JP4820122B2 - Pneumatic tire and rim assembly - Google Patents

Description

  The present invention relates to an assembly of a pneumatic tire and a rim that enables traveling during puncture without impairing traveling performance during normal traveling.

  Conventionally, various assemblies of pneumatic tires and rims that enable continuous running even during puncture have been proposed (see Patent Documents 1 and 2 below). These assemblies include a pneumatic tire, a rim, and a shock absorber made of an elastic foam or the like disposed in a tire lumen surrounded by the tire and the rim.

  However, the assembly of Patent Document 1 has a drawback that the number of parts is increased and the cost is high because the shock absorber includes a foam material and a tube. Further, since the inner peripheral surface of the tread portion is in contact with the buffer body not only during puncture travel but also during normal travel, there is a problem that the tire easily generates heat and the ride comfort is deteriorated.

  Moreover, since the assembly of the said patent document 2 forms an air filling area | region between a buffer body and the inner peripheral surface of a tread part at the time of normal driving | running | working, it can suppress deterioration of riding comfort. However, in a puncture state in which the internal pressure is reduced, for example, the shock absorber has a smaller cross-sectional area than the tire lumen, so that a relatively large gap is generated between the two and the tire is easily detached from the rim. In addition, since the amount of vertical deflection of the tire increases, there is room for further improvement in increasing the puncture continuous travel distance.

Japanese Patent Laid-Open No. 11-245637 Japanese Patent Laid-Open No. 11-59144

  The present invention has been devised in view of the above circumstances, and has a main part made of an elastic foam having closed cells and a specific gravity of 0.1 to 0.5, and having air impermeability. In addition, by using a load support that includes an outer skin portion that covers the entire surface of the main portion so as to keep the main portion airtight, the puncture continuous travel distance is increased without impairing riding comfort during normal travel. It is an object of the present invention to provide a pneumatic tire and rim assembly that is useful for the following.

The invention according to claim 1 is a pneumatic tire, a rim for assembling the pneumatic tire, and a ring-shaped load support body disposed in a tire lumen surrounded by the pneumatic tire and the rim. An assembly of a pneumatic tire and a rim, wherein the load support includes a main portion made of an elastic foam having closed cells and a specific gravity of 0.1 to 0.5, and air impermeability And an outer skin portion that airtightly holds the main portion by covering the entire surface of the main portion, and a normal load in which a normal internal pressure is filled in the tire lumen and a normal load is applied. In the state, the load support is compressed by the internal pressure, thereby forming a continuous air filling region in the tire circumferential direction between the load support and the inner peripheral surface of the tread portion, and the load support. The body may Bubbles expanded to support the load of the tread portion in substantially the tire within腔全body is expanded and deformed, moreover the load bearing body includes an air valve provided in the rim, between the air-filled region Air communication means capable of communicating with each other, and the air communication means comprises a plurality of grooves that extend radially around the load support and are spaced apart in the tire circumferential direction of the load support. And

  The invention according to claim 2 is the pneumatic tire and rim according to claim 1, wherein the load support body has a cross-sectional area of 30 to 70% of a total cross-sectional area of the tire lumen in the normal load state. It is an assembly.

According to a third aspect of the present invention, the outer skin portion comprises a thin film layer having a thickness of 1.0 mm or less formed by spraying a resin material on the surface of the main portion. An assembly of a pneumatic tire and a rim .

  In the present invention, a main portion made of an elastic foam having closed cells and a specific gravity of 0.1 to 0.5 in a tire lumen surrounded by a pneumatic tire and a rim, and having air impermeability and A load support including an outer skin portion that holds the main portion airtight by covering the entire surface of the main portion is disposed.

  In such a load support, air permeation to the main part is prevented by the outer skin part. Accordingly, the tire lumen is compressed by being filled with the internal pressure, whereby an air filling region can be formed between the load support and the inner peripheral surface of the tread portion. For this reason, during normal driving, the impact absorbability of the tread portion is increased and good riding comfort performance is obtained.

