JP5166044B2 - Pneumatic tire and run-flat tire / rim wheel assembly - Google Patents

Description

  The present invention relates to a pneumatic tire that is attached to a rim together with a core that supports a load by contacting the back side of the tread portion when the internal pressure is reduced, and a core-type run-flat tire / rim wheel assembly. The present invention relates to a pneumatic tire capable of extending a run-flat mileage and a run-flat tire / rim wheel assembly.

  As a run-flat tire / rim wheel assembly (generally called a safety tire or a run-flat tire), a pneumatic tire is mounted on a rim and a core is provided inside the tire. For example, Patent Document 1).

  In a conventional run-flat tire / rim wheel assembly with a core inside the tire, the inner surface of the tire and the core rub against each other when the tire is damaged and the load (vehicle weight) is supported by the core. In some cases, the inner surface of the tire was damaged, and finally the carcass ply was damaged, and the pneumatic tire was destroyed.

In order to solve such a problem, there is a method in which a lubricant is interposed between the pneumatic tire and the core (for example, Patent Document 2). By interposing the lubricant between the pneumatic tire and the core, friction and wear of the tire inner surface due to contact between the pneumatic tire and the core during the run-flat running can be reduced. Therefore, if the lubricant is interposed between the pneumatic tire and the core, the distance that can be traveled in the run-flat state can be increased as compared with the case where the lubricant is not used.
JP-A-10-278503 JP2003-326925A

However, wheeled vehicles such as trucks and buses are heavy in load and wear on the inner surface of the tire is fast, so that the distance that can be run in a run-flat state is not sufficient only by using a lubricant.
In consideration of the above facts, an object of the present invention is to provide a pneumatic tire and a run-flat tire / rim assembly that can sufficiently secure a distance that can be run in a run-flat state.

  In order to extend the travel distance until the carcass ply is exposed on the inner surface of the tire, the inventor thought that the thickness of the inner liner near the tire equator facing the outer peripheral surface of the core should be increased. As a result of investigating the run-flat tire and rim assembly during run-flat running and conducting various experiments, it is effective if the thickness of the inner liner near the equator of the tire is not increased but a certain range of thickness is increased It turns out that there is no.

A lateral force acts on the pneumatic tire during traveling when the steering is turned off. In normal running, the tread does not displace significantly in the width direction even when lateral force is applied.However, pneumatic tires that have been crushed by lowering the internal pressure have a significant decrease in lateral rigidity. The tread part is greatly displaced in the lateral direction due to the force, and the outer peripheral surface of the core is not near the tire equatorial plane of the tire, but is mainly a distance of 1/4 of the contact width of the tread part from the tire equatorial plane to the outside in the tread width direction It was found that contact was made between the spaced 1/4 point and the tire maximum width portion. Further, it has been found that the tread portion often remains largely displaced in the lateral direction until the next steering operation.
Further, a lateral force called a price tear acts on the pneumatic tire during traveling due to the influence of a reinforcing layer (belt or the like) inside the tread portion. A pneumatic tire that has been crushed due to a decrease in internal pressure has a significant decrease in lateral rigidity, and the tread portion may shift laterally due to the price tire of the pneumatic tire itself even when traveling straight. .

The invention described in claim 1 has been made in view of the above fact, and is a pneumatic tire that is attached to a rim together with a core that supports a load by contacting the back side of the tread portion when the internal pressure is reduced. A pair of left and right bead cores, a carcass straddling the pair of bead cores in a toroid shape, an inner rubber layer formed only of rubber formed inside the carcass, and a reinforcement disposed on the outer side in the tire radial direction of the carcass And a tread portion disposed on the outer side in the tire radial direction of the reinforcing layer, and the inner rubber layer is separated from the tire equator surface by a distance of 1/4 of the ground contact width of the tread portion in the tread width direction outer side. At least between a first normal that is perpendicular to the carcass through the 1/4 point and a second normal that is perpendicular to the carcass through the maximum tire width. Some first games Di is, is set larger than the second gauge in the other portions, on the inner peripheral surface in contact with at least said core, lubricant to reduce friction between the core are located, that It is a feature.

Next, the operation of the pneumatic tire according to claim 1 will be described.
When this pneumatic tire is mounted on a rim together with the core and used for running, and the pneumatic tire is punctured or the like and the internal pressure is reduced, the pneumatic tire is crushed and the inner surface side of the tread portion comes into contact with the outer periphery of the core. Since the core supports the load, the pneumatic tire can run even when punctured, that is, run-flat running is possible.

