Tire mold, tire manufacturing method using the same, and tire

Abstract

To provide a mold for molding a tire capable of suppressing an appearance defect caused by an exhaust mark at the time of vulcanization while suppressing a vulcanization defect and capable of reducing the air resistance of the tire, a method for manufacturing the tire using the same, and the tire.SOLUTION: The tire mold 20 of the present invention is a tire mold 20 for molding the tire T including the side block 15 protruding from the outer surface of the side wall portion 2 on the outer surface of the side wall portion 2, and has the side plate 21 for molding the side wall portion 2, and the side plate 21 has the recessed portion 25 corresponding to the side block 15 and the slit 26 for air bleeding formed so as to open to the bottom surface of the recessed portion 25.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 a tire; and more specifically, to a tire molding mold that can suppress poor vulcanization while suppressing poor appearance caused by exhaust marks during vulcanization and reducing the air resistance of the tire, a tire manufacturing method using the same, and a tire. [Background technology]

[0002] When manufacturing a tire, an unvulcanized tire is placed in a mold and vulcanized within the mold. If air remains between the molding surface of the mold and the unvulcanized tire, the tire and the mold do not make sufficient contact in the air pockets, resulting in poor vulcanization. Poor vulcanization refers to an abnormal appearance caused by an unexpected flow of rubber during tire vulcanization. While this does not affect tire performance, correcting the abnormal appearance requires a long period of additional work, which is undesirable from the perspective of production efficiency. Therefore, numerous cylindrical vent holes are formed on the molding surface of the mold, and air remaining between the molding surface of the mold and the unvulcanized tire is exhausted through these vent holes (see, for example, Patent Document 1).

[0003] However, providing vent holes in the mold requires a process of cutting out the spew formed by the rubber that has flowed into the vent holes after vulcanization, and the cut marks from the spew remain noticeable even after cutting, detracting from the tire's appearance. Furthermore, the cut marks from the spew can also increase the tire's air resistance. In particular, for tires with multiple side blocks protruding from the outer surface of the sidewall, it is necessary to provide sufficient exhaust means in the recesses in the mold corresponding to each side block, which tends to significantly deteriorate the tire's appearance and increase its air resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-168788 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a tire molding mold that can suppress poor vulcanization while suppressing poor appearance caused by exhaust marks during vulcanization and reducing the air resistance of the tire, as well as a tire manufacturing method and tire using the same. [Means for solving the problem]

[0006] In order to achieve the above object, the tire molding mold of the present invention is a tire molding mold for molding a tire having side blocks on the outer surface of a sidewall portion that protrude from the outer surface of the sidewall portion, and is characterized in that it has a side plate for molding the sidewall portion, and the side plate has a recess corresponding to the side block and an air vent slit formed so as to open into the bottom surface of the recess.

[0007] Furthermore, in order to achieve the above object, the tire manufacturing method of the present invention is a tire manufacturing method using the tire molding mold described above, 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.

[0008] Furthermore, in order to achieve the above object, the tire of the present invention is a tire manufactured by the above-mentioned tire manufacturing method, characterized in that the top surface of the side block has traces of the slits. [Effects of the Invention]

[0009] As a result of extensive research into exhaust methods for tire molds, the inventors discovered that by providing a slit-shaped exhaust mechanism instead of the conventional vent holes, it is possible to suppress poor vulcanization, reduce the appearance defects caused by exhaust marks during vulcanization, and reduce the tire's air resistance. Specifically, with conventional vent holes, rubber can 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 slit is a tiny gap, rubber is less likely to flow into it. Furthermore, 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's appearance is not impaired and the tire's air resistance is not adversely affected. Furthermore, the conventional process of removing the spew after vulcanization is unnecessary.

[0010] The present invention is based on this finding, and in a tire molding mold for molding tires having side blocks on the outer surface of the sidewall portion, the side plates have recesses corresponding to the side blocks and air vent slits formed to open into the bottom surfaces of the recesses, so that air remaining in the recesses corresponding to the side blocks, where poor vulcanization is likely to occur, is vented through the slits, thereby suppressing poor vulcanization while also suppressing poor appearance caused by exhaust marks during vulcanization and reducing the air resistance of 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 small, 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. The slit width is the dimension measured along the short side of the slit.

