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

Abstract

To provide a tire molding die capable of performing efficient exhaust during vulcanization without affecting tire appearance or air resistance around a tire and to provide a method for producing a tire and a tire using the same.SOLUTION: There is provided a tire molding die 20 for forming a tire having a side plate 21 for forming a sidewall part 2 of the tire and a sector 23 for forming a tread part 1 of the 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 at the position corresponding to the end of a tire constituent member.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, when vent holes are used for venting, rubber can flow into the vent holes, resulting in spews, or whisker-like protrusions, on the surface of the molded tire. Although such spews are removed before the tire is shipped, even after the spews are removed, traces of the spews (cut marks) may remain on the tire surface. In other words, the bases of the spews may remain as minute cylindrical protrusions. The presence of such cut marks can degrade the tire's appearance, and minute irregularities on the tire surface caused by the cut marks may affect the air resistance around the tire. For this reason, for example, Patent Document 1 proposes reducing the number of vent holes by providing grooves on the side molding surfaces of the mold as air vent channels. However, while such grooves can reduce the occurrence of spews, the rubber that flows into the air vent grooves remains on the tire as protrusions, which may not necessarily reduce the impact on 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-136617 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 enables efficient exhaust during vulcanization without affecting the tire's appearance or air resistance around the tire, 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 on the tire molding surfaces of the side plates, and the slits extend in the tire circumferential direction at positions corresponding to the ends of tire constituent members.

[0006] The tire manufacturing method of the present invention for achieving the above-mentioned 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 the slits.

[0007] In addition, the tire of the present invention for achieving the above object is a tire manufactured by the above tire manufacturing method, and is characterized in that it has traces of the slits on at least a part of the surface of the sidewall portion corresponding to the end position of the tire constituent member. [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 after 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 air-release slits as described above, particularly in positions corresponding to the ends of tire components where air is likely to accumulate, 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 slits are preferably located within 10 mm on both sides of the end positions of the tire constituent members in the tire radial direction, allowing for more efficient exhaust.

[0012] 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.

[0013] In the tire mold of the present invention, the ratio of the total length of the slits in the tire circumferential direction to the tire circumference at the positions corresponding to the ends of the tire constituent members is preferably 30% or more. By providing the slits with a sufficient length in this manner, it is possible to achieve good exhaust performance through the slits.

[0014] 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.

[0015] In the tire manufacturing method of the present invention, the unvulcanized tire preferably comprises, as tire constituent members, at least a tread rubber layer constituting a tread portion, a carcass layer mounted between bead portions, and a bead filler enclosed by the main portion and folded-up portion of the carcass layer in the bead portion. In a tire comprising such tire constituent members, arranging the slits at the above-mentioned positions enables more efficient exhaust. [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] 1 is an explanatory diagram showing an example of a tire vulcanizing apparatus including a tire molding mold of the present invention. FIG. [Figure 3] 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 4] 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] In the tread portion 1, a tread rubber layer 11 is disposed on the outer peripheral side of the carcass layer 4, belt layer 7, and belt reinforcing layer 8. The tread rubber layer 11 may have a structure in which two types of rubber layers with different physical properties (a cap tread layer that forms the tread surface of the tread portion 1 and an under tread layer disposed on its inner peripheral side) are laminated in the tire radial direction. A side rubber layer 12 is disposed on the outer peripheral side (outer side in the tire width direction) of the carcass layer 4 in the sidewall portion 2, and a rim cushion rubber layer 13 is disposed on the outer peripheral side (outer side in the tire width direction) of the carcass layer 4 in the bead portion 3.

[0021] In the following description, the term "tire constituent member" refers to the above-mentioned members, particularly those whose ends are disposed in the sidewall portion. Specific examples include the tread rubber layer 11, the carcass layer 4, and the bead filler 6. In addition, when an additional reinforcing layer (not shown) is provided in the sidewall portion 2 of the tire, the reinforcing layer also falls under the category of tire constituent member. When manufacturing the tire of FIG. 1, the end P of the tread rubber layer 11 isT , the end P of the carcass layer 4 C , and the end P of the bead filler 6 F are the ends of the tire constituent members.

[0022] FIG. 2 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 21).

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] The present invention relates to the arrangement of the above-mentioned slits 40. Specifically, the slits 40 of the present invention are arranged at the end of the tire constituent member (end P in FIG. 1). T , P C , P F ) and extends in the tire circumferential direction at this position. When there are multiple ends of tire constituent members in the sidewall portion 2 as shown in FIG. 1, it is advisable to provide slits 40 at at least one of the corresponding positions, and preferably at all of the corresponding positions. Since air is likely to accumulate at the end positions of tire constituent members during vulcanization, providing slits 40 at these locations makes it possible to achieve excellent exhaust performance, prevent poor appearance, and reduce air resistance around the tire.

