JP3568321B2 - Pneumatic tire and mold for molding the tire - Google Patents

Description

表１から明らかなように、本発明タイヤは、リムフランジを保護する隆起状突起に起因するエア溜まりの発生を抑制し、加硫故障を大幅に改善することができるのが判る。
【００２６】
【発明の効果】
上述したように本発明は、リムフランジを保護する隆起状突起を設けた空気入りタイヤにおいて、隆起状突起のリムフランジと対面するタイヤ内径側斜面を、その下端から上端にかけて延びる微小な凹部と凸部とを交互に配置した微小凹凸面に形成し、そのタイヤ内径側斜面上端にタイヤ周方向に連続して延びる微小凸部を設けたので、隆起状突起に起因するエア溜まりの発生を大きく抑え、加硫故障を大幅に低減することができる。
【図面の簡単な説明】
【図１】本発明の空気入りタイヤの一例を示すタイヤ子午線半断面図である。
【図２】図１のＡーＡ矢視拡大図である。
【図３】図１の空気入りタイヤを成形する本発明のタイヤ成形用金型の一例を示す要部断面図である。
【図４】図３のＢーＢ矢視拡大図である。
【図５】本発明の空気入りタイヤの他の例を示すタイヤ子午線半断面図である。
【符号の説明】
１ トレッド部 ２ ビード部
３ サイドウォール部 １０ 隆起状突起
１０ａ タイヤ内径側斜面 １０a₁ 下端
１０a₂ 上端 １０a₃ 微小凸部
１２Ａ，１２Ｂ ビード部成形面 １５ 成形凹部
１５ｃ 内径側壁面 １５c₁ 開口側端
１５c₂ 底側端 １６ ベントホール（エア抜き路）
Ｍ 金型 Ｍ１ 上型
Ｍ２ 下型 Ｘ リム
Ｘ１ リムフランジ ｍ 凹部
ｎ 凸部 ｘ 第１エア抜き溝
ｙ 第２エア抜き溝[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pneumatic tire and a mold for molding the tire, and more particularly, to a pneumatic tire provided with raised protrusions for protecting a rim flange, an air pocket generated due to the raised protrusions. The present invention relates to a pneumatic tire and a mold for molding the tire.
[0002]
[Prior art]
For example, a flat tire has a reduced tire cross-sectional height, and thus easily damages a flange of a rim mounted with curbs or holes. Therefore, conventionally, as a countermeasure, annular raised protrusions extending in the circumferential direction of the tire are respectively protruded from the bead base on the tread portion side to sidewall portions within a range of the tire maximum width point from a point of 22 mm from the bead base, and the rim is provided. There is a proposal to protect the flange.
[0003]
In general, the above-mentioned raised protrusion is made thicker by the thickness of the wall portion from the sidewall portion to the bead portion at the time of molding the green tire, and at the time of forming with a mold, the protrusion portion is raised and molded. ing. However, in order to protect the rim flange, it is necessary to protrude the raised protrusion so as to completely cover the rim flange, and a large volume change occurs during vulcanization.
[0004]
In particular, air accumulation is likely to occur on the slope side of the tire inner diameter side facing the rim flange of the raised protrusion having a large volume change, thereby causing a vulcanization failure such as a crack due to poor rubber flow.
[0005]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire capable of suppressing the occurrence of air pockets during vulcanization caused by raised protrusions for protecting a rim flange and reducing vulcanization failure, and a mold for molding the tire. To provide.
[0006]
[Means for Solving the Problems]
The pneumatic tire of the present invention that achieves the above object is a pneumatic tire in which raised protrusions for protecting rim flanges are respectively provided on left and right sidewall portions and extending in the tire circumferential direction, wherein the pneumatic tire faces the rim flange of the raised protrusions. The tire inner diameter side slope is formed on a minute uneven surface in which minute recesses and protrusions extending from the lower end to the upper end thereof are alternately arranged, and the minute protrusion continuously extending in the tire circumferential direction at the upper end of the tire inner diameter side slope. Is provided.
[0007]
Further, the tire molding die of the present invention is provided with a molding concave portion for molding a raised projection for protecting the rim flange on a side wall molding surface, and an inner diameter of a molding concave portion for molding a tire inner diameter side slope of the raised projection. the inner diameter side wall is formed on the fine uneven surface fine first air vent grooves in the side wall surface extending toward the bottom end from the open end of the inner diameter side wall is provided at a small predetermined distance, the inner diameter side wall A small second air vent groove extending continuously in the circumferential direction of the set tire is provided at the bottom end of the tire so as to communicate with the first air vent groove, and air is externally provided in the second air vent groove. An air bleeding path through which air can be derived is provided.
