JP5229485B2 - Tire deterioration determination tool and pneumatic tire using the same - Google Patents

Description

  The present invention relates to a tire deterioration determining tool for determining deterioration of a pneumatic tire used in, for example, passenger cars, trucks, buses, and the like, and a pneumatic tire using the same.

  Generally, in this type of pneumatic tire, an inner liner layer made of rubber having low gas permeability is provided on the inner surface of the tire so that air filled in the tire is kept at a predetermined pressure. However, since the filling air permeates the inner liner layer little by little as time passes, it causes deterioration of rubber, fibers and steel cords of the tie rubber, carcass layer and belt layer adjacent to the inner liner layer.

  In particular, in heavy-duty tires, when the remaining groove in the tread reaches the end of its life, the tread surface is cut and buffed, and a new tread is attached to the base tire made up of the remaining tire body. In such a case, it is extremely important to grasp the progress of deterioration of the base tire.

  Therefore, conventionally, a tire deterioration determination is made by covering a core rubber formed of rubber corresponding to a tire tie rubber or a carcass layer with a cover rubber having oxygen permeability equal to or higher than that of the tire inner liner layer. After using this tire deterioration determining tool inside the tire and using the tire, the tire deterioration state is determined nondestructively by taking out from the tire and examining the degree of hardening of the core rubber. Is known (for example, see Patent Document 1).

JP 2006-327469 A

  However, in the tire deterioration determining tool, since it is necessary to perform a bending test using a dedicated test device in order to examine the degree of curing of the core rubber taken out from the tire, it is difficult to determine the tire deterioration state. In addition, there is a problem that the determination result cannot be obtained promptly.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a tire deterioration determination tool capable of easily and quickly determining the deterioration state of a tire in a non-destructive manner and air using the same. The purpose is to provide tires.

  In order to achieve the above object, the present invention provides a tire deterioration determination tool that is attached to the inner surface of a pneumatic tire and determines deterioration of the tire due to air permeation through the rubber layer of the tire, and contains a redox indicator. The redox indicator is discolored according to the air permeation amount of the support.

  In order to achieve the above object, the present invention provides a tire deterioration determination tool for determining deterioration of a tire caused by air permeating through a rubber layer of the tire and containing a redox indicator. And a cover member that covers the support, and is configured to change the color of the redox indicator according to the air permeation amount of the support.

  In order to achieve the above object, the present invention wears the tire deterioration determining tool in a pneumatic tire.

  As a result, the oxidation / reduction indicator changes color according to the amount of air permeated through the rubber layer of the tire to which internal pressure is applied. It can be confirmed visually.

  According to the present invention, since the progress of deterioration of the tire due to air permeation can be visually confirmed, there is no need to examine the degree of rubber curing using a dedicated test device, and the deterioration state of the tire can be determined. Nondestructive and easy and quick.

Partial front sectional view of the pneumatic tire showing the first embodiment of the present invention The figure which shows the change of the color of a tire degradation determination tool Partial front sectional view of a pneumatic tire showing a second embodiment of the present invention Sectional drawing of the tire deterioration determination tool which shows the 3rd Embodiment of this invention. The figure which shows the change of the color of a tire degradation determination tool Sectional drawing of the tire deterioration determination tool which shows the 4th Embodiment of this invention. The figure which shows the change of the color of a tire degradation determination tool Partial front sectional view of a pneumatic tire showing a mounting range of a tire deterioration determination tool

  1 and 2 show a first embodiment of the present invention. The pneumatic tire shown in the figure includes a tread portion 1 formed on the tire outer peripheral surface side, sidewall portions 2 formed on both sides in the tire width direction, and beads formed on the tire radial direction inner side of the sidewall portions 2. Part 3. The pneumatic tire includes an inner liner 4 disposed on the inner surface of the tire, a carcass member 5 disposed on the outer side of the inner liner 4, a pair of bead members 6 disposed on both sides in the tire width direction, and a carcass. The belt 7 is disposed outside the member 5, the tread member 8 is disposed on the tire outer peripheral surface side, and the pair of sidewall members 9 are disposed on both tire side surfaces.

