JP2017128252A - Pneumatic tire, tire deterioration-determining method and method for determining tire reclamation possibility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire, a tire deterioration judging method and a tire rehabilitation judging method capable of easily judging the degree of tire degradation. A pneumatic tire according to the present invention includes a tire deterioration determining tool 10 made of a molded body 11 of a rubber composition, and the tire deterioration determining tool 10 is attached to a tire inner surface S in a state where an initial strain is applied. The The rupture state of the tire deterioration determination tool 10 is confirmed at an arbitrary time after the start of tire use, and the degree of deterioration of the pneumatic tire is determined based on the rupture state. In addition, the tire degradation determination tool 10 is checked for a ruptured state at the time of tire retreading, and whether or not a pneumatic tire can be retreaded is determined based on the ruptured state. [Selection] Figure 1

Description

  The present invention relates to a pneumatic tire provided with a tire deterioration determination tool and related technology, and more specifically, a pneumatic tire, a tire deterioration determination method, and tire regeneration possibility that can easily determine the degree of deterioration of the tire. It relates to a determination method.

  In recent years, from the viewpoint of effective utilization of resources and energy saving, retread tires obtained by regenerating a pneumatic tire after the tread portion of the pneumatic tire is worn and becomes unusable have become widespread. In particular, retreaded tires are widely used for heavy duty pneumatic tires used in trucks and buses.

  When a used pneumatic tire is rehabilitated, a base tire in which the tread rubber is ground is produced, and the base tire is covered with a new tread rubber. When performing such rehabilitation work, in order to confirm the remaining durability of the base tire, the presence of internal separation is confirmed by shearography inspection, and the presence or absence of trauma is confirmed by appearance inspection. ing. However, such an inspection requires a lot of time and is complicated.

  In addition, a tire deterioration determining tool in which a core rubber made of a sulfur-crosslinkable diene rubber composition is covered with a cover rubber having an oxygen permeability coefficient equal to or higher than that of the inner liner layer of the tire is installed on the inner surface of the tire, It has been proposed to determine the degree of deterioration of a pneumatic tire based on the result of the bending test of the tire deterioration determination tool (see, for example, Patent Document 1). However, in this case as well, it is necessary to remove the tire deterioration determination tool from the tire inner surface and perform a bending test on the tire deterioration determination tool, so that the degree of deterioration of the pneumatic tire cannot be immediately determined.

JP 2006-327469 A

  An object of the present invention is to provide a pneumatic tire, a tire deterioration determination method, and a tire rehabilitation determination method that can easily determine the degree of deterioration of a tire.

  In order to achieve the above object, a pneumatic tire according to the present invention includes a tire deterioration determination tool made of a molded rubber composition, and the tire deterioration determination tool is attached to the tire inner surface in a state where an initial strain is applied. It is characterized by being.

  Further, the tire deterioration determination method of the present invention for achieving the above object is a method for determining the degree of deterioration of the pneumatic tire described above, wherein the tire deterioration determination tool is broken at an arbitrary time after the start of tire use. The state is confirmed, and the degree of deterioration of the pneumatic tire is determined based on the fractured state.

  Furthermore, the tire rehabilitation determination method of the present invention for achieving the above object is a method for determining the renewal possibility of the pneumatic tire described above, and confirming the rupture state of the tire deterioration determination tool at the time of tire rehabilitation, Whether or not the pneumatic tire is rehabilitated is determined based on the fractured state.

  In the present invention, the pneumatic tire is provided with a tire deterioration determination tool made of a molded rubber composition, and the tire deterioration determination tool is attached to the tire inner surface with an initial strain applied. If the elongation at break of the tire deterioration determining tool decreases and falls below a preset initial strain, the tire deterioration determining tool will break. Therefore, it is possible to easily determine the degree of deterioration of the pneumatic tire based on the fracture state of the tire deterioration determining tool.

  In the pneumatic tire of the present invention, the tire deterioration determination tool is preferably a sheet-like molded body, and the tire deterioration determination tool is preferably attached to the tire inner surface via an adhesive layer in a state where an initial strain is applied. . Thereby, the tire deterioration determination tool can be held on the tire inner surface in a state where a desired initial strain is applied to the tire deterioration determination tool.

  Alternatively, the tire deterioration determination tool is made of a ring-shaped molded body, and a protrusion is formed on the inner surface of the tire. The tire deterioration determination tool is fitted around the protrusion and attached to the tire inner surface in an initial strain state. It is preferable. Thereby, the tire deterioration determination tool can be held on the tire inner surface in a state where a desired initial strain is applied to the tire deterioration determination tool.

