Tire molding die, method for producing tire and tire using the same

Abstract

To provide a tire molding die capable of improving tire appearance and air resistance around a tire while exhibiting good exhaust performance and to provide a method for producing a tire and a tire using the same.SOLUTION: There is provided a tire molding die 20 having a side plate 21 for forming a sidewall part 2 of a tire, wherein an air vent slit 40 formed to open into the tire forming surface of the side plate 21 is provided and the slit 40 is set to extend in the tire circumferential direction within the range of 0.2 times the tire cross-sectional height H on both radial sides of a tire radial direction from the position corresponding to the tire maximum width position P.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tire molding mold for molding tires, a tire manufacturing method using the same, and tires; and more particularly, to a tire molding mold for molding tires that can suppress defects in tire appearance and reduce air resistance around the tire, a tire manufacturing method using the same, and tires. [Background technology]

[0002] Tire molds typically have vent holes (thin exhaust holes) for venting air during vulcanization. However, using vent holes to vent air can result in rubber flowing into the vent holes, potentially creating spews, whisker-like protrusions, on the surface of the molded tire. While these spews are typically removed before the tire is shipped, there's a risk that traces of the spews (cut marks) remain on the tire surface. In other words, the bases of the spews may remain as tiny cylindrical protrusions. The presence of these cut marks can negatively impact the tire's appearance, and the minute irregularities on the tire surface caused by the cut marks can affect air resistance around the tire. For example, Patent Document 1 proposes reducing the number of vent holes by providing grooves on the mold's side molding surfaces as air vent channels. However, while these grooves can reduce the occurrence of spews, the rubber that flows into the air vent grooves remains on the tire as protrusions, potentially affecting air resistance. Therefore, further measures are needed to efficiently exhaust air during vulcanization without affecting the tire's appearance or the air resistance around the tire. In particular, since the maximum tire width position is the part of the tire sidewall that protrudes furthest outward in the tire width direction, any cut marks remaining at this position have a significant impact on air resistance, and therefore measures are strongly needed in the vicinity of this position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-305623 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a tire molding mold that makes it possible to improve the tire appearance and the air resistance around the tire while exhibiting good exhaust performance, a tire manufacturing method using the same, and a tire. [Means for solving the problem]

[0005] In order to achieve the above object, the tire molding mold of the present invention is characterized in that, in the tire molding mold having side plates for molding the sidewall portions of a tire, the mold is provided with air-bleeding slits formed so as to open into the tire molding surfaces of the side plates, and the slits extend in the tire circumferential direction within a range of 0.2 times the tire cross-sectional height H on both sides in the tire radial direction from a position corresponding to the maximum tire width position.

[0006] The tire manufacturing method of the present invention for achieving the above object is a tire manufacturing method using the tire molding mold, characterized in that an unvulcanized tire is placed into the tire molding mold, and the unvulcanized tire is vulcanized in the tire molding mold while air is removed through a slit.

[0007] Further, in order to achieve the above object, the tire of the present invention is a tire manufactured by the above tire manufacturing method, and is characterized in that it has traces of slits on at least a part of the surface of the sidewall portion. [Effects of the Invention]

[0008] The inventors of the present invention conducted extensive research into venting methods for tire molds and discovered that by providing a slit-shaped vent mechanism instead of the conventional vent holes, it is possible to maintain good venting performance, prevent poor appearance, and reduce air resistance around the tire. Specifically, with conventional vent holes, rubber may flow into the vent holes, causing spew, and even if the spew is removed, there is a possibility of a cut mark (the base of the spew remaining as a tiny cylindrical protrusion). However, because the slits are tiny gaps, rubber is less likely to flow into them. Even if a mark remains due to rubber that has flowed into the slit, it is only a very narrow linear mark, so the tire appearance is not impaired and air resistance around the tire is not adversely affected. The present invention is based on this discovery, and by providing the air-venting slits as described above, particularly at an appropriate position relative to the maximum tire width, it is possible to prevent poor appearance and reduce air resistance around the tire while maintaining excellent venting performance.

