JP2011031446A - Method for manufacturing tire, and tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress occurrence of air entry between a belt reinforcing layer and a tread when a rubber strip is laminated on the belt reinforcing layer formed in a divided state to form the tread having a base part and a cap part. <P>SOLUTION: The belt reinforcing layer 80 is divided in its width direction and reinforcing members 82 are superposed on the belt reinforcing layer 80 at the divided position D of the belt reinforcing layer 80 to be formed on the outer periphery of an object to be molded. Rubber strips G1 are laminated on the belt reinforcing layer 80 excepting the non-laminated range H including level differences of the superposed part of the belt reinforcing layer 80 and a base part 11 is formed without covering the superposed part of the belt reinforcing layer 80. Rubber strips G2 are successively superposed and laminated along the outer periphery of the base part 11 to form a cap part 12. The lamination interval of the rubber strips G2 is altered during the formation of the cap part 12 and made narrower than another range in the non-laminated range H of the base part 11 and the rubber strips G2 large in angle of lamination are laminated on the belt reinforcing layer 80. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire manufacturing method in which a rubber strip is laminated on a belt reinforcing layer to form a tread, and an unvulcanized tire is molded, and a tire manufactured by the tire manufacturing method.

  In a tire such as a pneumatic tire, a belt reinforcing layer having a cord extending in the tire circumferential direction is disposed between the belt and the tread of the outer peripheral surface, and the belt is reinforced to improve tire performance such as high-speed durability. Has been done. Conventionally, a tire is used which has a tread with a base portion on the inner surface side, which has high heat generation and a small thickness, and a cap portion on the outer surface side which mainly contributes to the tread performance, and ensures required performance.

By the way, there is known an apparatus for forming a belt reinforcing layer by providing a plurality of reinforcing member winding means for covering a cord with rubber or the like and forming a belt reinforcing layer by simultaneously winding a plurality of reinforcing members spirally around a molded object. (See Patent Document 1).
Further, conventionally, there is a tire manufacturing method in which a ribbon-shaped rubber strip is wound in a spiral shape and laminated, and a base portion and a cap portion that overlaps the outer periphery thereof are sequentially formed to form a tread in a predetermined cross-sectional shape and structure. It is known (see Patent Document 2).

FIG. 5 is a schematic view showing an example of a conventional tire manufacturing method for forming a belt reinforcing layer and a tread in this manner, and shows an enlarged main part of a tire width direction cross section.
Here, as shown in the figure, a belt reinforcing layer 80 and a tread 90 are sequentially formed on the outer periphery of the molded body 70 on which the belt 71 is disposed at a predetermined stage of unvulcanized tire molding. The belt reinforcing layer 80 (see FIG. 5A) starts winding a reinforcing member having a predetermined width from the side portion 72 around the rotating molded body 70 (arrow M1), and at the same time, reinforces from the vicinity of the tire equatorial plane CL. The winding of the member is started (arrow M2). In this way, the belt reinforcing layer 80 is divided in the width direction, and the reinforcing members are respectively wound in a spiral shape, and at the dividing position D, the reinforcing members of the belt reinforcing layers 80A and 80B that are separately formed are overlapped, One belt reinforcing layer 80 is formed on the molded body 70.

  On the other hand, the tread 90 (see FIG. 5B) continuously wraps the rubber strip of the base portion 91 spirally between the side portions 72 of the rotating molded body 70 (arrow M3). A base portion 91 is formed by laminating the entire outer periphery of 80. Subsequently, along the outer periphery of the base portion 91, the rubber strip of the cap portion 92 is spirally wound and laminated in order (arrow M4), the cap portion 92 is formed, and the formation of the tread 90 is completed.