  In the pneumatic tire of the present invention, it is preferable that the tire deterioration determination tool is mounted on the inner surface of the tire in a region of 75% of the center side of the tread width or a region of 25% or less of the tire cross-section height. In these regions, since the tire inner surface is difficult to deform during running of the tire, the strain applied to the tire deterioration determination tool can be reduced, and the degree of deterioration due to oxygen can be accurately determined.

  In the pneumatic tire of the present invention, the molded body constituting the tire deterioration determination tool has a colored portion colored in a color different from the inner surface of the tire, and the colored portion extends along the direction in which the initial strain is applied. Is preferred. When confirming the rupture state of the tire deterioration determination tool, it is difficult to determine the rupture state if the color of the tire deterioration determination tool and the color of the tire inner surface are the same. It can be easily judged.

  In the pneumatic tire of the present invention, it is preferable that a plurality of tire deterioration determination tools are mounted on the tire inner surface, and the initial strain values given to these tire deterioration determination tools are different from each other. As described above, by installing a plurality of tire deterioration determining tools having different initial strain values, it is possible to accurately determine the degree of deterioration of the pneumatic tire.

  Furthermore, according to the tire deterioration determination method of the present invention, the deterioration of the pneumatic tire is determined based on the rupture state of the tire deterioration determination tool by checking the rupture state of the tire deterioration determination tool at an arbitrary time after the start of tire use. The degree can be easily determined.

  Furthermore, according to the tire rehabilitation determination method of the present invention, it is possible to easily determine whether a pneumatic tire is rehabilitated based on the rupture state of the tire deterioration determination tool by checking the rupture state of the tire deterioration determination tool at the time of tire regeneration. can do.

1 is a meridian cross-sectional view showing a heavy duty pneumatic tire according to an embodiment of the present invention. It is a perspective view which shows the tire deterioration determination tool with which the pneumatic tire which consists of embodiment of this invention was mounted | worn. It is explanatory drawing which shows the mounting method of the tire degradation determination tool of FIG. It is a graph which shows the time-dependent change of the breaking elongation of the tire degradation determination tool in this invention. The other modification of the tire degradation determination tool which concerns on this invention is shown, (a) is a top view which shows the state before a fracture | rupture, (b) is a top view which shows the state after a fracture | rupture. It is a perspective view which shows the other modification of the tire deterioration determination tool which concerns on this invention. It is explanatory drawing which shows the mounting method of the tire degradation determination tool of FIG. It is a perspective view which shows the other modification of the tire deterioration determination tool which concerns on this invention. It is a perspective view which shows the other modification of the tire deterioration determination tool which concerns on this invention.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a heavy-duty pneumatic tire according to an embodiment of the present invention, and FIGS. 2 and 3 show a tire deterioration determining tool according to the present invention.

  As shown in FIG. 1, the pneumatic tire of the present embodiment includes a tread portion 1 that extends in the tire circumferential direction and has an annular shape, and a pair of sidewall portions 2, 2 disposed on both sides of the tread portion 1. And a pair of bead portions 3 and 3 disposed inside the sidewall portion 2 in the tire radial direction.

  A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded from the inside of the tire to the outside around the bead core 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross-section is disposed on the outer periphery of the bead core 5.

  On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in a range of, for example, 10 ° to 60 °. A steel cord is preferably used as the reinforcing cord of the belt layer 7.

  In the pneumatic tire, a tire deterioration determination tool 10 is attached to the tire inner surface S facing the tire chamber. As shown in FIG. 2, the tire deterioration determination tool 10 is a sheet-like rubber composition molded body 11 that is a rectangular parallelepiped. As the rubber composition constituting the molded body 11, for example, a sulfur-crosslinkable diene rubber composition can be used. Diene rubbers include natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), hydrogenated NBR, hydrogenated SBR, etc. Can be mentioned. However, the rubber used for the molded body 11 of the tire deterioration determining tool 10 is not limited to the diene rubber, and the rubber may be a filler such as sulfur, a vulcanization accelerator, an anti-aging agent, or carbon black. Additives such as softeners such as oil, metal salts such as resins, waxes and cobalt salts, stearic acid and zinc white can be appropriately blended. In particular, when determining the oxidative deterioration of a tire, a natural rubber-based rubber composition that easily causes oxidative deterioration is preferable, and those containing sulfur and metal salts are preferable.

