JP6686464B2 - Tire deterioration determination device and pneumatic tire including the same - Google Patents

Description

  The present invention relates to a tire deterioration determination device, which is equipped with a tire deterioration determination tool including a determination rubber layer that is subjected to a deterioration level determination test, on an inner surface of a tire with an adhesive layer, and a pneumatic tire including the tire deterioration determination device. The tire deterioration determination device which has a good workability when peeling the tire deterioration determination tool from the tire inner surface, and which can improve the determination accuracy by suppressing the strain applied to the determination rubber layer to a minimum, and A pneumatic tire provided with the same.

  In recent years, from the viewpoint of effective utilization of resources and energy saving, a retreaded tire obtained by recycling the pneumatic tire after the tread portion of the pneumatic tire has been worn out and is unusable has become widespread. In particular, retreaded tires are widely used as heavy-duty pneumatic tires used for trucks and buses.

  When a used pneumatic tire is rehabilitated, a base tire in which a tread rubber is ground is produced, and the base tire is coated with a new tread rubber. When performing such rehabilitation work, in order to confirm the remaining durability of the base tire, it is performed to confirm the presence or absence of internal separation by shearography inspection and the presence or absence of external damage by appearance inspection. ing. However, such an inspection cannot sufficiently evaluate the degree of deterioration of the rubber composition constituting the pneumatic tire.

  On the other hand, a tire deterioration determination 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 provided on the tire inner surface. It has been proposed to install and determine the degree of deterioration of a pneumatic tire based on the result of a bending test of the tire deterioration determining tool (for example, see Patent Document 1). However, when such a tire deterioration determination tool is firmly fixed to the tire inner surface by an adhesive layer, it is difficult to peel off the tire deterioration determination tool from the tire inner surface, and the tire deterioration determination tool during peeling work. If a large amount of strain occurs in the tire, there is a problem that the determination accuracy in determining the degree of deterioration of the pneumatic tire using the tire deterioration determining tool deteriorates.

JP, 2006-327469, A

  An object of the present invention is to configure a tire deterioration determining device including a tire deterioration determining tool including a determination rubber layer provided for a deterioration degree determining test on an inner surface of a tire with an adhesive layer. A tire deterioration determination device and a pneumatic tire equipped with the same, which have good workability when peeled from the inner surface of the tire, and are capable of improving the determination accuracy by minimizing the strain applied to the determination rubber layer. To provide.

  The tire deterioration determination device of the present invention for achieving the above object, a tire deterioration determination tool including a determination rubber layer made of a rubber composition and a reinforcing layer attached to the determination rubber layer, and the tire deterioration determination tool. The elastic modulus of the reinforcing layer is higher than that of the judgment rubber layer.

  Further, the pneumatic tire of the present invention for achieving the above object, a tire deterioration judging tool comprising a judgment rubber layer made of a rubber composition and a reinforcing layer attached to the judgment rubber layer, and the tire deterioration judging tool. A pneumatic tire comprising a tire deterioration determination device configured with a pressure-sensitive adhesive layer laminated to the elastic layer, wherein the elastic modulus of the reinforcing layer is set higher than the elastic modulus of the determination rubber layer, wherein the tire deterioration The determination tool is mounted on the inner surface of the tire via the adhesive layer.

  In the present invention, a tire deterioration determination is made from a tire deterioration determination tool including a determination rubber layer made of a rubber composition and a reinforcing layer attached to the determination rubber layer, and an adhesive layer laminated on the tire deterioration determination tool. In the pneumatic tire in which the device is configured and the elastic modulus of the reinforcing layer is higher than the elastic modulus of the determination rubber layer, the tire deterioration determining tool is a pneumatic tire mounted on the inner surface of the tire via the adhesive layer. When the rubber is peeled off from the inner surface of the tire, the reinforcing layer restricts the extension of the judgment rubber layer, so that the tire deterioration judging tool can be easily peeled off from the inner surface of the tire. Further, by peeling the judgment rubber layer without stretching it, the strain applied to the judgment rubber layer can be suppressed to a minimum, and the judgment accuracy when judging the degree of deterioration of the pneumatic tire using the judgment rubber layer Can be improved.

  In the present invention, it is preferable that a non-adhesive region that does not come into direct contact with the adhesive layer is present on the end portion of the tire deterioration determining tool and the surface on which the adhesive layer of the tire deterioration determining tool is laminated. Thus, by providing a non-adhesive region that does not directly contact the adhesive layer on the surface of the tire deterioration determining tool on which the adhesive layer of the tire deterioration determining tool is laminated, adhesiveness based on the adhesive layer can be obtained. The tire deterioration determination tool can be easily peeled off from the inner surface of the tire while being sufficiently maintained.