  During run-flat running, the tread portion is shifted laterally due to the price tear of the pneumatic tire itself, and the outer peripheral surface of the core is mainly between the first normal line and the second normal line. Although contacting the tire inner surface, the first gauge of the inner rubber layer between the first normal line and the second normal line is set thicker than the second gauge in the other part, Due to the friction between the inner surface of the tire and the core during run-flat travel, the travel distance in the run-flat state until the carcass is exposed on the inner surface of the tire can be extended. Therefore, the travel distance in the run-flat state can be extended compared with the conventional pneumatic tire.

Here, “contact width” means contact with a flat plate when a tire is mounted on an applicable rim, set to a specified air pressure, placed in a stationary state perpendicular to the flat plate, and a load corresponding to a specified mass is applied. The maximum linear distance in the tire axial direction on the surface. In Japan, according to the 2007 JATMA YEAR BOOK, the tire is mounted on a standard rim, the maximum load capacity in the applicable size and ply rating, and the corresponding air pressure (maximum air pressure) It is based on what was done. The “maximum tire width portion” is a portion having a cross-sectional width in JATMA YEAR BOOK.
When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.
Also, during run-flat running, friction between the inner peripheral surface of the pneumatic tire and the outer peripheral surface of the core is reduced by the action of the lubricant, so the wear of the inner rubber layer is reduced and the carcass is exposed on the inner surface of the tire. The mileage in the run flat state can be further extended.

  The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the first gauge is set within a range of 110 to 250% with respect to the second gauge. It is a feature.

Next, the operation of the pneumatic tire according to claim 2 will be described.
If the first gauge is less than 110% with respect to the second gauge, the travel distance in the run-flat state until the carcass is exposed on the tire inner surface cannot be extended sufficiently.
On the other hand, if the first gauge exceeds 250% with respect to the second gauge, the travel distance in the run-flat state until the carcass is exposed on the tire inner surface can be extended, but the travel distance is more than necessary. It only extends, and material costs are wasted and tire weight also increases.

  According to a third aspect of the present invention, in the pneumatic tire according to the first or second aspect, the inner rubber layer is disposed on the entire inner peripheral surface of the tire and is made of a material that is less likely to pass gas than other rubber. An inner liner is provided, and the first gauge and the second gauge are gauges of the inner liner.

Next, the operation of the pneumatic tire according to claim 3 will be described.
In the pneumatic tire according to claim 3, since the gauge of the inner liner is only partially increased, the pneumatic tire can be manufactured by a method that is not different from the conventional tire manufacturing method, and the manufacturing cost (members) The cost is slightly increased).

  According to a fourth aspect of the present invention, in the pneumatic tire according to the first or second aspect, the inner rubber layer is disposed on the entire inner circumferential surface of the tire and is made of a material that is less permeable to gas than other rubber. And a reinforcing rubber layer disposed between the first normal line and the second normal line and between the carcass and the inner liner. .

Next, the operation of the pneumatic tire according to claim 4 will be described.
By disposing the reinforcing rubber layer between the first normal line and the second normal line, a normal one having a constant thickness can be used as the inner liner, and the first inner rubber layer can be used. The gauge can be increased more easily than the other part of the second gauge.

Run flat tire rim wheel assembly as claimed in claim 5 is arranged with pneumatic tire according to the lumen portion of the pneumatic tire in any one of claims 1 to 5, decreased internal pressure It is characterized in that an annular core that sometimes supports a load is attached to the rim.

Next, the operation of the run-flat tire / rim wheel assembly according to claim 5 will be described .
In the run-flat tire / rim wheel assembly according to claim 5, when the pneumatic tire is punctured or the like and the internal pressure is reduced, the pneumatic tire is crushed and the inner surface side of the tread portion is in contact with the outer periphery of the core. Since the child supports the load, the pneumatic tire can run even when punctured, that is, run-flat running is possible.

  During run-flat running, the tread portion is shifted laterally due to the price tear of the pneumatic tire itself, and the outer peripheral surface of the core is mainly between the first normal line and the second normal line. Since the first gauge of the inner rubber layer between the first normal line and the second normal line is set to be thicker than the second gauge in the other part, the flat run is performed. Sometimes, the friction between the tire inner surface and the core can extend the running distance in the run-flat state until the carcass is exposed on the tire inner surface. Therefore, the travel distance in the run-flat state can be extended compared with the conventional pneumatic tire.