  As shown in FIG. 2, the tire degradation determination tool 10 is detachably attached to the tire inner surface S through a sheet-like adhesive layer 12 in a state where initial strain is applied. More specifically, as shown in FIG. 3, the molded body 11 of the tire deterioration determination tool 10 has a dimension before pasting smaller than the dimension after pasting, and the molded body 11 is uniaxially or biaxially. It is affixed on the tire inner surface S via the adhesive layer 12 while being pulled in the axial direction. Thereby, the tire deterioration determination tool 10 can be held on the tire inner surface S in a state where a desired initial strain is applied to the tire deterioration determination tool 10. As the adhesive layer 12, a double-sided tape, an adhesive, or the like can be used. In addition, when the adhesion layer 12 itself has elasticity, the initial distortion may be given to the tire deterioration determination tool 10 in a state where the molded body 11 and the adhesion layer 12 are integrated. As the initial strain, it is preferable to give a tensile strain of 5% or more, preferably 10% to 400%. Further, the form of strain may be torsional strain in addition to tensile strain in a uniaxial direction or biaxial direction.

  The pneumatic tire described above includes a tire deterioration determining tool 10 made of a molded article 11 of a rubber composition, and the tire deterioration determining tool 10 is attached to the tire inner surface S in a state where an initial strain is applied. If the elongation at break of the tire deterioration determining tool 10 decreases with deterioration and falls below the preset initial strain, the tire deterioration determining tool 10 will break. That is, as shown in FIG. 4, the tire deterioration determination tool 10 break elongation gradually decreases as the service period becomes longer, but if the break elongation falls below a preset initial strain A, the tire deterioration determination tool 10 10 breaks. Therefore, it is possible to easily determine the degree of deterioration of the pneumatic tire based on the fracture state of the tire deterioration determining tool 10.

  In the pneumatic tire, the tire deterioration determination tool 10 is mounted on the tire inner surface S within a range of an area X1 corresponding to 75% of the center side of the tread width TW or an area X2 of 25% or less of the tire cross-section height SH. It is good to be. In these regions X1 and X2, since the tire inner surface S is not easily deformed when the tire is running, the strain applied to the tire deterioration determining tool 10 can be reduced, and the degree of deterioration due to oxygen can be accurately determined. When the arrangement position of the tire deterioration determination tool 10 deviates from the regions X1 and X2, the physical property change occurs in the tire deterioration determination tool 10 due to repeated distortion applied to the tire deterioration determination tool 10 during traveling, and the degree of deterioration It becomes difficult to accurately determine

  5 (a) and 5 (b) show another modification of the tire deterioration determining tool according to the present invention. As shown in FIG. 5 (a), the molded body 11 constituting the tire deterioration determining tool 10 has a colored portion 13 colored in a color different from the tire inner surface S, and the colored portion 11a has an initial strain. It extends along the direction of application. As the color of the coloring portion 13, for example, a color other than black, such as yellow, white, or light blue, can be selected. Further, the colored portion 13 may be a colored rubber layer or a coating film formed by painting. When such a colored portion 13 is provided, as shown in FIG.5 (b), when the fracture occurs along the direction intersecting the initial strain applying direction with the deterioration of the tire deterioration determining tool 10, The broken state can be easily determined based on the colored portion 13. In confirming the fracture state of the tire deterioration determination tool 10, it is difficult to determine the break state if the color of the tire deterioration determination tool 10 and the color of the tire inner surface S are the same, but a colored portion 13 is provided in the molded body 11. Thus, the fracture state can be easily determined.

  6 and 7 show still another modification of the tire deterioration determining tool according to the present invention. In FIG. 6, the tire deterioration determining tool 10 is composed of a ring-shaped molded body 11, and a protrusion 14 is formed on the tire inner surface S. The shape of the protrusion 14 is preferably a conical shape or a cylindrical shape. The tire deterioration determining tool 10 is attached to the tire inner surface S in a state in which the tire deterioration determining tool 10 is fitted around the protrusion 14 and given an initial strain. More specifically, as shown in FIG. 7, the molded body 11 of the tire deterioration determination tool 10 has a dimension before pasting smaller than a dimension after pasting, and the molded body 11 is pulled. And is fitted around the protrusion 14. An annular groove 15 is formed on the outer peripheral surface of the protrusion 14, and the molded body 11 is fitted into the groove 15. Thereby, the tire deterioration determination tool 10 can be held on the tire inner surface S in a state where a desired initial strain is applied to the tire deterioration determination tool 10. Further, the initial strain of the tire deterioration determining tool 10 is defined based on the ratio between the inner peripheral length of the groove 15 and the inner peripheral length of the molded body 11.