[0012] In the tire mold of the present invention, the slits are preferably arranged along the edges of the side blocks, which ensures good exhaust performance, improves the appearance, and enhances the effect of reducing air resistance.

[0013] In the tire mold of the present invention, the total length of the slits is preferably 30% or more of the total edge length of the side blocks. By ensuring a sufficient length of the slits, good exhaust performance can be ensured.

[0014] In the tire mold of the present invention, the side plates preferably have a spare piece with at least one slit formed therein and a hole into which the spare piece is inserted. By providing a spare piece with a slit formed therein, the spare piece can be removed when cleaning the mold after vulcanization, thereby improving workability during cleaning.

[0015] In the tire mold of the present invention, the side blocks are preferably located within a range of 40% of the tire cross-sectional height from the tire's maximum outer diameter. Side blocks are generally located within this range, but their presence within this range is likely to result in poor vulcanization. Therefore, when vulcanizing a tire equipped with such side blocks, providing air-vent slits that open to the bottom surfaces of the recesses corresponding to the side blocks can suppress poor vulcanization, reduce appearance defects due to exhaust marks during vulcanization, and reduce the tire's air resistance.

[0016] According to the tire manufacturing method of the present invention, the above-described tire molding mold is used, and 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. This makes it possible to suppress poor vulcanization, suppress poor appearance due to exhaust marks during vulcanization, and reduce the air resistance of the tire.

[0017] The tire of the present invention is a tire manufactured by the above-mentioned tire manufacturing method, and has slit marks on the top surfaces of the side blocks. Such a tire has few vulcanization defects, has a good appearance as a tire product at the shipping stage, and also has low air resistance.

[0018] The tire of the present invention has a structure in which a tread rubber layer constituting the tread portion is laminated so as to cover the outer peripheral side of a side rubber layer constituting a sidewall portion, and it is preferable that an end portion of the tread rubber layer in the tire width direction is located between the division position on the sector side of the side plate and the slit traces. The end portion of the tread rubber layer in the tire width direction is a portion where air is likely to accumulate, whereas air is exhausted at the division position and the slit position on the sector side of the side plate. Therefore, by positioning the end portion of the tread rubber layer in the tire width direction between the division position on the sector side of the side plate and the slit traces, exhaust efficiency can be improved and poor vulcanization can be effectively suppressed. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a meridian cross-sectional view showing a pneumatic tire according to an embodiment of the present invention. [Figure 2] FIG. 2 is a side view showing a part of the pneumatic tire of FIG. 1 in the circumferential direction. [Figure 3] 1 is a cross-sectional view showing an example of a tire vulcanizing apparatus including a tire molding mold of the present invention. [Figure 4] FIG. 4 is an enlarged plan view showing a main part of the tire mold of FIG. 3. [Figure 5] FIG. 10 is a cutaway perspective view showing an example of a side plate having a recess and a slit. [Figure 6] FIG. 10 is a cutaway perspective view showing a modified example of a side plate having a recess and a slit. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: Figures 1 and 2 show a pneumatic tire according to an embodiment of the present invention.

[0021] As shown in FIG. 1, the pneumatic tire T of this embodiment includes a tread portion 1 extending circumferentially in a ring shape, a pair of sidewall portions 2, 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3, 3 arranged radially inward of the sidewall portions 2.

[0022] A carcass layer 4 is mounted between the pair of bead portions 3, 3. This carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the inside to the outside of the tire around a bead core 5 disposed in each bead portion 3. Organic fiber cords such as polyester cords are preferably used as the reinforcing cords of the carcass layer 4. A bead filler 6 made of a rubber composition and having a triangular cross section is disposed on the outer periphery of the bead core 5.

[0023] On the other hand, multiple belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include multiple reinforcing cords that are inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers. In the belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set to a range of 10° to 40°, for example. Steel cords are preferably used as the reinforcing cords of the belt layers 7. At least one belt cover layer 8 is arranged on the outer peripheral side of the belt layer 7, with the aim of improving high-speed durability, and the reinforcing cords are arranged at an angle of, for example, 5° or less with respect to the tire circumferential direction. As the reinforcing cords of the belt cover layer 8, organic fiber cords such as nylon and aramid are preferably used.

