Multiple layer foam insert for tires

Abstract

A multi-layer or multi-element foam insert for a pneumatic inner tube emulating the effect of air pressure, across a wide range of temperatures and pressures, while maintaining the weight of a conventional air-tilled pneumatic tube. By combining materials of different density and/or the orientation and thickness of such materials, favorable handling properties are achieved.

1 . A compliant insert for a wheel assembly including a compliant outer tire and an inner rim, the compliant insert comprising:
 at least one arcuate segment (i) filling at least a portion of an internal cavity defined by, and between, the compliant outer tire and inner rim, (ii) defining at least one cross-sectional plane aligned with a radial of the wheel assembly, (iii) having an outer portion circumscribing an inner portion along the at least one cross-sectional plane, and (iv) including interlocking end portions to form a continuous circumferential ring.   
     
     
         2 . The compliant insert of  claim 1 , wherein the outer portion is fabricated from a compliant material to conform with, and support, the internal geometry of the compliant outer tire. 
     
     
         3 . The compliant insert of  claim 1 , wherein the inner portion is fabricated from a first compliant material and the outer portion is fabricated from a second compliant material, the first compliant material having a different stiffness than the inner compliant material. 
     
     
         4 . The compliant insert of  claim 1 , further comprising multiple arcuate segments having interlocking ends wherein a first end of one arcuate segment interlocks with a second end of another arcuate segment. 
     
     
         5 . The compliant insert of  claim 1 , wherein the cavity defines a three-hundred and sixty degree (360°) circumferential arc and, furthermore, comprising at least two (2) arcuate segments which may be combined to fill the internal cavity. 
     
     
         6 . The compliant insert of  claim 1 , wherein the cavity defines a three-hundred and sixty degree (360°) circumferential arc and further comprising at least three (3) one-hundred and twenty degree (120°) arcuate segments. 
     
     
         7 . The compliant insert of  claim 1 , wherein the cavity defines a three-hundred and sixty degree (360°) circumferential arc and further comprising at least four (4) ninety degree (90°) arcuate segments. 
     
     
         8 . The compliant insert of  claim 1 , further comprising an adhesive for bonding outer portion of the arcuate segment to the inner portion of the arcuate segment. 
     
     
         9 . The compliant insert of  claim 2 , wherein the inner portion of the arcuate segment is eccentric relative to the outer portion of the arcuate segment, such that the thickness between the outer portion of the arcuate segment and the internal geometry of the compliant outer tire is less than the thickness between the inner portion of the arcuate segment and an internal surface of the inner rim. 
     
     
         10 . The compliant insert of  claim 3 , wherein the first compliant material defines a first stiffness value and the second compliant material defines a second stiffness value and wherein the first stiffness value is greater than the second stiffness value. 
     
     
         11 . The compliant insert of  claim 3 , wherein the first compliant material of the inner portion of the arcuate segment is a closed-cell foam material. 
     
     
         12 . The compliant insert of  claim 3 , wherein the first compliant material of the inner portion of the arcuate segment is a cross-linked ethylene copolymer foam material. 
     
     
         13 . The compliant insert of  claim 3 , wherein the first compliant material of the inner portion of the arcuate segment is a cross-linked polyethylene foam material. 
     
     
         14 . The compliant insert of  claim 3 , wherein the second compliant material of the outer portion of the arcuate segment is a thermoplastic elastomer. 
     
     
         15 . The compliant insert of  claim 3 , wherein the second compliant material of the outer portion of the arcuate segment is a styrene-butadiene-styrene block copolymer. 
     
     
         16 . A method of making a multi-element tire insert comprising the steps of:
 molding at least one arcuate segment defining an inner portion having a first compliant material of a first stiffness value and an outer portion having a second compliant material of a second stiffness value, the outer portion conforming to the internal geometry of a compliant tire;   bonding the inner portion of the arcuate segment to the outer portion of the arcuate segment,   interlocking the end portions of the arcuate segment to form a continuous circumferential ring.   
     
     
         17 . The method of  claim 16 , further comprising the step of applying adhesive to the end portions of the at least one arcuate segment to join the interlocking end portions thereof. 
     
     
         18 . The method of  claim 16 , further comprising the step of forming at least two (2) arcuate segments which, in combination, define an arcuate length of three-hundred and sixty degrees (360°.) 
     
     
         19 . The method of  claim 16 , further comprising the step of forming three (3) arcuate segments each having an arcuate length of one-hundred and twenty degrees (120°) which, in combination, are joined to form a continuous circumferential ring. 
     
     
         20 . The method of  claim 16 , further comprising the step of forming four (4) arcuate segments each having an arcuate length of ninety degrees (90°) which, in combination, are joined to form a continuous circumferential ring.