FIG. 6 is a main part sectional view showing the belt reinforcing layer 80 and the tread 90 formed as described above, and schematically shows a part around the tire equatorial plane CL. FIG. 7 is a sectional view schematically showing the Z range of FIG. 6 in an enlarged manner.
As shown in the figure, the belt reinforcing layer 80 is composed of a belt-like reinforcing member 82 in which a plurality (six in the figure) of parallel cords 81 (see FIG. 7) are covered with unvulcanized rubber. The side surfaces are brought into contact with each other and wound along the tire circumferential direction to form two layers. At that time, the two reinforcing members 82 are wound simultaneously, and the belt reinforcing layer 80 is divided and formed in the width direction, whereby the belt reinforcing layer 80 is efficiently formed and the formation time is shortened. However, in this case, in order to prevent a gap from being formed between the separately formed belt reinforcing layers 80A and 80B, it is necessary to overlap the reinforcing members 82 at the dividing position D, and the belt reinforcing layers 80A and 80B are overlapped. There is a difference in level.

  In the tread 90 (see FIG. 6), rubber strips G1 and G2 (G1 is hatched) are stacked on each other on the outer periphery of the belt reinforcing layer 80, and a base portion 91 and a cap portion 92 are sequentially formed. Is done. At this time, the base portion 91 and the cap portion 92 are formed by rubber strips G1 and G2 formed to have the same width in order to eliminate waste of rubber molding. In the base portion 91, the lamination interval of the rubber strips G1 is widened. Then, the overlap width and the stacking angle are reduced, and the gauge (thickness) is formed thin. On the other hand, in the cap portion 92, the tread 90 is formed in a necessary rubber gauge by narrowing the stacking interval of the rubber strips G2, increasing the overlap width and stacking angle, and increasing the gauge.

  However, when the tread 90 is formed as described above, the rubber strip G1 of the base portion 91 is disposed along the tire width direction, and the belt reinforcing layers 80A and 80B described above are formed by the relatively wide rubber strip G1. The steps of the overlapped parts may be covered. As a result, air is trapped in the overlapping portion (see FIG. 7) where the belt reinforcing layer 80 is divided by the wide rubber strip G1 without filling the step, and there is a possibility that a gap V is generated near the step. In addition, when the air gap V is generated in this way, the rubber strip G1 prevents air from being discharged, and air may easily accumulate. Therefore, from the viewpoint of suppressing the occurrence of air entering between the belt reinforcing layer 80 and the tread 90, it is required to cope with air confinement while preventing the rubber gauge of the tread 90 from being insufficient.

JP-A-7-314574 JP 2006-130880 A

  The present invention has been made in view of such conventional problems, and its purpose is to form a tread having a base portion and a cap portion by laminating a rubber strip on a separately formed belt reinforcing layer. While securing the rubber gauge of the tread, it is to prevent air from being trapped in the overlapped portion of the belt reinforcing layer and to suppress the occurrence of air entering between the belt reinforcing layer and the tread.

The present invention relates to a tire manufacturing method for forming an unvulcanized tire by forming a tread having a base portion and a cap portion by laminating rubber strips with a belt reinforcing layer sandwiched around the outer periphery of a molded body, The step of dividing the reinforcing layer in the width direction and overlapping each other at the dividing position to form the outer periphery of the molded body, and laminating the rubber strip on the belt reinforcing layer without covering at least the overlapped portion of the belt reinforcing layer Forming the base part, forming a cap part by sequentially laminating and laminating rubber strips along the outer periphery of the base part, and changing the lamination interval of the rubber strips during the formation of the cap part. And a step of narrowing the stacking interval in the range where the rubber strip of the base portion is not stacked, compared to other ranges.
Further, the present invention is a tire provided with a tread formed of a rubber strip, and is divided into a width direction and overlapped with each other at a division position, and a belt reinforcing layer disposed inside the tread is provided. Provided, the tread does not cover at least the overlapped portion of the belt reinforcing layer, and the base portion formed by laminating the rubber strip on the belt reinforcing layer and the rubber strip are sequentially laminated along the outer periphery of the base portion. And a cap portion in which the rubber strips in the range where the rubber strips in the base portion are not laminated are narrower than the lamination intervals in the other ranges.

  According to the present invention, when forming a tread having a base portion and a cap portion by laminating rubber strips on the separately formed belt reinforcing layer, the belt reinforcing layer is divided at the divided positions while ensuring the rubber gauge of the tread. Air can be prevented from being trapped in the portion, and the occurrence of air entering between the belt reinforcing layer and the tread can be suppressed.

