JP2006298305A - Tire particle assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire particle assembly surely reforming a tire with particles when a tire is blown, and providing stable travel after the tire is blown. <P>SOLUTION: The tire particle assembly is constituted of a tire having at least a side part, and a plurality of empty particles filling a tire air chamber defined by the tire and a rim together with high-pressure gas exceeding atmospheric pressure. A rubber layer with viscoelasticity higher than the rubber constituting the side part is disposed to at least a part of an area from near the maximum width part where the length in a tire width direction of the tire is the longest up to a ground end of the tread. The hollow particles are approximately spheres made of continuous phases and closed cells of the resin, and are inflated at least when pressure in the tire air chamber is decreased, or when a temperature in the tire air chamber reaches a predetermined temperature (Ts2). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tire particle assembly that is an assembly of a tire having at least a side portion and a plurality of hollow particles filled with a high-pressure gas exceeding atmospheric pressure in a tire chamber defined by the tire and the rim. .

  Conventionally, many proposals have been made on so-called safety tires that can travel even in a puncture state.

  For example, a run-flat tire having a reinforcing rubber on the side portion, a pneumatic tire having a support ring for supporting a load inside the tire, and the like are known.

  However, run-flat tires with reinforcing rubber on the side as described above, and pneumatic tires with a support ring to support the load inside the tire make it difficult to puncture or decrease the internal pressure when punctured However, it is difficult to perform normal running after puncture because the damaged part is not repaired.

Therefore, a pneumatic tire has been proposed in which particles having closed cells held at a pressure higher than atmospheric pressure are inserted into a tire chamber (for example, Patent Document 1). A pneumatic tire in which particles having closed cells held at a pressure higher than the atmospheric pressure are inserted into the tire chamber is filled with the particles when the tire is punctured. Can run like before puncture.
JP 2003-118332 A

  However, as described above, when the tire in which the hollow particles are inserted into the tire chamber is damaged, the hollow particles are supposed to block the damaged part, but when the damaged part is small, Since the internal pressure in the pneumatic tire is gradually reduced, the particles can block the damaged part before the side of the pneumatic tire contacts the ground, but if the damaged part is large, the internal pressure of the pneumatic tire There was a possibility that the tire would be damaged before the particles closed the damaged part, and the vehicle could not run.

  In view of the above problems, an object of the present invention is to provide a tire particle aggregate capable of reliably repairing a tire during puncture and obtaining stable running even after puncture.

  As a result of intensive studies to solve the above situation, the inventors have accelerated the speed at which the particles seal the damaged part at the time of puncture when the gas in the tire chamber leaks due to the damage. The inventors have found that it is necessary to reliably repair the damaged part without damaging the tire even when the tire is large, and have completed the present invention.

  First, a feature of the present invention is a tire that is an aggregate of a tire having at least a side part, and a plurality of hollow particles filled with a high-pressure gas exceeding atmospheric pressure in a tire air chamber defined by the tire and the rim. A rubber layer having a higher viscoelasticity than the rubber constituting the side portion in at least a part of the region from the vicinity of the maximum width portion where the length of the tire in the tire width direction is the longest to the contact end of the tread. The hollow particles have a substantially spherical shape composed of a continuous phase made of resin and closed cells, and at least when the internal pressure of the tire chamber decreases or the temperature inside the tire chamber reaches a predetermined temperature (Ts2). The gist of this is that it expands.

  According to such a feature, since the hollow particles expand at least when the internal pressure of the tire chamber is reduced, or when the temperature inside the tire chamber reaches a predetermined temperature (Ts2), the hollow particles are surely secured at the time of puncture. The internal pressure revival function can be demonstrated.

  Here, the function of restoring the internal pressure of the tire after being injured is a high-pressure gas filled in the tire chamber by the expansion of the hollow particles when the internal pressure in the tire chamber is reduced to the atmospheric pressure (a puncture state). This is a function that can restore the internal pressure of the tire chamber.

  Here, the predetermined temperature (Ts2) is a re-expansion start temperature corresponding to the glass transition temperature (Ts2) of the resin.

  The substantially spherical shape includes an oval and an ellipse due to the influence of manufacturing.

  In addition, since the hollow particles have a substantially spherical shape, it is possible to prevent the hollow particles from hitting the wall surface of the tire chamber and the like due to centrifugal force during running and damaging the hollow particles. As a result, the hollow particles can reliably exhibit the function of restoring the internal pressure after being damaged.

  In addition, a rubber layer having higher viscoelasticity than the rubber constituting the side portion is provided in at least a part of the region from the vicinity of the maximum width portion where the length in the tire width direction is the longest to the ground contact end of the tread. Further, the heat generation inside the tire can be increased during low internal pressure traveling, and the expansion speed of the hollow particles can be increased, so that the internal pressure can be reliably restored even when the damaged part is large.

  Although it may be possible to arrange the rubber layer from the vicinity of the maximum width portion where the length in the tire width direction of the tire is the longest to the rim guard, the distortion is suppressed by the bead portion even when the internal pressure is reduced. Therefore, the exothermic property is small, and the expansion promoting effect of the hollow particles is small.

  The viscoelasticity Tan δ of the rubber layer is preferably 0.2 or more.

  The rubber layer is preferably provided outside the carcass layer in the tire width direction.

  The rubber layer is preferably provided on the inner side in the tire width direction of the carcass layer.

  The rubber layer preferably has a width of 10 mm or more and a thickness of 1 mm or more.

In addition, the following general formula (I)
Filling ratio of hollow particles = (particle volume value / tire chamber volume value) × 100 (I)
The filling rate of the hollow particles calculated by the formula (1) is 5 vol% or more and 80 vol% or less, and the particle volume value is the total volume of all the hollow particles filled in the tire chamber under the atmospheric pressure, a total amount (cm ^3), the tire air chamber volume value was adjusted to be filled with only air used pressure (kPa) in the tire chamber, when the charge air pressure is discharged until the atmospheric pressure Using the amount of air discharged (cm ³ ), the following general formula (II)
Tire chamber volume value = (filled air discharge amount) / (internal pressure / atmospheric pressure) (II)
The value obtained from (cm ³ ) is preferred.

  Moreover, it is preferable that the hollow part pressure which is the internal pressure of a hollow particle is 70% or more of the internal pressure of a tire air chamber.

  Moreover, it is preferable that predetermined temperature (Ts2) is 90-200 degreeC.

Moreover, the average particle diameter of the hollow particle group which is a plurality of hollow particles filled in the tire chamber is 40 to 200 μm, and the average true specific gravity of the hollow particle group filled in the tire chamber is 0.01 to It is preferably 0.06 (g / cm ³ ).

The gas inside the hollow particles is nitrogen, air, a linear or branched aliphatic hydrocarbon having 2 to 8 carbon atoms and a fluorinated product thereof, an alicyclic hydrocarbon having 2 to 8 carbon atoms and its Fluorides and the following general formula (III):
R ¹ —O—R ² (III)
(Wherein R ¹ and R ² are each independently a monovalent hydrocarbon group having 1 to 5 carbon atoms, and part of the hydrogen atoms of the hydrocarbon group may be replaced by fluorine atoms) It is preferable that it is at least one gas selected from the group consisting of ether compounds represented by:

  The continuous phase of the hollow particles is preferably composed of at least one of a polyvinyl alcohol resin, an acrylonitrile polymer, an acrylic polymer, and a vinylidene chloride polymer.

