An improved shear band for use in non-pneumatic tires, pneumatic tires, and other technologies is provided. The shear band is constructed as a composite of layers that are combined in a specific manner. Each layer is constructed from one or more materials having certain selected physical properties. The layers are combined a specific manner to create a composite having physical properties and performance characteristics desirably outperforming that of the individual materials forming the layers. When used in tire construction, improvements in rolling resistance can also be obtained.
1. A shear band defining a radial direction, the shear band comprising:
a composite shear layer having an overall dynamic shear modulus, said composite shear layer comprising at least (i) one or more layers having a first dynamic shear modulus and a first total volume fraction, (ii) one or more layers having a second dynamic shear modulus and a second total volume fraction, wherein the ratio of the second dynamic shear modulus to the first dynamic shear modulus is at least about 3, and wherein said one or more layers having a first or second dynamic shear modulus are arranged in an alternating manner between layers having the first dynamic shear modulus and layers having the second dynamic shear modulus;
at least a first membrane adhered to a radially inward extent of said composite shear layer; and
at least a second membrane adhered to a radially outward extent of said composite shear layer;
wherein a ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 100:1.
2. A shear band according to claim 1 , wherein said one or more layers having a first dynamic shear modulus comprises at least one material having a hysteresis of less than about 0.2 at strains between about 15 percent and about 30 percent.
3. A shear band according to claim 1 , wherein said one or more layers having a first dynamic shear modulus comprises at least one material having a hysteresis of less than about 0.1 at strains between about 15 percent and about 30 percent.
4. A shear band according to claim 3 , wherein said one or more layers having a second dynamic shear modulus comprises at least one material having a hysteresis of less than about 0.07 at strains between about 0.1 percent and about 2 percent.
5. A shear band according to claim 3 , wherein said one or more layers having a second dynamic shear modulus comprises at least one material having a hysteresis of less than about 0.04 at strains between about 0.1 percent and about 2 percent.
6. A tire having a ground contacting portion and a tread portion, the tire comprising a shear band defining a radial direction, the shear band comprising:
a composite shear layer having an overall dynamic shear modulus, said composite shear layer comprising at least (i) one or more layers having a first dynamic shear modulus and a first total volume fraction, (ii) one or more layers having a second dynamic shear modulus and a second total volume fraction, wherein the ratio of the second dynamic shear modulus to the first dynamic shear modulus is at least about 3, and wherein said one or more layers having a first or second dynamic shear modulus are arranged in an alternating manner between layers having the first dynamic shear modulus and layers having the second dynamic shear modulus;
at least a first membrane adhered to a radially inward extent of said composite shear layer; and
at least a second membrane adhered to a radially outward extent of said composite shear layer;
wherein a ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 100:1,
wherein said one or more layers having a first dynamic shear modulus comprises at least one material having a hysteresis of less than about 0.1 at strains between about 15 percent and about 30 percent, and
wherein said one or more layers having a second dynamic shear modulus comprises at least one material having a hysteresis of less than about 0.04 at strains between about 0.1 percent and about 2 percent.
7. A tire for placement on a wheel, the tire defining a radial direction, comprising:
a ground contacting tread portion;
a reinforced annular band disposed radially inward of said tread portion, wherein said reinforced annular band comprises a composite shear layer having an overall dynamic shear modulus, said composite shear layer comprising:
(i) one or more layers constructed from materials having a first dynamic shear modulus and a first total volume fraction; and
(ii) one or more layers constructed from materials having a second dynamic shear modulus and a second total volume fraction;
wherein the ratio of the second dynamic shear modulus to the first dynamic shear modulus is at least about 3, and wherein said one or more layers of materials having either the first or second dynamic shear modulus are arranged in an alternating manner between the first dynamic shear modulus and the second dynamic shear modulus along the radial direction of the tire;
a support structure for mounting said band and said tread portion to the wheel, said support structure being located radially inward of said reinforced annular band;
at least a first membrane adhered to the radially inward extent of said composite shear layer; and
at least a second membrane adhered to the radially outward extent of said composite shear layer;
wherein a ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 100:1.