[0008]
As described above, in the present invention, the raised protrusions provided for protecting the rim flange are arranged alternately with small concave portions and convex portions extending from the lower end to the upper end of the tire inner diameter side slope facing the rim flange. By forming a small convex portion formed on the minute uneven surface and continuously extending in the tire circumferential direction at the upper end of the slope on the tire inner diameter side, the mold for molding this pneumatic tire has a raised shape with a large volume change. It is possible to provide a configuration in which a dedicated air vent groove is provided for extracting air that accumulates on the slope side of the tire inner diameter side facing the rim flange of the projection. For this reason, the occurrence of air pockets due to the raised protrusions that protect the rim flange can be greatly suppressed, and vulcanization failure can be greatly reduced.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of the pneumatic tire of the present invention, wherein 1 is a tread portion, 2 is a bead portion, and 3 is a sidewall portion. Left and right sidewall portions 3 are extended outwardly in the tire radial direction in connection with the left and right bead portions 2, and a tread portion 1 extending in the tire circumferential direction is provided between the left and right sidewall portions 3.
Two carcass layers 4A and 4B are provided inside the tire. Beat cores 5 are respectively embedded in the left and right bead portions 2, and bead fillers 6 are provided on the outer periphery of the beat cores 5. Both ends 4a of the inner carcass layer 4A are folded around the beat core 5 from the tire inside to the outside so as to sandwich the bead filler 6.
[0010]
Both ends 4b of the outer carcass layer 4B are wound down around the bead core 5 from the outside of the tire to the inside. A plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer of the tread portion 1. A belt cover layer 8 is provided on the outer peripheral side of the belt layer 7. A plurality of main grooves 9 extending in the tire circumferential direction are formed on the tread surface 1A.
[0011]
The right and left sides of the mounted rim X are located on the bead portion side outer surfaces of the left and right sidewall portions 3 within a range from a point D (in the tire radial direction) of 22 mm on the tread side to the tire maximum width point E from the bead base. Each of the raised protrusions 10 for protecting the flange X1 is provided. The raised protrusion 10 extends annularly along the tire circumferential direction. The tire meridian cross section is formed in a substantially trapezoidal shape, and when the rim is assembled, the raised protrusion 10 projects outward in the tire width direction from the rim flange maximum width position p and completely covers the rim flange X1.
[0012]
In the present invention, in the pneumatic tire having the above structure, the tire inner diameter side inclined surface 10a that faces the rim flange X1 of ridged projections 10, the period from the lower end 10a ₁ in contact with the outer surface 2a side of the bead portion 2 to the upper end 10a ₂ As shown in FIG. 2, a linear concave portion m and a convex portion n having minute widths and depths extending continuously are formed on a minute uneven surface in which alternately arranged. The upper end 10a _2, is provided an annular small protrusion 10a ₃ extending continuously in the tire circumferential direction.
[0013]
FIG. 3 shows a mold for molding the pneumatic tire. The mold M has a two-part structure including a pair of upper and lower annular dies M1 and M2. On the upper mold M1, a tread portion forming surface 11A for forming a tread portion on one side from the tire equatorial plane, a bead portion forming surface 12A for forming one side bead portion 2, and one sidewall portion 3 are formed. A side wall forming surface 13A is provided.
[0014]
The lower mold M2 has a tread portion forming surface 11B for forming a tread portion on the other side from the tire equatorial plane, a bead portion forming surface 12B for forming the other bead portion, and a sidewall for forming the other sidewall portion. A portion forming surface 13B is provided. A plurality of annular main groove forming projections 14 for forming the main grooves 9 extending in the tire circumferential direction are provided on both tread forming surfaces 11A and 11B of the upper mold M1 and the lower mold M2. The raised protrusions 10 are formed on the bead portion forming surfaces of the side wall forming surfaces 13A and 13B for forming a range from the point D of 22 mm to the tire maximum width point E from the bead base to the tread portion side of the formed tire. Is formed. The molding recess 15 extends in the circumferential direction of the set tire and is formed in an annular shape.
[0015]
The molding recess 15 has a bottom surface 15a and both wall surfaces 15b and 15c, and an inner diameter side wall surface 15c following the bead portion molding surfaces 12A and 12B is formed on the molding surface on which the tire inner diameter side slope 10a of the raised protrusion 10 is molded. Has become.