  The continuous phase of the hollow particles is composed of an acrylonitrile polymer, which is an acrylonitrile polymer, an acrylonitrile / methacrylonitrile copolymer, an acrylonitrile / methyl methacrylate copolymer, and an acrylonitrile / methacrylonitrile / methyl methacrylate. It is preferably at least one of a terpolymer and an acrylonitrile / methacrylonitrile / methacrylic acid terpolymer.

  Moreover, it is preferable to provide a first tire pressure drop alarm function that warns of a decrease in internal pressure in the tire chamber based on a direct measurement method of the pressure in the tire chamber using a tire pressure sensor.

  Moreover, it is preferable to provide the 2nd tire pressure fall warning function which warns the internal pressure fall in a tire chamber based on the wheel speed detected by a wheel speed sensor.

  In addition, it is preferable to provide a large number of foams that are mixed with the hollow particles and filled in the tire chamber in which the average bulk specific gravity under atmospheric pressure in the tire chamber is larger than the average true specific gravity of the hollow particles.

  The foam has a substantially spherical shape with a diameter of 1 to 15 mm or a cubic shape with one side of 1 to 15 mm, an average bulk specific gravity of 0.06 to 0.3 (g / cc), and closed cells or It is preferable to have open air bubbles.

  According to the present invention, it is possible to provide a tire particle aggregate capable of reliably repairing a tire during puncture and obtaining stable running even after puncture.

(Configuration of tire particle aggregate)
Next, an example of the tire particle aggregate according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  FIG. 1 shows a tire particle assembly 100 in the present embodiment. As shown in FIG. 1, a tire particle assembly 100 is filled with a high-pressure gas exceeding atmospheric pressure in a tire air chamber 3 defined by a tire 1 having at least a side portion 7 and a tire 1 and a rim 2. It is an aggregate with a plurality of hollow particles 4.

  The tire 1 has a pair of bead portions 5 including a bead core 5a and a bead filler 5b. Specifically, a steel cord or the like is used for the bead core 5a constituting the bead portion 5.

  The tire 1 has a carcass layer 6 that is folded from the inner side in the tire width direction to the outer side in the tire width direction around the bead core 5a.

  The tire 1 has a rubber layer 16 in at least a part of a region from the vicinity of the maximum width portion where the length in the tire width direction is the longest to the contact end of the tread portion 10 described later. Details of the rubber layer 16 will be described later.

  The tire 1 is a portion that is most bent during running of the tire, and has a side portion 7 to protect the carcass layer.

  An inner liner 8 that is a highly airtight rubber layer corresponding to a tube is provided inside the carcass layer 6 in the tire radial direction. A belt layer 9 is disposed on the outer side of the carcass layer 6 in the tire radial direction. Further, a tread portion 10 is disposed outside the belt layer 9 in the tire radial direction.

  The rim 2 is provided with a valve 12 that dams the hollow particles 4 in the tire air chamber 3 and allows only gas to pass outside the tire air chamber. As shown in FIG. 2, the valve 12 includes a filter 13 made of a predetermined fiber (for example, non-woven fabric).

  By attaching the tire valve 12 as described above, the gas replenishing operation can be performed without leaking the hollow particles 4 against the natural decrease in the internal pressure of the tire chamber 3 during normal running, and the tire chamber can be simply obtained. The internal pressure of 3 can be maintained. Further, when the tire particle assembly 100 of the present invention is manufactured, the hollow particles 4 can be filled into the tire chamber 3 with only one valve 12, so that a general-purpose rim having only one valve hole is provided. It can be used as it is.

  The hollow particles 4 are filled in a tire air chamber 3 defined by the tire 1 and the rim 2 together with a high-pressure gas exceeding atmospheric pressure. The details of the hollow particles 4 will be described later.

  Here, as long as the tire 1 is a tire according to the general standards such as tires for various automobiles, tires for trucks and buses, for example, tires for passenger cars, the structure is not particularly limited.

  By the way, when the vehicle travels while the internal pressure of the tire chamber 3 is lowered (so-called puncture), the internal pressure is restored by the mechanism of the hollow particles 4 described later, so that the driver notices that the puncture occurred depending on the situation. There may not be. In addition, since the tire 1 is punctured due to trauma, the tire 1 may break down if it continues to travel as it is, which is very dangerous.

  Therefore, the following functions can be given as a function for warning (notifying) that the driver has punctured. FIG. 3 is a cross-sectional view showing the tire particle assembly 100 in the present embodiment.

  As shown in FIG. 3, a tire pressure sensor 14 is disposed in the vicinity of the valve 12.

  The tire pressure sensor 14 warns a decrease in internal pressure in the tire chamber 3 based on a direct measurement method of the internal pressure of the tire chamber 3.

  Specifically, as shown in FIG. 4, the tire pressure sensor 14 detects that the internal pressure in the tire chamber 3 has decreased (so-called puncture) based on the direct measurement method of the internal pressure of the tire chamber 3. In this case, data related to the puncture is transmitted to the receiving unit 50a of the vehicle 50.

  When the receiving unit 50a of the vehicle 50 receives the data related to the puncture, the driver can be warned (notified) via the warning unit 50b.

  In the present embodiment, the function of warning (notifying) the driver that the vehicle has been punctured is not limited to the tire pressure sensor 14, and a wheel speed sensor may be used.

  For example, as shown in FIG. 4, the wheel speed sensor 15 in the anti-lock brake system warns (informs) the driver via the alarm unit 50 b when detecting that puncture has occurred based on the detected wheel speed. . The wheel speed sensor 15 is not limited to the wheel speed sensor 15 in the antilock brake system, and a wheel speed sensor different from the wheel speed sensor 15 in the antilock brake system may be used.

  In the present embodiment, the function capable of warning the driver using the tire pressure sensor 14 constitutes a first tire pressure drop warning function, and the wheel speed sensor 15 in the anti-lock brake system is used. The function capable of warning the driver constitutes a second tire pressure drop warning function.

(Composition of rubber layer)
Next, the structure of the rubber layer described above will be described.

  The rubber layer 16 is made of rubber having higher viscoelasticity than the rubber constituting the side portion 7 in at least a part of the region from the vicinity of the longest width portion of the tire 1 in the tire width direction to the contact end of the tread. Layer.

  The viscoelasticity Tan δ of the rubber layer 16 is 0.2 or more. If the viscoelasticity Tan δ of the rubber layer 16 is smaller than 0.2, the effect of the rubber layer 16 cannot be exhibited sufficiently. The viscoelasticity Tan δ is measured by a viscoelasticity measurement test.

  Here, the viscoelasticity measurement test is a test in which tan δ at 60 ° C. is measured under conditions of a dynamic strain of 3% and a frequency of 50 Hz using a viscoelasticity measurement tester manufactured by Rheometrics.

  As shown in FIG. 1, the rubber layer 16 is provided outside the carcass layer 6 in the tire width direction. As a result, the heat generation inside the tire can be increased during low internal pressure traveling, and the expansion speed of the hollow particles can be increased, so that the internal pressure can be reliably restored even when the damaged part is large.

