JP2006168596A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of enhancing the steering stability during the run flat traveling mode. <P>SOLUTION: In the pneumatic tire 2 which is used together with a run flat supporting body 3 consisting of a pair of elastic rings 5, 5 to be fitted to a rim 1 of a wheel and an annular shell 4 across the elastic rings 5, 5, a projection part 27 is provided on an inner surface of a tread part 21 and at a part on the outer side (OUT) of a vehicle than a maximum outside diameter part A of the run flat supporting body 3 when fitted to the vehicle. Further, a projection part 28 is provided on an inner surface of the tread part 21 and at a part on the inner side (IN) of the vehicle than the maximum outside diameter part A of the run flat supporting body 3 when fitted to the vehicle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire used in combination with a run-flat support that enables run-flat travel, and more particularly to a pneumatic tire that can improve steering stability during run-flat travel.

  Many technologies for enabling a certain degree of emergency traveling have been proposed in response to market demands even when a pneumatic tire punctures while the vehicle is traveling. The core (run flat support) is inserted into the cavity formed between the pneumatic tire and the wheel rim, and the flat tire can be supported by the core to enable run flat running. There is what I did.

  When such a run-flat support is used, a liquid or cream-like lubricant is applied to a contact portion between the outer surface of the support and the inner surface of the tire in order to reduce damage to the tire due to run-flat running. It has been broken. However, in the run-flat state, the phase difference between the rim and the tire increases as the run-flat support slides and moves in the tire with respect to the steering system movement caused by steering. The current situation is that sufficient properties are not obtained. Such behavior is an obstacle to moving the vehicle to a safe place.

As a countermeasure against this, while providing a protrusion at the center position in the width direction of the inner surface of the tread portion, a support portion is formed at the center position in the width direction of the rim, and a recess that engages the protrusion portion on the tread portion side is provided in the support portion. Has been proposed (see, for example, Patent Document 1). However, the above structure improves the tire following ability when the protrusion on the tread side and the depression on the rim side are engaged with each other, but if the protrusion and the depression do not engage with each other, the steering stability is remarkably improved. There is a problem of inhibiting.
Special table 2004-518574 gazette

  An object of the present invention is to provide a pneumatic tire that can improve the steering stability during run-flat traveling.

  In order to achieve the above object, the pneumatic tire of the present invention is an air used in combination with a run flat support comprising a pair of elastic rings fitted to the rim of a wheel and an annular shell straddling the elastic rings. The entering tire is characterized in that a protruding portion is provided on a portion of the inner surface of the tread portion that is outside the vehicle with respect to the maximum outer diameter portion of the run-flat support body when the vehicle is mounted.

  Further, the pneumatic tire of the present invention for achieving the above object is used in combination with a run flat support comprising a pair of elastic rings fitted to a rim of a wheel and an annular shell straddling the elastic rings. In the pneumatic tire according to the present invention, a protrusion is provided on each of the inner surface of the tread portion and the portion on the vehicle outer side and the vehicle inner side than the maximum outer diameter portion of the run flat support when the vehicle is mounted. To do.

  In the present invention, the run-flat support is formed so that the outer diameter is smaller than the inner diameter of the tread portion of the pneumatic tire and the inner diameter is the inner diameter of the bead portion of the pneumatic tire so as to maintain a certain distance from the pneumatic tire. And substantially the same dimensions. This run-flat support body is assembled to a rim of a wheel together with the pneumatic tire while being inserted into a hollow portion of the pneumatic tire, and constitutes a tire wheel assembly. When the pneumatic tire is punctured while the tire-wheel assembly is mounted on the vehicle, the punctured and crushed tire is supported by the run-flat support, and thus run-flat travel is possible.

  In the present invention, since the protruding portion is provided on the inner surface of the tread portion and on the outer side of the vehicle with respect to the maximum outer diameter portion of the run flat support when the vehicle is mounted, the outer surface of the run flat support and the pneumatic tire Even when the lubricant is applied to the contact portion with the inner surface, the run-flat support can be prevented from slipping outside the protrusion during the run-flat travel. Therefore, when a lateral force is generated by the steering operation, the relative movement in the tire width direction between the pneumatic tire and the run-flat support body is limited, and more excellent steering ability can be obtained. That is, it becomes possible to improve the handling stability during the run-flat running.

