JP2011245881A - Retreaded tire and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retreaded tire capable of improving durability by preventing separation of a precure tread, and to provide a method of manufacturing the same.SOLUTION: In the retreaded tire, the belt-like precure tread 2 is wound relative to a base tire 1 in which a tread part 11 is ground via a rubber layer 3 for adhesion. In a back face part positioned on the base tire side of the precure tread 2, a plurality of exhaust grooves 22 having width of 5-30 mm and depth of 0.1-1.0 mm and communicated at least with one end in the width direction of the back face part, are arranged. The ratio of the total area of the exhaust grooves 22 relative to the area of the back face part is 10-40%.

Description

  The present invention relates to a retread tire using a precure tread and a method for manufacturing the retread tire, and more particularly to a retread tire and a method for manufacturing the retread tire that can improve the durability by suppressing the separation of the precure tread.

  As a method of rehabilitating used tires, a pre-cured belt-shaped pre-cured tread is wound around an adhesive rubber layer and joined to a base tire whose tread portion has been polished. (For example, see Patent Documents 1 and 2). Such a precure tread type rehabilitation method is advantageous in that the rehabilitation equipment is not complicated and the rehabilitation work can be easily performed.

  However, in the precure tread type rehabilitation method, air is accumulated between the adhesive rubber layer and the precure tread when the belt-shaped precure tread is affixed to the base tire, and this is the separation of the precure tread. It may cause. Therefore, it is required to surely eliminate the air staying between the adhesive rubber layer and the precure tread.

JP 2000-79641 A JP 2005-111010 A

  An object of the present invention is to provide a retread tire and a method for manufacturing the same that can improve the durability by suppressing the separation of the precure tread.

  In order to achieve the above object, a retread tire according to the present invention is a retread tire in which a belt-like precure tread is wound around a base tire whose tread portion is polished via an adhesive rubber layer. A plurality of exhaust grooves having a width of 5 mm to 30 mm and a depth of 0.1 mm to 1.0 mm and communicating with at least one end portion in the width direction of the back surface portion are formed on the back surface portion located on the base tire side. The ratio of the total area of the exhaust groove to the area of the back surface portion is 10% to 40%.

  Moreover, the manufacturing method of the retread tire of this invention for achieving the said objective WHEREIN: While the tread part of a used tire is grind | polished and a base tire is shape | molded, the back surface located in the base tire side of a strip | belt-shaped pre-cure tread A plurality of exhaust grooves having a width of 5 mm to 30 mm and a depth of 0.1 mm to 1.0 mm and communicating with at least one end in the width direction of the back surface, The ratio of the total area of the exhaust groove to 10% to 40%, and the prepure tread is wound around the base tire through an unvulcanized rubber layer for adhesion, and the rubber layer is vulcanized. The base tire and the precure tread are joined to each other.

  In the present invention, when manufacturing a retread tire in which a belt-shaped precure tread is wound on a base tire via an adhesive rubber layer, a predetermined dimension is provided on the back surface portion of the precure tread located on the base tire side. And a plurality of exhaust grooves communicating with at least one end in the width direction of the back surface portion are provided at a predetermined density, so that when adhering a belt-shaped precure tread to a base tire, an adhesive rubber Air staying between the layer and the precure tread can be excluded outside the tire through the exhaust groove. As a result, separation of the precure tread can be suppressed and durability of the retreaded tire can be improved.

  In the present invention, the inclination angle of the exhaust groove with respect to the tire circumferential direction is preferably 30 ° to 70 °. Thereby, the effect of discharging air based on the exhaust groove can be maximized.

  The back portion of the precure tread located on the base tire side is provided with a plurality of microgrooves having a width of 2 mm or less and a depth of 0.5 mm or less and communicating with the exhaust groove. The total area ratio is preferably 20% to 60%. When such a microgroove is added, air can be guided from the wide area of the back portion of the precure tread through the microgroove to the exhaust groove, so that the air discharge effect can be further enhanced. .

  It is preferable that the precure tread has a diameter of 2 mm or less and a plurality of through holes penetrating in the thickness direction of the precure tread. In particular, the adhesive rubber layer is preferably filled in the through holes during vulcanization of the adhesive rubber layer. In this case, the air staying between the adhesive rubber layer and the precure tread can be excluded from the tire through the through hole. The through hole is preferably disposed at a position communicating with the exhaust groove. Thereby, the air discharge effect can be further enhanced.