8. A tire according to claim 7 , wherein the second total volume fraction is in the range of about 0.3 to about 0.7.
9. A tire according to claim 7 , wherein the second total volume fraction is about 0.5.
10. A tire according to claim 7 , wherein the ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 500:1.
11. A tire according to claim 7 , wherein the ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 1000:1.
12. A tire according to claim 7 , wherein the first dynamic shear modulus is greater than about 1.5 MPa but less than about 5 MPa.
13. A tire according to claim 7 , wherein the first dynamic modulus is greater than about 2 MPa but less than about 4 MPa.
14. A tire according to claim 7 , wherein the Elongation at Break at 100° C. is greater than about 100 percent for said one or more layers constructed from materials having a first dynamic shear modulus.
15. A tire according to claim 7 , wherein the Elongation at Break at 100° C. is greater than about 180 percent for said one or more layers constructed from materials having a first dynamic shear modulus.
16. A tire according to claim 7 , wherein each of said at least first and second membranes further comprise layers of substantially inextensible cord reinforcements embedded in a coating layer having a shear modulus of elasticity greater than or equal to at least the overall dynamic shear modulus of said composite shear layer.
17. A tire for placing on a wheel, comprising
a ground contacting tread portion;
a reinforced annular band disposed radially inward of said tread portion, wherein said band comprises a composite shear layer having an overall dynamic shear modulus, said composite shear layer comprising i) a first shear layer having a first dynamic shear modulus, ii) a second shear layer disposed radially outward of said first shear layer, said second shear layer having a second dynamic shear modulus, wherein the ratio of the second dynamic shear modulus to the first dynamic shear modulus is at least about 3;
a support structure for mounting said reinforced annular band and said tread portion to the wheel, said support structure being located radially inward of said reinforced annular band;
at least a first membrane adhered to the radially inward extent of said composite shear layer; and
at least a second membrane adhered to the radially outward extent of said composite shear layer;
wherein a ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 100:1.
18. A tire according to claim 17 , wherein said second material has a total volume fraction in the range of about 0.3 to about 0.7.
19. A tire according to claim 17 , wherein said second material has a total volume fraction of about 0.5.
20. A tire according to claim 19 , wherein the ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 500:1.
21. A tire according to claim 19 , wherein the ratio of the longitudinal tensile modulus of one of said membranes to the overall dynamic shear modulus of said composite shear layer is at least about 1000:1.
22. A tire according to claim 17 , wherein the first dynamic shear modulus is greater than about 1.5 MPa but less than about 5 MPa.
23. A tire according to claim 17 , wherein the first dynamic shear modulus is greater than about 2 MPa but less than about 4 MPa.
24. A tire according to claim 17 , wherein the Elongation at Break at 100° C. for the first shear layer is greater than about 100 percent.
25. A tire according to claim 17 , wherein the Elongation at Break at 100° C. for the first shear layer is greater than about 180 percent.
26. A tire according to claim 17 , wherein each of said at least first and second membranes further comprise layers of substantially inextensible cord reinforcements embedded in an elastomeric coating layer having a shear modulus of elasticity greater than or equal to at least the overall dynamic shear modulus of said first and second shear layers.
27. A tire according to claim 17 , wherein the first shear layer comprises at least one material having a hysteresis of less than about 0.2 at strains between about 15 percent and about 30 percent.
28. A tire according to claim 17 , wherein the first shear layer comprises at least one material having a hysteresis of less than about 0.1 at strains between about 15 percent and about 30 percent.
29. A tire according to claim 17 , wherein the second shear layer comprises at least one material having a hysteresis of less than about 0.07 at strains between about 0.1 percent and about 2 percent.
30. A tire according to claim 17 , wherein the second shear layer comprises at least one material having a hysteresis of less than about 0.04 at strains between about 0.1 percent and about 2 percent.