Tire noise reduction device and pneumatic tire provided with the same

1. A tire noise reduction device comprising:

a noise absorbing member made from a porous material that is formed into a band, the band being disposed along a tire circumferential direction on an inner surface of a tread portion of a pneumatic tire, wherein

the noise absorbing member is wound so as to be laminated with two layers or more on at least a part of the tire circumferential direction to form a circular body;

a crossing section where an inside layer and an outside layer of the noise absorbing member interchange is provided in at least one location on a periphery of the circular body; and

ends of a longitudinal direction of the noise absorbing member are disposed inward of an outermost layer of the noise absorbing member.

2. The tire noise reduction device according to claim 1 , wherein a pair of narrow width sections having a reduced size in a width direction are formed in positions corresponding to the crossing section of the noise absorbing member, and, in the crossing section, the pair of narrow width sections are disposed in positions mutually displaced in the width direction of the noise absorbing member.

3. The tire noise reduction device according to claim 2 , wherein a width Da of a first narrow width section and a width Db of a second narrow width section of the pair of narrow width sections in relation to a maximum width D of the noise absorbing member satisfy 0.7≦(Da+Db)/D≦1.0.

4. The tire noise reduction device according to claim 3 , wherein the width Da of the first narrow width section and the width Db of the second narrow width section of the pair of narrow width sections satisfy 0.8≦Da/Db≦1.2.

5. The tire noise reduction device according to claim 2 , wherein linear sections extending parallel to the longitudinal direction of the noise absorbing member are provided at positions mutually opposite the pair of narrow width sections, and a length of the linear sections is from 3 times to 30 times a thickness of the noise absorbing member.

6. The tire noise reduction device according to claim 1 , wherein an outer peripheral length of the circular body is from 85% to 99% of a maximum inner peripheral length of the tread portion of the pneumatic tire.

7. The tire noise reduction device according to claim 1 , wherein a laminated plurality of layers of the noise absorbing member are mutually secured using fasteners.

8. The tire noise reduction device according to claim 7 , wherein a thickness of the fasteners when in a secured state is from 5% to 95% of a total thickness of the laminated plurality of layers of the noise absorbing member.

9. The tire noise reduction device according to claim 1 , wherein the laminated plurality of layers of the noise absorbing member are mutually adhered.

10. The tire noise reduction device according to claim 1 , wherein when the circular body is divided at 30 degree intervals from an arbitrary position on the periphery, a difference in mass of a pair of opposing divisions on either side of a center axis of the circular body is 10% or less with respect to a mass of a heavier division thereof.

11. The tire noise reduction device according to claim 1 , wherein a density of the porous material forming the noise absorbing member is from 7 kg/m 3 to 40 kg/m 3 , and a ratio of a tear strength (N/cm) to the density (kg/m 3 ) of the porous material is from 0.3 to 0.9.

12. A pneumatic tire comprising the tire noise reduction device according to claim 1 in a cavity portion.

13. The tire noise reduction device according to claim 4 , wherein linear sections extending parallel to the longitudinal direction of the noise absorbing member are provided at positions mutually opposite the pair of narrow width sections, and a length of the linear sections is from 3 times to 30 times a thickness of the noise absorbing member.

14. The tire noise reduction device according to claim 5 , wherein an outer peripheral length of the circular body is from 85% to 99% of a maximum inner peripheral length of the tread portion of the pneumatic tire.

15. The tire noise reduction device according to claim 6 , wherein a laminated plurality of layers of the noise absorbing member are mutually secured using fasteners.

16. The tire noise reduction device according to claim 6 , wherein the laminated plurality of layers of the noise absorbing member are mutually adhered.

17. The tire noise reduction device according to claim 9 , wherein when the circular body is divided at 30 degree intervals from an arbitrary position on the periphery, a difference in mass of a pair of opposing divisions on either side of a center axis of the circular body is 10% or less with respect to a mass of a heavier division thereof.

18. The tire noise reduction device according to claim 10 , wherein a density of the porous material forming the noise absorbing member is from 7 kg/m 3 to 40 kg/m 3 , and a ratio of a tear strength (N/cm) to the density (kg/m 3 ) of the porous material is from 0.3 to 0.9.

19. A pneumatic tire comprising the tire noise reduction device according to claim 11 in a cavity portion.

20. The tire noise reduction device according to claim 2 , wherein a width Da of a first narrow width section and a width Db of a second narrow width section of the pair of narrow width sections in relation to a maximum width D of the noise absorbing member satisfy 0.75≦(Da+Db)/D≦0.98.