[0009] The tire manufacturing method of the present invention uses the tire mold of the present invention described above, and therefore air remaining in the mold during vulcanization can be efficiently vented to the outside of the mold through the slits. At this time, since the slits are minute gaps as described above, rubber does not substantially flow into them, and even if traces of the slits remain due to the rubber that has flowed into them, only fine linear traces remain in the tire, so the appearance of the tire is not impaired and air resistance around the tire can be reduced.

[0010] Furthermore, since the tire manufactured using the tire molding mold of the present invention (tire of the present invention) is manufactured by the manufacturing method of the present invention described above, substantially no traces of the air vent slits remain, as described above, preventing poor appearance and reducing air resistance around the tire.

[0011] In the tire mold of the present invention, the slit width is preferably 0.01 mm to 0.5 mm. By making the slit width sufficiently thin, it is possible to reliably prevent the inflow of rubber while maintaining exhaust performance, which is advantageous for preventing poor appearance and reducing air resistance. In the present invention, the "slit width" refers to the dimension measured along the short side of the slit.

[0012] In the tire mold of the present invention, the total length of the slits in the tire circumferential direction is preferably 30% or more of the tire circumference at the tire's widest point. By providing the slits with a sufficient length in this manner, it becomes possible to exhibit good exhaust performance through the slits.

[0013] The tire mold of the present invention can also be configured to include a spare piece having at least one slit formed therein and a hole formed in the side plate into which the spare piece is inserted. This configuration makes it easier to clean the inside of the slit when cleaning the mold after vulcanization, thereby improving productivity.

[0014] In the tire of the present invention, it is preferable that the distance h in the tire radial direction from the tire maximum width position to the slit traces satisfies the relationship h≦0.2H with respect to the tire cross-sectional height H. Even if traces of the exhaust mechanism remain near the tire maximum width position in this way, as a result of exhausting air through the slits as described above, the only traces that may remain are fine linear traces caused by the slits, which is advantageous for preventing poor appearance of the tire and reducing air resistance.

[0015] In the present invention, the "maximum tire width position" refers to the radial position of the tire where the distance in the tire width direction between the molding surface of the lower side plate and the molding surface of the upper side plate that constitute the mold is greatest. In a tire, this position corresponds to the radial position of the tire where the total tire width (the width of the tire including the patterns and lettering on the tire side and protrusions such as rim protect bars) is greatest when the tire is mounted on a standard rim, inflated to the standard internal pressure, and in an unloaded state. The "standard rim" refers to the rim specified for each tire by the standard on which the tire is based, for example, the standard rim for JATMA, the "Design Rim" for TRA, or the "Measuring Rim" for ETRTO. "Normal internal pressure" refers to the air pressure specified for each tire by each standard in the standard system, including the standard on which the tire is based. For JATMA, this is the maximum air pressure, for TRA, this is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and for ETRTO, this is the "INFLATION PRESSURE", but if the tire is for a passenger car, it shall be 180kPa. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a meridian cross-sectional view showing an example of a tire according to an embodiment of the present invention. [Figure 2] FIG. 3 is a meridian cross-sectional view showing another example of a tire according to an embodiment of the present invention. [Figure 3] 1 is an explanatory diagram showing an example of a tire vulcanizing apparatus including a tire molding mold of the present invention. FIG. [Figure 4] FIG. 2 is an explanatory diagram showing an enlarged view of a main part of a tire molding mold according to an embodiment of the present invention. [Figure 5] FIG. 4 is an explanatory view showing an enlarged view of a main part of a tire mold according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The configuration of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] FIG. 1 shows an example of a tire manufactured using the tire vulcanization mold of the present invention (hereinafter referred to as the "tire of the present invention"). The tire of FIG. 1 is a pneumatic tire that includes a tread portion 1 that contacts the road surface, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged radially inward of the sidewall portions 2. In FIG. 1, the symbol CL indicates the tire equator. Although not depicted in FIG. 1 because it is a meridian cross-section, the tread portion 1, sidewall portions 2, and bead portions 3 each extend circumferentially in the tire direction and form an annular shape, thereby forming the basic toroidal structure of a pneumatic tire. The following explanation using FIG. 1 will be based essentially on the meridian cross-section shown, but each tire component also extends circumferentially in the tire direction and forms an annular shape.