A sixth aspect of the present invention is the run flat tire / rim wheel assembly according to the fifth aspect , wherein the core has at least a portion in contact with an inner peripheral surface of the pneumatic tire. It is characterized by the fact that a lubricant that reduces friction with the material is disposed.

Next, the operation of the run-flat tire / rim wheel assembly according to claim 6 will be described .
During run-flat running, the friction between the inner peripheral surface of the pneumatic tire and the outer peripheral surface of the core is reduced by the action of the lubricant, so that the wear of the inner rubber layer is reduced and the carcass is exposed to the inner surface of the tire. The mileage in the run-flat state can be further extended.

  As described above, according to the pneumatic tire and the run-flat tire / rim wheel assembly of the present invention, there is an effect that the travel distance in the run-flat state can be extended as compared with the conventional case.

[First Embodiment]
Hereinafter, a pneumatic tire 10 according to a first embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a run-flat tire / rim wheel assembly 36 in which the pneumatic tire 10 and the core 32 of this embodiment are mounted on a rim 34. The core 32 is formed in an annular shape and is attached to the center portion in the width direction of the rim 34.

A pneumatic tire 10 according to this embodiment is a truck and bus tire defined by the JATMA standard, and includes a pair of right and left bead cores 12.
A carcass 14 straddles between the bead cores 12 in a toroidal shape, and an end portion of the carcass 14 is folded back to the outside of the tire.

A belt layer 18 composed of a plurality of belt plies is disposed outside the carcass 14 in the tire radial direction. The belt ply has a known configuration in which a plurality of cords are arranged in parallel with each other and covered with rubber, and the cords are inclined with respect to the tire equatorial plane CL. Further, in the adjacent belt ply, the inclination direction of the cord is opposite to the tire equatorial plane CL.
A tread rubber 22 constituting the tread portion 20 is disposed outside the belt layer 18 in the tire radial direction.

An inner rubber layer 24 is provided on the inner surface side of the carcass 14. The inner rubber layer 24 of the present embodiment includes an inner liner 26 and a reinforcing rubber layer 30, and the inner liner 26 is disposed on the innermost side, and the reinforcing rubber layer 30 includes the inner liner 26, the carcass 14, and the like. It is arranged between.
The rubber type of the reinforcing rubber layer 30 is not particularly limited.

  The reinforcing rubber layer 30 of the present embodiment is perpendicular to the carcass 14 through a quarter point P1 that is spaced from the tire equatorial plane CL by a distance of 1/4 of the ground contact width TW of the tread portion 20 outward in the tread width direction. Between the first normal line L1 and the second normal line L2 that is perpendicular to the carcass 14 through the tire maximum width part (cross-sectional width in JATMA (SW in FIG. 1)) P2. Has been placed.

The reinforcing rubber layer 30 is formed of a rubber different from that of the inner liner 26, and the thickness gradually decreases toward the tire equatorial plane CL side and the bead portion side. The reinforcing rubber layer 30 is provided continuously in the circumferential direction, but the gauge does not change in the circumferential direction.
On the other hand, the inner liner 26 of this embodiment is set to a constant thickness.

In the pneumatic tire 10 of the present embodiment, since such a reinforcing rubber layer 30 is disposed on the inner surface side of the carcass 14, the inner rubber layer between the first normal line L1 and the second normal line L2 is used. The first gauge G1 of 24 is thicker than the second gauge G2 of the inner rubber layer 24 in a portion other than between the first normal line L1 and the second normal line L2.
In addition, it is preferable to set the 1st gauge G1 in the range of 110-250% with respect to the 2nd gauge G2.

(Function)
In the state where the run-flat tire / rim wheel assembly 36 is mounted on a vehicle and used for running, when the pneumatic tire 10 is punctured or the like and the internal pressure is reduced, as shown by a two-dot chain line in FIG. 10 is crushed and the tread portion 20 is sandwiched between the core 32 and the road surface 38, and the inner surface of the tire contacts the outer peripheral surface of the core 32 and the core 32 supports the load.

  By the way, when run flat running, even when the vehicle is traveling straight, the pneumatic tire 10 is caused by its own price tear, and the tread portion 20 is displaced laterally as shown by the two-dot chain line in FIG. The outer peripheral surface of 32 mainly contacts the tire inner surface (the tire inner surface between the first normal L1 and the second normal L2 shown in FIG. 1) on which the reinforcing rubber layer 30 is disposed.