  Further, the load support body can expand substantially over the entire tire lumen due to a decrease in internal pressure, and can support the load of the tread portion. Therefore, during puncturing, the gap between the tire lumen and the load support body can be substantially eliminated, and thus the amount of longitudinal deflection of the tire can be reduced. Accordingly, the detachment of the tire from the rim is reduced, and the puncture continues. Helps increase distance.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a pneumatic tire and rim assembly (hereinafter, simply referred to as “assembly”) 1 according to the present embodiment. The assembly 1 is shown in a normal unloaded state in which a normal internal pressure is filled but no load is applied.

  Here, the normal internal pressure is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. The maximum air pressure is JATMA, and the table "TIRE LOAD LIMITS AT" is TRA. The maximum value described in “VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” if it is ETRTO, but if the tire is for passenger cars, it is uniformly 180 kPa.

  The assembly 1 includes a pneumatic tire 2, a rim 3 for assembling the pneumatic tire 2, and a ring-shaped load support disposed in a tire lumen i surrounded by the rim 3 and the pneumatic tire 2. Body 4.

  The pneumatic tire 2 includes a tread portion 2a that travels in contact with a road surface, side wall portions 2b and 2b that extend from both ends toward the inside in the tire radial direction, and the side wall portion 2b on the radially inward side. It has a hollow toroidal shape with each bead portion 2c. Further, the pneumatic tire 2 of the present embodiment includes, for example, a carcass 2e extending in a toroidal manner between the bead cores 2d disposed in the respective bead portions 2b, and a belt layer 2f disposed on the outer side in the tire radial direction. A radial tire for a passenger car of a tubeless type including is shown.

  The rim 3 connects a pair of rim seat portions 3a, 3a on which the bottom surface of the bead portion 2c is seated, a flange portion 3b continuously provided on the outer side in the axial direction, and the rim seat portions 3a, 3a, and a rim. A deep rim including a well portion 3c into which the bead portion 2c can be dropped when assembled is shown. However, a split-type rim from which one flange portion 2c can be removed can also be used. An air valve 3d for filling the tire lumen i with air from the outside of the rim is attached to a part of the well portion 3c.

  The rim 3 is appropriately selected according to the size of the pneumatic tire 2, and a regular rim is usually used. Here, the regular rim is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, a standard rim for JATMA, “Design Rim” for TRA, and ETRTO. If there is, “Measuring Rim”.

  The load support 4 has a main part 4A made of an elastic foam having closed cells and a specific gravity of 0.1 to 0.5, and has air impermeability and covers the entire surface of the main part 4A. Accordingly, the outer portion 4B is configured to hold the main portion 4A in an airtight manner.

  The main portion 4A is made of an elastic foam having closed cells. These bubbles are uniformly formed in the main portion 4A. Closed bubble means that each bubble is not substantially in communication with each other. Therefore, a foam having closed cells is preferable in that each cell independently exhibits a load supporting ability, and therefore has superior load support and impact mitigating ability compared to a foam having open cells.

  Further, in order for the load support 4 to effectively support the load from the pneumatic tire 2, the expansion ratio of the main portion 4A is preferably 400 to 1500%, more preferably 400 to 1100%. If the expansion ratio is less than 400%, the shock absorption tends to be insufficient, so that the ride comfort during puncture tends to be impaired. Conversely, if it exceeds 1500%, the load support 4 becomes extremely flexible. In addition, the rigidity is lowered and the load supporting ability is lowered.

The foaming ratio V (%) is
V = (ρ0 / ρ1 −1) × 100
Is obtained.
However, ρ0: density of solid phase part of foam (g / cm ³ )
ρ1: Density of foam (g / cm ³ ).

  The elastic foam constituting the main portion 4A has a specific gravity of 0.1 to 0.5. Although this specific gravity is apparent specific gravity, when this specific gravity is less than 0.1, the ratio which a bubble occupies increases and there exists a tendency for the intensity | strength and rigidity as the load support body 4 to fall. On the other hand, when the specific gravity exceeds 0.5, the weight of the load support 4 increases, and the fuel efficiency and rolling resistance tend to be excessively deteriorated. Particularly preferably, the specific gravity of the main portion 4A is desirably 0.15 or more, and the upper limit is desirably 0.3 or less.