  When the tire deterioration determining tool has a first direction along the surface direction of the adhesive layer and a second direction along the surface direction of the adhesive layer, which is orthogonal to the first direction, the elastic modulus of the reinforcing layer in the first direction is It is preferable that the elastic modulus of the reinforcing layer in the second direction is set to be higher, and the elastic modulus of the reinforcing layer in the first direction is set to be higher than that of the determination rubber layer. In this case, in the pneumatic tire, the tire deterioration determining tool is preferably mounted on the inner surface of the tire with the first direction oriented in the tire width direction. Pneumatic tires are distorted mainly in the tire circumferential direction during inflation and running, so by making the elastic modulus of the reinforcing layer in the second direction (that is, the tire circumferential direction) relatively low, It is possible to reduce the difference in rigidity between the reinforcing layer and the reinforcing layer, and to prevent the tire deterioration determination tool from falling off the tire inner surface. Further, when peeling the tire deterioration determining tool from the tire inner surface, the peeling operation can be easily performed by peeling the tire deterioration determining tool along the first direction (that is, the tire width direction).

  In establishing the relationship between the elastic modulus in the first direction and the elastic modulus in the second direction of the reinforcing layer, the length of the tire deterioration determining tool in the first direction is set to be larger than the length of the tire deterioration determining tool in the second direction. Preferably. When peeling the tire deterioration determining tool along the first direction (that is, the tire width direction), by relatively reducing the length of the tire deterioration determining tool in the second direction (that is, the tire circumferential direction), The peeling work can be easily performed.

  In the present invention, the elastic moduli (MPa) of the reinforcing layer and the judgment rubber layer are measured according to JIS-K6254. The elastic modulus of the reinforcing layer is the elastic modulus of the layer in which the reinforcing material is embedded.

1 is a meridional sectional view showing a pneumatic tire for heavy load according to an embodiment of the present invention. It is a side view showing a tire deterioration judging device which consists of an embodiment of the present invention. It is a side view which shows the state which has begun to peel off the tire deterioration determination tool in the tire deterioration determination apparatus of FIG. It is a side view which shows the modification of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the other modification of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the further another modification of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the further another modification of the tire deterioration determination apparatus which concerns on this invention. It is a top view which shows the reinforcement layer which comprises the tire deterioration determination apparatus which concerns on this invention. It is a perspective view which shows the tire deterioration determination tool provided with the reinforcement layer of FIG. It is a top view which shows the nonwoven fabric embedded in the reinforcement layer of FIG. It is a top view which shows the reinforcement cord embedded in the reinforcement layer of FIG.

  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 determination device according to an embodiment of the present invention.

  As shown in FIG. 1, the pneumatic tire according to the present embodiment includes a tread portion 1 extending in the tire circumferential direction and forming an annular shape, and a pair of sidewall portions 2 and 2 arranged on both sides of the tread portion 1. And a pair of bead portions 3, 3 arranged 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 back from the inside of the tire to the outside of a bead core 5 arranged in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross section is arranged 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 that are inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to intersect 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 the 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, the tire deterioration determining tool 10 is detachably attached to the tire inner surface S facing the tire air chamber via the adhesive layer 20. The tire deterioration determination tool 10 and the adhesive layer 20 constitute a tire deterioration determination device. It is desirable that the tire deterioration determination device is arranged in the tread portion 1 or the bead portion 3 which is relatively small in deformation during traveling.

  As shown in FIG. 2, the tire deterioration determination tool 10 includes a sheet-shaped determination rubber layer 11 made of a rubber composition, a sheet-shaped reinforcement layer 12 laminated on the determination rubber layer 11, a determination rubber layer 11, and a reinforcement layer. The sheet-like adhesive layer 13 is interposed between the sheet-like adhesive layer 12 and the sheet 12. The adhesive layer 13 is not always necessary, but when the adhesive layer 13 is provided, the determination rubber layer 11 and the reinforcing layer 12 can be easily separated.

  As the rubber composition forming the determination rubber layer 11, for example, a sulfur-crosslinkable diene rubber composition can be used. As the diene rubber, 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 judgment rubber layer 11 is not limited to the above-mentioned diene rubber, and the rubber includes sulfur, a vulcanization accelerator, an antioxidant, a filler such as carbon black, and a softening agent such as oil. Agents, resins, waxes, metal salts such as cobalt salts, and additives such as stearic acid and zinc white can be appropriately mixed. In particular, in determining the oxidative deterioration of a tire, a natural rubber-based rubber composition that easily causes oxidative deterioration is preferable, and one containing sulfur and further a metal salt is preferable.