[0024] The tire internal structure described above is a typical example of a pneumatic tire, but is not limited thereto. A tread rubber layer 1A is disposed on the outside of the belt cover layer 8 in the tread portion 1, a side rubber layer 2A is disposed on the outside of the carcass layer 4 in the sidewall portion 2, and a rim cushion rubber layer 3A is disposed on the outside of the carcass layer 4 in the bead portion 3.

[0025] The tread portion 1 has a plurality of main grooves 11 extending in the tire circumferential direction. These main grooves 11 define a plurality of rows of land portions 12 in the tread portion 1. Furthermore, at least the land portions 12 located on the outermost sides in the width direction of the tread portion 1 have a plurality of lug grooves 13 extending in the tire width direction formed therein. These lug grooves 13 define a plurality of shoulder blocks 14 in the land portions 12 located on the outermost sides in the width direction of the tread portion 1 (see FIG. 2). Meanwhile, on the outer surface of the sidewall portion 2, a plurality of side blocks 15 protruding from the outer surface of the sidewall portion 2 are formed along the tire circumferential direction at positions adjacent to the shoulder blocks 14. The shape of the side blocks 15 is not particularly limited, and they are arranged in a ratio of, for example, 1:1 or 2:1 to the side blocks 15.

[0026] 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, and FIG. 4 shows an enlarged view of the main parts thereof. This 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 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 a side plate 21, which will be described later, and therefore the structure of the tire vulcanizing apparatus is not limited to the example shown, as long as it comprises a mold 20 (particularly the side plate 21).

[0027] The mold 20 is composed of a pair of side plates 21 for molding the sidewall portion 2 of the tire T, a pair of bead rings 22 for molding the bead portion 3 of the tire T, and a plurality of sectors 23 for molding the tread portion 1 of the tire T, and the tire T is vulcanized and molded inside the mold 20.

[0028] 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 tire T is pressed from the inside toward the inner surface of the mold 20 based on the pressure. Note that it is also possible to use only steam as the heating and pressurizing medium.

[0029] Heating means (not shown) is attached to the side plates 21 and sectors 23 that constitute the mold 20, and the tire T is vulcanized by heating the mold 20 with the heating means.

[0030] In a tire vulcanizing apparatus configured in this manner, at least one of the pair of side plates 21 constituting the mold 20 has a recess 25 corresponding to the side block 15 and at least one air-vent slit 26 formed so as to open into the bottom surface of the recess 25, as shown in Figures 3 and 4. The slit 26 communicates with the outside of the mold 20 via, for example, an air passage 27. The air-vent slit 26 is a minute gap that opens into the bottom surface of the recess 25 of the side plate 21, and discharges air remaining in the mold 20 during vulcanization.

[0031] Unlike conventional vent holes (thin cylindrical exhaust holes), these air-release slits 26 hardly allow rubber to flow into them, so spew, as occurs with conventional vent holes, does not occur. Even if traces X (see FIG. 2) of the slits 26 are formed due to rubber that has flowed into the slits 26, only fine linear traces X remain, so the appearance is not marred and the air resistance of the tire T is not adversely affected. Moreover, the process of cutting off spew after vulcanization, as in the past, is no longer necessary.

[0032] In the tire molding mold 20 for molding a tire having side blocks 15 on the outer surface of the sidewall portion 2 in this manner, the side plate 21 has recesses 25 corresponding to the side blocks 15 and air vent slits 26 formed to open into the bottom surface of the recesses 25, so that air remaining in the recesses 25 corresponding to the side blocks 15, where poor vulcanization is likely to occur, is vented through the slits 26, thereby suppressing poor vulcanization while also suppressing poor appearance due to exhaust marks during vulcanization and reducing the air resistance of the tire.