  In addition, when projecting parts are provided on the inner surface of the tread and on the vehicle outer side and the vehicle inner side than the maximum outer diameter part of the run-flat support body when the vehicle is mounted, the run-flat support is possible even when the vehicle is going straight. Slip on the body can be suppressed, and stability when going straight can be improved at the same time. In this case, it is preferable that the vehicle-side protrusion and the vehicle-side protrusion are arranged symmetrically on both sides of the tire equator plane in consideration of the weight balance of the pneumatic tire.

  The protrusion is preferably provided so as to continuously extend in the tire circumferential direction in order to exhibit stable motion performance. Further, by arranging the protruding portion within the insertion range of the belt layer in the tread portion, it is possible to more effectively generate a lateral force during steering and further improve stability during straight traveling. The amount of protrusion from the inner surface of the tread portion of the protrusion is preferably smaller than the outer diameter difference between the annular shell of the run-flat support and the elastic ring, and larger than 50% of the outer diameter difference.

  The method of forming the protrusion is not particularly limited, but the protrusion is formed integrally with the inner liner layer with a rubber composition having the same or similar composition as the inner liner layer, or the protrusion is It can be formed by inserting a separate body from the inner liner layer inside the liner layer. In the former case, it is possible to improve the integrity of the protrusion and the inner liner layer. In the latter case, the inner liner layer can be processed into a flat sheet, which is advantageous in terms of tire productivity. .

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a meridian cross-sectional view showing the main part of a tire wheel assembly (wheel) according to an embodiment of the present invention, wherein 1 is a wheel rim, 2 is a pneumatic tire, and 3 is a run-flat support. The wheel rim 1, the pneumatic tire 2, and the run-flat support 3 are formed in an annular shape around a wheel rotation shaft (not shown). That is, the run-flat support 3 is inserted into a cavity formed between the pneumatic tire 2 and the wheel rim 1.

  The pneumatic tire 2 includes a tread portion 21, a pair of sidewall portions 22 and 22, and a pair of bead portions 23 and 23. A carcass layer 24 is mounted between the pair of bead portions 23 and 23. In addition, two belt layers 25 are embedded on the outer peripheral side of the carcass layer 24 in the tread portion 21. These belt layers 25 include a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers. Further, a belt cover layer 26 formed by winding an organic fiber cord in the tire circumferential direction is embedded on the outer peripheral side of the belt layer 25.

  The run-flat support 3 is composed mainly of an annular shell 4 and an elastic ring 5. The run flat support 3 is spaced apart from the inner surface of the pneumatic tire 2 during normal running, but supports the collapsed pneumatic tire 2 from the inside during puncture.

  The annular shell 4 projects a continuous support surface 4a for supporting a punctured tire to the outer peripheral side (radially outer side) and has leg portions 4b and 4b along both sides of the support surface 4a. It has become. The support surface 4a of the annular shell 4 is formed so that the shape in a cross section perpendicular to the circumferential direction thereof is a convex curved surface on the outer peripheral side. At least one convex curved surface may be present, but it is preferable that two or more convex curved surfaces are arranged in the tire axial direction. In this way, by forming the support surface 4a of the annular shell 4 so that two or more convex curved surfaces are arranged, the contact portions of the support surface 4a with the tire inner surface are dispersed into two or more, and local wear given to the tire inner surface is reduced. Because of the reduction, the run-flat running distance can be extended.

  The annular shell 4 is made of a rigid material because it needs to support the vehicle weight via the punctured pneumatic tire 2. A metal, resin, or the like can be used as the constituent material. Among these, steel, aluminum, etc. can be illustrated as a metal. On the other hand, the resin may be either a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include nylon, polyester, polyethylene, polypropylene, polystyrene, polyphenylene sulfide, and ABS. Examples of the thermosetting resin include an epoxy resin and an unsaturated polyester resin. The resin may be used alone, or may be used as a fiber reinforced resin by blending reinforcing fibers.

  The elastic ring 5 is attached to each of the leg portions 4 b and 4 b of the annular shell 4, and supports the annular shell 4 while contacting the rim 1 along the bead portion of the pneumatic tire 2. The elastic ring 5 reduces the impact and vibration received by the annular shell 4 from the punctured pneumatic tire 2, and prevents the slip against the rim seat to stably support the annular shell 4.

