JP5417198B2 - Unvulcanized tire and tire manufacturing method using the same - Google Patents

Description

  The present invention relates to an unvulcanized tire and a method of manufacturing a tire using the tire, and more specifically, occurrence of a side cut or the like to the tire due to pinching between the curb or the like and a rim on the side surface of the tire, etc. When manufacturing tires with rim guards on the sidewalls, the air tires are restrained from being caught in the rim guards during vulcanization molding, resulting in poor appearance of the product tires The present invention relates to a non-vulcanized tire that can prevent the occurrence of the problem, and a tire manufacturing method for vulcanizing and molding the unvulcanized tire.

  When the vehicle is rubbed against a curb, etc., the rubber on the side of the tire is sandwiched between the rim flange and the curb, etc., so that the side wall of the tire is damaged, so-called side cuts, curbs, etc. As a pneumatic tire for preventing the occurrence of damage to the rim flange due to contact, for example, there is a tire provided with a rim guard portion 311 on a side surface portion of a tire 301 as shown in FIG.

  This pneumatic tire 301 has a bead core 309 in a bead portion 302, and is folded around the bead core 309, for example, a carcass 304 including two carcass plies 303 a and 303 b, and along the outer side of the folded portion of the carcass 304. A rubber chafer 305 extending from the radially innermost end of the tire to the radially outer side with a certain length, a side rubber 307 partially overlapping the rubber chafer 305 to form a rim guard portion 311, and an inner covering the tire inner peripheral surface According to this, when the tire is rubbed against a curb or the like, the rim guard part 311 functions to prevent the tire side surface from being caught between the rim R and the curb or the like. As a result, the occurrence of side cuts on the tire is suppressed, and contact between the rim R and the curb is prevented. It supposed to be, so that the occurrence of damage to the rim R is prevented.

  With regard to such a rim guard portion, Patent Document 1 discloses that “a pair of bead portions, a pair of sidewall portions extending outward in the tire radial direction from both bead portions, and a tread portion extending across both sidewall portions. In the state where the tire is mounted on the standard rim, a ring that protrudes toward the outside in the tire width direction is provided at the outer surface position of the sidewall portion immediately above the rim flange by providing a rubber chafer at least in a portion of the bead portion that contacts the rim. In a pneumatic tire provided with a rim guard portion, the rim guard portion has an inner rubber portion made of hard rubber located on the inner side in the tire width direction and an outer rubber portion made of soft rubber located on the outer side in the tire width direction. And at least one composite reinforcing layer made of reinforcing element-containing rubber is provided so as to cover the outer surface of the inner rubber portion. According to this, “By optimizing the rim guard portion, damage to the rim flange can be suppressed even when there is a large input in the tire width direction”. It is possible to provide a pneumatic tire. "

  Further, Patent Document 2 discloses a pneumatic tire having a bead portion with an annular rim guard that protrudes outward in the tire rotation axis direction in the tire circumferential direction, and the rim guard substantially includes a rim flange side. The pneumatic tire is characterized in that a plurality of impact mitigating grooves extending along the radial direction are formed along the tire circumferential direction. According to this, “on the rim flange side of the rim guard” is described. Since a plurality of impact mitigating grooves extending substantially along the radial direction are formed along the tire circumferential direction, it is possible to mitigate the impact on the rim flange when riding over large protrusions and reduce damage to the rim flange. It has an excellent effect. "

However, in these tires, there is a problem that an air entrainment portion A illustrated in FIG. 5 is generated in the rim guard portion 311 of the product tire after vulcanization molding.
When such an air entrainment portion A is generated in the rim guard portion 311, the appearance of the product tire is remarkably impaired, so that it cannot be put on the market as a product.

FIG. 6 is a cross-sectional view of an essential part showing a state of these tires before vulcanization.
An unvulcanized tire 201 shown in FIG. 6 has a bead core 209 in a bead portion 202, a carcass material 204 composed of two carcass ply members 203 a and 203 b folded around the bead core 209, and the carcass material 204 folded back. An unvulcanized rubber chafer member 205 extending from the radially innermost end of the tire along the outer side of the tire in a certain length outward in the radial direction, and a side rubber member 207 extending partially overlapping the rubber chafer member 205 And an inner liner member 208 that covers the entire inner peripheral surface of the unvulcanized tire.

The inventors have been investigating to find the cause of air entrainment occurring in the rim guard part of the product tire after vulcanization molding. In the conventional unvulcanized tire 201 as shown in FIG. A rubber having a Mooney viscosity lower than that of the rubber chafer member 205 and having a high fluidity is used for the side rubber member 207 constituting the rim guard portion. When such an unvulcanized tire 201 is molded with a vulcanization mold, FIG. As shown to (a), the flow amount of the side rubber 207 in the part along the vulcanization molds M ₁ and M ₂ of the rim guard part increases, and the factor is that air is entrained during the flow. I found out.