  The reinforcing layer 12 has a structure in which a reinforcing material such as a woven cloth, a nonwoven cloth, and a reinforcing cord is embedded in a matrix made of a rubber composition. As a result, the elastic modulus of the reinforcing layer 12 is higher than the elastic modulus of the determination rubber layer 11.

  As the adhesive layer 20, a double-sided tape, an adhesive or the like can be used. The same adhesive material as the adhesive layer 20 can be used for the adhesive layer 13 interposed between the determination rubber layer 11 and the reinforcing layer 12. Further, the adhesiveness of the adhesive layer 20 and the adhesiveness of the adhesive layer 13 may be different from each other. For example, the adhesiveness of the adhesive layer 20 attached to the tire inner surface S can be made higher than the adhesiveness of the adhesive layer 13 interposed between the determination rubber layer 11 and the reinforcing layer 12. In this case, while the tire deterioration determination tool 10 is firmly fixed to the tire inner surface S, the determination rubber layer 11 can be easily separated from the reinforcing layer 12.

  In the pneumatic tire described above, a tire deterioration judging tool 10 including a judgment rubber layer 11 made of a rubber composition and a reinforcing layer 12 attached to the judgment rubber layer 11, and a tire deterioration judging tool 10 laminated on the tire deterioration judging tool 10. Since the tire deterioration determining device is configured from the adhesive layer 20 and the elastic modulus of the reinforcing layer 12 is set higher than the elastic modulus of the determining rubber layer 11, the tire deterioration determining tool 10 inserts the tire inner surface through the adhesive layer 20. In the pneumatic tire mounted on S, as shown in FIG. 3, when the tire deterioration determination tool 10 is peeled from the tire inner surface S, the extension of the determination rubber layer 11 is restricted by the reinforcing layer 12. As a result, the tire deterioration determining tool 10 is easily peeled off from the tire inner surface S, and the workability thereof is improved. Further, by peeling the judgment rubber layer 11 without stretching it, the strain applied to the judgment rubber layer 11 can be suppressed to a minimum, and when the deterioration degree of the pneumatic tire is judged using the judgment rubber layer 11. It is possible to improve the determination accuracy of.

  4 and 5 show modified examples of the tire deterioration determination device according to the present invention. In FIG. 4, the tire deterioration determination tool 10 is composed of two determination rubber layers 11 and 11 and a reinforcing layer 12 inserted between the determination rubber layers 11 and 11. On the other hand, in FIG. 5, the tire deterioration determination tool 10 includes a determination rubber layer 11 and a reinforcing layer 12 arranged around the determination rubber layer 11 so as to surround the determination rubber layer 11. Even when such a structure is adopted, the same effect as described above can be obtained.

  6 and 7 show modified examples of the tire deterioration determination device according to the present invention. In FIG. 6, the adhesive layer 20 is shorter than the tire deterioration determining tool 10. As a result, a non-adhesive region X that does not come into direct contact with the adhesive layer 20 is formed on the end of the tire deterioration determining tool 10 on the surface on which the adhesive layer 20 of the tire deterioration determining tool 10 is laminated. On the other hand, in FIG. 7, a release layer 21 made of a release agent is provided at a part of the interface between the tire deterioration determining tool 10 and the adhesive layer 20. As a result, a non-adhesive region X that does not come into direct contact with the adhesive layer 20 is formed on the end of the tire deterioration determining tool 10 on the surface on which the adhesive layer 20 of the tire deterioration determining tool 10 is laminated. By thus providing the non-adhesive region X on the end of the tire deterioration determining tool 10 and on the surface on which the adhesive layer 20 of the tire deterioration determining tool 10 is laminated, the adhesiveness based on the adhesive layer 20 is sufficiently maintained. However, the tire deterioration determining tool 10 can be easily peeled off from the tire inner surface S.

FIG. 8 shows a reinforcing layer constituting the tire deterioration judging device according to the present invention, and FIG. 9 shows a tire deterioration judging tool provided with the reinforcing layer of FIG. The tire deterioration determination tool 10 has a first direction (tire width direction W) along the surface direction of the adhesive layer 20 and a second direction (tire circumferential direction C) orthogonal to the first direction along the surface direction of the adhesive layer 20. When it has, as shown in FIG. 8, it is preferable that the elastic modulus M ₁ of the reinforcing layer 12 in the first direction is set higher than the elastic modulus M ₂ of the reinforcing layer 12 in the second direction. In particular, the elastic modulus M ₁ of the reinforcing layer 12 in the first direction is preferably 2 to 10 times the elastic modulus M ₂ of the second direction. At this time, at least the elastic modulus M ₁ of the reinforcing layer 12 in the first direction needs to be set higher than the elastic modulus of the determination rubber layer 12. In this case, in the pneumatic tire, the tire deterioration determining tool 10 is attached to the tire inner surface S in a state where the first direction thereof is oriented in the tire width direction W.