  As a constituent material of the elastic ring 5, rubber or resin can be used, and rubber is particularly preferable. As rubber, natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), hydrogenated NBR, hydrogenated SBR, ethylene propylene rubber (EPDM, EPM), butyl rubber (IIR) ), Acrylic rubber (ACM), chloroprene rubber (CR), silicone rubber, fluorine rubber and the like. Of course, additives such as a filler, a vulcanizing agent, a vulcanization accelerator, a softening agent, and an anti-aging agent can be appropriately blended with these rubbers. And a desired elasticity modulus can be obtained based on the mixing | blending of a rubber composition.

  In the tire wheel assembly, the run-flat support 3 has the maximum outer diameter portions A at two locations in the tire width direction. And the protrusion part 27 is formed in the inner surface of the tread part 21 of the pneumatic tire 2, and the site | part which becomes a vehicle outer side (OUT) rather than all the largest outer-diameter parts A of the run flat support body 3 at the time of vehicle mounting. Yes. Further, a projecting portion 28 is formed on the inner surface of the tread portion 21 of the pneumatic tire 2 and on a portion that is on the vehicle inner side (IN) with respect to all the maximum outer diameter portions A of the run flat support 3 when the vehicle is mounted. Yes. These protrusions 27 and 28 both extend continuously in the tire circumferential direction. The protrusions 27 and 28 are arranged so as to be symmetrical on both sides of the tire equatorial plane E. In addition, what is necessary is just to arrange | position a protrusion part on the basis of the largest outer diameter part when the largest outer diameter part is one place.

  In the tire wheel assembly, the protrusion 27 is provided on the inner surface of the tread portion 21 of the pneumatic tire 2 and on the outer side of the maximum outer diameter portion A of the run flat support 3 when the vehicle is mounted. The run-flat support 3 can be prevented from slipping outward from the protrusion 27 during run-flat travel. Of course, this effect is also enjoyed when a lubricant is applied to the contact portion between the outer surface of the run-flat support 3 and the inner surface of the pneumatic tire 2. Thereby, it becomes possible to improve the steering stability at the time of run-flat traveling.

  Further, in the tire wheel assembly, the protruding portion 28 is also provided on the inner surface of the tread portion 21 of the pneumatic tire 2 and on the inner side of the maximum outer diameter portion A of the run flat support 3 when the vehicle is mounted. Therefore, the side-slip of the run-flat support 3 can be suppressed even when going straight, and the stability when going straight can be improved at the same time.

  As shown in FIG. 1, the protruding portions 27 and 28 are disposed inside the insertion range Wb of the belt layer 25 in the tread portion 21. As a result, the force received by the protrusions 27 and 28 from the run-flat support 3 is sufficiently transmitted to the tire side, so that a lateral force can be generated more effectively during steering, and further, stability during straight travel. Can be increased.

  The protrusion amount H of the protrusions 27 and 28 from the inner surface of the tread portion 21 is smaller than the outer diameter difference Sh between the annular shell 4 and the elastic ring 5 of the run-flat support 3 and more than 50% of the outer diameter difference Sh. It is set large. When the protruding amount H of the protruding portions 27 and 28 is larger than the outer diameter difference Sh, the contact state between the annular shell 4 and the inner surface of the tread portion 21 becomes unstable, and conversely, when it is smaller than 50% of the outer diameter difference Sh. The effect of improving steering stability is insufficient.

  FIG. 2 is an enlarged view of an example of the protrusion formed on the inner surface of the tread portion. In FIG. 2, the protruding portion 31 is formed integrally with the inner liner layer 32 with a rubber composition having the same or similar composition as the inner liner layer 32. A rubber composition having a similar composition is one in which the polymer components are the same and only the compounding agent is different. For example, when the inner liner layer 32 is composed of a rubber composition containing butyl rubber as a polymer component, the protrusion 31 can be composed of a rubber composition of the same or similar composition containing butyl rubber as a polymer component. In this case, the integrity of the protrusion 31 and the inner liner layer 32 that receive force from the run-flat support can be enhanced.

  FIG. 3 is an enlarged view of a modified example of the protrusion formed on the inner surface of the tread portion. In FIG. 3, the protruding portion 33 is formed by inserting a separate object 35 from the inner liner layer 34 inside the inner liner layer 34. The separate object 35 can be composed of a rubber composition having the same or similar composition as the inner liner layer 34, but foamed rubber, low elastic modulus rubber, hard rubber or the like may be used. In this case, while the inner liner layer 34 is extruded into a flat sheet shape, the separate body 35 is extruded into a rod shape, and the inner liner layer 34 and the separate body 35 are appropriately combined to obtain a tire size. Accordingly, the position of the protrusion 33 can be arbitrarily set. For this reason, the members are shared, which is advantageous in terms of tire productivity.

