KR20060047747A - Pneumatic run-flat tire - Google Patents

Abstract

The air runflat tire of the present invention has a bead structure in which the axial inner end is radially inward of the axial outer end of the bead. The sidewalls of the tire from the bead region to the upper sidewalls are reinforced to form pillar supports on the sidewalls. This bead structure and pillar reinforcement allow the tire to lock itself onto the tire rim and support itself during low pressure operation.

Description

Pneumatic Run Flat Tires {PNEUMATIC RUN-FLAT TIRE}

1 is a cross-sectional view of a tire according to the present invention,

2 is another cross-sectional view of the tire,

3A and 3B are cross-sectional views of a tire with axial outer insulators of various heights,

4A and 4B show a variant of a tire with sidewall plies,

5 is a cross-sectional view of a tire comprising two carcass reinforcement plies,

6 is a view of a tire with adjacent multiple sidewall inserts,

7 shows a deformed structure of a tire with multiple sidewall inserts,

8 is an illustration of a tire of the present invention with different beads and sidewall diameters.

<Explanation of symbols for main parts of drawing>

10 tire 12 carcass reinforcement fly

14: bead part 18: turn-up part

20: bead ring 22: rubber wedge

24: Bead Tow 26: Bead Hill

The present invention relates to a tire with radial carcass reinforcements, and more particularly to a side wall structure of a tire. It also relates to an assembly formed of a tire and a rim.

In the tire industry, there are two basic systems that provide unexpanded operation of the tire. The first system utilizes a set of inserts in the wheel rim that support the underside of the tire tread when the tire is driven in an unexpanded state, one such system being disclosed in US Pat. No. 5,785,781. The second system utilizes self-supporting tires that are reinforced with tire sidewalls to enable the tire to support itself during unexpanded driving conditions, such self-supporting tires being described in US Pat. Nos. 4,365,659, 5,158,627, 5,358,082 and 6,453,961.

Each system has limitations and you must manufacture each system more appropriate than others for specific applications. Systems using wheel inserts not only result in penetrating lower sidewall tires and smaller tires, but also are more complex due to the wheel mounting support; Self-supporting tires for larger sidewall tires and larger tires have greater volume, thereby reducing rolling resistance and comfort.

The present invention is to combine two different solutions to be a simpler runflat solution. The present invention is suitable for medium size applications and combines the best features of both types of systems.

The present invention relates to a runflat tire system and a runflat tire. The tire has a radial carcass reinforcement ply, a belt structure and a pair of opposing bead regions. Each bead region has a bead wire, bead toe, and bead heel, the bead toe being axially outward and radially inward of the bead heel. The radial outer side of each bead area is the tire sidewall. The cross-sectional width of each sidewall from the radially outer side of the bead region to the end of the belt structure is substantially constant. To form a substantially constant width, the first rubber insert is positioned axially inside the carcass reinforcement ply and the second rubber insert is located radially outside of the bead wire and axially outside of the carcass reinforcement ply.

In the first embodiment of the present invention, the cross-sectional width of the side wall varies up to 30% or less of the minimum cross-sectional width. In various embodiments, the tire sidewalls at the bottom 50% of the tire height have various cross-sectional widths up to 20% or less of the minimum width of the sidewall cross-sectional width. Preferably, all changes in the cross-sectional width of the tire sidewall occur in the radially outer portion of the sidewall, whereby the radially inner portion of the sidewall maintains a substantially constant width.

In another embodiment of the tire, the first rubber and the second rubber insert may or may not be formed of the same material. At least the rubber for the first rubber insert has a Shore A hardness in the range of 575 to about 90 at 100 ° C.

In another embodiment of the tire, the first rubber insert has a radially innermost end radially overlapping the second rubber insert, the overlapping distance being in the range of 90 to 65% of the radial length of the second rubber insert. . The radially outer end of the second rubber insert at each sidewall is preferably located at a radial height of 25% to 89% of the tire height.

In another embodiment of the tire, the first rubber insert can be formed of multiple different rubber elements. When formed from two rubber elements, one of the rubber elements can have a larger Shore A hardness than the other. The rubber elements may be located radially adjacent to each other or axially adjacent to each other. When the elements are positioned radially adjacent to each other, the radially outer sides of the two rubber elements preferably have a Shore A hardness less than the radially inner rubber elements.

