Abstract
The present invention is directed to a pneumatic tire comprising a tread portion, two bead portions, two sidewalls extending between the tread portion and the respective bead portions, an inner surface defining a tire cavity, a sealant material layer covering the inner surface radially below the tread portion within the tire cavity, and at least one noise dampening strip which is partially covering and attached to the sealant material on a radially inner side and along a circumferential direction of the sealant material layer. The sealant material layer has at least one plateau region supporting the noise dampening element and one or more bottom regions provided laterally beside the plateau region, and wherein the plateau region extends out of the bottom regions in a radially inner direction.
Claims
1. A pneumatic tire comprising a tread portion, two bead portions, two sidewalls extending between the tread portion and the respective bead portions, an inner surface defining a tire cavity, a sealant material layer covering the inner surface radially below the tread portion within the tire cavity, at least one noise dampening strip which is partially covering and attached to the sealant material along a circumferential direction and on a radially inner side of the sealant material layer, wherein the sealant material layer has at least one plateau region supporting the noise dampening strip, and one or more bottom regions provided axially beside the plateau region, and wherein the plateau region extends out of the bottom regions in a radially inner direction.
2. The pneumatic tire of claim 1 wherein the plateau region extends no more than 20% of a total axial width of the sealant material layer beyond each axial side of the noise dampening strip.
3. The pneumatic tire of claim 1 wherein the bottom regions extend axially beside the noise dampening strip over 20% to 80% of a total axial width of the sealant layer.
4. The pneumatic tire of claim 1 wherein the noise dampening strip comprises a porous material.
5. The pneumatic tire of claim 1 wherein the plateau region extends axially over a width which is within a range of 60% to 90% of the axial width of the noise dampening strip.
6. The pneumatic tire of claim 1 wherein the noise dampening strip extends along a circumferential length which corresponds to at least 50% of an inner circumference of the tire measured along the inner surface at an axial center of the tire.
7. The pneumatic tire of claim 6 wherein the circumferential length corresponds to at least 80% of said inner circumference.
8. The pneumatic tire of claim 1 wherein the axial width of the noise dampening strip is within the range of 20% to 50% of the total axial width of the sealant material layer.
9. The pneumatic tire of claim 1 wherein the plateau region has an essentially constant thickness.
10. The pneumatic tire of claim 1 wherein the sealant material layer has shoulder regions extending between the plateau region and the bottom regions.
11. The pneumatic tire of claim 1 wherein the bottom regions have an essentially constant sealant material thickness measured perpendicular to the inner surface of the tire.
12. The pneumatic tire of claim 1 wherein the noise dampening strip is free of a coating or foil facing the sealant material layer.
13. The pneumatic tire of claim 1 wherein the noise dampening strip is a polymeric foam material strip having a density within a range of 0.01 g/cm.sup.3 to 1 g/cm.sup.3.
14. The pneumatic tire of claim 1 wherein a thickness of the plateau region is at least 15% larger than a thickness of the bottom regions.
15. The pneumatic tire of claim 14 wherein the thickness of the plateau region is at most 50% larger than a thickness of the bottom regions.
16. The pneumatic tire of claim 1 wherein the sealant material layer is comprised of (A) an axially adjacent sealant material strips extending circumferentially about an axis of the tire and along the inner surface of the tire or (B) one or more sealant material strips which are spirally wound about an axis of the tire and along the inner surface of the tire.
17. The pneumatic tire of claim 16 wherein the sealant material strips have a larger thickness in the plateau region than in the bottom regions and wherein multiple layers of strips are arranged on top of each other in the plateau region.
18. The pneumatic tire of claim 1 wherein the plateau region has a radial thickness which is in a range of 3 mm to 10 mm and the bottom region has a thickness which is in a range of 2 mm to 6 mm.
19. A pneumatic tire comprising a tread portion, two bead portions, two sidewalls extending between the tread portion and the respective bead portions, an inner surface defining a tire cavity, a sealant material layer covering the inner surface radially below the tread portion within the tire cavity, at least one noise dampening element which is partially covering and attached to the sealant material on a radially inner side of the sealant material layer, wherein the sealant material layer has at least one plateau region supporting the noise dampening element and one or more bottom regions provided laterally beside the plateau region, wherein the plateau region extends out of the bottom regions in a radially inner direction, and wherein the sealant material layer comprises i) one or more sealant material strips spirally wound about an axis of the tire and along the inner surface of the tire, or ii) axially adjacent sealant material strips extending circumferentially about an axis of the tire and along the inner surface of the tire, so as to form the sealant material layer.