It is a schematic diagram for demonstrating the tire manufacturing method of this embodiment. It is principal part sectional drawing which shows the belt reinforcement layer and tread which were formed with the tire manufacturing method of this embodiment. It is sectional drawing which expands and shows the Y range of FIG. It is sectional drawing which shows typically the rubber strip laminated | stacked by changing the lamination | stacking space | interval. It is a schematic diagram which shows the example of the conventional tire manufacturing method. It is principal part sectional drawing which shows the example of the conventional belt reinforcement layer and a tread. It is sectional drawing which expands and shows the Z range of FIG.

Hereinafter, a tire manufacturing method and a tire according to an embodiment of the present invention will be described with reference to the drawings.
In the tire manufacturing method of the present embodiment, a rubber strip is laminated on the outer periphery of the molded body, and a tread (tread rubber) having a base portion and a cap portion is formed to form an unvulcanized tire. To do. At this time, in the same manner as described above, the belt reinforcing layer is formed by a band-shaped reinforcing member in which a plurality of parallel cords are covered with unvulcanized rubber. Further, the base portion and the cap portion of the tread are formed of rubber strips made of different types and characteristics of rubber and molded to the same width.

  Here, the molded body is, for example, an unvulcanized tire in the middle of molding, an intermediate molded body such as a tire case, or a base tire before rehabilitation from which the tread is removed from the tire, and the belt is formed at a predetermined stage of tire molding. A reinforcing layer and a tread are formed. However, the molding object may be a molding drum for molding an assembly of a belt and a tread, and its configuration is not particularly limited as long as it is an object that forms at least a belt reinforcing layer and a tread. When the molded body is a molding drum, an unvulcanized tire is molded by bonding the molded belt / tread assembly to the outer periphery of another member disposed inside the molded body. The unvulcanized tire is a tire provided with an unvulcanized tread, and includes a retreaded tire before vulcanization in which an unvulcanized tread is newly arranged in addition to a raw tire. Hereinafter, a case where a raw tire is molded by forming a belt reinforcing layer and a tread on an unvulcanized tire in the middle of molding will be described as an example.

  FIG. 1 is a schematic diagram for explaining the tire manufacturing method of the present embodiment, and shows an enlarged main portion of a cross section in the tire width direction. FIG. 2 is a cross-sectional view of a main part showing a belt reinforcing layer and a tread formed by this tire manufacturing method, and schematically shows a part centering on the tire equatorial plane CL. FIG. 3 is a cross-sectional view schematically showing the Y range of FIG. 2 in an enlarged manner.

  In this tire manufacturing method, as shown in the figure, at a predetermined stage of unvulcanized tire molding, a belt reinforcing layer 80 made of a reinforcing member 82 and a rubber strip are provided on the outer periphery of a molded body 70 on which two belts 71 are arranged. A tread 10 composed of G1 and G2 (G1 is hatched) is formed in order. At that time, for example, the belt reinforcing layer 80 is formed by a supplying means or a winding means (not shown) of the reinforcing member 82, and the tread 10 is an extruder or a laminating means (not shown) of the rubber strips G1 and G2. It is formed by. That is, the reinforcing member 82 (see FIG. 2) is continuously supplied from the supply means, wound around the object 70 to be rotated by the pressing roller of the winding means, and wound along the outer surface of the object 70. The pressure roller that gradually moves is pressed against a predetermined position of the molded body 70 and disposed. Further, the rubber strips G1 and G2 are continuously formed by extruding unvulcanized rubber by an extruder, wound around the molding body 70 while being pressed by a laminating roller of a laminating means, and wound around the outer surface of the molding body 70. The laminated rollers that move gradually along the side are pressed and laminated at predetermined positions on the molded body 70. In the present embodiment, two sets of supplying means and winding means for the reinforcing member 82 are provided, and the belt reinforcing layer 80 is formed by the two reinforcing members 82. Further, two sets of extruders and laminating means for one rubber strip G1 are provided, and the base portion 11 of the tread 10 is formed by two rubber strips G1, and the cap portion 12 is formed by one rubber strip G2.