  In the above-described example, when the elongation at break of the tire deterioration determination tool 10 decreases with the oxidative deterioration and falls below a preset initial strain, the tire deterioration determination tool 10 breaks and falls off the protrusion 14. Become. Therefore, it is possible to easily determine the degree of deterioration of the pneumatic tire based on the fracture state of the tire deterioration determining tool 10.

  8 and 9 show still another modified example of the tire deterioration determining tool according to the present invention. In FIG. 8, a plurality of tire deterioration determining tools 10 (10A, 10B, 10C) made of sheet-shaped molded bodies 11 (11A, 11B, 11C) are mounted on the tire inner surface S, and these tire deterioration determinations are performed. The initial strain values given to the tools 10A, 10B, and 10C are different from each other. On the other hand, in FIG. 9, a common protrusion 14 is provided on the tire inner surface S, and a plurality of tire deterioration determination tools 10 made of a ring-shaped molded body 11 (11X, 11Y, 11Z) with respect to the protrusion 14. (10X, 10Y, 10Z) are mounted, and the initial strain values given to the tire deterioration determining tools 10X, 10Y, 10Z are different from each other.

  When a plurality of tire deterioration determining tools 10 having different initial strain values are installed as described above, the tire deterioration determining tool 10 is sequentially broken in accordance with the degree of deterioration, so that the pneumatic tire It is possible to accurately determine the degree of deterioration. For example, in arranging the three types of tire deterioration determining tools 10 as described above, the first largest initial strain is S1 (%), the second largest initial strain is S2 (%), and the third largest When the initial strain is S3 (%), it is preferable to satisfy the relationship of S1 / S2 ≧ 1.2 and S2 / S3 ≧ 1.2. It is also effective to color the tire deterioration determining tools 10 having different initial strain values with different colors in order to easily distinguish the tire deterioration determining tools 10 having different initial strain values.

  Hereinafter, the tire deterioration determination method using the tire deterioration determination tool 10 described above will be described in detail. First, in a pneumatic tire, the tire deterioration determination tool 10 is mounted on the tire inner surface S in a state where an initial strain is applied. The tire deterioration determining tool 10 may be mounted immediately after manufacturing the pneumatic tire, or may be mounted at the start of use of the pneumatic tire. Next, the rupture state of the tire deterioration determination tool 10 is confirmed at an arbitrary time after the start of tire use. The arbitrary time after the start of tire use is, for example, the time when an arbitrary mileage is reached in the tire use process, the time when rehabilitation work is performed, or the time when the tire is discarded. And the deterioration degree of a pneumatic tire is determined based on the fracture state of the tire deterioration determination tool 10. When the tire deterioration determining tool 10 is broken, it is determined that the deterioration of the pneumatic tire is sufficiently advanced.

  The deterioration progress rate of the tire deterioration determination tool 10 can be arbitrarily set based on the blending of the rubber composition constituting the molded body 11. Therefore, it is possible to adjust the degree of deterioration to be determined by adjusting the blending of the rubber composition constituting the molded body 11. Further, it is possible to adjust the degree of deterioration to be determined by adjusting the initial strain of the tire deterioration determining tool 10. Thereby, the deterioration degree of a pneumatic tire can be easily determined based on the fracture state of the tire deterioration determining tool 10.

  Hereinafter, a tire rehabilitation determination method using the above-described tire deterioration determination tool 10 will be described in detail. When rehabilitating a pneumatic tire, it is necessary to determine whether or not the pneumatic tire can be reused as a base tire. Such a determination can be made by the tire deterioration determination tool 10.

  Here, the tire deterioration determination tool 10 adjusted to correspond to the remaining durability of the internal parts of the pneumatic tire is prepared. In other words, the remaining durability of the internal parts of the pneumatic tire gradually decreases as it deteriorates, reaching the minimum remaining durability that is judged to be reusable as a base tire, and furthermore, cannot be reused as a base tire Remaining durability is reached. On the other hand, the deterioration characteristics and initial strain of the tire deterioration determination tool 10 are appropriate so that the pneumatic tires used will break before reaching the minimum remaining durability that is determined to be reusable as a base tire. Turn into.