  The inner liner 4 is made of a sheet-like rubber mainly composed of butyl rubber and having low gas permeability, and is disposed on the inner peripheral surface side of the carcass member 5. In this case, the inner liner 4 is affixed to the inner peripheral surface of the carcass member 5 via a tie rubber (not shown) made of rubber equivalent to the rubber of the carcass member 5.

  The carcass member 5 is made of a sheet-like rubber having a plurality of carcass cords 5a, and is folded back toward the sidewall portion 2 from the inner side to the outer side in the tire width direction so as to wind the bead member 6 at both ends in the width direction. .

  The bead member 6 includes a bead core 6a formed by bundling wires such as metal wires and a bead filler 6b formed of rubber having a substantially triangular cross section. The bead filler 6b is disposed on the outer peripheral side of the bead core 6a.

  The belt 7 is formed by coating a belt cord 7 a made of steel, high-strength fiber, or the like with a sheet-like rubber material, and is disposed on the outer peripheral surface side of the carcass member 5.

  The tread member 8 is made of rubber formed by extrusion molding, and is disposed so as to cover the outer peripheral surface side of the belt 7. A groove 1a of the tread portion 1 is formed on the outer peripheral surface of the tread member 8 at the time of vulcanization molding.

  The side wall member 9 is made of rubber formed by extrusion molding, and is disposed so as to cover the outer surfaces of both ends of the carcass member 5 in the width direction.

  A tire deterioration determination tool 10 for determining deterioration of the tire due to oxidation of rubber is attached to the inner peripheral surface of the pneumatic tire. The tire deterioration determining tool 10 includes a support 11 containing a redox indicator, and changes the color of the redox indicator according to the amount of air permeated. Examples of the redox indicator include phenosafranine, indigotetrasulfonic acid, methylene blue, diphenylamine, diphenylbenzidine, diphenylaminesulfonic acid, 5,6-dimethylferroin, erioglaucine A, 5-methylferroin, ferroin, nitroferroin. Etc. are used. The support 11 is made of solidified colloidal particles or nonwoven fabric, and is preferably a gas permeable member. A redox indicator is reduced in use and changes from colorless or light to dark when oxidized. A tire deterioration determining tool 10 is created by impregnating a white or light colored support 11 with an aqueous solution of a reduced redox indicator, and is installed on the inner surface of the tire. The created tire deterioration determination tool 10 is white or light colored, but changes from white or light colored to dark colored when the impregnated redox indicator is oxidized.

  The pneumatic tire configured as described above is filled with air at a predetermined pressure, and is used as a heavy duty tire such as a truck or a bus. For example, the filled air gradually passes the inner liner 4 over time. In order to permeate, the rubber layer of the adjacent tie rubber or carcass 5 is gradually deteriorated. At that time, since the air in the tire permeates the inner liner 4 through the support 11 at the mounting portion of the tire deterioration determination tool 10, the oxidation-reduction indicator of the support 11 gradually increases according to the amount of air permeation. Discolor. For example, when methylene blue is used as the redox indicator, the color gradually changes from white to blue.

  Here, when the pneumatic tire is reused as a retreaded tire, it can be determined whether or not it can be reused by the tire deterioration determining tool 10 mounted in the tire. That is, the support 11 of the tire deterioration determining tool 10 has a redox indicator that changes color according to the amount of air permeated during the tire use period. Therefore, by visually checking the color change of the redox indicator, It is possible to grasp the progress of deterioration of the tire due to permeation. For example, by observing the tire deterioration determining tool 10 of the tire removed from the rim, and when the redox indicator of the support 11 is white or close to white, it is determined that the degree of deterioration is low and that it can be reused. If the oxidation-reduction indicator has changed color to a predetermined color (for example, blue), it can be determined that the reuse is impossible because the degree of deterioration is high.

  As described above, according to the pneumatic tire of the present embodiment, the tire deterioration has the gas permeable support 11 containing the oxidation-reduction indicator, and changes the oxidation-reduction indicator according to the air permeation amount. Since the determination tool 10 is mounted on the inner surface of the tire, the progress of deterioration of the tire due to air permeation can be visually confirmed by the discoloration state of the redox indicator. Thereby, it is not necessary to check the degree of rubber curing using a dedicated test device, and the determination of the deterioration state of the tire can be performed easily and quickly without destruction.

  FIG. 3 is a partial front cross-sectional view of a pneumatic tire showing a second embodiment of the present invention, in which components equivalent to those of the above-described embodiment are given the same reference numerals.