  The belt reinforcing layer 80 (see FIG. 1A) rotates the molding 70 by rotating means, starts winding of the reinforcing member 82 from the side portion 72 around the outer periphery (arrow M1), and at the same time, the tire equatorial plane The winding of the reinforcing member 82 is also started from the vicinity of CL (arrow M2). These two reinforcing members 82 are gradually displaced in the tire width direction while being arranged along the tire circumferential direction, and are spirally wound around the object 70 to be rotated while abutting the side surfaces in order, and the tire equatorial plane CL And the side part 72 is laminated. As a result, the belt reinforcing layer 80 is divided and formed simultaneously in the width direction around the tire equatorial plane CL, and one or more reinforcing members 82 (here, Then, two layers) are stacked. Further, at the division position D (see FIG. 3) of the tire equatorial plane CL, the reinforcement members 82 of the belt reinforcement layers 80A and 80B that are separately formed are overlapped with each other to cover one belt reinforcement layer 80 in which they are integrated. It forms in the molded object 70 (refer FIG. 2).

  In this way, the belt reinforcing layer 80 is divided into two or more (here, two) in the width direction, and the side portions (reinforcing members 82) are overlapped with each other at the dividing position D and formed on the outer periphery of the molded body 70 Then, a belt reinforcing layer 80 in which a plurality of cords 81 spirally extending in the tire circumferential direction are arranged in parallel is disposed on the molded body 70. Next, the base portion 11 on the inner surface side that contacts the belt reinforcing layer 80 of the tread 10 and the cap portion 12 on the outer surface side where the tread pattern is formed are sequentially formed on the outer periphery of the molded body 70 on which the belt reinforcing layer 80 is formed. To do. Thereby, the tread 10 having the thin base portion 11 and the thick cap portion 12 is formed in a predetermined shape in a predetermined range on the outer periphery of the molded body 70 including the belt reinforcing layer 80.

  First, the base portion 11 (see FIG. 1B) starts the lamination of the rubber strip G1 constituting the base portion 11 from both side portions 72 of the rotating molded body 70 (arrows S1 and S2). Two rubber strips G1 are laminated simultaneously. These two rubber strips G1 are arranged along the tire circumferential direction, gradually displaced in the tire width direction and continuously wound in a spiral manner, and laminated with a predetermined range overlapping each other up to the vicinity of the tire equatorial plane CL. To do. Thus, the rubber strips G1 are laminated on both sides of the stepped portion (see FIG. 3) where the belt reinforcing layers 80A and 80B are overlapped, and the base portions 11A and 11B divided in the tire width direction are simultaneously formed.

  In the present embodiment, when the base portion 11 of the tread 10 is formed on the outer periphery of the molded body 70, the belt reinforcement is performed except for a predetermined non-lamination range of the belt reinforcement layer 80 (range H in FIGS. 2 and 3). The rubber strip G1 is laminated on the outer periphery of the layer 80 without any gap. The non-lamination range H includes a step of the overlapping portion of the belt reinforcing layer 80 and is set wider than that. The overlapping portion of the belt reinforcing layer 80 and the reinforcing member 82 in the range H is laminated with the rubber strip G1. Without being exposed from the base portion 11. In this manner, the base portion 11 is formed by laminating the rubber strip G1 on the belt reinforcing layer 80 without covering at least the overlapping portion of the belt reinforcing layer 80 (here, at least a predetermined range including the overlapping portion). .

  At that time, the opposed end portions of the divided base portions 11A and 11B are provided with grooves 13 (here, circumferential grooves extending in the tire circumferential direction) of the tread 10 (virtually indicated by a two-dot chain line in the upper part of FIG. 2). It is located inside or outside (here, inside) in the tire width direction with respect to the formed position (groove forming position M). That is, when the rubber strip G1 is laminated, the ends F1 and F2 of the rubber strip G1 on both sides (see FIG. 2) sandwiching the overlapped portion of the belt reinforcing layer 80 are removed from the groove forming position M of the tread 10, It is arranged at a position shifted from the inside in the tire radial direction. As a result, the ends F1 and F2 of the rubber strip G1 on both sides and the groove forming position M are arranged at different tire width direction positions across the tire equatorial plane CL and the non-lamination range H, and the lamination of the rubber strip G1 is completed. Thus, the base portion 11 is formed. Next, the cap part 12 of the tread 10 is formed so as to overlap the base part 11.