In another embodiment of the tire, the bead region has rubber wedges located axially outward of the bead wire. The rubber wedge has a Shore A hardness that is greater than the Shore A hardness of the first rubber insert or the second rubber insert.

In another embodiment of the invention, the tire may have additional sidewall reinforcement plies. In one embodiment, at least one short length reinforcement ply of the parallel cord extends from the bead portion of the tire to the upper sidewall. The short length reinforcement ply may or may not be immediately adjacent to the carcass reinforcement ply.

In another embodiment of the present invention, the carcass reinforcement ply consists of a pair of reinforcement cord plies. The tire may also have a third insert positioned on the tire sidewall. This third insert is preferably pressed between two carcass reinforcing cord plies.

In another embodiment of the present invention, the bead rings in each bead region have different bead diameters. Bead diameter is measured as the inner diameter of the bead wire ring. This is caused by asymmetric tires. The asymmetric tire may have a different sidewall structure. In one such configuration, the cross-sectional width of the radially outer sidewall of the large diameter bead ring is greater than the cross-sectional width of the radially outer sidewall of the small diameter bead ring. In another structure, the first rubber insert on the radially outer side of the large diameter bead ring has a Shore A hardness less than the first rubber insert on the radially outer sidewall of the small diameter bead ring.

The invention is illustrated by way of example with reference to the accompanying drawings.

The following terms represent the best predicted mode or modes of practicing the invention. The same features in the various embodiments are indicated by common reference signs. The following description is intended to illustrate the general principles of the invention and should not be taken in a limiting sense. It is intended that the scope of the invention only be limited by the appended claims.

1 shows a self supporting tire according to the invention; Only half of the cross-section of the tire is shown, and those skilled in the art may also have the opposite unillustrated tire half as shown, and possible variations of what is shown may be disclosed. The air tier 10 has a carcass including a carcass reinforcing ply 12 extending from one bead portion 14 to the opposing bead portion 14. The carcass reinforcement ply 12 is formed of a parallel reinforcement cord; The cord is inclined at an angle of 65 ° to 90 ° with respect to the equator plane of the tire 10. The cord may be formed from any conventional carcass cord material, including, but not limited to, nylon, rayon, polyester, aramid, pen, fiberglass, steel, or combinations thereof.

The carcass reinforcement ply 12 has a main portion 16 extending about the main torus portion of the tire 10. The turn-up portion 18 of the carcass reinforcement ply 12 is the outer end of the reinforcement ply 12, extends radially under the bead ring 20, and then the bead ring 20. Fold down again. The bead ring 20 has a diameter D _{B as} measured from the radially inner point of the bead ring. Each end of the carcass reinforcement ply 12 is compressed between the main portion of the carcass reinforcement ply 12 and the bead ring 20. In order to maintain the profile of the turnup portion 18 as the ply 12 folds back down the bead ring 20, the turnup portion 18 is a rubber wedge 20 located axially outward of the bead ring 20. It is folded around.

The bead portion has an outer end profile, and when the profile moves axially inward from the axial outer side of the bead portion, the bead profile is inclined radially upwards. In such a tire, the bead toe is in both the axial outward and radial inward directions of the bead heel. On the bead toe 24 are ribs 28 that help lock the tire on the wheel rim as described below. This bead profile is in contrast to conventional tires, which are bead hills that are radially and axially inside the bead toe bead heel and fit into the curved portion of the wheel rim where the rim seat and wheel flange meet.

The carcass reinforcement ply configuration in the bead portion 14 of the tire 10 is mounted on a wheel (not shown) and the figure corresponds to the outer configuration of the bead portion 914 in the following manner. do. When the carcass reinforcement ply 12 is positioned under tension by air pressure inside the tire 10, the reinforcement ply main portion 16 expands radially outward. When the main portion 16 is inflated, the main portion is pulled onto the turn-up portion 18, pulling the bead toe 24 radially inward into the wheel rim and flange, and the bead portion 14 of the tire 10. Locking on the wheel is performed efficiently.