In a pneumatic tire, distortion occurs mainly in the tire circumferential direction C during inflation and running, so that the elastic modulus M ₂ of the reinforcing layer 12 in the second direction (tire circumferential direction C) is relatively low. It is possible to reduce the difference in rigidity between the tire inner surface S and the reinforcing layer 12 and prevent the tire deterioration determination tool 10 from falling off the tire inner surface S. When peeling the tire deterioration determining tool 10 from the tire inner surface S, the peeling operation can be easily performed by peeling the tire deterioration determining tool 10 along the first direction (tire width direction W). .

The elastic modulus M ₂ of the first direction of the reinforcement layer 12 modulus M ₁ and the second direction (tire width direction W) (the tire circumferential direction C) In the above relationship, as shown in FIG. 9, the tire deterioration The length L ₁ of the determination tool 10 in the first direction (tire width direction W) is preferably set to be larger than the length L ₂ of the tire deterioration determination tool 10 in the second direction (tire circumferential direction C). When the tire deterioration determining tool 10 is peeled off along the first direction (tire width direction W), the length L ₂ of the tire deterioration determining tool 10 in the second direction (tire circumferential direction C) is made relatively small. , The peeling work can be easily performed. When the length L ₁ in the first direction and the length L ₂ in the second direction of the tire deterioration determining tool 10 are brought into the above relationship, the plan view shape of the tire deterioration determining tool 10 is not particularly limited. For example, various shapes such as a rectangle, an ellipse, an oval, and a pentagon can be used. Further, the length L ₁ of the tire deterioration determining tool 10 in the first direction is preferably 2 to 7 times the length L ₂ in the second direction.

10 shows the nonwoven fabric embedded in the reinforcing layer of FIG. 8, and FIG. 11 shows the reinforcing cord embedded in the reinforcing layer of FIG. The nonwoven fabric 12A shown in FIG. 10 has directionality in strength and elongation, and by embedding the nonwoven fabric 12A in the reinforcing layer 12, the elastic modulus M ₁ of the reinforcing layer 12 in the first direction (tire width direction W) is increased. Is higher than the elastic modulus M _{2 in} the second direction (tire circumferential direction C). The reinforcing cords 12B shown in FIG. 11 are arranged so as to extend along the first direction (tire width direction W), and by embedding the reinforcing cords 12B in the reinforcing layer 12, the first direction of the reinforcing layer 12 is obtained. The elastic modulus M ₁ in the (tire width direction W) becomes higher than the elastic modulus M _{2 in} the second direction (tire circumferential direction C). As the reinforcing cord 12B, a metal cord such as a steel cord or an organic fiber cord such as a nylon cord is used.

  Hereinafter, a tire deterioration determination method using the above-described tire deterioration determination device will be briefly described. First, in a pneumatic tire, the tire deterioration determining tool 10 including the determination rubber layer 11 and the reinforcing layer 12 is attached to the tire inner surface S via the adhesive layer 20. The tire deterioration determining tool 10 may be mounted immediately after the pneumatic tire is manufactured, or may be mounted at the start of use of the pneumatic tire. The determination rubber layer 11 of the tire deterioration determination tool 10 is a layer in which the physical characteristics of a new product are grasped in advance. Next, the tire deterioration determination tool 10 mounted on the tire inner surface S is removed at an arbitrary time after the start of use of the tire. For example, the tire deterioration determining tool 10 is removed from the tire inner surface S at the time when the vehicle travels an arbitrary mileage during the tire use process, when performing rehabilitation work, or when discarding the tire. Then, the judgment rubber layer 11 is separated from the tire deterioration judging tool 10, the physical characteristics of the judgment rubber layer 11 are measured, the amount of change in the physical characteristics from the time of new article is obtained using the measured value, and the change The degree of deterioration of the pneumatic tire is determined based on the amount.

  Examples of physical properties include weight (specific gravity), oxygen adsorption amount, electric resistance, hardness, breaking property, viscoelastic property, and the like. When the judgment rubber layer 11 of the tire deterioration judging tool 10 deteriorates due to oxidation, the weight (specific gravity), the amount of oxygen adsorbed, the electric resistance, the hardness, the breaking property, and the viscoelastic property change with the deterioration. It is possible to accurately determine the degree of deterioration of the pneumatic tire based on the amount of change from the time of new product. It is also possible to chemically analyze the judgment rubber layer 11 of the tire deterioration judging tool 10 and use the analysis result as an index of the deterioration degree.

