JP6113951B2 - Pneumatic tire and tire mold - Google Patents

Description

  The present invention relates to a pneumatic tire in which a first circumferential ridge extending in the tire circumferential direction is provided on the outer side in the tire width direction of a bead portion so that a distance from the outer circumference of the rim flange is constant when the rim is mounted, and the air The present invention relates to a mold for molding a tire for molding a tire.

  The following method is illustrated as a manufacturing method of a general pneumatic tire. First, tire members such as an inner liner, a carcass ply, a bead, and a sidewall rubber are disposed at predetermined positions on a cylindrical molding drum. An unvulcanized tire is formed by expanding the diameter of the center of the forming drum and attaching a belt layer or tread rubber to the outside of the carcass ply. And a pneumatic tire is manufactured by carrying out the vulcanization molding of the unvulcanized tire with the tire shaping die.

  When each tire member is disposed on the molding drum, a step is likely to occur on the tire surface at the end of the member, so that air tends to accumulate during vulcanization molding, and the rubber flow is poor. In addition, since each tire member disposed on the forming drum is bulged and deformed by the diameter expansion mechanism on the inner side from the bead part, the tire surface shape near the boundary between the bead part and the sidewall part is recessed inward. Become. However, since the original profile is convex outward, the rubber flow is particularly poor near the boundary between the bead portion and the sidewall portion.

  In addition, a bead portion of a general pneumatic tire is provided with a rim strip having excellent wear resistance at least at a portion in contact with the rim. The outer end in the tire radial direction of the rim strip is disposed on the sidewall portion. It is connected to the arranged side wall rubber. Since the interface between the rim strip and the sidewall rubber is near the boundary between the bead portion and the sidewall portion, product defects such as cracks due to defective rubber flow are particularly likely to occur.

  In the following Patent Document 1, for the purpose of suppressing the occurrence of cracks at and near the interface between the rim strip and the sidewall rubber, from the outermost boundary line in the tire axial direction between the rim strip and the sidewall rubber, There is described a pneumatic tire in which a wrapping rubber is provided in a region between positions separating 5 mm in and out of the tire radial direction so as to cover this region and prevent the boundary line from being exposed. However, this pneumatic tire is not preferable in production because the number of molding steps increases because a tape-like wrapping rubber is applied. Furthermore, although the generation of cracks at and near the interface between the two rubbers can be suppressed by the wrapping rubber, there is a possibility that new cracks may occur at the interface between the wrapping rubber and the rim strip or the interface between the wrapping rubber and the side wall rubber. .

JP 2006-151329 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic tire and a tire molding die that can reduce product defects such as cracks at and near the interface between the rim strip and the sidewall rubber. It is to provide.

  The above object can be achieved by the present invention as described below. That is, in the pneumatic tire according to the present invention, the first circumferential ridge extending in the tire circumferential direction is provided on the outer side in the tire width direction of the bead portion so that the distance from the outer circumference of the rim flange is constant when the rim is mounted. In the pneumatic tire, the second circumferential ridge having a protruding height lower than that of the first circumferential ridge is spaced from the first circumferential ridge in the tire radial direction outside or inside. A first radial ridge extending in the tire radial direction and extending in the tire radial direction, and extending from the first circumferential ridge and the second circumferential ridge, and an interface between the rim strip and the sidewall rubber Is characterized in that it reaches the outer surface of the tire between the first circumferential ridge and the second circumferential ridge.

  According to the pneumatic tire of the present invention, at the time of vulcanization molding, air between the unvulcanized tire and a tire molding die (hereinafter sometimes simply referred to as a die) is used as the first circumferential ridge. The first circumferential groove of the mold corresponding to the second circumferential groove of the mold corresponding to the second circumferential protrusion, the first radial groove of the mold corresponding to the first radial protrusion Can be collected and discharged. Furthermore, the second circumferential ridge has a lower protruding height than the first circumferential ridge, in other words, the first circumferential ridge has a higher protruding height than the second circumferential ridge. The first circumferential groove is deeper than the second circumferential groove, and the air in the second circumferential groove is concentrated to the first circumferential groove through the first radial groove. Can be made. Thereby, the air discharge | emission at the time of vulcanization molding between a 1st circumferential direction protruding item | line and a 2nd circumferential direction protruding item | line can be performed effectively. Therefore, the interface between the rim strip and the sidewall rubber of the present invention reaches the outer surface of the tire between the first circumferential ridge and the second circumferential ridge. The air flow can be suppressed, and the rubber flow is improved. As a result, product defects such as cracks can be reduced.