The inner diameter side wall 15c is a bead portion molding surface 12A, over the open end 15c ₁ in contact with 12B side to the bottom side edge 15c ₂ in contact with the bottom surface 15a, small width and depth extending continuously as shown in FIG. 3 Are formed at small minute intervals, and the inner diameter side wall surface 15c is a minute uneven surface. The bottom surface 15a of the bottom end 15c ₂ is located, the second air vent grooves y annular is provided with a small width and depth extending continuously in the circumferential direction of the set tire.
[0016]
Each first air vent groove x is in communication with the second air vent grooves y provided in the bottom end 15c _2. In the second air vent groove y, a plurality of vent holes 16 for venting air capable of leading air to the outside are arranged at predetermined intervals. The upper mold M1 and the lower mold M2 are formed with vent holes at appropriate places as in the conventional case, so that air can be vented.
[0017]
According to the mold M having such a configuration, when a green tire is set and vulcanized by a usual method using a bladder, the tire inner diameter side facing the rim flange X1 of the raised projection 10 having a large volume change. air is provided along the first air vent grooves x dedicated formed in the radially inner side wall surface 15c of the molding recess 15 for molding a tire the inner diameter side inclined surface 10a on the bottom side edge 15c ₂ to be Tamaro the slope 10a side It can escape to the dedicated second air vent groove y, from which it can be discharged outside through the vent hole 16.
As a result, air accumulation is less likely to occur on the tire inner diameter side slope portion side facing the rim flange X1 of the raised protrusion 10 having a large volume change, thereby improving the rubber flow and preventing the occurrence of vulcanization failures such as cracks. It can be greatly reduced. Therefore, it is possible to significantly reduce vulcanization failure.
[0018]
When air passes through the first air release groove x and the second air release groove y, the rubber being vulcanized flows into both of the grooves x and y, so that the pneumatic tire completed after vulcanization is completed. as shown in FIGS. 1 and 2, the tire inner diameter side inclined surface 10a that faces the rim flange X1 of ridged projections 10 are formed on the irregular surface as above, the tire circumferential direction on the tire inner diameter side slope upper end 10a ₂ continuous become structure provided with fine convex portions 10a ₃ extending to.
[0019]
In the present invention, in the above-mentioned mold M, the method of making the inner diameter side wall surface 15c of the molding concave portion 15 a minute uneven surface is preferably performed by knurling. The use number can be # 12 to # 42 specified in JIS. As a matter of course, instead of the knurling, the minute uneven surface may be formed by ordinary machining. In that case, the groove depth of the first air vent groove x forming the minute uneven surface is 0.2 to 1.0 mm, the groove width is 0.5 to 2.0 mm, and the arrangement interval of the first air vent groove x Can be between 0.5 and 2.0 mm.
[0020]
The first air bleed grooves x are arranged along the radial direction (the radial direction of the set green tire) of each of the molds M1 and M2 formed in an annular shape in plan view, or with respect to the radial direction. May be slightly inclined.
In the above-described embodiment, the vent hole 16 is used as an air bleed path for escaping the air collected in the second air bleed groove y to the outside. However, the present invention is not limited thereto. Alternatively, an air vent path such as a slit may be provided.
[0021]
Also, the case where the mold M has a split structure of a pair of upper and lower parts including an upper mold M1 and a lower mold M2 has been described, but an upper mold for molding one sidewall portion of the tire and another sidewall. It may be a lower mold for molding a portion, or a sectional mold having a plurality of sectors for integrally molding a tread portion and both shoulder portions of a tire and upper and lower bead rings for molding a bead portion.
FIG. 5 shows another example of the pneumatic tire of the present invention. In the pneumatic tire of FIG. 1, the raised protrusion 10 is formed in a substantially triangular cross-section in the tire meridian instead of the raised protrusion 10 formed in a trapezoidal cross section. Such even ridged projections 10 to form the tire inner diameter side slope 10a on the fine uneven surface which are alternately arranged and recesses m and the projection n in the same manner as described above, the tire circumferential direction on the upper end 10a ₂ it may be provided minute projections 10a ₃ of annular extending continuously.
[0022]
In the case of the pneumatic tire and the mold of the present invention, in the case of a groove or a recess, the depth is 0.2 to 1.0 mm, the width on the surface is 0.5 to 2.0 mm, In this case, the height is 0.2 to 1.0 mm and the width at the base end is 0.5 to 2.0 mm.