  The tire deterioration determination tool 20 of the present embodiment includes a gas-permeable support 21 containing a redox indicator and a rubber cover member 22 that covers the support 21. The redox indicator of the support 21 is discolored according to the amount of permeation.

  In the pneumatic tire of the present embodiment, air in the tire permeates through the inner liner 4 via the support 21 and the cover member 22 at the mounting portion of the tire deterioration determination tool 20, so The redox indicator of the support 21 gradually changes color according to the amount of permeation. Further, when determining the deterioration state of the tire, the tire is removed from the rim, the cover member 22 of the tire deterioration determination tool 20 is opened, and the discoloration state of the support 21 is visually checked, so that It is possible to grasp the progress of deterioration.

  At that time, since the support body 21 is covered with the cover member 22, the support body 21 is not exposed to the outside until the tire is removed from the rim and the determination work is performed. Deterioration can be prevented.

  4 and 5 show a third embodiment of the present invention, and tire components other than the tire deterioration determination tool are the same as those in the second embodiment, and are not shown.

  In the present embodiment, a plurality of tire deterioration determining tools 30, 40, 50 are mounted at a plurality of locations on the tire inner surface, and each tire deterioration determining tool 30, 40, 50 is a gas permeable support containing a redox indicator. 31, 41, 51 and rubber cover members 32, 42, 52 covering the supports 31, 41, 51, and the redox indicator of the supports 31, 41, 51 is air as in the above embodiment. The color is changed according to the amount of transmitted light. In this case, the cover members 32, 42, and 52 have different thicknesses t1, t2, and t3 in the tire radial direction (vertical direction in the figure) as shown in FIGS. 4 (a), (b), and (c). (T1 <t2 <t3). Further, the cover members 32, 42, and 52 have thicknesses t1, t2, and t3 in the tire radial direction, thicknesses t1 ', t2', t3 'in the tire width direction (left and right direction in the figure), and tire circumferential direction, respectively. It is formed to be smaller than the thickness (not shown).

  In the pneumatic tire of the present embodiment, the air in the tire passes through the support members 31, 41, 51 and the cover members 32, 42, 52 at the mounting portions of the tire deterioration determination tools 30, 40, 50. Since it permeates, the oxidation-reduction indicator of the supports 31, 41, 51 gradually changes color according to the amount of permeated air, as in the first embodiment. Further, when determining the deterioration state of the tire, the tire is removed from the rim, the cover members 32, 42, 52 are cut open, and the discoloration state of the support bodies 31, 41, 51 is visually confirmed, thereby causing the air permeation. The progress of tire deterioration can be grasped.

  At that time, since the support bodies 31, 41, 51 are covered with the cover members 32, 42, 52, the support body 31 until the determination work is performed after removing the tire from the rim, as in the second embodiment. , 41, 51 are not exposed to the outside, and the support 31, 41, 51 can be prevented from being soiled or deteriorated.

  Further, since the cover members 32, 42, 52 of the tire deterioration determining tools 30, 40, 50 have different thicknesses t1, t2, t3, the amount of air permeation is larger when the thickness is larger than when the thickness is smaller. And the redox indicator discoloration rate is reduced. That is, as shown in FIG. 6, the discoloration states A1, A2, and A3 of the respective tire deterioration determining tools 30, 40, and 50 are sequentially colored with a time difference. ], [2], and [3]. For example, when the tire deterioration determining tool 50 having the slowest discoloration speed has been discolored (deterioration level [3]), it can be determined that reuse is impossible because the degree of progress of deterioration is high.

  As described above, according to the present embodiment, by confirming the discoloration states of the plurality of tire deterioration determination tools 30, 40, and 50 having different discoloration speeds, the degree of progress of tire deterioration due to air permeation can be subdivided. Since it can be grasped, the deterioration state of the tire can be determined more accurately.

  In this case, since the discoloration rates of the oxidation-reduction indicators of the supports 31, 41, 51 are made different by the cover members 32, 42, 52 having different thicknesses t1, t2, t3 in the tire radial direction, Different tire deterioration determination tools 30, 40, and 50 can be easily formed, and the deterioration degree of the tire can be accurately grasped.