  The JIS-C hardness of the main part 4A is preferably 10 to 35 degrees, more preferably 10 to 30 degrees. When the JIS-C hardness of the main portion 4A is less than 10 degrees, the ability to support the load of the tread portion 2a tends to be insufficient, and conversely, when it exceeds 35 degrees, it tends to be difficult to assemble the rim. Particularly preferably, the JIS-C hardness of the main portion 4A is more preferably 15 degrees or more.

  Such a main part 4A is vulcanized and molded in a predetermined mold by blending various additives, reinforcing agents, foaming agents and the like with air-impermeable butyl rubber such as butyl rubber or halogenated butyl rubber. Can be easily obtained. The main portion 4A is formed in a ring shape from the beginning, and the main portion 4A is formed in a ring shape by bending a linearly molded one and joining both end portions thereof. It can be made by various methods such as those formed as a ring by joining the divided ring pieces.

  As the outer skin portion 4B, various materials such as rubber or resin can be adopted as long as they have air impermeability. However, a material that can be elastically deformed integrally with the main portion 4A following the main portion 4A is desirable.

  The material of the outer skin portion 4B is not particularly limited as long as it has air impermeability that does not substantially transmit air, and various materials are used. The outer skin portion 4B of the present embodiment is formed by spraying a resin material on the entire surface of the main portion 4A that has been foam-molded in advance. The thermal spraying is a method in which a melted resin material is blown off with a gas jet or the like in the form of fine particles and adhered to a base material (main part 4A) to form a surface film. Such thermal spraying is useful for forming a uniform and thin surface coating even if the substrate has a complicated shape. In the present embodiment, the outer skin portion 4B having a very thin thickness t is formed by attaching the nylon resin to the entire surface of the main portion 4A by the above-described thermal spraying. For example, the outer skin portion 4B can be formed by welding a nylon film or the like to the outer peripheral surface of the main portion 4A.

  The thickness t of the outer skin part 4B is not particularly limited. However, if it is too small, there is a tendency that sufficient air impermeability cannot be obtained, and conversely, if it is too large, the flexible deformation of the main part 4A may be hindered. From such a viewpoint, the thickness t is preferably 1.0 mm or less, more preferably about 0.3 to 0.8 mm.

  Further, the load support 4 disposed in the tire lumen i in the normal no-load state shown in FIG. 1 is compressed by the internal pressure. Since the outer skin portion 4B of the load support 4 has air impermeability, the internal pressure of the tire lumen i does not reach the main portion 4A, and the main portion 4A is compressed and deformed through the outer skin portion 4B. That is, the volume of each closed cell in the main portion 4A is reduced (in other words, the pressure of each closed cell in the main portion is increased). Thereby, in the assembly 1 of this embodiment, the air filling area | region A extended continuously in a tire peripheral direction is formed between the load support body 4 and the internal peripheral surface 2ai of the tread part 2a.

  FIG. 2 is a cross-sectional view of the assembly 1 in a normal load state in which a normal inner pressure is filled in the tire lumen i and a normal load is applied to be grounded on the road surface. Here, the normal load is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. If it is JATMA, it is the maximum load capacity, and if it is TRA, the table "TIRE LOAD LIMITS" The maximum value described in “AT VARIOUS COLD INFLATION PRESSURES”, “LOAD CAPACITY” if ETRTO is used, but if the tire is for a passenger car, the load is uniformly equivalent to 88% of the load.

  Even in this normal load state, in the assembly 1 of the present embodiment, an air filling region A extending in the tire circumferential direction is formed between the load support 4 and the inner peripheral surface 2ai of the tread portion 2a. Accordingly, during standard normal running, the inner peripheral surface 2i of the tread portion 2a does not come into direct contact with the load support 4, and the load applied to the tread portion 2a is the internal pressure charged in the air filling region A. Can be supported by the carcass cord tension and the belt cord tension. Therefore, the assembly 1 of the present embodiment can provide an excellent ride comfort during normal travel. Moreover, since the outer skin part 4B has air impermeability, the air in the air filling area A does not diffuse into the main part 4A even if time passes. Therefore, the load support 4 can be maintained in a compressed and deformed state for a long time, and as a result, the excellent riding comfort can be maintained.