[0030] A plurality of slits 40 may be provided at positions corresponding to the ends of the tire constituent members. Alternatively, a single slit 40 may be provided at a position corresponding to the end of the tire constituent member and extending around the entire circumference of the tire. In either case, the slits 40 are preferably arranged within a range of 10 mm, more preferably 5 mm, on both sides of the end position of the tire constituent member in the tire radial direction. In particular, when a plurality of slits 40 are provided, it is preferable that each individual slit 40 is arranged within the above-mentioned range. By arranging the slits 40 at positions sufficiently close to the ends of the tire constituent members in this way, more efficient exhaust is possible.

[0031] The slits 40 should have a sufficient length, and in particular, the ratio of the total length of the slits 40 in the tire circumferential direction to the tire circumference at the position corresponding to the end of the tire constituent member should preferably be 30% or more, more preferably 50% or more. When the slits 40 are provided at the ends of a plurality of tire constituent members, the above-mentioned ratio is calculated for each individual tire constituent member. That is, the end P of the carcass layer 4 C The slit 40 provided at the position corresponding to the end P of the carcass layer 4 C and the tire circumferential length of the slit 40 provided at this position (total length if multiple slits 40 are provided), and calculate the ratio based on the circumferential length at the position corresponding to the end P of the bead filler 6. F The slit 40 provided at the position corresponding to the end P of the bead filler 6 F The ratio is calculated based on the circumferential length at the position corresponding to the slit 40 and the circumferential length of the slit 40 provided at that position (the total length if multiple slits 40 are provided) (the same applies to slits 40 provided at the ends of other tire constituent members). By providing the slits 40 with a sufficient length in this way, it is possible to achieve good exhaust performance through the slits 40. If the total circumferential length of the slits 40 at each end position is less than 30% of the circumferential length of the slits 40, the slits 40 cannot be provided with a sufficient length, which may result in a decrease in exhaust performance.

[0032] When slits 40 are provided at positions corresponding to the ends of multiple tire constituent members, the slits 40 provided at the positions corresponding to each end are arranged concentrically, and auxiliary slits (not shown) may be provided to connect these slits in the tire radial direction. By providing such auxiliary slits, multiple rows of slits 40 that are arranged concentrically and form intermittent or continuous rings are connected to each other, further improving the effectiveness of air evacuation within the mold. Because the auxiliary slits are also fine grooves like the slits 40, almost no trace of the slits 40 remains on the tire, and providing the auxiliary slits does not adversely affect the tire's appearance or air resistance.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Any tire can be manufactured using the above method, but the position of the slit 40 is determined by the ends of the tire constituent members, so it is preferable that the unvulcanized tire has, as tire constituent members, at least the tread rubber layer 11 that forms the tread portion 1, the carcass layer 4 installed between the bead portions 3, and the bead filler 6 that is enclosed by the main portion and folded-up portion of the carcass layer 4 in the bead portions 3. Optionally, a reinforcing layer may be provided in the sidewall portion 2. If the ends of the tire constituent members are present in the sidewall portion 2, air is likely to accumulate at the end positions, so locating the slits in the above positions enables more efficient exhaust.

[0037] 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]

[0038] In manufacturing a tire having a tire size of 245 / 50R19 95Y and the structure illustrated in Fig. 1, the type of exhaust mechanism, width of the exhaust mechanism, length of the exhaust mechanism, distance from the end of the member, and method of forming the exhaust mechanism were varied for the tire molding mold (Conventional Example 1, Comparative Examples 1 and 2, Examples 1 to 11), as shown in Tables 1 and 2. Note that the numerical values ​​etc. are listed for the exhaust mechanisms provided at positions corresponding to the end positions of the tread rubber layer, the carcass layer, and the bead filler.

[0039] 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. Note that a circumferential groove is a groove provided in an annular shape on the inner periphery of the sector division position, which connects vent holes to facilitate air flow, and is basically an exhaust mechanism used in combination with a vent hole as in Conventional Example 1 (Comparative Example 2 has only a circumferential groove, so it does not actually function as an exhaust mechanism, but is presented for comparison).

[0040] In Tables 1 and 2, the "Exhaust mechanism width" column 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 location. 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 shown as a percentage (unit: %) of the tire circumference at the position where the exhaust mechanism is installed (the end position of the tire constituent member). In the "Exhaust mechanism width" and "Exhaust mechanism length" columns, if a combination of circumferential grooves and vent holes is used, the numerical value for the circumferential groove is listed in the upper row of each column, and the numerical value for the vent hole is listed in the lower row.

[0041] The "Distance from component end" column in Table 1 shows the radial distance from each component end to the exhaust mechanism. The "Exhaust mechanism formation method" column indicates when the exhaust mechanism (slit, vent hole, circumferential groove) is directly installed in the side plate as "direct installation," and when a replacement piece with the exhaust mechanism formed on it is used as "replacement piece."