  The rubber layer 16 has a width of 10 mm or more and a thickness of 1 mm or more. If the width of the rubber layer 16 is smaller than 10 mm and the thickness is smaller than 1 mm, the rubber layer 16 is too small, so that the effect of the rubber layer 16 cannot be exhibited sufficiently.

(Change example)
Below, the example of a change of the rubber layer in this embodiment is demonstrated.

  Here, only portions different from the present embodiment will be described, and descriptions regarding overlapping portions will be omitted.

  As shown in FIG. 5, the rubber layer 160 is provided inside the carcass layer 6 in the tire width direction.

  Thereby, the heat generation of the rubber layer 160 during low internal pressure traveling can be directly transmitted to the hollow particles 4, so that the expansion speed of the hollow particles 4 can be further increased.

(Configuration of hollow particles)
Next, the structure of the hollow particles described above will be described.

  The hollow particle 4 has closed cells surrounded by a continuous phase of a substantially spherical resin, for example, a hollow body having a particle size distribution in the range of about 10 μm to 500 μm, or a large number of small chambers by closed cells. Is a spongy structure.

  That is, the hollow particles 4 are particles that enclose closed closed cells that do not communicate with the outside, and the number of closed cells may be singular or plural.

  In the present embodiment, the “inside closed cells of the hollow particle group” is abbreviated as “hollow part”. The hollow particles 4 having closed cells indicate that the hollow particles 4 have “resin shells” for enclosing the closed cells in a sealed state. Furthermore, the continuous phase by the above-mentioned resin refers to this “continuous phase on the component composition constituting the resin shell”. The composition of the resin shell will be described later.

  The hollow particle group, which is a plurality (a large number) of the hollow particles 4, is filled inside the tire chamber 3 together with the high-pressure gas, so that the “internal pressure” of the tire is partially increased under normal use conditions. In addition, when the tire is injured (hereinafter referred to as “injured”), it serves as a source of the function of restoring (recovering) the internal pressure lost in the tire chamber 3. This “internal pressure restoration function” will be described later.

  Here, “internal pressure” refers to “a tire chamber pressure value (gauge pressure value) for each mounting position specified by an automobile manufacturer for each vehicle”.

  Now, when the conventional pneumatic tire is run in a state where the internal pressure of the tire chamber 3 is reduced to the atmospheric pressure, the tire 1 is greatly bent due to the load. Therefore, the side portion 7 comes into contact with the road surface, and the hollow particles There is a problem that the tire 1 is destroyed before the tire expands.

  Therefore, in this embodiment, when the gas in the tire chamber 3 leaks due to trauma, the provision of the rubber layer 16 increases heat generation, increases the speed at which the hollow particles expand, and then travels thereafter. The main purpose is to appropriately apply the minimum internal pressure of the tire chamber 3 required for the recovery of the internal pressure and to restore the lost internal pressure more quickly. Therefore, in this embodiment, the tire chamber 3 partitioned by the tire 1 and the rim 2 is regarded as a pressure vessel.

  That is, the pressure lost by causing the hollow particles 4 to function more quickly after temporarily sealing the damaged portion of the tire chamber 3 damaged by the puncture with the hollow particle group filled in the tire chamber 3. The goal is to achieve this goal by reviving it faster.

  Even if the internal pressure of the tire chamber 3 is reduced to the atmospheric pressure, it is important to function as a pressure vessel by demonstrating the function of recovering the internal pressure lost early (an internal pressure recovery function described later).

More specifically, the hollow particles 4 filled in the tire chamber 3 are represented by the following formula (I)
Filling rate of hollow particles 4 = (particle volume value / tire chamber 3 volume value) × 100 (I)
It is preferable that the filling rate of the hollow particles 4 calculated by the above is 5 vol% or more and 80 vol% or less.

Here, the particle volume value is a total amount (cm ³ ) of the total volume of the hollow particle group filled in the tire chamber 3 under the atmospheric pressure and the void volume around the particle, and can be calculated by the following method. .

First, the average bulk specific gravity of the hollow particles 4 under atmospheric pressure is determined. For example, it is calculated by measuring the weight of a known volume under atmospheric pressure. First, the hollow particles 4 are weighed in a graduated cylinder under atmospheric pressure, and vibration is applied in an ultrasonic aqueous solution, and the packing between the hollow particles 4 is stabilized, and the total volume of the hollow particles 4 (around the particles) The average bulk specific gravity under the atmospheric pressure is calculated by measuring the void volume) and the total weight of the hollow particles 4. That is, the average bulk specific gravity of the hollow particles 4 under atmospheric pressure is
Average bulk specific gravity of hollow particles under atmospheric pressure = (total weight of particles) / (total volume of particles)
It is.

Next, the total weight of the hollow particles 4 filled in the tire chamber 3 is measured, and divided by the average bulk specific gravity of the hollow particles 4 under the atmospheric pressure described above, the “particles filled inside the tire 1” Volume "can be calculated. That is,
Particle volume = (total weight of particles filled in tire) / (average bulk specific gravity of particles under atmospheric pressure)
It is.

  In addition, the hollow particles 4 having a desired particle volume can be filled in the tire 1 by a method of filling the tire chamber 3 while measuring the particles in a container having a known volume.

Further, the tire chamber volume value is adjusted until the tire chamber 3 defined by the tire 1 and the rim 2 is filled with only air and adjusted to the use internal pressure (kPa), and then the filled air is changed to the atmospheric pressure. It is a value (cm ³ ) obtained from the following formula (II) using the amount of filled air discharged (cm ³ ) when discharged.

Tire chamber volume value = (filled air discharge amount) / (internal pressure / atmospheric pressure) (II)
In the formula (II), the internal pressure used is a gauge internal pressure (kPa), and the atmospheric pressure value is an absolute value (kPa) measured by a barometer. That is, the atmospheric pressure is represented by 0 [kPa] in terms of the gauge pressure, but the atmospheric pressure value itself changes every day, so the absolute value observed from the barometer at that time is used. Therefore, for example, when the atmospheric pressure at a certain time is 1013 hPa, 101.3 kPa is used as the absolute value of atmospheric pressure in the formula (II).

  Next, the reason why the filling rate of the hollow particles 4 is 5 vol% or more and 80 vol% or less will be described in order from the normal use to the puncture state.

  First, the case where the tire air chamber 3 is filled with a large number of hollow particles 4 and the tire air chamber 3 is further filled with high-pressure gas, and the internal pressure of the tire air chamber 3 is set to the use internal pressure will be described.

  In this embodiment, after the tire chamber 3 is filled with the hollow particles 4, the internal space 11 around the hollow particles 4, in other words, the internal pressure of the tire chamber 3 is a desired use internal pressure such as a specified vehicle internal pressure. Thus, it is important to fill a high-pressure gas such as air or nitrogen.

  When the tire chamber 3 is filled with the hollow particles 4 and further filled with gas, and the internal pressure of the tire chamber 3 is set to a desired internal pressure, the hollow portion pressure of the hollow particles (internal pressure in the closed cells) is initially set to the tire gas. Since it is less than the internal pressure of chamber 3, the particles are reduced in volume. The shape of the hollow particles 4 at this time is not a substantially spherical shape, but is a flattened and distorted shape from a spherical shape (a so-called collapsed rugby ball shape).