Bead ring 20 is shown as having a generally circular configuration. Bead ring 20 is a co-extensible hoop of steel formed from multiple windings of steel. In addition, the bead ring 20 may have other overall configurations, such as hexagons or squares, or any combination of circles, hexagons, and squares.

The belt structure 30 is radially outward of the carcass reinforcement ply main portion 16. Belt structure 30 includes one to four reinforcing plies 32 of parallel cord. The cord of the reinforcing ply 32 may be woven or nonwoven and is inclined at an angle of 17 ° to 35 ° relative to the equator plane EP of the tire 10. Preferably, the cords of all adjacent belt plies 32 are inclined in opposite directions with respect to the equator plane EP of the tire 10. Cords of belt ply 32 may be formed of any conventional belt cord material including, but not limited to, steel, aramid, nylon, rayon, fiberglass, polyester, pens, or combinations thereof.

Depending on the final tire characteristics required of the tire engineer, a conventional 0 ° ply (not shown) can be located within the belt structure 30.

The other radial side of the belt structure 30 is the tire thread 36. Tread 36 is shown having multiple circumferential grooves 38. The tread 36 may have any number or pattern of circumferential and / or lateral grooves or combinations of grooves. The tread pattern selected by the tire engineer depends on the tire's intended application, i.e. small passenger car, medium sized car, small to medium sized passenger truck and the like.

At the axially outer edges of the tread 36 and the belt structure 30 and the radially outer side of the bead portion 14 are tire sidewalls 40. According to the invention, the cross-sectional width W of the tire side wall 40 at the radially outer side of the bead portion 14 is substantially constant. The initial point of the substantially constant width W is 15% of the radial height H of the tire 10 as measured at the bead base line B drawn at the radially innermost point of the bead toe 24. From 25% and from 5% or less of the radial height H of the tire 10 from the radially outer surface of the bead ring 20. The width W is measured as the maximum distance between the outer surface of the tire and the innermost surface of the tire 10 and is perpendicular to the point along the curvature C of the tire sidewall 40.

The deformation of the width W of the tire side wall 40 at the bottom 50% of the tire height H is no more than 20% of the minimum width. At radially outer 50% of the tire height H, the tire sidewall 40 may have a maximum change in width due to the increased thickness of the tire shoulder 42. The substantially constant radially outermost point of the tire 10 is at the axially outermost edge of the belt structure 30. The change in width W at radially outer 50% of tire height H is no more than 30% of the minimum width of radially outer 50% of tire height H.

By forming the tire 10 having a substantially constant width starting from the bead region 14, a pillar effect is generated in the tire 10. This pillar provides the tire 10 with the support required for continuous operation when the tire 10 is at reduced internal pressure. By forming the lower sidewall region with a constant thickness, the bead region 14 provides a fixture or non-moving base to the pillar. In addition, the pillar effect during reduced pressure operation helps ensure that the carcass reinforcing ply 12 is always kept in tension and that the locking bead effect of the carcass is not separated from the self supporting properties of the sidewall pillars.

In the tire of FIG. 2, the thickness of the tire in the shoulder 42 or upper sidewall area is reduced as compared to the tire of FIG. 1. Reducing the tire thickness in the shoulder 42 makes the upper sidewalls more flexible and improves the overall tire ride comfort. Therefore, in the tie of FIG. 2, the change in width W is 15% or less when measured perpendicular to the point along curvature C of tire sidewall 40. This reduction in the top sidewall thickness can be achieved by reducing the shoulder rubber gauge on the axially outer side of the carcass reinforcing ply 12 or on the gauge of all rubber located axially inside the carcass reinforcing ply 12.

Substantially constant sidewall thickness is produced by at least one insert 44. The insert 44 is lenticular in shape, the middle third of the insert 44 has a substantially constant thickness, and the end of the insert 44 is tapered. The insert 44 extends from the bead portion 14 to the radially inner side of the belt structure 30. When the insert extends through the entire sidewall 40, the insert has an axial inward side of the bead ring 20 and a radially inner starting point 46 of the radially outermost surface of the bead ring 20, the insert A radial overlap is formed between the inner end of 44 and the bead ring 20. The insert 44 shown is squeezed between the carcass reinforcement ply 12 and the tire inner liner 48.

