of steel, wherein the length of each blank is equal to the width of the sheet;
- rotating each blank through 90 degrees;
- roll forming each blank to form a curve along its width, with one or more thick section and one or more thin section in parallel along the length of the blank;
- heating each blank to a temperature between 950° C. and 1400° C., during a period of 2 to 10 seconds;
- cooling each blank to a temperature below 200° C. within 10 seconds;
- cutting each blank into a plurality of steel spokes having a width between 80 mm and 400 mm;
- providing a lower ring and an upper ring;
- arranging the plurality of steel spokes between the lower ring and the upper ring.
A non-pneumatic tire comprising:
- a lower ring having a first diameter;
- an upper ring having a second diameter greater than the first diameter, the upper ring being substantially coaxial with the lower ring;
- and
- a plurality of curved, steel spokes extending between the lower ring and the upper ring,
- wherein each of the plurality of curved, steel spokes has a 0.2% yield strength of at least 1300 MPA, a tensile strength of at least 1400 MPa, and a hardness of at least 50 HRC.
A method of making a spoke for a nonpneumatic tire, the method comprising:
- providing a rolled sheet of steel having a carbon content between 0.28% and 0.50%;
- unwinding the rolled sheet of steel;
- roll forming the sheet of steel to form a curve along its width;
- heating the sheet of steel to a temperature between 950° C. and 1400° C., during a period of 2 to 10 seconds;
- cooling the sheet of steel to a temperature below 200° C. within 10 seconds;
- cutting a steel spoke from the sheet of steel, the steel spoke having a width between 80 mm and 400 mm.
Dependencies are inferred from the claim text.