  When the vehicle starts running with the shape of the hollow particles 4 flattened and distorted, the hollow particles 4 collide with the hollow particles 4 and the inner surfaces of the tire 1 and the rim 2 as compared with the spherical shape. It becomes easy to destroy by the collision. That is, when the hollow particles 4 are flattened and distorted, the input due to the collision cannot be uniformly dispersed, resulting in a great disadvantage in terms of durability.

  On the other hand, the flattened and distorted hollow particles 4 are in a state where the volume is reduced due to the difference between the hollow portion pressure and the internal pressure of the tire chamber 3, but the tire chamber 3 (the void 11 around the particle) over a certain period of time. The internal pressure of the hollow particles 4, in other words, the internal pressure of the closed cells of the hollow particles 4 can be increased to about the internal pressure of the tire chamber 3. That is, since the flattened hollow particles 4 are deformed, a force is exerted on the shell portion to return to the original substantially spherical shape.

  Moreover, since the hollow part pressure of the flattened hollow particles 4 is lower than the internal pressure of the tire air chamber 3, in order to eliminate the internal pressure difference, the gas molecules in the tire air chamber 3 are shells of a continuous phase made of resin. And penetrates into the hollow portion of the particle. Furthermore, since the hollow part of the hollow particle 4 is a closed cell and the gas in it is filled with the gas resulting from the foaming agent, it is different from the gas in the tire chamber 3 (the void 11 around the particle). There is. In this case, the high-pressure gas in the tire chamber 3 permeates into the particle hollow portion while following the partial pressure difference of the gas as well as the above-described difference in internal pressure until the partial pressure difference is eliminated.

  Thus, since the high pressure gas in the tire chamber 3 penetrates into the hollow portion of the hollow particle 4 with time, the internal pressure of the tire chamber 3 is reduced by the amount permeated into the hollow portion. Therefore, in order to make up for the amount of the hollow particles 4 that have penetrated into the hollow portion, the tire of the present embodiment adjusted to the desired use internal pressure can be obtained by continuously applying the desired internal pressure after filling the high-pressure gas. it can.

  The internal pressure in the hollow portion of the hollow particle 4 approaches the internal pressure of the tire chamber 3 (the void 11 around the hollow particle 4), and the particle volume once reduced is restored, and the particle shape is flattened and distorted. The shape will be restored to the original spherical shape. In the process of reviving this shape, the internal pressure in the hollow part of the hollow particles 4 increases to at least 70% with respect to the internal pressure of the tire chamber 3, so that the particle shape is changed from a flattened state to a substantially spherical shape. Thus, the durability of the hollow particles 4 described above can be ensured.

  In this way, high-pressure gas is interposed around the hollow particles 4, and the load borne by the hollow particles 4 during normal travel can be reduced to a negligible level. Further, in the hollow particles 4 whose particle volume has been restored, the particle shape is restored to a substantially spherical shape, so that fatigue and breakage applied to the hollow particles 4 can be significantly reduced along with repeated deformation during tire rolling. As a result, the durability of the hollow particles 4 is not impaired. The range in which the durability of the hollow particles 4 is not impaired is that the pressure of the hollow portion 4 is restored while the volume of the hollow particles 4 is restored in a desired high-pressure environment such as the specified internal pressure of the vehicle in which the tire chamber 3 is mounted. In the process of increasing, the hollow part pressure of the hollow particles 4 is preferably 70% or more of the internal pressure of the tire chamber 3. Furthermore, it is recommended to set a high value of 80% or more, 90% or more, and 100% or more.

  Here, when the hollow part pressure of the hollow particles 4 is 70% or more of the internal pressure of the tire chamber 3, the desired tire air chamber such as the vehicle-designated internal pressure to be mounted is set as the pressure of the void gas around the hollow particles 4 at least. The internal pressure of 3 is maintained in a state where the pressure is increased to 70% or more, and an appropriate time may be allowed to elapse while the pressure is continuously applied. Alternatively, the hollow particles 4 are filled in a pressure vessel different from the tire 1, and the internal pressure of the voids 11 around the hollow particles 4 is held at least 70% higher than the internal pressure of the tire chamber 3. The tire chamber 3 is filled with the surrounding particles together with the surrounding gas after the pressure is maintained in the pressure vessel for an appropriate time while the pressure is continuously applied and the hollow portion pressure of the hollow particles 4 is increased. Also, the desired tire particle aggregate 100 can be obtained.

  The appropriate holding time described above is set in consideration of the permeability of the void gas to the shell portion of the hollow particle 4, that is, the continuous phase of the hollow particle, and the partial pressure difference between the gas in the particle hollow portion and the void gas. do it.

  Appropriately select and adjust the type and pressure of the gas filled in the tire chamber 3 (the void 11 around the hollow particles 4) in accordance with the process of changing the mechanism, shape, and volume of the hollow particles 4 described above. Thus, the hollow part pressure of the hollow particles 4 can be set in a desired range.

  As described above, the hollow particles 4 in which the hollow portion pressure of the hollow particles 4 is 70% or more of the internal pressure of the tire air chamber 3 are filled in the tire air chamber 3, so that the internal pressure of the tire air chamber 3 is atmospheric pressure. When the vehicle travels from this state, it is necessary to realize that the internal pressure of the tire chamber 3 is restored to at least the internal pressure of the tire chamber that enables traveling for a certain distance.

  Next, the function of restoring the internal pressure lost in the tire chamber 3 described above (so-called “internal pressure recovery function”) will be described.

  In the tire particle assembly 100 in which the above-described hollow particle group is filled in the tire chamber 3, when the tire 1 is damaged, the high-pressure gas in the tire chamber 3 existing in the void 11 around the hollow particles 4 is outside the tire 1. As a result, the internal pressure of the tire chamber 3 decreases to an internal pressure similar to the atmospheric pressure. In the process of lowering the internal pressure of the tire chamber 3, the following occurs in the tire chamber 3.

  First, when the tire 1 is damaged and the internal pressure of the tire chamber 3 starts to decrease, a large number of hollow particles 4 seal the damaged portion that is the damaged tire portion, and the abrupt tire chamber 3 Suppresses the decrease in internal pressure.

  Here, in the present embodiment, the hollow part pressure of the hollow particles 4 is specified to be at least 70% of the internal pressure of the vehicle-designated tire at the time of normal use, but the sealing ability of the damaged part depends on the hollow part pressure. To do. That is, although it has been described above that the substantially spherical shape can be maintained if the hollow portion pressure is 70% or more, good fluidity and elasticity can be expressed by maintaining the substantially spherical shape, so that the internal pressure of the hollow portion is low. Compared to the case, the sealing limit of the damaged part is greatly improved.

  Further, as the internal pressure of the tire chamber 3 decreases, the amount of deflection of the tire 1 increases and the tire chamber volume decreases. Further, when the internal pressure of the tire chamber 3 decreases, the tire is greatly bent, and the temperature of the tire chamber 3 starts to increase due to the heat generated by the tire 1 itself.