  When determining whether tire regeneration is possible, the tire deterioration determination tool 10 mounted on the tire inner surface S is visually confirmed during tire regeneration. Then, it is determined whether the pneumatic tire can be rehabilitated based on the fracture state of the tire deterioration determining tool 10. When the tire deterioration determination tool 10 is broken, it is determined that the tire deterioration determination tool 10 is inappropriate as a base tire. On the other hand, when the tire deterioration determination tool 10 is not broken, it is determined that the tire deterioration determination tool 10 is suitable as a base tire. Thereby, it is possible to easily determine whether or not the pneumatic tire can be rehabilitated based on the fracture state of the tire deterioration determining tool 10.

  In the pneumatic tire of tire size 11R22.5, tires of Examples 1 to 5 including tire deterioration determining tools having different structures as described below were produced. The tire deterioration determination tool was attached to the tire inner surface at the tire equator position.

  As shown in FIG. 1, the tire of Example 1 includes a tire deterioration determination tool made of a sheet-like molded body, and the tire deterioration determination tool is applied to the tire inner surface through an adhesive layer in a state where an initial strain is applied. Attached.

  As shown in FIG. 5, the tire of Example 2 includes a tire deterioration determination tool made of a sheet-like molded body, and the tire deterioration determination tool is applied to the tire inner surface through an adhesive layer in a state where an initial strain is applied. A colored portion colored by a color different from the inner surface of the tire is provided on the molded body.

  As shown in FIG. 6, the tire of Example 3 includes a protrusion formed on the inner surface of the tire and a tire deterioration determination tool made of a ring-shaped molded body, and the tire deterioration determination tool is fitted around the protrusion. In addition, the tire is mounted on the inner surface of the tire with initial strain applied.

  As shown in FIG. 8, the tire of Example 4 includes a plurality of tire deterioration determination tools made of a sheet-like molded body, and these tire deterioration determination tools are provided with an initial strain through an adhesive layer. The initial strain values attached to the tire inner surface and given to the tire deterioration determination tool are different from each other.

  As shown in FIG. 9, the tire of Example 5 includes protrusions formed on the inner surface of the tire and a plurality of tire deterioration determination tools made of a ring-shaped molded body. The tire is fitted to the periphery and attached to the inner surface of the tire in a state where an initial strain is applied, and the values of the initial strain applied to the tire deterioration determination tool are different from each other.

  The tires of Examples 1 to 5 were actually used, and the rupture state of the tire deterioration determination tool was examined over time. As a result, as the usage time increased, the tire deterioration determination tool broke in a timely manner. As is clear from this, according to the tire deterioration determination tools of Examples 1 to 5, it is possible to easily determine the degree of deterioration of the pneumatic tire, and whether or not the pneumatic tire can be rehabilitated. Can be easily determined.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 10 Tire deterioration determination tool 11 Molded body 12 Adhesive layer 13 Colored part 14 Protrusion 15 Groove

Claims (8)

  A pneumatic tire comprising a tire deterioration determination tool made of a molded product of a rubber composition, and the tire deterioration determination tool is attached to the tire inner surface in a state where an initial strain is applied.   The tire deterioration determining tool is formed of a sheet-like molded body, and the tire deterioration determining tool is attached to the tire inner surface through an adhesive layer in a state where an initial strain is applied. Pneumatic tires.   The tire deterioration determining tool is formed of a ring-shaped molded body, and a protrusion is formed on the tire inner surface, and the tire deterioration determining tool is fitted around the protrusion to be applied to the tire inner surface in an initial strain state. The pneumatic tire according to claim 1, wherein the pneumatic tire is mounted.   The tire deterioration determining tool is mounted on the inner surface of the tire in a region of 75% on the center side of the tread width or a region of 25% or less of the tire cross-section height. Pneumatic tire.   The molded body constituting the tire deterioration determining tool has a colored portion colored in a color different from the inner surface of the tire, and the colored portion extends along a direction in which the initial strain is applied. The pneumatic tire according to any one of 1 to 4.   6. The air according to claim 1, wherein a plurality of tire deterioration determination tools are mounted on the tire inner surface, and the initial strain values given to the tire deterioration determination tools are different from each other. Tires.   A method for determining the degree of deterioration of a pneumatic tire according to any one of claims 1 to 6, wherein the rupture state of the tire deterioration determination tool is confirmed at an arbitrary time after the start of tire use, and the rupture state is obtained. A tire deterioration determination method, comprising: determining a degree of deterioration of the pneumatic tire based on the method.   A method for determining whether or not a pneumatic tire can be rehabilitated according to any one of claims 1 to 6, wherein when the tire is rehabilitated, a rupture state of the tire deterioration determination tool is confirmed, and the pneumatic tire is based on the rupture state. A method for determining whether or not a tire can be rehabilitated is determined.

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