[0019] In the tire of FIG. 1, a carcass layer 4 is installed between a pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction and is folded back from the inner side to the outer side in the tire width direction around a bead core 5 arranged in each bead portion 3. A bead filler 6 is arranged on the outer periphery of the bead core 5, and this bead filler 6 is wrapped by the main portion and the folded back portion of the carcass layer 4. Meanwhile, a plurality of belt layers 7 (two layers in FIG. 1) are embedded on the outer periphery of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to cross each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set, for example, in the range of 10° to 40°. Furthermore, at least one belt reinforcing layer 8 (two layers in FIG. 1) is provided on the outer periphery of the belt layer 7. The belt reinforcing layer 8 includes organic fiber cords oriented in the tire circumferential direction. In the belt reinforcing layer 8, the organic fiber cords are set at an angle of, for example, 0° to 5° with respect to the tire circumferential direction.

[0020] As will be described later, the present invention relates to the tire's maximum width position P (the radial position of the tire where the total tire width is greatest when the tire is mounted on a standard rim, inflated to the standard internal pressure, and no load is applied). However, when a rim protect bar 9 is provided as shown in Figure 2, the point at which the rim protect bar 9 protrudes the furthest in the tire width direction may be the tire's maximum width position P. The tire in Figure 2 has the same structure as the tire in Figure 1 except for the rim protect bar 9. The rim protect bar 9 is provided to prevent the rim flange (not shown) from colliding with obstacles such as curbs while the tire is in motion, and is provided at least on the sidewall portion 2 that is on the outer side of the vehicle when mounted on the vehicle. The rim protect bar 9 is formed so that the sidewall portion 2 bulges outward in the tire width direction at a position adjacent to the rim flange when mounted on the rim, and has a generally triangular cross section, for example, as shown in the figure.

[0021] FIG. 3 shows an example of a tire vulcanizing apparatus including a tire vulcanizing mold (hereinafter, sometimes simply referred to as "mold") of the present invention. The tire vulcanizing apparatus comprises a mold 20 that molds the outer surface of the tire T, and a cylindrical bladder 30 that is inserted inside the pneumatic tire T. This tire vulcanizing apparatus also comprises a heating and pressurizing medium supply means (not shown) that supplies a heating and pressurizing medium such as steam into the bladder 30, and a heating means (not shown) that heats the mold 20. Note that the present invention mainly relates to an exhaust mechanism formed in the side plate 21 described below, and so the structure of the tire vulcanizing apparatus is not limited to the example shown in the figure, as long as it comprises the mold 20 (particularly the side plate and sector).

[0022] The mold 20 is composed of a pair of side plates 21 (lower side plate 21A and upper side plate 21B) for molding the sidewall portion of the tire, a pair of bead rings 22 (lower bead ring 22A and upper bead ring 22B) for molding the bead portion of the pneumatic tire T, and a plurality of sectors 23 for molding the tread portion of the pneumatic tire T, and the pneumatic tire T is vulcanized and molded inside the mold 20.

[0023] The heating and pressurizing medium supply means (not shown) is configured to supply steam adjusted to a predetermined temperature and pressure and nitrogen gas adjusted to a predetermined pressure as the heating and pressurizing medium at appropriate times. When such heating and pressurizing medium is introduced into the bladder 30, the pressure of the heating and pressurizing medium presses the pneumatic tire T from the inside toward the inner surface of the mold 20. Note that it is also possible to use only steam as the heating and pressurizing medium.

[0024] The heating means (not shown) is attached to the lower side plate 21, the upper side plate 22, and the sector 23 that make up the mold 20, and the mold 20 is heated by the heating means to vulcanize the pneumatic tire T.