  Therefore, in order to prevent the occurrence of air entrainment in the rim guard part, it is effective to suppress the flow of the side rubber member 207 at the time of vulcanization molding. A more detailed study is also necessary for the structure of the unvulcanized tire before the formation.

JP 2005-145319 A Japanese Patent Laid-Open No. 10-244815

  Accordingly, the present invention solves the above-mentioned problems, prevents the air from being generated in the rim guard part during vulcanization molding, and can reduce the occurrence of poor appearance of the product tire, as well as the unvulcanized tire. It aims at providing the manufacturing method of the tire using a sulfurated tire.

The gist configuration of the present invention for solving the above problems is as follows.
An unvulcanized tire of the present invention has a rubber chafer member on the outer side in the tire width direction of the bead portion as a skeleton with a carcass material composed of at least one carcass ply member straddling between a pair of bead portions. It has a tread rubber member on the radially outer side of the crown portion, has a side rubber member extending across the rubber chafer member and the tread rubber member, and the innermost end portion in the tire radial direction of the side rubber member An unvulcanized tire that overlaps the maximum thickness position of the rubber chafer member,
In the cross section in the width direction of the unvulcanized tire, in the section within 4 mm from the innermost end in the tire radial direction of the side rubber member along the outer circumferential surface of the side rubber member in the tire radial direction outward direction, the side rubber member The thickness is 1.2 mm or less.

  Here, the “thickness” of the rubber chafer member or the side rubber member means a thickness measured in the normal direction of the inner surface in the tire width direction of the rubber chafer member or the side rubber member.

  More preferably, the maximum thickness of the rubber chafer member is 4 to 4.5 mm.

  The method for producing a tire according to the present invention consists in vulcanizing and molding the unvulcanized tire according to claim 1 or 2 in a vulcanization mold to obtain a product tire.

  The unvulcanized tire of the present invention is configured such that the thickness of the inner side portion in the tire radial direction of the side rubber member having high fluidity is thinner than that of a conventional unvulcanized tire. Since the amount of flow of the side rubber member at the portion of the rim guard portion along the surface of the vulcanization mold during vulcanization molding can be effectively reduced, the side rubber member winds air during its flow. It is possible to effectively reduce the risk of entrainment.

  Therefore, according to the unvulcanized tire and the manufacturing method of the tire according to the present invention, which is obtained by vulcanizing and molding the unvulcanized tire, air entrainment generated in the rim guard portion during vulcanization is suppressed. Thus, it is possible to effectively prevent the appearance defect of the product tire due to this.

  Further, in the unvulcanized tire and the tire manufacturing method, if the maximum thickness of the rubber chafer member is in the range of 4 to 4.5 mm, the thickness of the side rubber member is reduced and the vulcanization molding is performed. The volume of rubber in the rim guard part corresponding to the vulcanization mold can be more effectively compensated for by increasing the number of rubber chafer members that have low fluidity during vulcanization molding. Can be reduced.

1 is a half sectional view in the width direction showing an embodiment of an unvulcanized tire of the present invention. It is an expanded sectional view which shows the principal part of the unvulcanized tire of FIG. It is a contour figure which shows the thickness of a rubber chafer member and a side rubber member by the distribution along the tire width direction inner side surface of this rubber chafer member and a side rubber member about the unvulcanized tire of this invention, and the conventional unvulcanized tire. It is an expanded sectional view showing the important section of the product tire obtained by vulcanizing the unvulcanized tire of the present invention. It is an expanded sectional view which shows the principal part of the conventional product tire. It is an expanded sectional view which shows the principal part of the conventional unvulcanized tire. (A) is principal part sectional drawing which shows the conventional unvulcanized tire shape | molded in a vulcanization mold, (b) shows the unvulcanized tire of this invention shape | molded in a vulcanization mold. It is principal part sectional drawing. It is a diagram showing a relationship between sd _max and air entrainment incidence.

Hereinafter, the present invention will be described in detail with reference to the drawings.
In the embodiment shown in FIG. 1, the unvulcanized tire 1 has a bead portion 2 with a carcass material 4 made up of at least one carcass ply member 3a, 3b in the illustrated example straddling between a pair of bead portions 2 as a skeleton. The rubber chafer member 5 is provided on the outer side in the tire width direction, the tread rubber member 6 is provided on the outer side in the radial direction of the crown portion of the carcass material 4, and the side rubber member 7 extends across the rubber chafer member 5 and the tread rubber member 6. The innermost end SE _{1 in} the tire radial direction of the side rubber member 7 overlaps the measurement position of the maximum thickness CHD _max of the rubber chafer member 5.