[0023]
【Example】
The tire size was made common to 255/40 ZR17, the slope on the tire inner diameter side of the raised protrusion was formed on the minute uneven surface of FIG. 2, and the minute convex portion extending continuously in the tire circumferential direction was provided at the upper end of the slope on the tire inner diameter side. In the tire 1 of the present invention having the configuration shown in FIG. 1 and the tire 1 of the present invention, the tire inner diameter of the tire 2 of the present invention and the tire inner diameter of the tire 1 of the present invention in which the direction in which the uneven portions extend is inclined (30 °) with respect to the tire radial direction. Each of the comparative tire 1 having no minute convex portion at the upper end of the side slope, the comparative tire 2 having no minute irregular surface, and the conventional tire having no minute irregular surface and the minute convex portion at the raised protrusion are each 100. This was produced.
[0024]
The minute uneven surface formed on the inner diameter side wall surface of the mold concave portion was formed by knurling of # 30. The second air vent groove is formed in a semicircular cross section, and has a radius of 0.5 mm.
In each of the test tires, the state of occurrence of vulcanization failure such as a crack generated on the slope on the tire inner diameter side of the raised protrusion was observed, and the degree of failure occurrence was examined. The results shown in Table 1 were obtained. In addition, the result shown in Table 1 is the number of tires in which failure occurred in 100 tires.
[0025]
[Table 1]

As is evident from Table 1, the tire of the present invention can suppress the occurrence of air pockets due to the raised protrusions that protect the rim flange, and can significantly improve vulcanization failure.
[0026]
【The invention's effect】
As described above, the present invention relates to a pneumatic tire provided with raised protrusions for protecting a rim flange, in which a tire inner diameter side slope facing the rim flange of the raised protrusion is formed with a minute concave and convex extending from the lower end to the upper end. Are formed on the minute uneven surface alternately arranged, and a minute convex portion extending continuously in the tire circumferential direction is provided at the upper end of the slope on the tire inner diameter side, so that the occurrence of air accumulation due to the raised protrusion is largely suppressed. In addition, vulcanization failure can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is a half sectional view of a tire meridian showing an example of a pneumatic tire of the present invention.
FIG. 2 is an enlarged view taken along the line AA of FIG. 1;
FIG. 3 is a sectional view of a main part showing an example of a tire molding die of the present invention for molding the pneumatic tire of FIG.
FIG. 4 is an enlarged view as viewed from arrows BB in FIG. 3;
FIG. 5 is a tire meridian half sectional view showing another example of the pneumatic tire of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tread part 2 Bead part 3 Side wall part 10 Raised protrusion 10a Tire inner diameter side slope 10a ₁ Lower end 10a ₂ Upper end 10a ₃ Micro convex part 12A, 12B Bead part forming surface 15 Mold recess 15c Inner diameter side wall surface 15c ₁ Opening side end 15c ₂ the bottom end 16 a vent hole (air vent passage)
M mold M1 upper mold M2 lower mold X rim X1 rim flange m concave part n convex part x first air release groove y second air release groove

Claims (4)

In a pneumatic tire in which raised protrusions protecting the rim flanges are respectively provided on the left and right sidewall portions in the tire circumferential direction,
The slope on the tire inner diameter side facing the rim flange of the raised projection is formed on a minute uneven surface in which minute concave portions and convex portions extending from the lower end to the upper end are alternately arranged, and the tire circumferential surface is formed on the upper end of the tire inner diameter side slope. A pneumatic tire provided with minute projections extending continuously in a direction. 2. The pneumatic tire according to claim 1, wherein when the rim is assembled, the raised protrusion projects outward in the tire width direction from a rim flange maximum width position p. A molding recess is formed on the side wall molding surface to form a protruding protrusion for protecting the rim flange, and an inner side wall surface of the forming recess forming the tire inner diameter side slope of the protruding projection is formed from the opening end of the inner wall surface. Minute first air vent grooves extending toward the bottom end are provided at minute predetermined intervals to form the inner diameter side wall surface as minute irregularities , and the tire periphery set at the bottom end of the inner diameter side wall surface is provided. A small second air vent groove extending continuously in the direction is provided so as to communicate with the first air vent groove, and an air vent path through which air can be led to the outside is provided in the second air vent groove. Mold for molding. 4. The tire molding die according to claim 3, wherein a knurling process is performed on an inner diameter side wall surface of the molding concave portion to form a minute uneven surface.

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