  The cap part 12 (see FIG. 1B) starts the lamination of the rubber strip G2 constituting the cap part 12 from one side part 72 of the rotating molded body 70 (arrow S3). The rubber strip G <b> 2 is gradually displaced in the tire width direction while being arranged along the tire circumferential direction and continuously wound in a spiral manner, and the predetermined range is overlapped and laminated to the other side portion 72. Thereby, along the outer periphery of the base portion 11 (including the range where the rubber strip G1 is not laminated), the rubber strip G2 is sequentially overlapped and laminated over the entire outer periphery to form the cap portion 12. A tread 10 having a predetermined shape is formed on the outer periphery of the molded body 70 (see FIGS. 2 and 3). However, in the present embodiment, the stacking interval of the rubber strips G2 is changed during the formation of the cap portion 12, and the other portions (the rubber strip G1 of the rubber strip G1) are not stacked in the non-stacking range H where the rubber strip G1 of the base portion 11 is not stacked. The stacking interval is made narrower than the stacking range.

FIG. 4 is a cross-sectional view schematically showing the rubber strips G1 and G2 laminated by changing the lamination interval, and the lamination interval (P1>P2> P3) becomes narrower in the order of A to C.
As shown in the figure, the rubber strips G1 and G2 have the same overlap width and stacking angle with respect to the stacked surface as the stacking interval is narrow, even when the width is the same, and the gauge (thickness) as a whole after stacking is increased. Become thicker. In this way, the rubber gauge can be changed according to the stacking interval, and by using this, each part of the base part 11 and the cap part 12 is formed in each necessary thickness. Specifically, in the base portion 11 (see FIG. 4A), the lamination interval P1 of the rubber strip G1 is widened to reduce the lamination angle, and the gauge T1 is thinly formed.

  On the other hand, in the cap portion 12 (see FIGS. 4B and 4C), the lamination intervals P2 and P3 of the rubber strip G2 are narrowed to increase the lamination angle, and the gauges T2 and T3 are formed thick. The cap portion 12 is formed by laminating the rubber strip G2 on the base portion 11 at the lamination interval P2 in the lamination range (see FIG. 4B) of the rubber strip G1 of the base portion 11, and in the non-lamination range H (see FIG. 4C). The rubber strip G2 is laminated on the belt reinforcing layer 80 by relatively narrowing the lamination interval P3. As described above, in the cap portion 12, the rubber strip G2 is laminated with the lamination interval continuously changed between the non-lamination range H and the range before and after the non-lamination range H, and the non-lamination range H is laminated with a narrow lamination interval P3. Thus, the gauge T3 is made thicker. As a result, the cap portion 12 is thickened according to the gauge T1 of the base portion 11 at a portion where the rubber strip G1 of the base portion 11 is not present (see FIGS. 2 and 3), and the tread 10 including the base portion 11 and the cap portion 12 is formed. The entire thickness of the rubber is made uniform to form the required rubber gauge. At the same time, in the non-lamination range H (see FIG. 3), the side portions in the width direction of the rubber strip G2 are arranged in accordance with the surface of the belt reinforcing layer 80, and are laminated in contact with the step portions.

  The unvulcanized tire molded through these steps is housed in a vulcanization mold of a tire vulcanizer and vulcanized. Thereby, the predetermined tread pattern which consists of the groove | channel 13 (refer FIG. 2) etc. is formed in the tread 10, and various tires, such as a pneumatic tire, are manufactured.