  On the other hand, the hollow part pressure of the hollow particles 4 existing under the use internal pressure described above (the bubble internal pressure in the closed cells) remains high after the damage, in other words, before the damage. Therefore, it exists in the tire chamber 3 while maintaining the particle volume and the hollow portion pressure. Therefore, when the tire rolls further, the temperature of the hollow particles increases as the temperature of the tire chamber 3 increases.

  When the hollow particle temperature exceeds the re-expansion start temperature (Ts2: corresponding to the glass transition temperature of the resin), the shell of the hollow particle 4 starts to soften. At this time, in addition to the pressure inside the hollow part of the hollow particle 4 being a high pressure according to the working internal pressure, the hollow part pressure is further increased due to the rise in the temperature of the hollow particle, so that the hollow particle 4 expands in volume, Since the gas in the void 11 around the hollow particle 4 is compressed, the internal pressure of the tire chamber 3 can be restored (recovered).

  That is, the hollow particles 4 expand (at least when the pressure of the high-pressure gas filled in the tire chamber 3 is reduced (so-called tire is damaged) and when the temperature inside the tire chamber 3 is increased ( Re-inflate). In the present embodiment, the re-expansion start temperature “Ts2” indicates a predetermined temperature.

  In order to restore the internal pressure of the tire chamber 3, the hollow air particles 4 whose hollow portion internal pressure is at least 70% of the used internal pressure are filled into the tire chamber under a filling rate of 5 vol% or more and 80 vol% or less. It is important to keep it. The reason is shown below.

  When the filling rate of the hollow particles 4 is smaller than 5 vol%, the damaged portion can be sealed without any problem, but since the absolute amount of the hollow particles 4 is insufficient, it is difficult to obtain a sufficient recovery internal pressure. On the other hand, when the filling rate of the hollow particles exceeds 80 vol%, some tires expand due to heat generation due to particle friction during high-speed running during normal use, resulting in expansion exceeding the re-expansion start temperature (Ts2) of the hollow particles 4. The internal pressure restoration function, which is the main function of the present embodiment, may be lost.

  Further, in order to reliably develop the internal pressure recovery function, it is important to securely seal the damaged portion before the internal pressure recovery function is expressed. That is, if the wound part is not completely sealed, the internal pressure that should have been restored will leak from the wound part, and the internal pressure obtained by the internal pressure restoration function can only temporarily contribute to the subsequent travel. In addition, the running performance after the tire is damaged may not be guaranteed.

  Since the hollow particle 4 is a particle having a low specific gravity and high elasticity due to the hollow structure, when the void gas around the hollow particle starts to leak from the damaged portion where the tire 1 has been damaged, the flow due to the leakage of the void gas Get on the wound and immediately gather in the wound area, instantly seal the wound of the wound area. Thus, the sealing function of the damaged part by the hollow particles 1 is an essential function that supports the internal pressure restoration function of the present embodiment.

  As described above, when the tire air chamber 3 partitioned by the tire 1 and the rim 2 is filled with the hollow particles 4, the tire air chamber volume is reduced and the amount of deflection of the tire 1 is increased due to a decrease in the internal pressure after puncture. Thus, the increase in the temperature of the hollow particles 4 accompanying the increase in the temperature of the tire chamber 3 restores the internal pressure due to the expansion of the hollow particles 4, thereby realizing safe traveling after being damaged.

  By the way, although the friction between the hollow particles 4 in the tire particle aggregate 100 is minute, it is generated even under normal running. However, in the region where the traveling speed is 100 km / h or less, the generated frictional heat is small, and the generated heat is radiated to the outside air, so that the friction between the hollow particles 4 can be suppressed.

  However, in a high-speed region exceeding 150 km / h, and in an extremely hot environment where the temperature circulation of the outside air is extremely high, the generated heat of friction is increased, but the heat release to the outside air is insufficient, and the hollow particles 4 are hollow. The friction between the particles 4 cannot be suppressed (that is, the friction between the hollow particles 4 is remarkably deteriorated). If such a situation continues for a long time, the temperature of the hollow particles 4 exceeds the re-expansion start temperature (Ts2), so that the hollow particles expand. As a result, the above-mentioned “internal pressure restoration function at the time of puncture is realized. There is something that can't be done (loss).

  That is, the tire 1 generates centrifugal force corresponding to the speed by rotating at high speed. The hollow particle group filled in the tire chamber 3 is also subjected to the same centrifugal force. This centrifugal force is proportional to the weight of the hollow particles 4 and proportional to the square of the speed, and inversely proportional to the radius of the tire 1. Furthermore, the tire 1 has a certain amount of bending caused by bearing a load, and the area that is in contact with the road surface is in a state parallel to the road surface. Therefore, the contact area does not have a curvature. The centrifugal force becomes almost zero.

  As a result, the hollow particles 4 in the tire particle assembly 100 that rotates while bearing a load are subjected to centrifugal force as described above in a non-grounding region that is not in contact with the road surface. On the other hand, the hollow particles 4 are placed in a “state where centrifugal force fluctuations are repeated” in which the centrifugal force is released at the moment of entering the ground contact region.

  Therefore, it is preferable to suppress the particle weight as much as possible for the hollow particle group filled in the tire chamber 3. That is, the average true specific gravity of the hollow particles 4 is preferably selected as small as possible.

  If the filling rate of the hollow particles 4 exceeds 80 vol%, depending on the tire, due to heat generation due to particle friction at high speed during normal use, the hollow particles 4 expand beyond the reexpansion start temperature (Ts2), Since the internal pressure restoration function which is the main function of this embodiment may be lost, it is not preferable. Therefore, the preferable range of the hollow particle filling rate is 5 vol% or more and 80 vol% or less, and further 70 vol% or less, 60 vol% or less, and 50 vol% or less.

  Moreover, about the average particle diameter of a hollow particle, a preferable range is the range of 40-200 micrometers. When the average particle size of the hollow particles is less than 40 μm, the above-mentioned true specific gravity distribution spreads, and the heat resistance is deteriorated due to the relative inertia force difference of the large true specific gravity particle group with respect to the small true specific gravity particle group and the frictional heat generated by the motion. Therefore, it is not preferable. On the other hand, when the average particle size of the hollow particles exceeds 200 μm, the situation where the particles collide with each other under normal running or when the internal pressure of the tire chamber 3 becomes atmospheric pressure due to puncture (scratching). In the situation where the hollow particle group directly supports the load in the so-called puncture state, the particles are selectively broken from the particles on the large particle size side, and there is a disadvantage that the desired running performance after being damaged cannot be obtained. This is not preferable because of fear.

  Furthermore, the average true specific gravity of the hollow particles 4 is preferably in the range of 0.01 to 0.06 g / cc. That is, if it is smaller than 0.01 g / cc, the durability of the hollow particles 4 under normal running is lowered, and the “internal pressure restoration function” may be lost during normal use. On the other hand, if it exceeds 0.06 g / cc, the centrifugal force fluctuation input in the regular high-speed running becomes large and the calorific value becomes large, which is not preferable.

  Incidentally, the inventors diligently studied the actual heat generation of the hollow particles 4 and achieved further improvement in heat resistance and durability of the hollow particles 4.