[0033] 5 and 6 show examples of side plates with recesses and slits, respectively. As described above, the slits 26 are minute gaps at their openings. The width W of the slits 26 is preferably 0.01 mm to 0.5 mm, and more preferably 0.02 mm to 0.05 mm. By making the width W of the slits 26 sufficiently small, rubber does not substantially flow into the slits 26. Even if traces X of the slits 26 remain due to the rubber that has flowed into the slits 26, these traces X are merely linear traces of a minute width. This prevents damage to the tire's appearance and prevents poor appearance. If the width W of the slits 26 is less than 0.01 mm, it becomes difficult to ensure sufficient exhaust performance. Furthermore, the slits 26 are too thin, making mold manufacturing (processing the slits 26) difficult. If the width W of the slits 26 exceeds 0.5 mm, rubber tends to flow into the slits 26, leaving traces X of the slits 26. Furthermore, the ratio L / W of the length L of the slit 26 to the width W of the slit 26 is preferably 5 or more, and more preferably in the range of 10 to 100. By increasing the ratio L / W, it is possible to ensure good exhaust performance while preventing the inflow of rubber.

[0034] In the tire mold 20, one or more slits 26 can be provided in each recess 25. In this case, it is preferable that the slits 26 are arranged so as to follow the edges of the side blocks 15. By arranging the slits 26 so as to follow the edges of the side blocks 15 in this manner, good exhaust performance is ensured, the appearance is improved, and the air resistance reduction effect can be enhanced. In particular, it is preferable that the total length of the slits 26 be 30% or more, more preferably 50% or more, of the total edge length of the side blocks 15. By ensuring a sufficient length of the slits 26 in this manner, good exhaust performance can be ensured. The total edge length of the side blocks 15 is the total length of the edges formed on the top surfaces of the side blocks 15.

[0035] The slits 26 may be formed directly in the side plate 21 (see FIG. 5 ). Alternatively, as shown in FIG. 6 , the side plate 21 may have a replacement piece 28 with at least one slit 26 formed therein and a hole 29 into which the replacement piece 28 is inserted. The replacement piece 28 is a component that is detachably inserted into a hole 29 provided in the side plate 21, and when inserted into the hole 29, it constitutes a part of the molding surface of the side plate 21. When the replacement piece 28 is inserted into the hole 29 in this manner, a slit 26 is formed between the side surface of the replacement piece 28 and the inner surface of the hole 28. Normally, when cleaning the mold 20, the cleaning work is performed with the mold 20 removed from the tire vulcanization apparatus. However, when a replacement piece 28 with a slit 26 formed therein is used, the molding surface, including the slit 26, can be cleaned by removing only the replacement piece 28 without removing the mold 20 from the tire vulcanization apparatus. This improves the workability when cleaning the mold 20 (particularly the side plate 21) after vulcanization. In order to fill the gap between the side plate 21 and the spare piece 28, it is desirable that the thermal expansion coefficient of the material constituting the spare piece 28 be higher than the thermal expansion coefficient of the material constituting the side plate 21.

[0036] The slit 26 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 28 as described above.

[0037] In the tire mold 20, it is preferable that the side blocks 15 (and the corresponding recesses 25) are located within a range of 40% of the tire cross-sectional height H from the tire's maximum outer diameter position. Side blocks 15 are generally located within this range, but if side blocks 15 (and the corresponding recesses 25) are located within this range, poor vulcanization is likely to occur. Therefore, when vulcanizing a tire T equipped with such side blocks 15, providing air-vent slits 26 opening into the bottom surfaces of the recesses 25 corresponding to the side blocks 15 can suppress poor vulcanization, reduce appearance defects due to exhaust marks during vulcanization, and reduce the air resistance of the tire T. Furthermore, because the side blocks 15 are locations where automatic spew trimming is difficult, eliminating spew from these locations is extremely meaningful.

[0038] When manufacturing a tire T using the tire mold 20 described above, an unvulcanized tire T is molded and then vulcanized in the tire mold 20. At this time, air is removed from the mold 20 through the slits 26. Because the slits 26 are tiny gaps into which almost no rubber flows, traces X resulting from the removal of air are hardly formed on the surfaces of the side blocks 15 (locations where air is removed using the slits 26) in the vulcanized tire T. Even if traces X of the slits 26 are formed due to rubber that has flowed into the slits 26, only fine linear traces X remain in a portion of the tire. Even if traces X of the slits 26 are formed, because they are tiny linear traces, they are not easily visible, and the traces X of the slits 26 do not impair the appearance of the sidewall portion 2. Furthermore, the traces X of the slits 26 do not impair the air resistance of the tire T.