  On the other hand, FIG. 3 shows the assembly 1 in a puncture state. In the load support body 4 of the assembly 1 of the present embodiment, each of the air bubbles therein expands and deforms due to a decrease in the pressure in the air filling area A of the tire lumen i, and the load support body 4 itself substantially becomes the tire. The whole lumen i expands. As a result, the air filling area A is substantially eliminated, and the load support 4 is in direct contact with the inner peripheral surfaces 2ai, 2bi, and 2ci of the tread portion 2a, the sidewall portion 2b, and the bead portion 2c. Take charge of the load. Thereby, at the time of puncturing, this load support body 4 receives a load from the tire 2 and absorbs an impact from the road surface, thereby enabling continuous traveling. Further, the bead portion 2 c is strongly pressed against the flange portion 3 b of the rim 3 by the load support 4, thereby preventing the pneumatic tire 2 from coming off the rim.

  In the cross section of the tire meridian in the normal load state, the load support 4 preferably has a cross-sectional area of 30 to 70% of the total cross-sectional area of the tire lumen i. When the cross-sectional area of the load support 4 is less than 30% of the total cross-sectional area of the tire lumen i, the load support 4 needs to be disposed in the tire lumen i with a larger compression ratio. In other words, since the load support body 4 has a large volume in a free state, the rim assembly property is likely to deteriorate. Conversely, when the cross-sectional area of the load support 4 exceeds 70% of the total cross-sectional area of the tire lumen i, the distance in the tire radial direction of the air-filled region A becomes small, and when the vehicle runs on an uneven road surface, The inner peripheral surface 2ai of the tread portion 2a may come into contact with the load support body 4 due to an increase in the travel speed and the ride comfort may be deteriorated.

  Further, in the assembly 1, it is desirable to define the cross-sectional compressibility of the load support 4 in order to balance the improvement in riding comfort and the rim assembly in a normal load state with a good balance. Here, the cross-sectional compression ratio is a ratio of the cross-sectional area Sf of the load support 4 in a free state not arranged in the tire lumen i and the cross-sectional area Si of the load support 4 in a normal load state (Si / Sf). The cross-sectional compressibility is substantially determined by the ratio of the air pressure filled in the tire lumen and the ratio of the main portion 4A, but is preferably 40% or more, more preferably 45% or more, and the upper limit is preferably 60% or less. More preferably, 55% or less is desirable.

  In addition, air is provided from the air valve 3d to the tire lumen i of the assembly 1, and at this time, as shown in FIG. 4, for example, the air is provided between the air valve 3d and the air filling area A. It is desirable to communicate with the communication means 5. The air communication means 5 shown in FIG. 4 includes a tube body 6 having flexibility. In this embodiment, the inner end 5i is connected to the air valve 3d, and the other end 5o is connected to the air filling area A. It is arranged.

  The tube body 6 is made of, for example, a rubber or an elastomer material having higher compression resistance than the load support body 4 so as not to be crushed by the load support body 4, while reducing the actual vehicle running performance of the tire. In order to prevent this, it is desirable to have a bending rigidity that is softer than that of the sidewall portion.

  In addition, the air communication means 5 may be provided with, for example, a guide hole, a groove, or the like that allows the air valve 3 d and the air filling area A to communicate directly with the load support 4 instead of the tube body 6. FIG. 5 shows a cross-sectional view of the assembly 1 at the position of the tire equator C (however, the load support 4 is not cross-sectional). The load support 4 has a plurality of radially extending grooves 7 spaced apart in the tire circumferential direction. In this embodiment, the groove 7 extends continuously around the load support 4. The width, depth, and arrangement pitch of the grooves 7 can be arbitrarily determined. FIG. 6 is a cross-sectional view taken along the YY position in FIG. As is clear from FIG. 6, the groove 7 of the load support 4 has a portion that does not contact the tire 2 and the rim 3. Therefore, the air pressure to the air filling area A can be applied by communicating this portion with the air hole 3d1 of the air valve 3d. Note that the air valve 3d can be improved so that air can be supplied from, for example, the tip 3d1 having a T-shape so that air can be supplied along the groove 7. In addition, air is fed to each groove 7 spaced in the tire circumferential direction through a circumferential gap E surrounded by, for example, the rim 3, the bead toe of the tire 2 and the load support 4.