  The manufactured tire is provided with a tread 10 formed of rubber strips G1 and G2 in the tread portion, and is divided in the width direction and overlapped with each other at the division position D, and is disposed inside the tread 10. The belt reinforcing layer 80 is provided. Further, the tread 10 does not cover at least the overlapped portion of the belt reinforcing layer 80, and the base portion 11 formed by laminating the rubber strip G1 on the belt reinforcing layer 80, and the rubber strip along the outer periphery of the base portion 11 And a cap portion 12 formed by sequentially laminating G2. The base portion 11 is formed by laminating a rubber strip G1 on the belt reinforcement layer 80 except for a non-lamination range H that is set to include a step in the overlapping portion of the belt reinforcement layer 80. Further, in this tire, in the base portion 11, the end portions F <b> 1 and F <b> 2 of the rubber strips G <b> 1 on both sides sandwiching the overlapping portion of the belt reinforcing layer 80 are arranged with the groove forming position M of the tread 10 being removed. On the other hand, in the cap portion 12, the lamination interval P3 of the rubber strip G2 in the range where the rubber strip G1 of the base portion 11 is not laminated is narrower than the lamination interval P2 in the other range.

  As described above, in the present embodiment, the belt reinforcing layer 80 is divided in the width direction and overlapped with each other at the dividing position D to be formed on the outer periphery of the molded body 70. The formation time can be shortened by forming efficiently. Further, after forming the base portion 11 of the tread 10 without covering the portion where the belt reinforcing layer 80 is overlapped, the rubber strip G2 is sequentially overlapped and laminated along the outer periphery of the base portion 11 to form the cap portion 12. To do. Therefore, the rubber strip G1 of the base portion 11 does not cover the step of the overlapped portion of the belt reinforcing layer 80, and air is not confined in the vicinity thereof, and it is possible to prevent a gap from being generated in the vicinity of the step.

  In addition, the overall thickness of the tread 10 is reduced as described above by narrowing the stacking interval of the rubber strips G2 of the cap portion 12 in a range where the rubber strip G1 of the base portion 11 is not stacked, as described above. The thickness can be made uniform and the required rubber gauge can be formed. Further, since the side portions of the rubber strip G2 having a large lamination angle can be laminated in contact with the step portions of the belt reinforcement layer 80, the rubber strip G2 is laminated on the surface of the belt reinforcement layer 80 to fill the steps. An effect is obtained. At the same time, even if air remains between the belt reinforcing layer 80 and the cap portion 12, air is relatively easily discharged to the outside through the plurality of rubber strips G2 having a large lamination angle during vulcanization molding. It is possible to suppress the accumulation of air between them.

  Therefore, according to this embodiment, when the tread 10 having the base portion 11 and the cap portion 12 is formed by laminating the rubber strips G1 and G2 on the separately formed belt reinforcing layer 80, the necessary rubber gauge of the tread 10 is provided. The cross-sectional shape can be secured and set. In addition, air can be prevented from being trapped in the overlapped portion of the belt reinforcing layer 80 at the division position D, and the occurrence of air entering between the belt reinforcing layer 80 and the tread 10 can be suppressed. Further, here, a non-lamination range H is set including the step of the overlapped portion of the belt reinforcement layer 80, and the rubber strip G1 is laminated on the belt reinforcement layer 80 except for the range H. At that time, the non-lamination range H is appropriately set according to the range and position error or variation of the belt reinforcing layer 80 where the reinforcing members 82 are overlapped, or the degree of the level difference generated. The rubber strip G1 can be laminated in an appropriate range without reliably covering the covered portion.

  Here, when the base portion 11 (see FIG. 2) is formed, the end portions F1 and F2 of the rubber strips G1 on both sides sandwiching the overlapping portion of the belt reinforcing layer 80 are placed in the groove forming position M of the tread 10. If it arrange | positions, the pressure accompanying formation of the groove | channel 13 will act large on edge part F1, F2 at the time of a vulcanization molding. Further, due to the influence of the rubber flow according to the formation of the groove 13, a force for changing the position acts on the end portions F1 and F2 of the rubber strip G1. As a result, the end portions F1 and F2 are displaced from the predetermined arrangement positions to approach the stepped portion of the belt reinforcing layer 80, or the range without the rubber strip G1 of the base portion 11 is wider or narrower than the desired range. There is a risk of becoming. Therefore, it is desirable that the end portions F1 and F2 of the rubber strip G1 are arranged with the groove forming position M of the tread 10 removed. However, when it is necessary to arrange the end portions F1 and F2 of the rubber strip G1 in the groove forming position M, the center position N of the groove 13 on which the greatest force acts is removed, thereby generating a large displacement. Can be suppressed.