  Now, the hollow particles 4 are obtained by heating and expanding the “expandable resin particles” that are the raw material, and the expandable resin particles have an expansion start temperature “Ts1”. Further, when the hollow particles 4 obtained by the thermal expansion are heated again, the hollow particles 4 start to expand further, and there exists a re-expansion start temperature “Ts2” of the hollow particles.

  As a result of manufacturing the hollow particles 4 from a large number of expandable resin particles and studying them, the inventors have used the expansion start temperature “Ts1” as an index of heat resistance, but as an index of heat resistance, It has been found that the re-expansion start temperature “Ts2” is appropriate.

  First, the expansion behavior in the case of expanding (heating expansion) the expandable resin particles was observed. Since the expandable resin particles are in a stage before expansion, the particle diameter is extremely small and the thickness of the resin shell is extremely thick compared to the state of the hollow particles 4. Therefore, the microcapsule has a high rigidity. Therefore, even if the continuous phase of the resin shell exceeds the glass transition point in the process of thermal expansion, the expansion force of the internal gas wins over the rigidity of the shell until the shell is softened to some extent by further heating. I can't. Therefore, the expansion start temperature “Ts1” is higher than the actual glass transition point of the shell.

  On the other hand, when the hollow particles are expanded again (reheat expansion), the thickness of the shell of the hollow particles 4 is extremely thin, and the rigidity of the hollow body is low. Therefore, since the expansion of the continuous phase of the shell exceeds the glass transition point in the process of heating and expansion, the re-expansion start temperature “Ts2” is positioned lower than the expansion start temperature “Ts1”.

  In the present embodiment, since the expansion characteristics of the hollow particles 4 that have been expanded are utilized instead of utilizing the expansion characteristics of the expandable resin particles, in order to discuss heat resistance (durability) Instead of the conventional expansion start temperature “Ts1”, the reexpansion start temperature “Ts2” should be used as an index.

  It is important that the re-expansion start temperature “Ts2” of the hollow particles 4 is 90 ° C. to 200 ° C. This is because if the re-expansion start temperature “Ts2” of the hollow particles 4 is lower than 90 ° C., depending on the selected tire size, the hollow particles 4 may start to re-expand before reaching the guaranteed speed of the tire. Because there is.

  On the other hand, when the re-expansion start temperature “Ts2” of the hollow particles 4 exceeds 200 ° C., the re-expansion start temperature even if a sudden temperature rise due to frictional heat generation of the hollow particles 4 occurs in the run flat running after the damage. “Ts2” may not be reached, and thus the intended “internal pressure restoration function” may not be sufficiently developed.

  Therefore, the range of the re-expansion start temperature “Ts2” is 90 ° C. to 200 ° C., preferably 110 ° C. to 200 ° C., more preferably 130 ° C. to 200 ° C., and most preferably 160 ° C. to 200 ° C. is there.

  As described above, when the upper limit value and the lower limit value described above are followed, by filling the hollow particles 4 having the re-expansion start temperature “Ts2”, the function of restoring the internal pressure is surely exhibited, and the heat resistance during high-speed running is increased. By improving the durability, “internal pressure restoration function retention” during regular running is achieved.

Next, the gas inside the hollow particles is nitrogen, air, a linear or branched aliphatic hydrocarbon having 2 to 8 carbon atoms and a fluorinated product thereof, an alicyclic hydrocarbon having 2 to 8 carbon atoms, and The fluorinated product and the following general formula (III):
R ¹ —O—R ² (III)
(Wherein R ¹ and R ² are each independently a monovalent hydrocarbon group having 1 to 5 carbon atoms, and part of the hydrogen atoms of the hydrocarbon group may be replaced by fluorine atoms) It is preferable that it is at least one gas selected from the group consisting of ether compounds represented by:

  In addition, the gas filled in the tire chamber 3 may be air, but when the gas in the hollow particles 4 is not a fluorinated product, a gas containing no oxygen, such as nitrogen or an inert gas, is used for safety. There may be.

  The method for obtaining the hollow particles 4 having closed cells is not particularly limited, but a general method is to obtain “expandable resin particles” using a foaming agent and to expand them by heating. Examples of the foaming agent include a method utilizing vapor pressure such as high-pressure compressed gas and liquefied gas, and a method utilizing a thermally decomposable foaming agent that generates gas by thermal decomposition. In particular, many thermally decomposable foaming agents are characterized by generating nitrogen, and the particles obtained by appropriately controlling the reaction of the expandable resin particles obtained by foaming by these have mainly nitrogen in the bubbles. It will be a thing.

  Preferred examples of the thermally decomposable foaming agent include, but are not limited to, dinitrosopentamethylenetetramine, azodicarbonamide, paratoluenesulfonylhydrazine and derivatives thereof, and oxybisbenzenesulfonylhydrazine.

  Hereinafter, a method of obtaining “expandable resin particles” that become the hollow particles 4 by utilizing the vapor pressure of high-pressure compressed gas and liquefied gas will be described.

  When polymerizing the continuous phase of the resin that forms the hollow particles 4, a linear or branched aliphatic hydrocarbon having 2 to 8 carbon atoms and a fluorinated product thereof, an alicyclic hydrocarbon having 2 to 8 carbon atoms and its At least one selected from the group consisting of the fluorinated product and the ether compound represented by the above general formula (III) is liquefied under high pressure as a foaming agent, and emulsified while being dispersed in the reaction solvent. This is a polymerization method.

  This makes it possible to obtain the “expandable resin particles” encapsulated in the above-described resin continuous phase using the gas component shown above as a liquid foaming agent. Can be obtained.

  In addition, the surface of the “expandable resin particles” is coated with an anti-blocking agent such as silica particles, carbon black fine powder, antistatic agent, surfactant, oil agent, etc. Obtainable.

  The following methods can be cited as a device for further enhancing the effect of the present embodiment. That is, in addition to the hollow particles 4 described above, “expandable resin particles” are partly added. Thereby, the internal pressure restoration function according to the present embodiment after the tire is damaged can be realized even earlier.

  However, since it becomes a factor of reducing the durability of the coexisting hollow particles 4, application in the following range is preferable. As a range in which the contradictory properties of both can be used well, the content of the “expandable resin particles” is 40 mass% or less, further the content is 30 mass% or less, 20 mass% with respect to the total particle weight filled in the tire chamber 3. Below, it is preferable to set it as 10 mass% or less.

  Further, in order to apply the necessary minimum internal pressure by the hollow particles 4 in a state where the internal pressure of the tire chamber 3 is reduced due to the damage, the gas sealed at a predetermined pressure in the hollow portion of the hollow particles 4 is transferred to the outside of the particles. In other words, it is important that the continuous phase of the resin corresponding to the shell part of the hollow particles has a property that gas is difficult to permeate.

  That is, the resin constituting the continuous phase is made of a material having low gas permeability, specifically, at least one of an acrylonitrile copolymer, an acrylic copolymer, and a vinylidene chloride copolymer. It is important. Since these materials have flexibility as hollow particles with respect to input due to tire deformation, they are particularly effective in this embodiment.