[0025] In the tire vulcanization apparatus configured as described above, the tire molding mold (mold 20) of the present invention is provided with an air-bleeding slit 40, as shown in FIG. 3, in at least one of a pair of side plates 21 (lower side plate 21A and upper side plate 21B) for molding the sidewall portion 2 of the tire T. The air-bleeding slit 40 is a minute gap that opens on the tire molding surface of the side plate 21, and as shown in FIG. 3, penetrates the mold 20 (side plate 21) and reaches an exhaust mechanism (not shown) within the tire molding mold or the outside of the tire molding mold, thereby discharging air remaining in the mold during tire molding. The slit 40 also extends in the tire circumferential direction (the circumferential direction of the tire manufactured using this mold). A single slit 40 may be provided extending around the entire circumference of the tire, or multiple slits 40 may be provided intermittently around the tire. When the slit 40 extends in the tire circumferential direction, it may extend at an angle relative to the tire circumferential direction.

[0026] Unlike conventional vent holes (thin cylindrical exhaust holes), these air-release slits 40 do not allow rubber to flow into them, so spew does not occur as occurs with conventional vent holes. Even if traces of the slits 40 are formed due to rubber flowing into the slits 40, they are only fine linear traces, so they do not mar the appearance or worsen air resistance around the tire.

[0027] As described above, the slit 40 is a minute gap at the opening, and the width w of the slit 40 is preferably 0.01 mm to 0.5 mm, more preferably 0.02 mm to 0.05 mm. By making the width of the slit 40 sufficiently small, rubber does not substantially flow into the slit 40. Even if traces of the slit 40 remain due to the rubber that has flowed into the slit 40, they only remain as minute linear traces. This prevents damage to the tire's appearance and prevents poor appearance. If the width w of the slit 40 is smaller than 0.01 mm, it becomes difficult to ensure sufficient exhaust performance. Furthermore, the slit 40 is too thin, making it difficult to manufacture a mold (process the slit 40). If the width w of the slit 40 exceeds 0.5 mm, rubber tends to flow into the slit 40, leaving traces of the slit 40.

[0028] The present invention relates to the arrangement of the slits 40 described above. Specifically, the slits 40 extend in the tire circumferential direction within a range of 0.2 times, and preferably 0.1 times, the tire cross-sectional height H on both sides of the tire radial direction from a position corresponding to the maximum width position P of the tire (a tire radial position where the distance in the tire width direction between the molding surface of the lower side plate 21 and the molding surface of the upper side plate 22 that constitute the mold 20 is greatest). In other words, if the tire radial distance from the position corresponding to the maximum width position P to the slit 40 is h, the distance h and the tire cross-sectional height H should satisfy the relationship h≦0.2H, preferably h≦0.1H. The slits 40 may be arranged either radially inward or radially outward from the position corresponding to the maximum width position P of the tire. In other words, the distance h should satisfy the relationship −0.2H≦h≦0.2H, preferably −0.1H≦h≦0.1H, assuming that the distance h is a negative value on the inner side in the tire direction and a positive value on the outer side in the tire direction. By providing the slits 40 at appropriate positions relative to the tire maximum width point P in this way, it is possible to prevent poor appearance and reduce air resistance around the tire while achieving excellent exhaust performance. In particular, the vicinity of the tire maximum width point P is the part of the sidewall portion 2 that protrudes furthest outward in the tire width direction and has a significant impact on air resistance, so using the slits 40 to substantially remove traces of the exhaust mechanism is effective in reducing air resistance. If the distance h and the tire cross-sectional height H have a relationship of h > 0.2H, the slits 40 will be spaced away from the tire maximum width point P, and the above-mentioned effect cannot be fully expected. Note that when the slits 40 extend at an angle relative to the tire circumferential direction, it is preferable that any position of the slits 40 satisfy the relationship (h ≦ 0.2H, preferably h ≦ 0.1H) (i.e., it is preferable that the part of the slits 40 farthest from the tire maximum width point P also falls within the above-mentioned range).