20. The pneumatic tire of claim 19, wherein said strips have a larger thickness in the plateau region than in the bottom regions, wherein multiple layers of strips are arranged on top of each other in the plateau region, wherein the sealant material strips have an axial width within a range of 2 mm to 15 mm, and wherein the thickness of the sealant material strips is at least 15% larger in the in the plateau region than in the bottom regions.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0101] The structure, operation and advantages of the invention will become more apparent upon contemplation of the following description taken in conjunction with the accompanying drawings, wherein:
[0102] FIG. 1 shows a schematic cross section of an embodiment of a tire comprising a noise dampening strip attached to a sealant material layer within the tire cavity.
[0103] FIG. 2 shows a schematic cross section of another embodiment of a tire comprising two noise dampening strips attached to a sealant material layer within the tire cavity.
[0104] FIG. 3 shows a schematic partial top view onto the sealant material layer of FIG. 1, viewed from a radially inner position within the tire cavity.
[0105] FIG. 4 shows a schematic partial top view onto the sealant material layer of FIG. 2, viewed from a radially inner position within the tire cavity.
[0106] FIG. 5 shows a schematic partial top view onto another embodiment of a sealant layer carrying two block-shaped noise dampening elements.
[0107] FIG. 6 shows a schematic partial top view of a sealant material layer with the attached noise dampening strip of FIG. 1, in which circumferential sealant material strips are schematically indicated.
[0108] FIG. 7 shows a schematic cross section of an embodiment of a tire comprising a noise dampening strip attached to a plateau region of sealant material which is narrower than the noise dampening strip.
[0109] FIG. 8 shows a schematic cross section of another embodiment of a tire comprising a noise dampening strip attached to two plateau regions radially below the strip.
DETAILED DESCRIPTION OF THE INVENTION
[0110] FIG. 1 is a schematic cross-section of a tire 1, in accordance with a non-limiting embodiment of the invention. The example tire 1 has a tread portion 10, two bead portions 3, and two sidewalls 2 joining outer axial edges of the tread portion 10 with the respective bead portions 3. Such tire constructions are as such known in the tire art. The tire 1 has an inner surface defining a tire cavity 6. Optionally, the tire may have an inner liner (not shown in FIG. 1) defining the tire cavity 6. A sealant material layer 30 is provided on the inner side or surface of the tire 1 in an area opposite to the tread portion 10. The sealant material layer preferably extends in circumferential direction c and in axial direction a along the inner surface of the tire 1. A noise dampening element, such as a foam strip 20 is attached to the sealant material layer 30 in a plateau portion or region 40 of the sealant material layer 30. In the present non-limiting example, the foam strip 20 extends in the circumferential direction and is directly attached to the sealant material layer 30 on a radially inner side of the plateau region 40. Axially beside or adjacent the plateau region 40, the sealant material layer comprises two bottom portions or regions 50 in which the sealant material layer 30 has a smaller thickness than in the plateau region 40. In particular, the plateau region 40 is not created by an elevation in the inner surface of the tire 1, e.g. of the inner liner in this example. In the present embodiment, the foam strip 20 is arranged along an axial center line of the tire 1, or in other words essentially in parallel to the equatorial plane EP of the tire 1.
[0111] For the sake of better comprehensibility, the axial direction a, the circumferential direction c and the radial direction r have been indicated in FIG. 1 as commonly used in the description of tire geometries. The term direction shall not be limited to a certain orientation unless otherwise indicated herein. An axial direction a may be understood as a direction in parallel to the rotation axis of the tire 1. The circumferential direction c is concentric to the rotation axis of the tire 1 and the radial direction r extends radially from the latter as common in the tire art.
[0112] As visible in FIG. 1, the amount of sealant material is smaller in the bottom regions 50 than in the plateau region 40. Limiting the amount of sealant material axially beside the foam strip 20 reduces costs and improves heat conductivity of the tire 1 towards the tire cavity 6. The larger material thickness in the plateau region 40 improves sealing performance under the foam strip 20. In particular, it has been found by the inventors that the same thin sealant material thickness supporting the foam strip 20 as in the bottom regions 50 would not always result in the desired sealing performance.