  Moreover, it is preferable to apply any one of an acrylonitrile polymer, an acrylic polymer, and a vinylidene chloride polymer to the continuous phase of the hollow particles 4. More specifically, the polymer constituting the polymer is a polymer selected from acrylonitrile, methacrylonitrile, methyl methacrylate, methacrylic acid, and vinylidene chloride, preferably acrylonitrile / methacrylonitrile / methyl methacrylate terpolymer, acrylonitrile. At least one selected from the group consisting of / methacrylonitrile / methacrylic acid terpolymer is advantageously suitable. Since all of these materials have a small gas permeability coefficient and are difficult for gas to permeate, the gas in the hollow part of the hollow particles hardly leaks to the outside, and the pressure in the hollow part can be appropriately maintained.

Further, the continuous phase of the hollow particles 4 has a gas permeability coefficient at 30 ° C. of 300 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less, preferably a gas permeability coefficient at 30 ° C. of 20 × 10 ^−12. (Cc · cm / cm ² · s · cmHg) or less, more preferably a gas permeability coefficient at 30 ° C. of 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less is recommended.

This is because the gas permeability coefficient of the inner liner in a normal pneumatic tire is at a level of 300 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less and has a sufficient internal pressure holding function. In view of the above, the gas permeation coefficient at 30 ° C. was set to 300 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less for the continuous phase of the particles. However, at this bus permeability coefficient level, it is necessary to replenish the internal pressure once every 3 to 6 months. Therefore, from the standpoint of maintenance, 20 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less, more preferably 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less is recommended.

  Here, according to the present embodiment, when the tire air chamber 3 is filled with the hollow particles 4, the average bulk specific gravity is the average of the hollow particles in order to enhance the sealing function of the damaged portion when the tire 1 is damaged. Means for mixing a large number of foams larger than the true specific gravity in the hollow particle group is effective.

  Specifically, it has a substantially spherical shape with a diameter of 1 to 15 mm or a cubic shape with one side of 1 to 15 mm, has independent or open cells, has an average bulk specific gravity of 0.06 to 0.3 g / cc, and By adding a large number of foams having a bulk specific gravity value larger than the average true specific gravity of the particles, the period (timing) for restoring the internal pressure is accelerated, and the running ability after the tire is damaged can be increased.

  That is, since the hollow particles 4 have a substantially spherical shape, the fluidity is high, so that the inside of the tire chamber 3 can be easily filled from the inlet having a small inner diameter such as the tire valve 13. On the other hand, when the tire is damaged, the hollow particles 4 try to blow out together with the high-pressure gas in the tire chamber 3 from the damaged portion to the outside of the tire and collect on the inner surface of the damaged portion.

  However, since the wound path from the inner surface of the scratched part to the outer peripheral surface of the tire is not a straight line but presents a complicated and complicated shape, the hollow particles 4 entering from the wounded part are obstructed by the path along the path. 4 will gather in a compressed state on the inner surface of the damaged part, and the damaged part is temporarily sealed. Here, provisionally sealing refers to a state in which the gas in the void 11 around the hollow particle 4 gradually leaks, although the hollow particle 4 itself does not leak.

  At that time, depending on the shape and size of the wound at the wounded part, provisional sealing with only hollow particles may be incomplete. In such a case, the level of sealing can be improved as follows by adding a large number of the foams described above.

  That is, in the tire air chamber 3 that is rolling, a centrifugal force corresponding to the speed is generated. Under the centrifugal force, the foam having a large bulk specific gravity is directed to the inner liner 8 side of the tire 1 and has a true specific gravity. The small hollow particles 4 are unevenly distributed to the side closer to the rotation center than the foam.

  In this state, even if there is an external damage that cannot be sealed with the hollow particles 4 alone, many foams are unevenly distributed in the vicinity of the inner liner 8 disposed on the inner surface of the tire 1. When the foam is about to blow out to the outside of the tire 1 and quickly comes into close contact with the inner surface of the damaged part, the damaged part is sealed, which is extremely effective.

  In particular, if the foam is a foam made of thermoplastic urethane with open cells, it is highly compressible and easily adheres to the shape of the tire damage, and as a result, the large damage area is extremely complicated and refined by the foam. By being able to do so, it is possible to change the dissipated flow path of the complicated and miniaturized gas to a state most suitable for sealing with the hollow particles 4, which is a very effective means.

(Operation / Effect of Tire Particle Aggregation According to this Embodiment)
According to the tire particle assembly of the present invention, the hollow particles expand at least when the internal pressure of the tire chamber is reduced or when the temperature inside the tire chamber reaches a predetermined temperature (Ts2). At times, the internal pressure restoration function can be surely exhibited.

  Here, the function of restoring the internal pressure of the tire after being injured is a high-pressure gas filled in the tire chamber by the expansion of the hollow particles when the internal pressure in the tire chamber is reduced to the atmospheric pressure (a puncture state). This is a function that can restore the internal pressure of the tire chamber.

  In addition, since the hollow particles have a substantially spherical shape, it is possible to prevent the hollow particles from hitting the wall surface of the tire chamber and the like due to centrifugal force during running and damaging the hollow particles. As a result, the hollow particles can reliably exhibit the function of restoring the internal pressure after being damaged.

  In addition, a rubber layer having higher viscoelasticity than the rubber constituting the side portion is provided in at least a part of the region from the vicinity of the maximum width portion where the length in the tire width direction is the longest to the ground contact end of the tread. Further, the heat generation inside the tire can be increased during low internal pressure traveling, and the expansion speed of the hollow particles can be increased, so that the internal pressure can be reliably restored even when the damaged part is large.

  Thereby, the particles can reliably repair the tire at the time of puncture, and stable running can be obtained even after puncture.

  Examples of the tire particle aggregate according to the embodiment of the present invention will be described in detail below.

  A tire particle assembly (Examples 1 to 4) having a rubber layer of the present invention is manufactured, mounted on the right rear wheel of a vehicle, and 80 km / h at two low internal pressures of 50 kPa and 0 kPa at the start of traveling. The time until the hollow particles expanded and the tire internal pressure recovered to 160 kPa was measured. The tire internal pressure was measured with an internal pressure monitoring device. For comparison, tire particle aggregates (Comparative Example 1 and Comparative Example 2) having no rubber layer of the present invention were manufactured and investigated under the same conditions.

  The size of the tire was 205 / 55R16, and the filling amount of the hollow particles into the tire was 50 vol%.

  The measured time is in units of 15 seconds.

(Example 1)
The tire particle aggregate of Example 1 has a maximum width portion having the longest tire width direction length in the side portion and a width of 10 mm on the outer side in the tire width direction of the carcass layer, a thickness of 1 mm, and a tan δ of It has a rubber layer that is 0.2.

(Example 2)
The tire particle aggregate of Example 2 has a width of 10 mm at an intermediate position in the region from the vicinity of the maximum width portion where the length in the tire width direction in the side portion is the longest to the contact end of the tread, and outside the carcass layer. It has a rubber layer with a thickness of 1 mm and a tan δ of 0.2.

Example 3
The tire particle aggregate of Example 3 has a maximum width portion having the longest tire width direction length in the side portion and a width of 10 mm on the inner side in the tire width direction of the carcass layer, a thickness of 1 mm, and a tan δ of It has a rubber layer that is 0.2.

Example 4
The tire particle aggregate of Example 4 has a maximum width portion having the longest tire width direction length in the side portion and a width of 20 mm on the outside of the carcass layer, a thickness of 2 mm, and a tan δ of 0.2. Having a rubber layer.