  In the pneumatic tire according to the present invention, the tip of the first radial ridge is a straight line or a concentric circle of the profile connecting the tip of the first circumferential ridge and the tip of the second circumferential ridge. It is preferable to form along. According to this configuration, the air of the second circumferential recess of the mold corresponding to the second circumferential ridge is passed through the first radial recess of the mold corresponding to the first radial ridge. It is possible to efficiently concentrate on the first circumferential recess of the mold corresponding to the first circumferential projection.

  In the pneumatic tire according to the present invention, the first circumferential convexity is spaced from the first circumferential convexity on the outer side or the inner side in the tire radial direction and opposite to the second circumferential convexity. A third circumferential ridge having a protrusion height lower than that of the ridge extends in the tire circumferential direction, and a second radial ridge continuous with the first circumferential ridge and the third circumferential ridge is a tire. It is preferable to extend in the radial direction. According to this structure, since air can be collected and discharged also to the 3rd circumferential groove of the metal mold | die corresponding to a 3rd circumferential protrusion, the air discharge | emission at the time of vulcanization molding can be accelerated | stimulated.

  A tire molding die according to the present invention is a tire molding die for molding the pneumatic tire described above, and the tire molding surface has a first corresponding to the first circumferential protrusion. A first circumferential recess comprising a circumferential recess, a second circumferential recess corresponding to the second circumferential projection, and a first radial recess corresponding to the first radial projection. A vent hole is formed at the intersection of the strip and the first radial recess.

  According to the tire molding die of the present invention, during vulcanization molding, the air between the unvulcanized tire and the tire molding die is a first circumferential recess corresponding to the first circumferential projection, The second circumferential ridge corresponding to the second circumferential ridge and the first radial ridge corresponding to the first radial ridge can be collected and discharged. Further, the second circumferential ridge has a lower protruding height than the first circumferential ridge, in other words, the first circumferential ridge has a higher protruding height than the second circumferential ridge. The direction groove is deeper than the second circumferential groove, and the air of the second circumferential groove can be concentrated to the first circumferential groove through the first radial groove. it can. At this time, since the vent hole is formed at the intersection of the first circumferential groove and the first radial groove, the air that has passed through the first radial groove is transferred from the vent hole to the outside of the mold. Easily discharged. Thereby, the air discharge | emission at the time of vulcanization molding between a 1st circumferential direction protruding item | line and a 2nd circumferential direction protruding item | line can be performed effectively. Therefore, the interface between the rim strip and the sidewall rubber of the present invention reaches the outer surface of the tire between the first circumferential ridge and the second circumferential ridge. The air flow can be suppressed, and the rubber flow is improved. As a result, product defects such as cracks can be reduced.

Tire meridian cross-sectional view showing an example of a pneumatic tire according to the present invention Tire meridian cross-sectional view showing the main part of the pneumatic tire of FIG. 1 in an enlarged manner The front view which shows the principal part of an example of the pneumatic tire which concerns on this invention Tire meridian cross-sectional view showing a pneumatic tire according to another embodiment Tire meridian cross-sectional view showing a pneumatic tire according to another embodiment

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a tire meridian cross-sectional view showing an example of a pneumatic tire according to the present invention, and FIG. 2 is an enlarged view showing an essential part of the pneumatic tire of FIG. FIG. 3 is a front view showing a main part of the pneumatic tire according to the present invention.

  A pneumatic tire T according to the present invention includes a pair of annular bead portions 1, sidewall portions 2 extending from the bead portions 1 to the outer peripheral side, and outer peripheral side ends of the sidewall portions 2. And a tread portion (not shown) connected via a not shown.

  A bead core 4 surrounded by the carcass layer 3 is disposed in the bead portion 1, and the end portion of the carcass layer 3 is rewound and locked by the bead core 4 so that the space between the bead portions 1 is reinforced by the carcass layer 3. In this state, the pneumatic tire T is firmly fitted onto the rim R. A rim strip 5 and sidewall rubber 6 are disposed outside the carcass layer 3 in the tire width direction. The rim strip 5 has excellent wear resistance and is provided at least in a portion of the bead portion 1 that contacts the rim R.