[0113] FIG. 2 shows another embodiment of a tire 1′, the tire 1′ having similar to tire 1 of FIG. 1 a tread portion 10, sidewalls 2, bead portions 3, a cavity 6, and a sealant material layer 31. In contrast to the embodiment shown in FIG. 1, the embodiment of FIG. 2 has two plateau regions 41, 42 and three bottom regions 51, 52, 53. To each one of the plateau regions 41, 42 is attached a foam strip 21, 22. Similar to the first embodiment, the sealant material layer 31 has in the bottom regions 51, 52, 53 a smaller thickness, in particular measured perpendicular to the inner surface of the tire 1′, than in the plateau regions 41, 42.
[0114] As shown in FIG. 1, the plateau regions 41, 42 may be slightly axially broader than the axial width of the foam strips 21, 22. This may help to ease the positioning and/or application of the strips 21, 22 onto the sealant material in the plateau regions 41, 42.
[0115] FIG. 3 shows a schematic top view of the sealant material layer 30 of FIG. 1 within the tire cavity. The foam strip 20 is attached to the sealant material layer 30 in the plateau region 40. The bottom regions 50 are provided on both axial sides of the plateau region 40.
[0116] FIG. 4 shows another schematic top view, i.e. a top view of the embodiment as already discussed with respect to FIG. 2. As visible in FIG. 4, the two foam strips 21, 22 are attached to the sealant material layer 31 in plateau regions 41 and 42. On each side of the respective plateau regions 41, 42 a respective bottom region 51, 52, 53 is provided.
[0117] In accordance with the embodiment of FIG. 5, instead of strip-shaped noise dampening elements, block-shaped noise dampening elements are provided on a sealant material layer 32. Thus, two noise dampening blocks 23, 23′, e.g. foam blocks, are positioned on plateau regions 43, 44. In this embodiment, the blocks 23, 24 and plateau regions 43, 44 have an essentially rectangular shape. However, the present invention shall not be limited to such shapes. Rather the shape of the blocks or sheets of noise dampening material could have other shapes and the shape of corresponding plateau regions could be chosen accordingly. The plateau regions 43, 43′ are surrounded by a bottom portion 53′. In other words, the plateau regions 43, 44 extend or protrude out of a laterally neighboring bottom portion. In particular, “laterally” includes axial and/or circumferential directions. While the noise dampening blocks 23, 24 have been shown in an axial center position of the sealant material layer 32, other positions would be possible, such as an arrangement axially beside each other.
[0118] FIG. 6 shows again schematically the arrangement already shown in FIG. 1, including more details about an example of potential application and structure of the sealant material layer 30. In this embodiment, the sealant material layer 30 comprises a plurality of essentially circumferential adjacent strips s.sub.bi and s.sub.pi, wherein the strips s.sub.bi have been extruded or applied onto the inner surface of the tire (not shown as such) with a first thickness essentially corresponding to the thickness of the bottom portion 50 and the strips s.sub.pi have been extruded or applied with a second thickness essentially corresponding to the thickness of the plateau region 40. The foam strip 20 is attached afterwards onto the plateau region 40. Preferably, the strips touch each other and/or are essentially free of overlaps so as to provide a smooth and/or continuous radially inner surface. In another embodiment, not shown, it would be possible to apply a first layer of strips with essentially the same thickness in regions 40 and 50 and applying a second layer of strips only in region 40, so as to create the plateau region 40 with a larger thickness than in the bottom region 50.
[0119] FIG. 7 shows another embodiment of a tire 1″ with elements already shown in FIGS. 1 and 2. In contrast to the embodiments of those, the noise dampening strip 24 is supported by a plateau region 44 of the sealant material layer 34 that does not extend over the full axial width of the noise dampening strip 24. Providing the plateau region 44 radially below the strip 24 with an axial extension that is narrower than the axial width of the strip 24, helps to save sealant material while still providing sufficient sealing properties. Moreover, the heat build-up below the strip 24 is further reduced. The bottom regions 54 have a smaller thickness than the plateau region 44 as discussed in relation to the embodiments of FIGS. 1 and 2.
[0120] FIG. 8 shows yet another embodiment of a tire 1′″. As for FIG. 7, same reference numerals as in FIG. 1 have been used where applicable. In the embodiment of FIG. 8, a sealant material layer 35 has multiple (here two) plateau regions 45, 46 which extend radially out of the bottom regions 55, 56, 57. Such an embodiment may be of particular advantage in case of relatively broad noise dampening strips, such as strip 25, and may help to save sealant material while still ensuring appropriate puncture sealing properties.
[0121] While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention.