[0039] The tire T manufactured using the tire mold 20 described above is recognized as having minute traces X of the slits 26 on the top surfaces of the side blocks 15. Such a tire T has few vulcanization defects, has a good appearance as a tire product at the shipping stage, and also has low air resistance.

[0040] The tire T has a laminated structure in which a tread rubber layer 1A constituting the tread portion 1 covers the outer peripheral side of a side rubber layer 2A constituting the sidewall portion 2, and it is desirable that an end E in the tire width direction of the tread rubber layer 1A (see FIG. 1) be positioned between a dividing position P1 (see FIG. 3) on the sector 23 side of the side plate 21 and a trace X of the slit 26 (position P2 of the slit 26). The end E in the tire width direction of the tread rubber layer 1A is a location where air is likely to accumulate, whereas air is exhausted at the dividing position P1 on the sector 23 side of the side plate 21 and position P2 of the slit 26. Therefore, by positioning the end E in the tire width direction of the tread rubber layer 1A between the dividing position P1 on the sector 23 side of the side plate 21 and the trace X of the slit 26 (position P2 of the slit 26), exhaust efficiency can be improved and poor vulcanization can be effectively suppressed. [Example]

[0041] In manufacturing a tire with a tire size of 265 / 70R17 113T and having side blocks on the outer surface of the sidewall portion, an exhaust mechanism was provided in the side plate constituting the tire molding mold, opening to the bottom of a recess corresponding to the side block, and the type of exhaust mechanism (vent hole or slit), the width of the exhaust mechanism, the presence or absence of slits along the side block edge, the ratio of the slit length, the method of forming the exhaust mechanism, the position of the inner end of the side block in the tire radial direction, and the position of the end of the tread rubber layer relative to the slit were set as shown in Table 1 (Conventional Example, Comparative Example 1, and Examples 1 to 10).

[0042] Regarding the "exhaust mechanism width," in the case of vent holes, the width of the exhaust mechanism is the diameter of the vent hole. The "slit length ratio" is the ratio (%) of the total length of the slits formed in the recesses corresponding to each side block to the total edge length of each side block. Regarding the "exhaust mechanism formation method," the "direct mounting" refers to the case where the exhaust mechanism (slits, vent holes) is directly mounted on the side plate, and the "replacement" refers to the case where a replacement block with an exhaust mechanism is used. The "radial inner edge position of the side block" is expressed as the ratio of the distance from the maximum outer diameter of the tire to the radial inner edge position of the side block to the tire cross-sectional height H. Regarding the "tread rubber layer end position," the case where the tire width direction end of the tread rubber layer is located radially inward from the slit position (P2) is expressed as "below the slit," and the case where the tire width direction end of the tread rubber layer is located between the division position P1 on the sector side of the side plate and the slit position P2 is expressed as "between P1 and P2."

[0043] The productivity, appearance, low air resistance, and cleaning workability of these conventional example, comparative example 1, and examples 1 to 10 were evaluated by the following evaluation methods. The results are shown in Table 1.

[0044] Productivity: 1,000 tires were vulcanized using each tire molding mold, and the tires were visually inspected immediately after vulcanization. The number of tires with vulcanization defects due to poor exhaust was counted to determine the rate of vulcanization defects. The evaluation results were expressed as an index using the reciprocal of the rate of vulcanization defects, with the conventional example being set at 100. The higher the index value, the fewer tires with vulcanization defects, indicating better productivity.

[0045] Appearance: For tires that did not show any vulcanization defects in the above-mentioned productivity evaluation, the spews were cut off and other work was carried out to return them to the state they were in at the time of shipment. These tires were then visually inspected and subjected to a sensory evaluation for any defects in appearance (such as deterioration in appearance due to cut marks on the spews). The evaluation results were expressed as an index, with the conventional example being set at 100. The higher the index value, the better the appearance.

[0046] Low air resistance: The pneumatic tires manufactured using each tire molding mold were mounted on wheels with a rim size of 17 x 8.0J, the air pressure was set to 230kPa, and the tires were then mounted on a test vehicle. In accordance with JIS D1012, the vehicle speed while coasting was measured 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 the conventional example being set at 100. The higher the index value, the lower the air resistance.