It is a meridian half section view showing a retread tire which consists of an embodiment of the present invention. It is a rear view which shows the precure tread used by this invention. It is a rear view which shows the other precure tread used by this invention. It is a rear view which shows the other precure tread used by this invention. It is sectional drawing which expands and shows the exhaust groove and microgroove formed in the back part of a precure tread. It is meridian sectional drawing which shows the manufacturing method of the retread tire which consists of embodiment of this invention. It is a perspective sectional view showing other precure treads used in the present invention. It is a perspective sectional view which expands and shows the principal part of FIG.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a retread tire according to an embodiment of the present invention, FIGS. 2 to 4 show a precure tread used in the present invention, and FIG. 5 shows an exhaust groove and a micro groove formed on the back surface of the precure tread. Is shown in an enlarged manner.

  In FIG. 1, a base tire 1 is formed by polishing (buffing) a tread portion of a used tire, 11 is a tread portion, 12 is a sidewall portion, and 13 is a bead portion. A precure tread 2 is wound around and joined to the base tire 1 with the tread portion 11 polished on the outer periphery of the tread portion 11 via an adhesive rubber layer 3.

  The precure tread 2 is a strip having a length corresponding to the tire outer peripheral length before being bonded to the base tire 1, and is vulcanized prior to rehabilitation work. A plurality of grooves 21 are formed on the tread surface of the precure tread 2. An arbitrary groove pattern can be provided on the tread surface of the precure tread 2.

  On the other hand, as shown in FIGS. 2 to 4, a plurality of exhaust grooves 22 and a plurality of microgrooves 23 are formed on the back surface portion of the precure tread 2 located on the base tire side. 2 to 4, C means the tire circumferential direction. The exhaust groove 22 is disposed so as to be inclined with respect to the tire circumferential direction C, and communicates with at least one end portion in the width direction of the precure tread 2 in the width direction (direction perpendicular to the tire circumferential direction C). . The micro groove 23 is smaller in width and depth than the exhaust groove 22 and communicates with the exhaust groove 22 described above. These microgrooves 23 may be arranged in a random mesh shape as shown in FIG. 2, may be arranged so as to be inclined with respect to the tire circumferential direction as shown in FIG. In this way, they may be arranged in a regular mesh shape.

  As shown in FIG. 5, the exhaust groove 22 has a width W1 in the range of 5 mm ≦ W1 ≦ 30 mm, a depth D1 in the range of 0.1 mm ≦ D1 ≦ 1.0 mm, and the back surface of the precure tread 2 The ratio (density) of the total area of the exhaust grooves 22 to the area of the portion (that is, the area when the back surface portion is projected in the thickness direction) is set in the range of 10% to 40%.

  As shown in FIG. 5, the microgroove 23 has a width W2 in the range of W2 ≦ 2 mm, a depth D2 in the range of D2 ≦ 0.5 mm, and the area of the back surface of the precure tread 2 (ie, The ratio (density) of the total area of the microgroove 23 to the area when the back surface portion is projected in the thickness direction is set in the range of 20% to 60%.

  When manufacturing the retreaded tire mentioned above, as shown in FIG. 6, the tread part of a used tire is grind | polished first and the base tire 1 is shape | molded. On the other hand, an exhaust groove 22 and a micro groove 23 are formed in advance on the back surface portion of the belt-shaped precure tread 2 located on the base tire side. Then, the precure tread 2 is wound around the base tire 1 through the unvulcanized rubber layer 3 for adhesion, and the assembly is heated in a vulcanizing can to vulcanize the rubber layer 3. The base tire 1 and the precure tread 2 are joined to each other. This completes the rehabilitation work.

  According to the above-described embodiment, the plurality of exhaust grooves 22 having a predetermined size and communicating with at least one end in the width direction of the back surface portion are provided on the back surface portion of the precure tread 2 on the base tire side. Therefore, when the belt-shaped precure tread 2 is attached to the base tire 1, air staying between the adhesive rubber layer 3 and the precure tread 2 is exhausted through the exhaust groove 22. It can be excluded outside the tire. Therefore, the durability of the retreaded tire can be improved by suppressing the separation of the precure tread 2.