In the illustrated example, the unvulcanized tire 1 includes three belt layers 11 between the carcass material 4 and the tread rubber member 6.
The carcass material 4 is folded around the bead core 9, and the rubber chafer member 5 extends radially outward from the innermost end in the tire radial direction along the outer side of the folded portion of the carcass material 4. The side rubber member 7 partially overlaps with the rubber chafer member 5 and extends in the tire radial direction.
Moreover, the unvulcanized tire 1 includes an inner liner member 8 that covers the entire inner peripheral surface of the unvulcanized tire 1.

Here, as shown in an enlarged view of the main part in FIG. 2, in the unvulcanized tire 1, the side rubber member 7 has an innermost end SE _{1 in} the tire radial direction of the side rubber member 7 within the cross section in the width direction. The thickness Sd of the side rubber member 7 is set to 1.2 mm or less in a section within 4 mm in the tire radial direction outward direction along the outer peripheral surface.

  In the contour diagram of FIG. 3, the distribution of the thickness of the rubber chafer member 5 and the side rubber member 7 of the unvulcanized tire 1 of the present invention along the inner surface in the tire width direction is indicated by a solid line, and the conventional example illustrated in FIG. A similar thickness distribution of the unvulcanized tire 201 is indicated by a broken line.

In FIG. 3, the vertical axis indicates the sum of the thickness CHd of the rubber chafer member 5 and the thickness Sd of the side rubber member 7, that is, CHd + Sd, and the horizontal axis indicates the inner side in the tire width direction of the side rubber member 7 and the rubber chafer member 5. along the surface, the path length from the outermost end SE ₂ in the tire radial direction of the side rubber member 7 to the innermost end in the tire radial direction CHE ₁ of rubber chafer member 5.

As shown in FIG. 3, the conventional green tire, the thickness Sd of the side rubber member in the tire radial direction relative to the innermost end SE ₁ to drastically increases toward the outer side in the tire radial direction, of the present invention the unvulcanized tire, the gradient of the increase in the thickness Sd near the innermost end SE ₁ in the tire radial direction is gentle.

In the example shown, of a conventional unvulcanized tire, in a section within 4mm in the tire radial direction outer side along the innermost end SE ₁ in the tire radial direction of the side rubber member to the outer circumferential surface of the side rubber member, The maximum value Sd _max of the thickness Sd of the side rubber member is 2 to 4 mm, while the maximum value Sd _max of the unvulcanized tire of the present invention is 1.2 mm.

Also, in this figure, the maximum thickness of the rubber chafer member is larger in the unvulcanized tire of the present invention than in the conventional unvulcanized tire. The maximum thickness CHd _max (before) of the rubber chafer member of the conventional unvulcanized tire is 3.5 to 4 mm, whereas the maximum thickness CHd of the rubber chafer member of the unvulcanized tire of the present invention in FIG. _max (after) is 4 to 4.5 mm.
In the unvulcanized tire of the present invention, it is preferable that the maximum thickness CHd _max of the rubber chafer member is in the range of 4 to 4.5 mm.

According to the tire manufacturing method of the present invention in which the unvulcanized tire of the present invention is vulcanized and molded in a vulcanization mold to obtain a product tire, as shown in FIG. by the thickness of the vicinity of the innermost end SE ₁ in the tire radial direction of the side rubber 7 is thin, the flow amount of the side rubber 7 in a portion along the vulcanization mold M _1, M ₂ of the rim guard portion is suppressed, thereby Thus, air entrainment during the flow is sufficiently prevented.

The product tire obtained by the tire manufacturing method of the present invention is, for example, the innermost end SE in the tire radial direction of the side rubber 107 in the cross section in the width direction, like a pneumatic tire 101 shown in FIG. A thickness PSd of the side rubber is 1 mm or less in a section within 1 mm from ₁ to the outer side in the tire radial direction along the outer peripheral surface of the side rubber 107.

  The pneumatic tire 101 has a bead core 109 in a bead portion 102 and is folded around the bead core 109, for example, a carcass 104 including two carcass plies 103a and 103b, and an outer side of the folded portion of the carcass 104. A rubber chafer 105 extending from the radially innermost end portion of the tire along the radial direction along the outer circumference in a certain length, a side rubber 107 partially overlapping the rubber chafer 105 to form a rim guard portion 111, and a tire inner peripheral surface And an inner liner 108 for covering.