[0029] A plurality of slits 40 may be provided at the above-mentioned positions. Alternatively, a single slit 40 may be provided at the above-mentioned position, extending around the entire circumference of the tire. In either case, the total circumferential length of the slits 40 is preferably 30% or more, more preferably 50% or more, of the tire circumference at the tire maximum width position P. By providing the slits 40 with a sufficient length in this manner, it is possible to achieve good exhaust performance through the slits 40. If the total circumferential length of the slits 40 is less than 30% of the tire circumference at the tire maximum width position P, the slits 40 may not be long enough, which may result in a decrease in exhaust performance.

[0030] The slit 40 may be formed directly in the mold 20 (side plate 21). Alternatively, as shown in FIG. 4, the side plate 21 may be configured to include a side plate main body 21a and a replacement piece 21b with the slit 40 formed therein, with the side plate main body 21a provided with a hole into which the replacement piece 21b is inserted. The replacement piece 21b is a component that is removably inserted into a hole formed in the side plate main body 21a. The molding surface of the side plate 21 is formed by inserting and fitting the replacement piece 21b into the hole. Note that FIG. 4 shows the replacement piece 21b inserted into the hole in the side plate main body 21a. In this configuration, the slit 40 can be formed at any position in the replacement piece 21b. However, as shown in the example, it is preferable to form the slit 40 by recessing the surface of the replacement piece 21b that abuts against the side of the hole when fitted. This configuration makes it easier to clean the inside of the slit 40 when cleaning the mold 20 (especially the side plate 21) after vulcanization, thereby improving productivity.

[0031] The slit 40 can be formed by any method (e.g., wire processing, laser processing, etc.) that can process a minute gap of the above-mentioned dimensions, whether it is formed directly in the side plate 21 or by using the replacement piece 21b as described above.

[0032] When manufacturing a tire using the tire mold described above, a typical method is used, that is, an unvulcanized tire is molded and then vulcanized in the tire mold described above. Air is removed from the mold using the slits 40 described above. Because the slits 40 are tiny gaps through which almost no rubber flows, the tire of the present invention generally leaves no traces of air removal on the surface of the sidewall portion 2 (the area where air is removed using the slits 40). Even if traces of the slits 40 are left behind due to rubber flowing into the slits 40, they are only small, linear traces in a certain area. Even if traces of the slits 40 are formed, they are not easily visible because, as described above, they are small, linear traces, and do not detract from the appearance of the sidewall portion 2. Furthermore, the traces of the slits 40 do not impair the air resistance around the tire.

[0033] As described above, a tire manufactured using the tire mold of the present invention (tire of the present invention) does not substantially leave traces of the air-bleeding slits, thereby preventing poor appearance and reducing air resistance around the tire. When traces of the slits 40 are present on at least a portion of the surface of the sidewall portion 2, the mold of the present invention provides the slits 40 near a position corresponding to the tire's maximum width position P as described above. Therefore, the traces of the slits 40 are formed near the tire's maximum width position P (either above the tire's maximum width position P or located radially inward or outward from the tire's maximum width position P). The tire's radial distance h to the traces of the slits 40 preferably satisfies the relationship h≦0.2H, more preferably h≦0.1H, relative to the tire cross-sectional height H. Even if traces of the exhaust mechanism remain near the tire's maximum width position P, as a result of exhausting air through the slits 40 as described above, the only traces that may remain are fine linear traces caused by the slits 40. This prevents poor appearance of the tire and reduces air resistance.

[0034] The present invention will be further explained below with reference to examples, but the scope of the present invention is not limited to these examples. [Example]

[0035] In manufacturing tires with a tire size of 245 / 50R19 95Y and having the structure illustrated in Fig. 1 or 2, the type of exhaust mechanism, width of the exhaust mechanism, length of the exhaust mechanism, position of the exhaust mechanism, distance h, and method of forming the exhaust mechanism were varied for the tire molding mold, as shown in Tables 1 and 2 (Conventional Examples 1 and 2, Comparative Examples 1 to 6, and Examples 1 to 14). Table 1 shows an example of a tire manufactured with the structure illustrated in Fig. 1, and Table 2 shows an example of a tire manufactured with the structure illustrated in Fig. 2 (a tire equipped with a rim protect bar).