  In the pneumatic tire 10 of the present embodiment, the first gauge G1 of the inner rubber layer 24 in the portion where the reinforcing rubber layer 30 is disposed (between the first normal L1 and the second normal L2) is Since the thickness is set to be thicker than the second gauge G2 of the inner surface rubber layer 24 in other portions, the run until the carcass 14 is exposed to the inner surface of the tire due to friction between the inner surface of the tire and the core 32 during the run flat running. The mileage in the flat state can be extended.

  If the price tear is attached to the vehicle, it acts in a fixed direction for each tire. Therefore, considering only the price tear, the first gauge G1 to be thickened is only on one side of the tire equatorial plane CL. Although it is good, the lateral rigidity of the pneumatic tire 10 is extremely reduced during run-flat driving. For example, when the vehicle turns to the left, the tread portion 20 moves to the right and turns to the right. In this case, the tread portion 20 approaches the left side. Therefore, it is preferable that the first gauge G1 to be thickened is on both sides of the tire equatorial plane CL.

  In the pneumatic tire 10 of the present embodiment, the reinforcing rubber layer 30 is disposed between the first normal line L1 and the second normal line L2, so that the inner liner 26 is a normal one having a constant thickness. The first gauge G1 of the inner rubber layer 24 can be increased more easily than the second gauge G2 of other portions.

  Here, if the first gauge G1 is less than 110% with respect to the second gauge G2, the travel distance in the run-flat state until the carcass 14 is exposed on the tire inner surface cannot be sufficiently extended. On the other hand, if the first gauge G1 exceeds 250% with respect to the second gauge G2, the travel distance in the run-flat state until the carcass 14 is exposed on the tire inner surface can be extended, but the vehicle travels more than necessary. Only the distance is increased, the material cost is wasted, and the tire weight is also increased.

[Second Embodiment]
Hereinafter, a pneumatic tire 10 according to a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.
In the first embodiment, the reinforcing rubber layer 30 is disposed between the carcass 14 and the inner liner 26. However, in the second embodiment, as shown in FIG. It is arranged on the inner surface side (the tire lumen side).

  Also in the pneumatic tire 10 of the present embodiment, the first gauge G1 of the inner rubber layer 24 in the portion where the reinforcing rubber layer 30 is disposed is more than the second gauge G2 of the inner rubber layer 24 in the other portion. Since it is set thick, the run distance in the run flat state until the carcass 14 is exposed to the tire inner surface can be extended by the friction between the tire inner surface and the core 32 during the run flat running.

[Third Embodiment]
Hereinafter, a pneumatic tire 10 according to a third embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 4, the pneumatic tire 10 of the present embodiment is not provided with the reinforcing rubber layer 30 between the carcass 14 and the inner liner 26. Instead, the gauge of the inner liner 26 is Between the first normal line L1 and the second normal line L2, it is formed thicker than other portions other than between the first normal line L1 and the second normal line L2.

  In the pneumatic tire 10 of the present embodiment, since the gauge of the inner liner 26 is only partially increased, the type of rubber member does not increase, and the pneumatic tire 10 is not different from the conventional tire manufacturing method. Therefore, the manufacturing cost can be reduced as usual.

[Other Embodiments]
In the run-flat tire / rim wheel assembly 36, lubrication for reducing friction with the pneumatic tire 10 at least in a portion in contact with the inner surface of the pneumatic tire 10 during the run-flat running out of the outer surface of the core 32. An agent may be arranged. Moreover, you may arrange | position a lubricant to the part which contacts the core 32 at the time of run flat driving | running | working among the inner surfaces of the pneumatic tire 10. FIG. As a result, during run-flat running, friction between the inner peripheral surface of the pneumatic tire 10 and the outer peripheral surface of the core 32 is reduced by the action of the lubricant, the wear of the inner rubber layer 24 is reduced, and the carcass 14 becomes the tire. The running distance in the run flat state until it is exposed to the inner surface can be further extended.
As the lubricant, silicone type, polyethylene glycol type, hydrocarbon type, ether type, allomer type, fluorine grease, molybdenum disulfide, etc. can be used, but it has excellent heat resistance and extremely little deterioration against tire rubber etc. For example, it is preferable to use silicone oil, polyoxyethylene polyoxypropylene glycol compound, or the like.

  The pneumatic tire 10 of the above embodiment is a truck and bus tire, but the present invention is not limited to a truck and bus tire, but a construction vehicle tire, an industrial vehicle tire, a small truck tire, and a light truck. Needless to say, the present invention can be applied to other types of tires such as tires for passenger cars and tires for passenger cars.