  In a pneumatic tire having a tire size of 185 / 65R14 and used in combination with a run-flat support body comprising a pair of elastic rings fitted to the rim of a wheel and an annular shell straddling the elastic rings, a tread portion Conventional tires, comparative examples, and tires of Examples 1 and 2 in which only the inner surface shape of the tires were varied were produced. A run-flat support having a structure shown in FIG. 1 was prepared.

  In the conventional example, no protrusion is provided on the inner surface of the tread portion. In the comparative example, a projecting portion that continuously extends in the tire circumferential direction is provided on the inner surface of the tread portion and in the center in the tire width direction. In the first embodiment, a projecting portion that continuously extends in the tire circumferential direction is provided on the inner surface of the tread portion and on the outer side of the vehicle from the maximum outer diameter portion of the run-flat support when the vehicle is mounted. . In the second embodiment, the inner surface of the tread portion is a protrusion that continuously extends in the tire circumferential direction to a portion that is on the vehicle outer side and a portion that is on the vehicle inner side than the maximum outer diameter portion of the run flat support when the vehicle is mounted. A part is provided.

These test tires are assembled with a run-flat support on a wheel with a rim size of 14 x 5 J, and each is mounted on four wheels of a front-wheel drive vehicle with a displacement of 1400 cc. A ring test was conducted to evaluate steering stability and straight-line stability. The results are shown in Table 1. The evaluation results of the steering stability and the straight running stability are indicated by an index with a feeling of 100 when all four wheels are filled with the standard air pressure of the vehicle. A larger index value means better feeling, and 95 points is an acceptable limit.

  As shown in Table 1, in the tires of Examples 1 and 2, the steering stability and the straight running stability during the run-flat running were good in comparison with the conventional example. On the other hand, the tire of the comparative example was insufficient in improving the steering stability and the straight running stability during the run-flat running.

It is a meridian sectional view showing a tire wheel assembly which consists of an embodiment of the present invention. It is sectional drawing which expands and shows an example of the projection part formed in the inner surface of a tread part. It is sectional drawing which expands and shows the modification of the projection part formed in the inner surface of a tread part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel rim 2 Pneumatic tire 3 Run flat support 4 Annular shell 4a Support surface 4b Leg part 5 Elastic ring 21 Tread part 22 Side wall part 23 Bead part 24 Carcass layer 25 Belt layer 26 Belt cover layer 27, 28 Protrusion part

Claims (9)

In a pneumatic tire used in combination with a run-flat support body including a pair of elastic rings fitted to a rim of a wheel and an annular shell straddling the elastic rings, the inner surface of the tread portion is A pneumatic tire in which a protrusion is provided at a portion on the vehicle outer side than the maximum outer diameter portion of the run-flat support. In a pneumatic tire used in combination with a run-flat support body including a pair of elastic rings fitted to a rim of a wheel and an annular shell straddling the elastic rings, the inner surface of the tread portion is The pneumatic tire which provided the protrusion part in the site | part which becomes a vehicle outer side and the vehicle inner side from the largest outer diameter part of a run flat support body, respectively. The pneumatic tire according to claim 2, wherein the protrusions are arranged symmetrically on both sides of the tire equatorial plane. The pneumatic tire according to any one of claims 1 to 3, wherein the protruding portion is provided so as to continuously extend in a tire circumferential direction. The pneumatic tire according to any one of claims 1 to 4, wherein the protruding portion is disposed within a belt layer insertion range in the tread portion. The pneumatic tire according to any one of claims 1 to 5, wherein an amount of protrusion from an inner surface of the tread portion of the protrusion is smaller than a difference in outer diameter between the annular shell and the elastic ring of the run-flat support. The pneumatic according to any one of claims 1 to 6, wherein an amount of protrusion from the inner surface of the tread portion of the protrusion is larger than 50% of an outer diameter difference between the annular shell and the elastic ring of the run-flat support. tire. The pneumatic tire according to any one of claims 1 to 7, wherein the protrusion is formed integrally with the inner liner layer with a rubber composition having the same or similar composition as the inner liner layer. The pneumatic tire according to claim 1, wherein the protruding portion is formed by inserting a separate object from the inner liner layer inside the inner liner layer.

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