[0036] In Tables 1 and 2, the column for "Type of exhaust mechanism" indicates whether a slit, vent hole, or circumferential groove was used as the exhaust mechanism. Circumferential grooves are concentric grooves provided on the inner periphery of the sector division position, connecting vent holes to facilitate airflow, and are basically exhaust mechanisms used in combination with vent holes, as in Conventional Examples 1 and 2. (Comparative Examples 2 and 5 only have circumferential grooves, so they do not actually function as exhaust mechanisms, but are presented for comparison.)

[0037] The "Exhaust mechanism width" column in Tables 1 and 2 lists the width of the exhaust mechanism used in each mold. Note that the vent hole width is essentially the diameter of the vent hole. The "Exhaust mechanism length" column lists the length of the exhaust mechanism used in each mold. The vent hole length is essentially the diameter of the vent hole and is listed as a real value (unit: mm). The length of the slits and circumferential grooves is the sum of their respective lengths in the tire circumferential direction and is expressed as a percentage (unit: %) of the tire circumference at the widest point of the tire. In the "Exhaust mechanism width" and "Exhaust mechanism length" columns, if a combination of circumferential grooves and vent holes is used, the value for the circumferential groove is listed in the upper row of each column and the value for the vent hole in the lower row.

[0038] In the "Exhaust mechanism position" column of Tables 1 and 2, the case where the exhaust mechanism is installed at (or near) the position corresponding to) the maximum tire width position in the tire shown in FIG. 1 (a tire without a rim protector) is labeled "Maximum width position," and the case where the exhaust mechanism is installed at (or near) the position corresponding to (or near) the maximum tire width position (rim protect bar) in the tire shown in FIG. 2 (a tire with a rim protector) is labeled "RPB." The "Distance h" column indicates the distance in the tire radial direction from the maximum tire width position (maximum protruding position of the rim protector bar) to the slit, and is expressed as a percentage of the tire cross-sectional height H. The "Exhaust mechanism formation method" column indicates the case where the exhaust mechanism (slit, vent hole, circumferential groove) is directly installed in the side plate as "Direct" and the case where a replacement piece with an exhaust mechanism formed therein is used as "Replacement piece."

[0039] These examples were evaluated for appearance defect prevention, low air resistance, and workability using the following evaluation methods, and the results are shown in Tables 1 and 2.

[0040] Prevents appearance defects 1,000 tires were vulcanized using each tire mold, and the resulting tires were visually inspected to count the number of tires that developed visual defects (poor appearance due to poor rubber flow or incorrect vent cutting) and determine the incidence of visual defects. The evaluation results are expressed as an index using the reciprocal of the measured values, with Conventional Example 1 being assigned a value of 100 in Table 1 and Conventional Example 2 being assigned a value of 100 in Table 2. The higher the index value, the fewer tires developed visual defects, indicating better prevention of visual defects.

[0041] Low air resistance Pneumatic tires (test tires) manufactured using each tire molding mold were mounted on wheels with a rim size of 19 x 7.5J, the internal tire pressure was adjusted to 230 kPa, and the tires were mounted on test vehicles. The vehicle speed while coasting was measured in accordance with JIS D1012, and the running resistance was calculated using the multi-point regression method. The evaluation results were expressed as an index using the reciprocal of the measured value, with Conventional Example 1 being assigned a value of 100 in Table 1 and Conventional Example 2 being assigned a value of 100 in Table 2. The higher the index value, the lower the air resistance, indicating superior low air resistance.

[0042] Workability The time required to clean the mold (exhaust mechanism) after a tire was vulcanized using each tire mold was measured. The evaluation results were expressed as an index using the reciprocal of the measured value, with Conventional Example 1 being assigned a value of 100 in Table 1 and Conventional Example 2 being assigned a value of 100 in Table 2. The higher the index value, the shorter the time required to clean the mold, indicating better workability.