  In addition, the core of the above embodiment is a mountain type that contacts only one location on the tire inner surface when viewed in a cross section along the tire rotation axis, but the core contacts at two locations on the tire inner surface. It may be a double mountain (or three or more mountain) type.

(Test example)
Next, trial tires with various changes in the gauge of the inner rubber layer were manufactured, and the run-flat running performance was compared.
The size of the prototype tire is 365 / 80R20.
Conventional tire: inner liner gauge is constant at 4.1 mm.
Tire of Example 1: The inner rubber layer is formed such that a rubber gauge in the range of 60 to 120 mm along the inner surface of the tire from the tire equatorial plane to the bead portion is 0.9 mm thicker than the rubber gauges of other portions. (The maximum value of the rubber gauge of the inner rubber layer is 5.0 mm).
Tire of Example 2: The inner rubber layer is formed such that a rubber gauge in the range of 60 to 120 mm along the inner surface of the tire from the tire equatorial plane to the bead portion side is 2.9 mm thicker than the rubber gauge of other portions. (The maximum value of the rubber gauge of the inner rubber layer is 7.0 mm).
In the tire of the example, the inner rubber layer is partially thickened by arranging a reinforcing rubber layer between the inner liner and the carcass (see FIG. 1).

In the test, a prototype tire was mounted on a vehicle of shaft type 2-2B-B, the tire on the left side of the vehicle was set to the prescribed internal pressure, and the tire on the right side was set to 0 kPa. The load per tire was 30 kN. The vehicle equipped with the prototype tire was run at 30 km / h until the tire broke down, and the run-flat mileage was measured.
The test results are shown in Table 1 below.

  As a result of the test, in the tires of Examples 1 and 2 in which the gauge of the inner rubber layer in the range of 60 to 120 mm in the distance along the tire inner surface from the tire equator surface to the bead portion is thicker than the other portions, the inner rubber layer It was found that the run-flat mileage could be extended compared to the conventional tire with a constant thickness.

1 is a cross-sectional view of a run-flat tire / rim assembly according to a first embodiment of the present invention. It is sectional drawing which shows the run-flat tire and rim assembly at the time of no load and at the time of run-flat driving. It is sectional drawing of the run flat tire and rim assembly which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the run flat tire and rim assembly which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Bead core 14 Carcass 18 Belt 26 Inner liner 20 Tread part 24 Inner surface rubber layer 30 Reinforcement rubber layer 36 Run flat tire and rim assembly

Claims (6)

A pneumatic tire that is attached to the rim together with a core that supports the load by contacting the back side of the tread when the internal pressure is reduced,
A pair of left and right bead cores,
A carcass straddling the pair of bead cores in a toroidal shape;
An inner rubber layer made only of rubber formed inside the carcass;
A reinforcing layer disposed on the outer side in the tire radial direction of the carcass;
A tread portion disposed outside the reinforcing layer in the tire radial direction;
With
The inner rubber layer has a first normal line that is perpendicular to the carcass through a ¼ point spaced from the tire equatorial plane by 1/4 distance of the contact width of the tread portion outward in the tread width direction. And at least a portion of the first gauge between the second normal line passing through the tire maximum width portion and perpendicular to the carcass is set to be thicker than the second gauge in the other portion. and,
A pneumatic tire characterized in that a lubricant that reduces friction with the core is disposed at least on an inner peripheral surface that is in contact with the core .   The pneumatic tire according to claim 1, wherein the first gauge is set in a range of 110 to 250% with respect to the second gauge.   The inner rubber layer includes an inner liner that is disposed on the entire inner peripheral surface of the tire and is made of a material that is less permeable to gas than other rubber, and the first gauge and the second gauge are the inner liner. The pneumatic tire according to claim 1, wherein the pneumatic tire is a gauge.   The inner rubber layer is disposed on the entire inner circumferential surface of the tire, and is formed between an inner liner made of a material that is less likely to pass gas than other rubber, the first normal line and the second normal line, and The pneumatic tire according to claim 1, further comprising a reinforcing rubber layer disposed between the carcass and the inner liner. The pneumatic tire according to any one of claims 1 to 4, and
A run-flat tire / rim wheel assembly, wherein an annular core that is disposed in a lumen portion of the pneumatic tire and supports a load when an internal pressure is reduced is attached to a rim. 6. The lubricant according to claim 5 , wherein a lubricant that reduces friction with the pneumatic tire is disposed at least in a portion that contacts the inner peripheral surface of the pneumatic tire. Run-flat tire / rim wheel assembly.

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