[0047] Cleaning 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 the conventional example being set at 100. The higher the index value, the shorter the time required to clean the mold and the better the cleaning workability.

[0048] [Table 1]

[0049] As can be seen from Table 1, in comparison with the conventional example in which the side plate was provided with a vent hole as an exhaust mechanism, Examples 1 to 10 were able to improve appearance and low air resistance while maintaining good productivity (exhaust performance), and furthermore, cleaning workability was also good. On the other hand, although Comparative Example 1 had good appearance and low air resistance, since the side plate did not have an exhaust mechanism, poor vulcanization was likely to occur due to poor exhaust, and productivity was reduced.

[0050] The present disclosure includes the following inventions [1] to [9]. Invention [1] is a tire molding mold for molding a tire having side blocks on the outer surface of a sidewall portion that protrude from the outer surface of the sidewall portion, the tire molding mold having a side plate for molding the sidewall portion, the side plate having a recess corresponding to the side block and an air vent slit formed so as to open into the bottom surface of the recess. Invention [2] is the tire mold according to invention [1], characterized in that the width of the slit is 0.01 mm to 0.5 mm. Invention [3] is the tire molding mold according to invention [1] or [2], characterized in that the slits are arranged along the edges of the side blocks. Invention [4] is a tire molding mold according to any one of inventions [1] to [3], characterized in that the total length of the slits is 30% or more of the total edge length of the side blocks. Invention [5] is a tire molding mold according to any one of Inventions [1] to [4], characterized in that the side plate has a spare piece in which at least one of the slits is formed, and a hole into which the spare piece is inserted. Invention [6] is a tire molding mold according to any one of inventions [1] to [5], characterized in that the side blocks are present within a range of 40% of the tire cross-sectional height from the maximum outer diameter position of the tire. Invention [7] is a method for manufacturing a tire using a tire mold according to any one of Inventions [1] to [6], 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 [8] is a tire manufactured by the tire manufacturing method described in Invention [7], characterized in that the top surface of the side block has traces of the slits. Invention [9] is a tire according to invention [8], characterized in that the tread rubber layer constituting the tread portion is laminated so as to cover the outer peripheral side of the side rubber layer constituting the sidewall portion, and the tire width direction end of the tread rubber layer is located between the division position on the sector side of the side plate and the trace of the slit. [Explanation of symbols]

[0051] 1 Tread section 1A Tread rubber layer 2 Sidewall 2A Side rubber layer 3 Bead section 3A Rim cushion rubber layer 11 Main groove 12 Land 13 Lug groove 14 Shoulder Block 15 Side Block 20 Mold 21 Side Plate 22 bead ring 23 sectors 25 recess 26 Slit 27 Ventilation channel 28 Spare Piece 29 Hole 30 Bladder

Claims

1. A tire molding mold for molding a tire having side blocks on the outer surfaces of sidewall portions that protrude from the outer surfaces of the sidewall portions, the tire molding mold comprising a side plate for molding the sidewall portions, the side plate having recesses corresponding to the side blocks and air vent slits formed in the bottom surfaces of the recesses so as to open.

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 slits are arranged along the edges of the side blocks.

4. 2. The tire mold according to claim 1, wherein the total length of the slits is 30% or more of the total edge length of the side block.

5. 2. The tire mold according to claim 1, wherein the side plate has a replacement piece in which at least one of the slits is formed, and a hole into which the replacement piece is inserted.

6. 2. The tire mold according to claim 1, wherein the side blocks are present within a range of 40% of the tire cross-sectional height from the maximum outer diameter position of the tire.

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

8. A tire manufactured by the tire manufacturing method according to claim 7, characterized in that the top surfaces of the side blocks have traces of the slits.

9. 9. The tire according to claim 8, wherein the tread rubber layer constituting the tread portion has a laminated structure so as to cover the outer peripheral side of the side rubber layer constituting the sidewall portion, and an end portion in the tire width direction of the tread rubber layer is located between a division position on the sector side of the side plate and the trace of the slit.

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