  Further, since the cover members 32, 42, 52 are formed such that the thicknesses t1, t2, t3 in the tire radial direction are smaller than the thicknesses in the tire width direction and the circumferential direction, the air permeation amount in the tire radial direction is reduced. It can always be larger than the tire width direction and the circumferential direction, and the surfaces of the supports 31, 41, 51 in the tire radial direction can be uniformly discolored.

  6 and 7 show a fourth embodiment of the present invention, and tire components other than the tire deterioration determination tool are the same as those in the second embodiment, and are not shown.

  In the present embodiment, a plurality of tire deterioration determination tools 60 and 70 are respectively mounted at a plurality of locations on the tire inner surface, and each of the tire deterioration determination tools 60 and 70 includes gas permeable supports 61 and 71 containing a redox indicator. And the rubber cover members 62 and 72 covering the supports 61 and 71, and the oxidation-reduction indicator of the supports 61 and 71 is discolored according to the amount of air permeation as in the above embodiment. ing. In this case, each support 61, 71 contains an oxidation-reduction indicator that changes to a different color, and each cover member 62, 72 has a tire radial direction (see FIG. 6), as shown in FIGS. The thicknesses t1 and t2 in the middle and vertical direction are different from each other (t1 <t2). The cover members 62 and 72 have thicknesses t1 and t2 in the tire radial direction, thicknesses t1 'and t2' in the tire width direction (left and right in the figure), and thicknesses in the tire circumferential direction (not shown). ) To be smaller than.

  In the pneumatic tire of the present embodiment, the air in the tire permeates through the inner liner layer through the support members 61 and 71 and the cover members 62 and 72 at the mounting portions of the tire deterioration determination tools 60 and 70. As in the embodiment, the redox indicator of the supports 61 and 71 gradually changes color according to the amount of air permeation. Further, when determining the deterioration state of the tire, the tire is removed from the rim, the cover members 62 and 72 are opened, and the discoloration state of the supports 61 and 71 is visually checked, so that the deterioration of the tire due to air permeation is reduced. It is possible to grasp the progress.

  At this time, since the support bodies 61 and 71 are covered with the cover members 62 and 72, the support bodies 61 and 71 are externally mounted until the determination work is performed after removing the tire from the rim, as in the second embodiment. It is possible to prevent the supports 61 and 71 from being soiled and deteriorated.

  Further, since the cover members 62 and 72 of the tire deterioration determining tools 60 and 70 have different thicknesses t1 and t2, the larger the thickness, the smaller the thickness is, and the smaller the thickness, the less air permeation occurs. The color change rate of the indicator is slow. That is, as shown in FIG. 7, the discoloration states B1 and B2 of the respective tire deterioration determining tools 60 and 70 are sequentially changed to colored with a time lag, so that these deterioration levels [1], [2 ] Can be determined. At that time, since the tire deterioration determining tools 60 and 70 change to colors different from each other, for example, a redox indicator (for example, methylene blue) that changes to blue is used for one tire deterioration determining tool 60, and the other tire deterioration determination is performed. By using a redox indicator (for example, phenosafranine) that changes to red in the tool 70, when the tire deterioration determining tool 70 having a slow discoloration speed changes to red (deterioration level [2]), the progress of deterioration If the degree is high, it can be determined that reuse is impossible.

  As described above, according to the present embodiment, by confirming the changed colors of the plurality of tire deterioration determining tools 60 and 70 having different discoloration speeds, the progress of curing due to the oxidation of rubber is clarified by the difference in color. Since it can be grasped, the deterioration state of the tire can be determined more accurately.

  In the third and fourth embodiments, the cover members having different thicknesses are used to change the discoloration speed of the tire deterioration determination tool. However, the cover members have the same thickness. By using different types of redox indicators, the discoloration rate of the redox indicators may be different.

  Further, in the first to fourth embodiments, the tire deterioration determination tool is adhered to the tire inner surface after vulcanization with an adhesive or an adhesive tape, or in the second to fourth embodiments, the tire inner surface If it is attached at the time of tire molding, such as vulcanizing integrally, it can be easily attached to the tire, which is extremely advantageous for practical use.

  Furthermore, in the said 3rd and 4th embodiment, if a tire degradation determination tool is arrange | positioned at equal intervals in a tire peripheral direction, there exists an advantage that a tire static balance property improves and a uniformity is not deteriorated.