The insert 44 is formed of hard rubber having a Shore A hardness in the range of about 55 to about 90, preferably in the range of 60 to 70 at 100 ° C. With regard to the additional properties of the insert, the properties disclosed in US Pat. No. 6,230,773 are suitable for the insert 44 of the present invention. This property can be obtained by the compounds disclosed in the above-mentioned US patent, or other compounds exhibiting the disclosed properties can be used. The rubber forming the insert 44 may also be flock loaded or blended with reinforcing fibers. Useful fibers can be natural or artificial, and are characterized by having a length of at least 100 times the diameter or width. Flock is smaller particles than fibers. And one of cotton, aramid, nylon, polyester, PET, PEN, carbon fiber, steel, fiberglass, or a combination thereof. Flock loading of fiber or rubber ranges from 5 to 35 pieces of 100 rubber pieces.

The lenticular structure of the insert keeps the carcass main part in the desired structure. The majority of the carcass reinforcement ply, located at the bottom 50% of the tire height, is maintained at an angle α of 15 ° up to 30 ° relative to the equator plane of the tire (see FIG. 1). Keeping the carcass ply in this structure creates a concave ply path when viewed from the inside of the tire, thus allowing the ply to be in better tension under the action of a load.

A second insert 50 is located radially outward of the bead ring 20 and axially outward of the main carcass turnup 18. This insert 50 has a generally triangular shape similar to a conventional apex. The second insert 50 decreases as the width of the first insert 44 increases and maintains a molded pillar of substantially constant thickness in the lower sidewall region of the tire 10. The radial overlap of the first insert 44 and the second insert 55 ranges from 90% to 65% of the radial length of the second insert 50.

The second insert 50 has a radially outer end point of height H ₂ which can vary from 25% to 80% of the tire height H (see FIGS. 3A and 3B). In FIG. 2, the second insert 50 has an end height H2 of about 40%, but the end height H2 in FIGS. 3A and 3B is about 59% to 70%, respectively. As the height H2 of the second or axially outer insert 50 increases, the gauge of the axially inner second insert 44 decreases. Preferably, due to the corresponding increase / decrease of the gauges of the two inserts 44, 50, the total cross-sectional gauge of the inserts 44, 50 is not connected to the belt structure 30 from the radially outer surface of the bead wire 20. Is substantially constant up to the axially outer end of the.

The second insert 50 preferably has the first insert 44 having a Shore A hardness equal to the Shore A hardness. However, to change the performance characteristics of the tire, the Shore A hardness of the second insert can be greater or smaller than that of the first insert 44.

4A shows another variant of the tie. During fabrication of the tie, when the sidewall insert 44 is placed on the building drum and the carcass reinforcement ply 12 is ready, at least one fabric or steel ply 52 is placed on the carcass reinforcement ply main part 16. Are placed adjacent to each other. The fabric or steel ply 52 consists of a parallel cord coated with rubber. The ply 52 is cut so that the parallel cord is inclined at an angle of 30 ° to 50 ° with respect to the circumferential direction of the tire. If more than one fabric or steel ply 52 is used, the cords of adjacent plies 52 are laid so as to slope in opposite directions. The cord may be formed of steel, aramid, polyester, nylon or rayon. The presence of the ply 52 reinforces the side wall 40 and reduces the cross-sectional area of the side wall 40 when a portion of the tire load is supported by the ply 52.

4B is a tire similar to FIG. 4A. However, additional plies 52 have been placed axially outward of the triangular insert 50 to reinforce the side walls 40 of the tire. When placed in this position, the ply 52 is compressed and placed instead of the tension as in FIG. 4A.

To increase tire load bearing capacity, the carcass may include a second reinforcement ply 54 (see FIG. 5). The second reinforcement ply 54 is applied simultaneously with the first reinforcement ply 12 and follows a substantially same path as the first reinforcement ply 12. However, the second reinforcement ply 54 does not fully sense around the hard rubber wedge 22. The material forming the cord on the second ply 54 is preferably the same as the material forming the cord of the first ply 12 but may vary depending on the desired tire characteristics. If the cord of the first carcass reinforcing ply 12 is inclined at an angle of 90 degrees or less with respect to the equator plane, the cord of the second ply 54 is preferably inclined at the same angle, but in the opposite direction.