[0042] These examples were evaluated for appearance defect prevention, low air resistance, and workability using the following evaluation methods, and the results are shown in Table 1.

[0043] 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 with visual defects (poor rubber flow or poor aesthetics due to incorrect vent cutting) and determine the incidence of visual defects. The evaluation results were expressed as an index using the reciprocal of the measured value, with Conventional Example 1's value being 100. The higher the index value, the fewer tires with visual defects, meaning better prevention of visual defects.

[0044] Low air resistance The pneumatic tires (test tires) manufactured using each tire molding mold were mounted on wheels with a rim size of 19 x 7.5J, the tire internal pressure was set 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 multipoint regression method. The evaluation results were expressed as an index using the reciprocal of the measured value, with Conventional Example 1's value being set at 100. The higher the index value, the lower the air resistance, indicating excellent low air resistance.

[0045] Workability The time required to clean the mold (exhaust mechanism) after vulcanizing a tire 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's value being set at 100. The higher the index value, the shorter the time required to clean the mold, indicating better workability.

[0046] [Table 1]

[0047] [Table 2]

[0048] As is clear from Tables 1 and 2, when manufactured using the molds of Examples 1 to 11, poor appearance was prevented, air resistance was reduced, and excellent workability was demonstrated compared to Conventional Example 1. In addition, since Examples 9 to 11 are examples in which a slit-shaped exhaust mechanism is provided at only one of the positions corresponding to the end position of the tread rubber layer, the end position of the carcass layer, or the end position of the bead filler, the evaluation results were slightly lower compared to Example 4 in which similar slits were provided at all positions. However, compared to Conventional Example 1 (and Comparative Examples 1 and 2), sufficiently good results were shown in terms of prevention of poor appearance, low air resistance, and workability. On the other hand, Comparative Example 1 had poor prevention of poor appearance because only vent holes were provided. Comparative Example 2 had poor prevention of poor appearance because only circumferential grooves were provided.

[0049] The present disclosure encompasses 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 into the tire molding surface of the side plate, the slit extending in the tire circumferential direction at any one of positions corresponding to an end of a tire constituent member. Invention [2] A tire molding mold according to invention [1], characterized in that the slits are arranged within a range of 10 mm on both sides of the end position of the tire constituent member in the tire radial direction. Invention [3] The tire mold according to invention [1] or [2], wherein the width of the slit is 0.01 mm to 0.5 mm. Invention [4] A tire molding mold according to any one of inventions [1] to [3], characterized in that the ratio of the total length of the slits in the tire circumferential direction to the tire circumference at a position corresponding to the end of the tire constituent member is 30% or more. Invention [5] A tire molding mold according to any one of inventions [1] to [4], 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 [6] A method for manufacturing a tire using a tire mold according to any one of Inventions [1] to [5], 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 slit. Invention [7] The unvulcanized tire is characterized in that it comprises, as tire constituent components, a tread rubber layer constituting at least the tread portion, a carcass layer mounted between bead portions, and a bead filler enclosed by the main portion and folded portion of the carcass layer in the bead portion. Invention [8] A tire manufactured by the tire manufacturing method according to Invention [7], A tire having a trace of the slit on at least a part of the surface of the sidewall portion corresponding to the end position of the tire constituent member. [Explanation of symbols]

[0050] 1 Tread section 2 Sidewall 3 Bead section 4 carcass layers 5 bead core 6 Bead filler 7 Belt Layer 8 Belt reinforcement layer 20 Mold 21 Side Plate 22 bead ring 23 sectors 30 Bladder 40 slits CL Tire Equator

Claims

1. In a tire 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 into the tire molding surface of the side plate, the slit extending in the tire circumferential direction at a position corresponding to an end of a tire constituent member.

2. A tire molding mold characterized in that the slits are arranged within a range of 10 mm on both sides in the tire radial direction of the end positions of the tire constituent members.

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

4. 2. The tire mold according to claim 1, wherein a ratio of a total length of the slits in the tire circumferential direction to the tire circumference at a position corresponding to an end of the tire constituent member is 30% or more.

5. 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.

6. A tire manufacturing method using the tire molding mold according to any one of claims 1 to 5, 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.

7. 7. The tire manufacturing method according to claim 6, wherein the unvulcanized tire comprises, as tire constituent members, at least a tread rubber layer constituting a tread portion, a carcass layer mounted between bead portions, and a bead filler enclosed by a main portion and a folded portion of the carcass layer in the bead portion.

8. A tire manufactured by the tire manufacturing method according to claim 7, A tire having a trace of the slit on at least a part of the surface of the sidewall portion corresponding to the end position of the tire constituent member.

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