  Further, in the second to fourth embodiments, the tire deterioration determination tool is mounted on the inner surface of the tire. However, if there is no problem in running and attachment to the rim, for example, other surfaces such as the outer surface of the bead portion. It is also possible to attach to the position.

  Further, also in the first embodiment, the tire deterioration determination tool 10 is mounted at a plurality of locations in the circumferential direction of the tire, and redox indicators having different discoloration speeds are used for each tire deterioration determination tool 10 or different colors are used. Alternatively, a redox indicator that changes to may be used.

  In each of the above embodiments, as shown in FIG. 8, a range W1 within 75% of the tread width W from the center in the tire width direction, or a range H1 within 25% of the tire cross-section height H from the inner end in the tire radial direction. If the tire deterioration determining tool is disposed in the area, these ranges W1 and H1 are portions where there is little bending during traveling, and this is effective in preventing damage and peeling of the tire deterioration determining tool. Here, the tire cross-section height H is the tire cross-section height in a state where the tire is filled with a normal internal pressure defined by JATMA and a normal load is applied.

  In each of the above embodiments, those used for heavy duty tires are shown, but the present invention can also be applied to passenger tires and pneumatic tires for other purposes.

  10, 20, 30, 40, 50, 60, 70 ... tire deterioration determining tool, 11, 21, 31, 41, 51, 61, 71 ... support, 22, 32, 42, 52, 62, 72 ... cover member .

Claims (14)

In a tire deterioration determining tool for determining deterioration of a tire that is attached to the inner surface of a pneumatic tire and air passes through the rubber layer of the tire,
Comprising a support containing a redox indicator,
A tire deterioration determining tool, characterized in that the redox indicator is discolored in accordance with the air permeation amount of the support. In a tire deterioration determination tool for determining deterioration of a tire due to air passing through a rubber layer of the tire, which is attached to a pneumatic tire,
A support containing a redox indicator;
A cover member covering the support,
A tire deterioration determining tool, characterized in that the redox indicator is discolored in accordance with the air permeation amount of the support. The tire deterioration determining tool according to claim 2, wherein the cover member is formed of rubber. The tire deterioration determination tool according to claim 2 or 3, wherein the cover member is formed such that a thickness in a tire radial direction is smaller than a thickness in a tire width direction and a circumferential direction. It is a tire deterioration determination tool attached to a plurality of locations of a pneumatic tire,
The tire deterioration determination tool according to claim 1, 2, 3 or 4, wherein the redox indicator is formed to have a different color change rate from that of other tire deterioration determination tools. It is a tire deterioration determination tool attached to a plurality of locations of a pneumatic tire,
The use of a redox indicator of a different type from that of other tire deterioration determining tools makes the discoloration rate of the redox indicator different from that of other tire deterioration determining tools. Or the tire degradation determination tool of 4. It is a tire deterioration determination tool attached to a plurality of locations of a pneumatic tire,
The cover member having a thickness different from that of the other tire deterioration determining tool is used so that the discoloration rate of the oxidation-reduction indicator is different from that of the other tire deterioration determining tool. The tire deterioration determining tool described. It is a tire deterioration determination tool attached to a plurality of locations of a pneumatic tire,
The tire deterioration determination tool according to claim 1, 2, 3, or 4, wherein the oxidation-reduction indicator is formed to change color to a different color from other tire deterioration determination tools. A pneumatic tire comprising the tire deterioration determining tool according to claim 1, 2, 3, 4, 5, 6, 7 or 8. The pneumatic tire according to claim 9, wherein the tire deterioration determining tools are arranged at equal intervals in the tire circumferential direction. The pneumatic tire according to claim 9 or 10, wherein the tire deterioration determining tool is attached to a vulcanized pneumatic tire. The pneumatic tire according to claim 9 or 10, wherein the tire deterioration determining tool is attached at the time of forming the pneumatic tire. The pneumatic tire according to claim 9, 10, 11 or 12, wherein the tire deterioration determining tool is disposed in a range within 75% of a tread width from a center in a tire width direction. The pneumatic tire according to claim 9, 10, 11 or 12, wherein the tire deterioration determination tool is disposed within a range of 25% or less of a tire cross-section height from an inner end portion in a tire radial direction.

Images