  The width W1 of the exhaust groove 22 is in the range of 5 mm to 30 mm, more preferably in the range of 10 mm to 20 mm. If the width W1 is too small, the exhaust effect will be insufficient. Conversely, if it is too large, air will remain in the groove. The depth D1 of the exhaust groove 22 is in the range of 0.1 mm to 1.0 mm, more preferably in the range of 0.5 mm to 0.8 mm. If the depth D1 is too small, the exhaust effect will be insufficient, and conversely if too large, air will remain in the groove.

  The ratio of the total area of the exhaust groove 22 to the area of the back surface of the precure tread 2 is in the range of 10% to 40%, more preferably in the range of 20% to 30%. If this ratio is too small, the exhaust effect will be insufficient, and conversely if too large, air will remain in the groove.

  As shown in FIG. 2, the inclination angle θ of the exhaust groove 22 with respect to the tire circumferential direction is in the range of 30 ° to 70 °, and more preferably in the range of 40 ° to 60 °. By disposing the exhaust groove 22 with an inclination angle θ with respect to the tire circumferential direction, air can be effectively discharged when the precure tread 2 is pressed along the tire circumferential direction by a stitcher during molding. it can. When the inclination angle θ is out of the above range, it is difficult to guide air to the outside in the width direction of the precure tread 2.

  In the above embodiment, the plurality of microgrooves 23 having a predetermined size and communicating with the exhaust groove 22 are provided at a predetermined density on the back surface portion of the precure tread 2 located on the base tire side. The air can be guided to the exhaust groove 22 through the microgroove 23 from a wide area on the back surface of the precure tread 2. Therefore, the air discharge effect can be further enhanced. However, although it is preferable to provide the microgroove 23 together with the exhaust groove 22, it is not always necessary.

  The width W2 of the microgroove 23 is 2 mm or less, more preferably in the range of 1 mm to 2 mm. If the width W2 is too small, the exhaust effect will be insufficient. Conversely, if it is too large, air will remain in the groove. Further, the depth D2 of the microgroove 23 is 0.5 mm or less, and more preferably in the range of 0.2 mm to 0.5 mm. If the depth D2 is too small, the exhaust effect will be insufficient, and conversely if too large, air will remain in the groove. In order to allow air to escape from the microgroove 23 to the exhaust groove 23, the depth D2 of the microgroove 23 needs to be smaller than the depth D1 of the exhaust groove 22.

  The ratio of the total area of the microgrooves 23 to the area of the back portion of the precure tread 2 is preferably in the range of 20% to 60%. If this ratio is too small, the exhaust effect will be insufficient, and conversely if too large, air will remain in the groove.

  FIG. 7 shows another precure tread used in the present invention, and FIG. 8 shows its main part. 7 and 8, the precure tread 2 has a diameter of 2 mm or less and a plurality of through holes 24 penetrating in the thickness direction of the precure tread 2. The inside of the through hole 24 is filled with an adhesive rubber layer 3. That is, a part of the unvulcanized rubber layer 3 flows into the through hole 24 due to the pressure during vulcanization, and the rubber layer 3 is vulcanized to close the through hole 24. Further, the through hole 24 is disposed at a position communicating with the exhaust groove 22.

  According to the above embodiment, the air staying between the adhesive rubber layer 3 and the precure tread 2 can be excluded from the tire from the through hole 24 as well, so that the air discharge effect can be further enhanced. it can. If the diameter of the through hole 24 exceeds 2 mm, the rubber layer 3 cannot sufficiently flow into the through hole 24 during vulcanization, and a clear trace of the through hole 24 remains in the tread after vulcanization. This is not preferable because it impairs the appearance of the product. However, even if the adhesive rubber layer 3 is not filled in the through hole 24, the effect of eliminating the air staying between the adhesive rubber layer 3 and the precure tread 2 outside the tire is sufficient. Secured.

  When the used tire of tire size 11R22.5 was rehabilitated by the precure tread method, the retreaded tires of the conventional examples and Examples 1 to 5 were obtained by changing the structure of the precure tread as shown in Table 1.

  In Comparative Example 1 and Example 1, a plurality of exhaust grooves having a predetermined dimension and communicating with at least one end in the width direction of the back surface portion are formed on the back surface portion of the precure tread on the base tire side. It was provided at a predetermined density.