To better tune the tire for desirable tire characteristics, the tire may be provided with multiple lenticular inserts to produce the desired pillar sidewall strength (see FIG. 6). The tire has an elongated first insert applied to the outside of the tire inner liner 48 prior to the application of the carcass reinforcing ply 12. After the first carcass reinforcing ply 12 is wound on the building drum, but before winding around the rubber wedge 22, an elongated second insert 58 is applied. The short carcass reinforcement ply 60 lies outside the elongated second insert 58. Next, the rubber wedge 33 is raised on the ends of the reinforcing plies 12, 60, the turn-up portion 18 of the first carcass reinforcing ply 12 is wound around the rubber wedge 22, and the bead ring ( 20 is applied to lock the end of turn-up section 18. In this way, the end of the short carcass reinforcement ply 60 and the radially inner end of the axially outer elongate insert 58 are the main part 16 and the turnup 18 of the first carcass reinforcement ply 12. ) Is fixed in between.

The physical properties of the two elongate inserts 56, 58 may be the same or different. Preferably, the radially inner first insert 56 has a smaller Shore A hardness than that of the radially outer second insert 58. In addition, the relative widths of the two inserts 56, 58 may be the same or different. Whatever the relative width of the two inserts 56, 58 is chosen, a substantially constant width of the tire sidewall 40 is maintained.

In the tire of FIG. 7, the combination of the two lenticular inserts 62, 64 is again combined to form an entirely lenticular support as part of the pillar structure of the tire sidewall 40, but the two inserts 62, 64. Are mainly radially adjacent and not as axially adjacent as previous tires. Two inserts 62, 64 are disposed axially inward of the carcass reinforcement ply 12, and the carcass reinforcement may be one or multiple plies. The radially outer insert 62 has a Shore A hardness less than that of the radially inner insert 64. The more flexible insert 62 in the shoulder region of the tire maximizes the runflat characteristics of the tire with minimal degradation of ride comfort.

In each of the tires described above, the opposing bead rings 20 will have sidewalls 40 each having the same diameter and height. That is, the tire part which is not shown is mirror image with the tire part shown. However, it is also within the scope of the present invention to form the tire described above so that the diameters of the opposing beads 20 are different as shown in FIG. 8.

The tire of FIG. 8 has a short sidewall 66 with a bead ring 68 of relatively large diameter D _BS and a long sidewall 70 with a bead ring 72 of relatively small diameter D _BNS . When mounted in a vehicle, the short sidewall 66 is mounted inward, referred to as an unstamped side, and the opposing sidewall 70 is referred to as a stamped sidewall, which is typically referred to as sidewall marking. Water is provided. The tire is mounted on a tire rim having a corresponding offset rim diameter to accommodate various bead diameters.

Each sidewall 66, 70 has a substantially constant width from the bead portion 12 to the axial edge of the belt structure 30, regardless of length. The relative heights of the sidewall inserts 74, 74 ′, 76, 76 ′, based on the tire height, are based on the height of the side walls 66, 70 where the inserts 74, 74 ′, 76, 76 ′ are located. Is measured. Thus, the triangular insert 74 has a height based on the sidewall height H _S and the triangular insert 74 ′ has a height based on the sidewall height H _NS . The state heights of the inserts 74, 74 ′ are substantially similar. The same applies to the lenticular inserts 76.76 '. Any of the various insert and reinforcement ply embodiments described above may be used with the asymmetric tire of FIG. 8.

The relative Shore A hardness of the inserts 74, 74 ′, 76, 76 ′ of the opposing sidewalls 66, 70 is the same for simplicity of manufacture, and between inserts 74, 74 ′, 76, 76 ′. The only difference is the radial length. However, for larger size tires or tires with large deviations in the side wall heights H _S , H _SN , the characteristics of the side walls may be used to balance the characteristics of the tires with the spring rates of the two side walls 66, 70. It needs to be different. One way to balance is that the inserts 74 ', 76' present in the long sidewall 70 having a small bead diameter D _BS are present in the short sidewall 66 having a large bead diameter D _BNS . The Shore A hardness is smaller than the Shore A hardness of the corresponding insert 74, 76. In another variation, the cross-sectional width W of the short sidewall 66 with the large bead diameter D _BNS is greater than the cross-sectional width W of the long sidewall 70 with the small bead diameter D _BS .