  Although the embodiment of the present invention has been described above, the present invention is particularly suitable as a tire for a passenger car, but can also be preferably implemented as a tire assembly for a rally car used for a rally competition with a high puncture frequency. .

  Based on the specifications in Table 1, an assembly of a tubeless pneumatic tire (215 / 60R16) and a rim (16 × 6.5JJ) was prototyped, and performance was tested on them. The same tire and rim were used, and only the load support was changed. Each of the load supports is made of a butyl rubber foam. Each specific gravity was adjusted by changing the expansion ratio. Moreover, about the Example which has an outer skin part, this was formed with the sprayed layer of nylon resin. The test method is as follows.

<Riding comfort during normal driving>
Fill the tire lumen with an internal pressure of 200 kPa and mount it on the four wheels of a domestic passenger car with a displacement of 2000 cc. The sensory evaluation was performed with respect to ruggedness, push-up, and dumping, and the evaluation was performed by a 10-point method with Comparative Example 1 being 6 points. The larger the value, the better.

<Continuous mileage during puncture>
Remove the valve core from the right front wheel assembly of the domestic passenger car (FF car) and put it in a punctured state. Was measured and indexed. The larger the value, the better. In the test course, a straight line was run at a speed of 80 km / h and a corner was run at 60 km / h.

<Air impermeability of load support>
Immediately after each pneumatic tire and load support are mounted on the rim and filled with an internal pressure of 200 kPa and after 12 months (at room temperature and normal pressure), the cross section of the assembly is imaged with a CT scanner, and the load support The expansion coefficient of the cross section was examined. The smaller the expansion rate (100% indicates no growth), the better the air impermeability.
Table 1 shows the test results.

  As a result of the test, it was confirmed that the assembly of the example increased the puncture continuous travel distance while maintaining high riding comfort during normal travel. Moreover, it has also confirmed that the outer skin | coated part which sprayed the nylon resin to the main part gave favorable air impermeability to a load support body.

It is sectional drawing of the assembly of the pneumatic tire and rim | limb of this embodiment. It is sectional drawing which shows the normal load state. It is sectional drawing which shows the puncture drive state of FIG. It is sectional drawing which shows one Example of an air communication means. It is a fragmentary sectional view in the tire equator of an assembly. It is sectional drawing in the YY position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Assembly 2 Pneumatic tire 3 Rim 4 Load support 4A Main part 4B Outer skin part i Tire lumen

Claims (3)

A pneumatic tire and rim assembly comprising a pneumatic tire, a rim for assembling the pneumatic tire, and a ring-shaped load support body disposed in a tire lumen surrounded by the pneumatic tire and the rim. Because
The load support has a main part made of an elastic foam having closed cells and a specific gravity of 0.1 to 0.5,
An outer skin part that has air impermeability and covers the entire surface of the main part to hold the main part airtight,
And, in a normal load state in which the tire lumen is filled with normal internal pressure and a normal load is applied, the load support is compressed by the internal pressure, thereby the load support and the inner peripheral surface of the tread portion. And an air-filled region continuous in the tire circumferential direction is formed between
The load support body supports the load of the tread portion by expanding and deforming the closed cell due to a decrease in internal pressure and expanding substantially over the entire tire lumen ,
Moreover, the load support includes air communication means capable of communicating between an air valve provided on the rim and the air filling region,
The pneumatic communication means comprises a plurality of grooves radially extending in the tire circumferential direction of the load support and extending continuously around the load support. Solid.   2. The pneumatic tire and rim assembly according to claim 1, wherein the load support body has a cross-sectional area of 30 to 70% of a total cross-sectional area of the tire lumen in the normal load state.   The pneumatic tire and rim assembly according to claim 1 or 2, wherein the outer skin portion is formed of a thin film layer having a thickness of 1.0 mm or less formed by spraying a resin material on a surface of the main portion. .

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