In accordance with the configuration of the unvulcanized tire 1 shown in FIG. 1, in a section within 4 mm from the innermost end SE _{1 in} the tire radial direction of the side rubber member 7 along the outer peripheral surface of the side rubber member 7 in the tire radial outer direction. The unvulcanized tire of the present invention in which the maximum thickness Sd _max of the side rubber member 7 is 1.2 mm and the maximum thickness CHd _max of the rubber chafer member 5 is in the range of 4 to 4.5 mm, The model was introduced into a mass production factory, and pneumatic tires for passenger cars of size 225 / 50R17 were manufactured.

Furthermore, copying the structure of the unvulcanized tire 6 showing the essential portion thereof in FIG. 6, the innermost end SE ₁ in the tire radial direction of the side rubber member 207, the outer side in the tire radial direction along the outer peripheral surface of the side rubber member 207 The thickness Sd _max of the side rubber member 207 is within a range of 2 to 4 mm, and the maximum thickness CHd _max of the rubber chafer member 205 is within a range of 3.5 to 4 mm. The unvulcanized tire was put into a mass production factory to produce a pneumatic tire for passenger cars of the same size as above.

  As a result, in the production method using the unvulcanized tire of the present invention, the section within 4 mm from the innermost end portion of the side rubber in the tire radial direction to the outer side in the tire radial direction along the outer peripheral surface of the side rubber in the cross section in the width direction. A pneumatic tire having a side rubber thickness PSd of 1 mm or less was obtained.

  Further, in the manufacturing method using the conventional unvulcanized tire, the incidence of air entrainment was 2.0%, whereas in the manufacturing method using the unvulcanized tire of the present invention, the air entrainment occurred. The occurrence rate was 0%.

  Furthermore, when the tire size of the product tire was changed to 205 / 55R15 and the same comparison was made between the case of using the conventional unvulcanized tire and the case of using the unvulcanized tire of the present invention, In the production method using the unvulcanized tire, the air entrainment rate was 1.7%, whereas in the production method using the unvulcanized tire of the present invention, the air entrainment rate was It was 0.15%.

Next, the maximum thickness Sd _max in the section of the side rubber member of the unvulcanized tire is variously changed to manufacture a product tire having a tire size = 225 / 50R17, and the maximum thickness Sd of the unvulcanized tire is manufactured. _When the relationship between _max and the occurrence rate of air was evaluated, an evaluation result as shown in FIG. 8 could be obtained. Table 1 shows the arithmetic average value of the air entrainment occurrence rate at each value of the maximum thickness Sd _max obtained based on the evaluation result.

According to the evaluation results shown in Table 1, the side rubber member in a section within 4 mm in the tire radial direction outer side along the outer peripheral surface of the side rubber member from the tire radial innermost end of the side rubber member of the unvulcanized tire. When the maximum thickness Sd _max is 1.2 mm or less, the occurrence rate of air entrainment in the product tire is 0.02% on average, and the occurrence rate when Sd _max is 1.5 mm is 0.34% Therefore, it is understood that the occurrence rate of air entrainment is remarkably lowered by setting the maximum thickness Sd _max to 1.2 mm or less.

In addition, as shown in FIG. 8, when the maximum thickness Sd _max is 1.2 mm or less, the occurrence rate of air entrainment is sufficiently small, less than 0.1%, and does not affect the production line. Can be reduced.

  From the above results, the unvulcanized tire of the present invention and the tire manufacturing method using the same prevent air entrainment generated in the rim guard part during vulcanization molding, and sufficiently suppress the appearance failure of the product tire. It can be said that it is possible.

DESCRIPTION OF SYMBOLS 1 Unvulcanized tire 2 Bead part 3a, 3b Carcass ply member 4 Carcass material 5 Rubber chafer member 6 Tread rubber member 7 Side rubber member 8 Inner liner 9 Bead core 11 Belt layer

Claims (3)

With a carcass made of at least one carcass ply straddling between a pair of bead portions as a skeleton, a rubber chafer member is provided on the outer side in the tire width direction of the bead portion, and a tread rubber member is provided on the outer side in the radial direction of the crown portion of the carcass. A side rubber member extending across the rubber chafer member and the tread rubber member, and an innermost end portion in the tire radial direction of the side rubber member is overlapped with a maximum thickness position of the rubber chafer member. A vulcanized tire,
In the cross section in the width direction of the unvulcanized tire, in the section within 4 mm from the innermost end in the tire radial direction of the side rubber member along the outer circumferential surface of the side rubber member in the tire radial direction outward direction, the side rubber member An unvulcanized tire having a thickness of 1.2 mm or less.   The unvulcanized tire according to claim 1, wherein the rubber chafer member has a maximum thickness of 4 to 4.5 mm.   A method for producing a tire by vulcanizing and molding the unvulcanized tire according to claim 1 or 2 in a vulcanization mold.

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