[0043] [Table 1]

[0044] [Table 2]

[0045] As is clear from Tables 1 and 2, when manufactured using the molds of Examples 1 to 14, air resistance was reduced and excellent workability was demonstrated while suppressing appearance defects to the same extent or more compared to Conventional Example 1 or Conventional Example 2. On the other hand, Comparative Examples 1 and 4 had reduced appearance defect prevention capabilities because only vent holes were provided. Comparative Examples 2 and 5 had reduced appearance defect prevention capabilities because only circumferential grooves were provided. Comparative Examples 3 and 6 had reduced appearance defect prevention capabilities because the distance h was large and the slit was far from the maximum tire width position (maximum protruding position of the rim protect bar).

[0046] The present disclosure includes the following inventions. Invention [1] A tire molding mold having a side plate for molding a tire sidewall portion, a tire molding mold comprising an air-bleeding slit formed so as to open to the tire molding surface of the side plate, the slit extending in the tire circumferential direction within a range of 0.2 times the tire cross-sectional height H on both sides in the tire radial direction from a position corresponding to the maximum tire width position. Invention [2] The tire mold according to invention [1], wherein the width of the slit is 0.01 mm to 0.5 mm. Invention [3] A tire molding mold according to invention [1] or [2], characterized in that the total length of the slits in the tire circumferential direction is 30% or more of the tire circumference at the tire's maximum width position. Invention [4] A tire molding mold according to any one of inventions [1] to [3], characterized in that it comprises a spare piece in which at least one of the slits is formed, and a hole formed in the side plate into which the spare piece is inserted. Invention [5] A method for manufacturing a tire using a tire mold according to any one of Inventions [1] to [4], characterized in that an unvulcanized tire is placed in the tire mold, and the unvulcanized tire is vulcanized in the tire mold while air is removed through the slits. Invention [6] A tire manufactured by the tire manufacturing method according to Invention [5], A tire having traces of the slits on at least a portion of the surface of the sidewall portion. Invention [7] A tire according to invention [6], characterized in that the distance h in the tire radial direction from the maximum width position of the tire to the trace of the slit satisfies the relationship h≦0.2H with respect to the tire cross-sectional height H. [Explanation of symbols]

[0047] 1 Tread section 2 Sidewall 3 Bead section 4 carcass layers 5 bead core 6 Bead filler 7 Belt Layer 8 Belt reinforcement layer 9 Rim protect bar 20 Mold 21 Side Plate 22 bead ring 23 sectors 30 Bladder 40 slits CL Tire Equator

Claims

1. In a tire molding mold having a side plate for molding a sidewall portion of a tire, a tire molding mold comprising an air-bleeding slit formed so as to open to the tire molding surface of the side plate, the slit extending in the tire circumferential direction within a range of 0.2 times the tire cross-sectional height H on both sides in the tire radial direction from a position corresponding to the maximum tire width position.

2. 2. The tire mold according to claim 1, wherein the width of the slit is 0.01 mm to 0.5 mm.

3. 2. The tire mold according to claim 1, wherein the total length of the slits in the tire circumferential direction is 30% or more of the tire circumference at the maximum width position of the tire.

4. 2. The tire molding mold according to claim 1, further comprising: a spare piece having at least one of the slits formed therein; and a hole formed in the side plate into which the spare piece is inserted.

5. A tire manufacturing method using the tire molding mold according to any one of claims 1 to 4, characterized in that an unvulcanized tire is placed in the tire molding mold, and the unvulcanized tire is vulcanized in the tire molding mold while air is removed through the slits.

6. A tire manufactured by the tire manufacturing method according to claim 5, A tire having traces of the slits on at least a portion of the surface of the sidewall portion.

7. 7. The tire according to claim 6, wherein a distance h in the tire radial direction from a maximum width position of the tire to the trace of the slit satisfies the relationship h≦0.2H where H is a tire cross-sectional height.

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