  The tire deterioration determination devices of Examples 1 to 3 were prepared, and these tire deterioration determination devices were attached to the inner surfaces of pneumatic tires having a tire size of 11R22.5. Example 1 has the structure shown in FIG. 2, Example 2 has the structure shown in FIG. 6, and Example 3 has the structure shown in FIG. These tire deterioration determination devices were mounted on the tire inner surface at the tire equator position.

  In addition, a conventional tire deterioration determining device including a tire deterioration determining tool including only a determination rubber layer and an adhesive layer was prepared, and the tire deterioration determining tool was attached to the inner surface of the tire via the adhesive layer.

  After the pneumatic tires equipped with the tire deterioration determining devices of the conventional example and Examples 1 to 3 described above were actually used under the same conditions, the tire deterioration determining tool was peeled off from the tire inner surface. As a result, in Examples 1 to 3, since the expansion of the determination rubber layer was restricted by the reinforcing layer when the tire deterioration determination tool was peeled from the tire inner surface, the tire deterioration determination tool could be easily peeled off from the tire inner surface. . Further, no large strain was applied to the collected judgment rubber layer, which was in a preferable state as a sample for judging the degree of deterioration of the pneumatic tire. On the other hand, in the conventional example, when peeling the tire deterioration judging tool from the inner surface of the tire, the judgment rubber layer was greatly expanded, and the peeling operation was difficult. Further, since a large strain was applied to the collected judgment rubber layer, it was not in a preferable state as a sample for judging the degree of deterioration of the pneumatic tire.

1 Tread Part 2 Sidewall Part 3 Bead Part 4 Carcass Layer 5 Bead Core 6 Bead Filler 7 Belt Layer 10 Tire Deterioration Judgment Tool 11 Judgment Rubber Layer 12 Reinforcing Layer 20 Adhesive Layer

Claims (8)

  A tire deterioration determination tool including a determination rubber layer made of a rubber composition and a reinforcement layer attached to the determination rubber layer, and an adhesive layer laminated to the tire deterioration determination tool, the reinforcing layer being composed of A tire deterioration determination device, wherein an elastic modulus is higher than an elastic modulus of the determination rubber layer.   The non-adhesive region which does not come into direct contact with the adhesive layer exists on an end portion of the tire deterioration determining tool, which is a surface on which the adhesive layer is laminated, of the tire deterioration determining tool. Tire deterioration determination device.   When the tire deterioration determining tool has a first direction along the surface direction of the adhesive layer and a second direction along the surface direction of the adhesive layer that is orthogonal to the first direction, the first direction of the reinforcing layer. 3. The elastic modulus of the reinforcing layer is higher than the elastic modulus of the reinforcing layer in the second direction, and the elastic modulus of the reinforcing layer in the first direction is higher than the elastic modulus of the judgment rubber layer. The tire deterioration determination device according to.   The tire deterioration determination device according to claim 3, wherein a length of the tire deterioration determination tool in the first direction is larger than a length of the tire deterioration determination tool in the second direction.   A tire deterioration determination tool including a determination rubber layer made of a rubber composition and a reinforcement layer attached to the determination rubber layer, and an adhesive layer laminated to the tire deterioration determination tool, the reinforcing layer being composed of A pneumatic tire having a tire deterioration determination device whose elastic modulus is set higher than the elastic modulus of the determination rubber layer, wherein the tire deterioration determination tool is attached to the tire inner surface via the adhesive layer. Pneumatic tire characterized by.   The non-adhesive region which does not come into direct contact with the adhesive layer is present on an end portion of the tire deterioration determining tool on which the adhesive layer of the tire deterioration determining tool is laminated. Pneumatic tire.   When the tire deterioration determining tool has a first direction along the surface direction of the adhesive layer and a second direction along the surface direction of the adhesive layer that is orthogonal to the first direction, the first direction of the reinforcing layer. Of the reinforcing layer is set higher than the elastic modulus of the reinforcing layer in the second direction, and the elastic modulus of the reinforcing layer in the first direction is set to be higher than the elastic modulus of the determination rubber layer. The pneumatic tire according to claim 5 or 6, wherein the determining tool is mounted on the inner surface of the tire with the first direction oriented in the tire width direction.   The pneumatic tire according to claim 7, wherein a length of the tire deterioration determining tool in the first direction is larger than a length of the tire deterioration determining tool in the second direction.

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