The present invention shows progress in run flat tires. In known self-supporting tires, due to the use of conventional tire rims and manufacturing tolerances of known rims, self-supporting tires had to be made with very tight tolerances and bead areas to prevent bead unseating of the tires. . The use of a carcass profile that locks the bead area into the wheel rim during inflation of the tire allows tire designers to produce self-supporting tires tuned to better runflat performance, including increased load performance.

Claims (20)

A radial carcass reinforcing ply, a belt structure, a pair of opposing bead regions, and radially outer sidewalls of each bead region, each bead region comprising a bead toe and bead heel ( and a bead toe is located axially outward and radially inward of the bead heel, each bead region having bead wires, The cross-sectional width of the sidewall from the radially outer side of the bead region to the end of the belt structure is substantially constant, A first rubber insert is located axially inward of the carcass reinforcing ply, the first rubber insert having a generally lenticular cross-sectional structure, radially outward of the bead wire and axially outward of the carcass reinforcing ply. Where the second rubber insert is located Pneumatic tires. The method of claim 1, The cross-sectional width of the sidewall varies from 30% or less of the minimum cross-sectional width. Pneumatic tires. The method of claim 1, Tire sidewalls present at the bottom 50% of the tire height vary from less than 20% of the minimum width of the sidewall cross-sectional width. Pneumatic tires. The method of claim 1, The change in cross-sectional width of the tire sidewall is greater at the radially outer portion of the sidewall than the radially inner sidewall portion. Pneumatic tires. The method of claim 1, The first rubber insert and the second rubber insert are formed of the same material Pneumatic tires. The method of claim 1, The total cross section gauge of the rubber insert is substantially constant from the radially outer surface of the bead wire to the axially outer end of the belt structure. Pneumatic tires. The method of claim 1, The bead region further comprises a rubber wedge located axially outward of the bead wire, the rubber wedge having a Shore A hardness greater than Shore A hardness of either the first rubber insert or the second rubber insert. Pneumatic tires. The method of claim 1, The first insert has a Shore A hardness in the range of about 55 to about 90 at 100 ° C. Pneumatic tires. The method of claim 1, The first rubber insert has a radially innermost end radially overlapping the second rubber insert, the overlapping distance being in the range of 90 to 65% of the radial length of the second rubber insert. Pneumatic tires. The method of claim 1, The radially outer end of the second rubber insert present on each sidewall is at a radial height of 25% to 80% of the tire height. Pneumatic tires. The method of claim 1, The tire further comprises at least one short reinforcement ply of a parallel cord extending from the bead portion to the upper sidewall of the tire. Pneumatic tires. The method of claim 11, The at least one short reinforcement ply is at least partially adjacent to the carcass reinforcement ply Pneumatic tires. The method of claim 11, The at least one short reinforcement ply does not contact the carcass reinforcement ply at the bead portion of the tire. Pneumatic tires. The method of claim 1, The first insert consists of at least two different rubber inserts, the one insert having a Shore A hardness greater than the other insert Pneumatic tires. The method of claim 14, One of the two different rubber inserts forming the first insert is radially outer of the other rubber insert and has a Shore A hardness less than the other rubber inserts radially inward Pneumatic tires. The method of claim 1, The carcass reinforcement ply consists of a pair of reinforcement cord plies, and the second ply terminates radially inward of the bead ring. Pneumatic tires. The method of claim 1, The carcass reinforcement ply is comprised of a pair of reinforcement cord plies, the tire further comprising a third insert located on the tire sidewall, the third insert being sandwiched between the two carcass reinforcement cord plies. felled Pneumatic tires. The method of claim 1, The bead ring present in each bead region has a different bead diameter. The method of claim 18, The cross-sectional width of the radially outer sidewall of the large diameter bead ring is greater than the cross-sectional width of the radially outer sidewall of the small diameter bead ring Pneumatic tires. The method of claim 18, The first rubber insert present on the radially outer sidewall of the large diameter bead ring has a Shore A hardness greater than the first rubber insert present on the radially outer sidewall of the small diameter bead ring. Pneumatic tires.

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