(Comparative Example 1)
The tire particle aggregate of Comparative Example 1 has a normal side rubber having a tan δ of 0.10 at the side portion.

(Comparative Example 2)
The tire particle aggregate of Comparative Example 2 has a width of 10 mm at the middle position in the region from the vicinity of the maximum width portion where the tire width direction length is the longest in the side portion to the rim guard, and outside the carcass layer, and the thickness is It has a rubber layer of 1 mm and tan δ of 0.15 (at 30 ° C.).

The examination results are shown in Table 1.

  From the results in Table 1, it was found that Examples 1 to 4 were able to restore the internal pressure at an early stage without causing a failure as compared with Comparative Examples 1 and 2.

  Thereby, by arranging a rubber layer having higher viscoelasticity than the rubber constituting the side portion in at least a part of the region from the vicinity of the maximum width portion where the tire width direction length is the longest to the ground contact end of the tread. It can increase the heat generation inside the tire during low internal pressure running, increase the expansion speed of the hollow particles, reliably restore the internal pressure even when the damaged part is large, and provide stable running even after puncture I understood.

It is a tire width direction sectional view showing a tire particle aggregate concerning an embodiment of the present invention. It is a figure which shows an example of the valve | bulb for tire provided with the filter used together with the hollow particle with which the tire particle aggregate which concerns on embodiment of this invention is filled, and gas filling. It is a tire width direction sectional view showing a tire particle aggregate provided with a tire pressure sensor concerning an embodiment of the present invention. It is a block diagram which shows the apparatus and alarm which alert | report the fall of the pressure of the tire chamber which concerns on embodiment of this invention. It is a tire width direction sectional view showing a tire particle aggregate concerning an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tire 2 ... Rim 3 ... Tire air chamber 4 ... Hollow particle 5 ... Bead part 5a ... Bead core 5b ... Bead filler 6 ... Carcass layer 7 ... Side part 8 ... Inner liner 9 ... Belt layer 10 ... Tread part 11 ... Hollow particle Air gap 12 around ... Valve 13 ... Filter 14 ... Tire pressure sensor 15 ... Vehicle speed sensor 16, 160 ... Rubber layer 50 ... Vehicle 50a ... Receiver 50b ... Alarm unit

Claims (16)

A tire particle assembly that is an assembly of a tire having at least a side part, and a plurality of hollow particles filled with a high-pressure gas exceeding atmospheric pressure into a tire air chamber partitioned by the tire and the rim,
A rubber layer having a higher viscoelasticity than rubber constituting the side portion is provided in at least a part of the region from the vicinity of the maximum width portion where the tire width direction length of the tire is the longest to the contact end of the tread,
The hollow particles have a substantially spherical shape composed of a continuous phase made of resin and closed cells, and at least when the internal pressure of the tire chamber is lowered, or the temperature inside the tire chamber is set to a predetermined temperature (Ts2). A tire particle aggregate that expands when reached.   The tire particle assembly according to claim 1, wherein Tan δ of viscoelasticity of the rubber layer is 0.2 or more.   The tire particle assembly according to claim 1, wherein the rubber layer is provided on the outer side in the tire width direction of the carcass layer.   The tire particle assembly according to any one of claims 1 to 3, wherein the rubber layer is provided inside the carcass layer in the tire width direction.   The tire particle assembly according to any one of claims 1 to 4, wherein the rubber layer has a width of 10 mm or more and a thickness of 1 mm or more. The following general formula (I)
Filling ratio of hollow particles = (particle volume value / tire chamber volume value) × 100 (I)
The filling rate of the hollow particles calculated by the following is 5 vol% or more and 80 vol% or less,
The particle volume value is a total amount (cm ³ ) of the total volume under atmospheric pressure of all the hollow particles filled in the tire chamber and the void volume around the particles,
The volume value of the tire chamber is the amount of filled air discharged (cm ³ ) when the tire chamber is filled with only air and adjusted to the working internal pressure (kPa) and then the filled air is discharged until the internal pressure reaches atmospheric pressure. Using the following general formula (II)
Tire chamber volume value = (filled air discharge amount) / (internal pressure / atmospheric pressure) (II)
The tire particle aggregate according to any one of claims 1 to 5, wherein the tire particle aggregate is a value (cm ³ ) obtained from the formula (1).   The tire particle assembly according to any one of claims 1 to 6, wherein a hollow portion pressure, which is an internal pressure of the hollow particles, is 70% or more of an internal pressure of the tire chamber.   The tire particle assembly according to any one of claims 1 to 7, wherein the predetermined temperature (Ts2) is 90 to 200 ° C. The average particle diameter of the hollow particle group that is the plurality of hollow particles filled in the tire chamber is 40 to 200 μm,
The average true specific gravity of the hollow particle group filled in the tire air chamber is 0.01 to 0.06 (g / cm ³ ). The tire particle aggregate described in 1. The gas inside the hollow particles includes nitrogen, air, a linear or branched aliphatic hydrocarbon having 2 to 8 carbon atoms and a fluorinated product thereof, an alicyclic hydrocarbon having 2 to 8 carbon atoms and a fluoro thereof. And the following general formula (III):
R ¹ —O—R ² (III)
(Wherein R ¹ and R ² are each independently a monovalent hydrocarbon group having 1 to 5 carbon atoms, and part of the hydrogen atoms of the hydrocarbon group may be replaced by fluorine atoms) The tire particle aggregate according to any one of claims 1 to 9, wherein the tire particle aggregate is at least one gas selected from the group consisting of ether compounds represented by:   The continuous phase of the hollow particles is composed of at least one of a polyvinyl alcohol resin, an acrylonitrile-based polymer, an acrylic polymer, and a vinylidene chloride-based polymer. The tire particle aggregate according to 1.   The continuous phase of the hollow particles is composed of an acrylonitrile-based polymer, and the acrylonitrile-based polymer is an acrylonitrile polymer, an acrylonitrile / methacrylonitrile copolymer, an acrylonitrile / methyl methacrylate copolymer, or an acrylonitrile / methacrylonitrile / methyl methacrylate 3. The tire particle aggregate according to any one of claims 1 to 11, wherein the tire particle aggregate is at least one of an original copolymer and an acrylonitrile / methacrylonitrile / methacrylic acid ternary copolymer.   13. A first tire pressure lowering alarm function for alarming a decrease in internal pressure in the tire chamber based on a direct measurement method of the pressure in the tire chamber by a tire pressure sensor. The tire particle aggregate according to any one of the above.   14. The vehicle according to claim 1, further comprising a second tire pressure decrease warning function that warns of a decrease in internal pressure in the tire chamber based on a wheel speed detected by a wheel speed sensor. The tire particle aggregate as described.   An average bulk specific gravity under atmospheric pressure in the tire chamber is larger than an average true specific gravity of the hollow particles, and includes a large number of foams mixed with the hollow particles and filled in the tire chamber. The tire particle aggregate according to any one of claims 1 to 14. The foam has a substantially spherical shape with a diameter of 1 to 15 mm or a cubic shape with one side of 1 to 15 mm, an average bulk specific gravity of 0.06 to 0.3 (g / cc), and has closed cells or communication. The tire particle aggregate according to claim 15, which has bubbles.

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