Shear band having ultra-low hysteresis rubber
AssigneeCompagnie Generale Des Etablissements Michelin
InventorsClifford WILSON, Clayton Jr BOHN
Life of this patent
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Abstract
A shear band (205) that may be used e.g., in a non-pneumatic tire is provided. The shear band uses interlaced reinforcing elements (250) positioned within a shear layer of elastomeric material. A variety of configurations may be used to create the interlaced positioning of the reinforcing elements including e.g., a horizontal diamond or vertical diamond configuration. The shear layer is formed from a rubber composition having a very low hysteresis reinforced with silica and carbon black.
Claims20
An annular shear band defining axial, radial and circumferential directions, the annular shear band comprising:
- an annular shear layer constructed from a rubber composition;
- a plurality of discrete, annular reinforcing elements positioned along a plurality of axially-oriented rows throughout the annular shear layer, the reinforcing elements separated from one another by a predetermined distance, each reinforcing element having a centerpoint, wherein the reinforcing elements are interlaced along the axial or radial direction of the shear band such that the centerpoints of reinforcing elements of adjacent, axially-oriented rows are arranged to form a rhombus having non-orthogonal angles between sides of the rhombus, wherein the rubber composition is based upon a cross-linkable rubber composition, the cross-linkable rubber composition comprising, in parts by weight per 100 parts by weight of rubber (phr):
- between 50 phr and 100 phr of a natural rubber;
- between 0 phr and 50 phr of a second rubber component selected from the group consisting of polybutadiene rubber, a copolymer of polybutadiene and styrene wherein the copolymer has no more than 5 mol % styrene and combinations thereof;
- between 25 phr and 60 phr of a reinforcing fillers that is limited to a first portion that is a silica between 35 wt % and 70 wt % of the total reinforcing fillers and has a target surface area of between 40 m2/g and 55 m2/g and a second portion that is a carbon black between 30 wt % and 65 wt % of the total amount of the reinforcing fillers and has a target surface area of between 15 m2/g and 45 m2/g;
- and
- a sulfur cure system.
The annular shear band of any of the preceding claims, wherein the target surface area of the first portion of the silica is between 40 m2/g and 45 m2/g.
The annular shear band of any of the preceding claims, wherein the target surface area of the second portion of the carbon black is between 32 m2/g and 39 m2/g.
The annular shear band of any of the preceding claims, wherein the rubber composition includes 100 phr of natural rubber.
The annular shear band of any of the preceding claims, wherein the cross-linkable rubber composition further comprises between 0 phr and 20 phr of a third rubber component that is a functionalized styrene-butadiene copolymer having between 1 mol % and 35 mol % styrene, wherein the styrene-butadiene copolymer is functionalized with a moiety capable of bonding with the silica reinforcing filler.
The annular shear band of any of the preceding claims, wherein the rubber composition has a tan delta measured at 23° C. and at 80% strain of between 0.015 and 0.025, a shear modulus G* measured at 23° C. and at 80% strain of at least 1.30 MPa, and a strain at break of greater than 80%.
The annular shear band of any of the preceding claims, wherein the reinforcing elements are interlaced along the axial direction.
The annular shear band of any of the preceding claims, wherein the reinforcing elements are interlaced along the radial direction.
The annular shear band of claim 11 or claim 12, wherein the reinforcing elements each have a nominal diameter Φ, and wherein adjacent, axially-oriented rows of the reinforcing elements are separated from each other by a predetermined distance, ws, in the range of between Φ/2 and Φ/10 or is Φ/4.
The annular shear band of claim 13, wherein the predetermined distance, ws, separating adjacent, axially-oriented rows of said reinforcing elements is.
The annular shear band of any of the preceding claims, wherein the reinforcing elements comprise metal, nylon, PET, or glass fibers impregnated in a thermosetting resin.
A non-pneumatic wheel comprising the annular shear band of any of the preceding claims.
Dependencies are inferred from the claim text.