  In the present embodiment, the belt reinforcing layer 80 is divided into two parts on the tire equatorial plane CL. However, the belt reinforcing layer 80 may be divided and formed at a position other than the tire equatorial plane CL. Further, the belt reinforcing layer 80 may be formed by being divided into three or more. In this case, the base portion 11 and the cap portion 12 of the tread 10 are formed in the same manner as described above at each division position. On the other hand, the tread 10 may also be a rubber member having another rubber layer such as a side portion along both side portions in addition to the base portion 11 and the cap portion 12.

(Tire manufacturing test)
In order to confirm the effect of the present invention, the belt reinforcing layer 80 and the tread 10 were formed by the tire manufacturing method described above to form an unvulcanized tire, and then the tire was manufactured by vulcanization molding. This tire was inspected by an inspection device (here, shearography) that can identify the internal defects non-destructively, and checked for the presence of air. In the test, 41 and 30 radial ply tires for passenger cars having tire sizes 235 / 35R19 and 235 / 40R18 defined by JATMA YEAR BOOK (2009, Japan Automobile Tire Association Standard) were manufactured, and each of them was inspected for air entry. The test results are shown in Table 1.

  As a result, as shown in Table 1, all tires were not inflated, and the inspection pass rates were 41% for 41 tires and 30% for 30 tires, respectively. As a result, it has been proved that the present invention can prevent air from being trapped in the overlapped portion of the dividing position D of the belt reinforcing layer 80 and suppress the occurrence of air entering between the belt reinforcing layer 80 and the tread 10.

  DESCRIPTION OF SYMBOLS 10 ... Tread, 11 ... Base part, 12 ... Cap part, 70 ... Molded object, 71 ... Belt, 80 ... Belt reinforcement layer, 81 ... Cord, 82. ..Reinforcing member, CL: Tire equatorial plane, D: Dividing position, G1, G2: Rubber strip.

Claims (6)

A tire manufacturing method for forming an unvulcanized tire by forming a tread having a base portion and a cap portion by laminating a rubber strip with a belt reinforcing layer sandwiched on the outer periphery of a molded body,
Dividing the belt reinforcing layer in the width direction and forming the belt reinforcing layer on the outer periphery of the molding by overlapping each other at the dividing position;
Forming a base portion by laminating a rubber strip on the belt reinforcing layer without covering at least the overlapped portion of the belt reinforcing layer;
A process of forming a cap portion by sequentially laminating and laminating rubber strips along the outer periphery of the base portion;
Changing the lamination interval of the rubber strip during the formation of the cap portion, and making the lamination interval narrower than the other range in a range where the rubber strip of the base portion is not laminated;
A tire manufacturing method comprising: In the tire manufacturing method according to claim 1,
The tire manufacturing method characterized in that the step of forming the base portion includes the step of disposing the ends of the rubber strips on both sides sandwiching the overlapped portion of the belt reinforcing layer with the groove forming position of the tread being removed. In the tire manufacturing method according to claim 1 or 2,
The method of manufacturing a tire characterized in that the step of forming the base portion includes a step of laminating a rubber strip on the belt reinforcement layer except for a non-lamination range set including a step of the overlapped portion of the belt reinforcement layer. . A tire with a tread formed by a rubber strip,
A belt reinforcing layer that is divided in the width direction and overlapped with each other at the dividing position and is disposed inside the tread,
The tread does not cover at least the overlapped portion of the belt reinforcement layer, and the base portion formed by laminating the rubber strip on the belt reinforcement layer and the rubber strip are sequentially laminated and laminated along the outer periphery of the base portion. A tire having a cap portion that is formed and in which a rubber strip in a range where the rubber strip of the base portion is not laminated is narrower than a lamination interval in another range. In the tire according to claim 4,
The tire is characterized in that the base portion is arranged with the ends of the rubber strips on both sides sandwiching the overlapped portion of the belt reinforcing layer being removed from the tread groove forming position. In the tire according to claim 4 or 5,
A tire characterized in that a base portion is formed by laminating a rubber strip on a belt reinforcing layer except for a non-lamination range set including a step difference in a portion where belt reinforcing layers are overlapped.

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