  In the pneumatic tire T according to the present invention, as shown in the figure, the first circumferential ridge 11 extending in the tire circumferential direction CD has a bead portion 1 so that the distance from the outer circumference of the rim flange RF is constant when the rim is mounted. Is provided on the outer side in the tire width direction. The first circumferential ridge 11 extends in the tire circumferential direction CD so that the distance from the outer periphery of the rim flange RF is constant when the rim is mounted, and is the pneumatic tire T properly mounted on the rim R? It is for confirming whether or not. The first circumferential ridges 11 are provided such that the distance from the outer periphery of the rim flange RF is about 0 to 30 mm.

  The pneumatic tire T of the present embodiment is spaced from the first circumferential ridge 11 on the outer side in the tire radial direction, and the second circumferential ridge 12 has a lower protruding height than the first circumferential ridge 11. Are extended in the tire circumferential direction CD, and the first radial ridges 14 connected to the first circumferential ridges 11 and the second circumferential ridges 12 are extended in the tire radial direction. In addition, the tire outer surface on which the first circumferential ridges 11 and the second circumferential ridges 12 are provided is convex outward.

  The distance D between the first circumferential ridges 11 and the second circumferential ridges 12 is preferably 5 to 35 mm. Moreover, this space | interval D changes also with the kind of ply cord of the carcass layer 3, and 5-15 mm is preferable in the case of an organic fiber cord, and 8-10 mm is more preferable. In the case of a steel cord, 20-35 mm is preferable and 25-30 mm is more preferable. In addition, both the space | interval D is based on the center of the front-end | tip part of the 1st circumferential direction protruding item | line 11 and the 2nd circumferential direction protruding item | line 12, respectively.

  The cross-sectional shapes of the first circumferential ridge 11 and the second circumferential ridge 12 are substantially trapezoidal. However, the cross-sectional shapes of the first circumferential ridges 11 and the second circumferential ridges 12 are not limited to trapezoids, and may be squares, rectangles, triangles, semicircles, or the like.

  The protrusion heights H1 and H2 of the first circumferential ridge 11 and the second circumferential ridge 12 from the outer surface of the tire are preferably 0.3 to 1.5 mm from the viewpoint of appropriately discharging air. 8-1.0 mm is more preferable. Moreover, the width | variety of the 1st circumferential direction protruding item | line 11 and the 2nd circumferential direction protruding item | line 12 has preferable 1.0-2.0 mm from a viewpoint which performs air discharge | emission appropriately.

  The protrusion height H2 of the second circumferential ridge 12 is preferably 0.5 mm or more lower than the protrusion height H1 of the first circumferential ridge 11. When the difference in protrusion height between the second circumferential ridge 12 and the first circumferential ridge 11 is smaller than 0.5 mm, the air in the second circumferential ridge 12 passes through the first radial ridge 14. It becomes difficult to be discharged to the first circumferential protrusion 11. Furthermore, since the first circumferential ridge 11 is more conspicuous when the projection height H1 of the first circumferential ridge 11 is higher than the projection height H2 of the second circumferential ridge 12 by 0.5 mm or more, air It is easy to confirm whether the entering tire T is properly attached to the rim R, and there are few mistakes. Moreover, it is preferable that the difference of the protrusion height of the 2nd circumferential direction protruding item | line 12 and the 1st circumferential direction protruding item | line 11 is 1 mm or less. If this difference is greater than 1 mm, uneven air discharge occurs, leading to poor rubber flow.

  The first radial ridges 14 are connected to the first circumferential ridges 11 and the second circumferential ridges 12 and extend in the tire radial direction. The first radial ridges 14 extend in the tire radial direction or a direction inclined from the tire radial direction in a front view. In the present invention, from the viewpoint of efficiently discharging air, the extending direction of the first radial protrusion 14 is preferably within ± 15 ° in the tire radial direction, and more preferably in the tire radial direction.

  A plurality of first radial ridges 14 are preferably provided at intervals in the tire circumferential direction CD from the viewpoint of efficiently discharging air. The number of the first radial ridges 14 is preferably 8 to 24, and the first radial ridges 14 are preferably arranged at equal intervals in the tire circumferential direction CD.

  The cross-sectional shape of the first radial ridge 14 is substantially trapezoidal like the first circumferential ridge 11 and the second circumferential ridge 12. However, the cross-sectional shape of the first radial protrusion 14 is not limited to a trapezoid, and may be a square, a rectangle, a triangle, a semicircle, or the like.