  In Examples 2 to 5, a plurality of exhaust grooves having a predetermined size and communicating with at least one end in the width direction of the back surface portion are provided on the back surface portion of the precure tread on the base tire side. A plurality of microgrooves having a predetermined size and having a predetermined size and communicating with the exhaust groove were provided at a predetermined density. In Example 4, a plurality of through holes having a diameter of 2 mm are provided in the precure tread at a position communicating with the exhaust groove, and in Example 5, a plurality of through holes having a diameter of 2 mm are exhausted in the precure tread. It was provided at a position not communicating with the groove.

  In the conventional example, the precure tread was wound around the base tire via the rubber layer for adhesion without providing the exhaust groove and the micro groove as described above.

  The durability of these test tires was evaluated by the following evaluation method, and the results are also shown in Table 1.

durability:
A durability test was performed on each test tire after retreading, and the travel distance until the separation failure occurred in the tread was measured. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the durability.

  As is clear from Table 1, the tires of Examples 1 to 5 were superior in durability compared to the conventional examples. On the other hand, the tire of Comparative Example 1 was not sufficient although a slight improvement effect was observed.

1 tire 2 Precured tread 3 Adhesive rubber layer 11 Tread part 12 Side wall part 13 Bead part 21 Groove 22 Exhaust groove 23 Micro groove 24 Through hole

Claims (12)

  In a retreaded tire in which a belt-shaped precure tread is wound through an adhesive rubber layer on a base tire whose tread portion has been polished, a width of 5 mm to a back portion located on the base tire side of the precure tread A plurality of exhaust grooves having a depth of 30 mm and a depth of 0.1 mm to 1.0 mm and communicating with at least one end of the back surface in the width direction are provided, and the total area of the exhaust grooves with respect to the area of the back surface A retread tire characterized by having a ratio of 10 to 40%.   The retread tire according to claim 1, wherein an inclination angle of the exhaust groove with respect to a tire circumferential direction is set to 30 ° to 70 °.   A plurality of microgrooves having a width of 2 mm or less and a depth of 0.5 mm or less and communicating with the exhaust groove are provided on the back surface portion of the precure tread that is located on the base tire side. The retread tire according to claim 1 or 2, wherein a ratio of a total area of the microgrooves is set to 20% to 60%.   The retread tire according to any one of claims 1 to 3, wherein the precure tread is provided with a plurality of through holes having a diameter of 2 mm or less and penetrating in a thickness direction of the precure tread.   The rehabilitated tire according to claim 4, wherein the through hole is disposed at a position communicating with the exhaust groove.   6. The retread tire according to claim 4, wherein the adhesive rubber layer is filled in the through hole.   While polishing the tread part of the used tire to form a base tire, the back part located on the base tire side of the belt-shaped precure tread has a width of 5 to 30 mm and a depth of 0.1 to 1.0 mm. And a plurality of exhaust grooves communicating with at least one end in the width direction of the back surface portion, the ratio of the total area of the exhaust grooves to the area of the back surface portion being 10% to 40%, Wrapping the precure tread through an unvulcanized rubber layer for adhesion to a tire, and vulcanizing the rubber layer to join the base tire and the precure tread together. Manufacturing method for retreaded tires.   The method for manufacturing a retread tire according to claim 7, wherein an inclination angle of the exhaust groove with respect to a tire circumferential direction is set to 30 ° to 70 °.   A plurality of microgrooves having a width of 2 mm or less and a depth of 0.5 mm or less and communicating with the exhaust groove are provided on the back surface portion of the precure tread that is located on the base tire side. The method for producing a retread tire according to claim 7 or 8, wherein a ratio of a total area of the microgrooves is set to 20% to 60%.   The retread tire according to any one of claims 7 to 9, wherein the precure tread is provided with a plurality of through holes having a diameter of 2 mm or less and penetrating in a thickness direction of the precure tread. Production method.   The method for manufacturing a retread tire according to claim 10, wherein the through hole is disposed at a position communicating with the exhaust groove.   The method for producing a retread tire according to claim 10 or 11, wherein the rubber layer for adhesion is filled in the through hole when the rubber layer for adhesion is vulcanized.

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