  At the intersection 141 between the first radial ridge 14 and the first circumferential ridge 11, the protruding heights of the first radial ridge 14 and the first circumferential ridge 11 are equal. Further, at the intersection 142 of the first radial ridge 14 and the second circumferential ridge 12, the protruding heights of the first radial ridge 14 and the second circumferential ridge 12 are equal.

  The distal end portion 14 a of the first radial ridge 14 is formed along a straight line or a concentric circle of the profile connecting the distal end portion 11 a of the first circumferential ridge 11 and the distal end portion 12 a of the second circumferential ridge 12. It is preferable.

  The protrusion height of the first radial ridge 14 from the outer surface of the tire is more preferably 0.3 to 1.5 mm from the viewpoint of appropriately discharging air. Further, the width of the first radial protrusion 14 is preferably 1.0 to 2.0 mm from the viewpoint of appropriately discharging air.

  In the pneumatic tire T of the present invention, the interface 56 between the rim strip 5 and the sidewall rubber 6 reaches the tire outer surface between the first circumferential ridge 11 and the second circumferential ridge 12. The interface 56 only needs to reach the outer surface of the tire between the first circumferential ridge 11 and the second circumferential ridge 12, and the first circumferential ridge 11 or the second circumferential ridge 12 is installed. The outer surface of the tire may be reached at the position. However, the interface 56 reaches the tire outer surface within a range of 40% of the distance D between the first circumferential ridge 11 and the second circumferential ridge 12 with the first circumferential ridge 11 as a reference. Is preferred. Thereby, the crack at the time of the vulcanization molding in the interface 56 of the rim strip 5 and the side wall rubber 6 and its vicinity can be prevented effectively.

  At the intersection 141 between the first circumferential ridge 11 and the first radial ridge 14, a portion of the vent spew 16 may remain at the vent hole position of the tire molding die. The vent spew 16 can be completely excised.

  The pneumatic tire T of the present invention is the same as the normal pneumatic tire T except that the first circumferential ridge 11, the second circumferential ridge 12, and the first radial ridge 14 are provided. A structure, a tread pattern, a material, and a manufacturing method, and any conventionally known one can be applied.

  The pneumatic tire T of the present invention can be manufactured by the tire molding die of the present invention. That is, the tire molding die of the present invention is a tire molding die for molding the pneumatic tire T as described above, and the tire molding surface corresponds to the first circumferential ridge 11. A first circumferential recess, a first circumferential recess, a second circumferential recess corresponding to the second circumferential projection 12, and a first radial recess corresponding to the first radial projection 14; A vent hole is formed at the intersection of the strip and the first radial recess.

  Air between the tire outer surface of the unvulcanized tire and the tire molding surface of the tire molding die gathers in the first circumferential recess, the second circumferential recess, and the first radial recess, and finally Specifically, it is accumulated in the first circumferential recess. This is because in the pneumatic tire T of the present invention, the first circumferential ridge 11 has a higher projection height than the second circumferential ridge 12, so the first circumferential ridge is more than the second circumferential ridge. Because it is deep.

  The tire molding die of the present invention has the same structure and material as those of conventional dies except that each of the above-mentioned concave stripes and vent holes is provided, and any conventionally known ones can be applied.

<Another embodiment>
(1) In the above-described embodiment, the example in which the second circumferential ridge 12 is provided on the outer side in the tire radial direction than the first circumferential ridge 11 is shown. However, as shown in FIG. 12 may be extended in the tire circumferential direction CD with an interval on the inner side in the tire radial direction from the first circumferential protrusion 11. In this case, the distance D between the first circumferential ridges 11 and the second circumferential ridges 12 is preferably 5 to 10 mm, and more preferably 5 to 8 mm. If the distance D is too large, the second circumferential ridge 12 interferes with the rim flange RF, and the fitting with the rim R becomes worse.

  (2) In the pneumatic tire of the present invention, the first circumferential direction is spaced on the outer side or the inner side in the tire radial direction from the first circumferential ridge 11 and opposite to the second circumferential ridge 12. A third circumferential ridge 13 having a protrusion height lower than that of the ridge 11 extends in the tire circumferential direction CD, and is connected to the first circumferential ridge 11 and the third circumferential ridge 13 in the second radial direction. It is preferable that the ridges 15 extend in the tire radial direction. In FIG. 5, the second circumferential ridge 12 is provided outside the first circumferential ridge 11 in the tire radial direction, and the third circumferential ridge 13 is arranged inside the tire radial direction from the first circumferential ridge 11. An example is shown. A second circumferential ridge 12 is provided on the inner side in the tire radial direction from the first circumferential ridge 11, and a third circumferential ridge 13 is provided on the outer side in the tire radial direction from the first circumferential ridge 11. It doesn't matter.

  In this embodiment, the interface 56 between the rim strip 5 and the sidewall rubber 6 only needs to reach the tire outer surface between the second circumferential ridge 12 and the third circumferential ridge 13. The distance between the first circumferential ridges 11 and the second circumferential ridges 12 is preferably 5 to 35 mm, more preferably 8 to 10 mm when the ply cord of the carcass layer 3 is an organic fiber cord, 25-30 mm is more preferable. Moreover, 5-10 mm is preferable and, as for the space | interval of the 1st circumferential direction protruding item | line 11 and the 3rd circumferential direction protruding item | line 13, 5-8 mm is more preferable.

  Further, in this embodiment, the first radial ridges 14 and the second radial ridges 15 are not necessarily provided at the same position in the tire circumferential direction CD, and may be provided so as to be shifted from each other in the tire circumferential direction CD. .

  (3) In the above-described embodiment, an example in which a vent hole is formed at the intersection of the first circumferential groove and the first radial groove in the tire mold is described. The formation position is not limited to this. However, the vent hole is preferably formed along at least the first circumferential recess.

DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 5 Rim strip 6 Side wall rubber 11 1st circumferential direction protruding item | line 12 2nd circumferential direction protruding item | line 13 3rd circumferential direction protruding item | line 14 1st radial direction protruding item | line 15 2nd radial direction protruding item | line T Pneumatic tire R rim RF rim flange H1 Projection height of first circumferential ridge H2 Projection height of second circumferential ridge

Claims (5)

A first circumferential ridge extending in the tire circumferential direction is formed on the outer surface of the tire on the outer side in the tire width direction of the bead portion so that the distance from the outer circumference of the rim flange is constant outside the rim flange in the tire radial direction when the rim is mounted. In the pneumatic tire provided to protrude ,
A second circumferential ridge extends in the tire circumferential direction with an interval on the outer side or the inner side in the tire radial direction than the first circumferential ridge, and the first circumferential ridge and the second circumferential ridge A first radial ridge extending to the ridge extends in the tire radial direction,
The protrusion height in the direction perpendicular to the tire outer surface from the tire outer surface of the bead portion to the tip of the first circumferential ridge is 1.5 mm or less,
The protruding height in the direction perpendicular to the tire outer surface from the tire outer surface of the bead portion to the tip end portion of the second circumferential ridge is the height of the first circumferential ridge from the tire outer surface of the bead portion. 0.5 mm or more lower than the protruding height in the direction perpendicular to the outer surface of the tire up to the tip,
The pneumatic tire is characterized in that the interface between the rim strip and the sidewall rubber reaches the outer surface of the tire between the first circumferential ridge and the second circumferential ridge.   The tip of the first radial ridge is formed along a concentric circle of a straight line or profile connecting the tip of the first circumferential ridge and the tip of the second circumferential ridge. The pneumatic tire according to claim 1. A tip portion from the outer surface of the tire to the outer circumferential surface of the first circumferential ridge, with an interval on the outer side or inner side in the tire radial direction from the first circumferential ridge and opposite to the second circumferential ridge. A third circumferential ridge having a low protrusion height in a direction perpendicular to the outer surface of the tire is extended in the tire circumferential direction, and is continuous with the first circumferential ridge and the third circumferential ridge. The pneumatic tire according to claim 1 or 2, wherein the second radial ridge is extended in the tire radial direction.   The interface reaches the tire outer surface within a range of 40% of the interval between the first circumferential ridge and the second circumferential ridge, with the first circumferential ridge as a reference. The pneumatic tire according to any one of claims 1 to 3. A mold for molding a tire for molding the pneumatic tire according to claim 1,
Corresponding to the first circumferential ridge corresponding to the first circumferential ridge, the second circumferential ridge corresponding to the second circumferential ridge, and the first radial ridge on the tire molding surface A first radial recess to be
A mold for molding a tire, wherein a vent hole is formed at an intersection between the first circumferential groove and the first radial groove.