Tire curing mold

Abstract

To provide a tire vulcanization mold that can discharge air between the inner surface of the tire and the bladder, even with a thin-walled bead ring.SOLUTION: The tire vulcanization mold comprises a tread mold part for forming a tire tread, a side mold part coming into contact with a sidewall of the tire from outside in the axial direction of the tire, and a bead ring coming into contact with a bead of the tire from outside in the axial direction of the tire. The side mold part has an exhaust hole opening on an inner side in the axial direction of the tire adjacent to the bead ring. The bead ring has a straight first hole extending from a bladder contact surface in contact with the inflated bladder toward the outside of the tire axial direction, and a connection path connecting the first hole and the exhaust hole.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a tire curing mold. [Background technology]

[0002] The following Patent Document 1 discloses a bead ring provided with a vent hole for discharging air between the inner surface of the tire and the bladder during vulcanization molding. One end of the vent hole opens on a bladder contact surface that can be pressed against the bladder by the expansion of the bladder, and extends from the one end toward the outside in the tire axial direction. The other end of the vent hole opens on the outer side surface of the bead ring in the tire axial direction.

[0003] Meanwhile, the central mechanism of the tire vulcanizing device is disposed on the inner periphery side of the bead ring. The central mechanism is equipped with a bladder and piping for supplying and discharging a heating and pressurizing medium to the bladder. Since the central mechanism has a predetermined size, the inner diameter of the bead ring is determined accordingly. As a result, when the inner diameter of the tire (corresponding to the rim diameter) is small, a thin bead ring with a small thickness in the tire radial direction is used.

[0004] The vent hole in Patent Document 1 has the other end open on the axially outer surface of the bead ring, but in the case of a thin bead ring, the other end becomes blocked by the axially inner surface of the side mold section adjacent to the bead ring, making it impossible to vent air. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-75428 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a tire vulcanizing mold that can evacuate air between the inner surface of a tire and a bladder, even in the case of a thin bead ring. [Means for solving the problem]

[0007] The pneumatic tire vulcanization mold of the present disclosure includes a tread mold portion for molding a tire tread, a side mold portion that contacts a sidewall of the tire from an outer side in the tire axial direction, and a bead ring that contacts a bead of the tire from an outer side in the tire axial direction, the side mold portion has an exhaust hole that opens to an axially inner surface of the tire adjacent to the bead ring, The bead ring has a linear first hole portion extending from a bladder contact surface that contacts the inflated bladder toward the outside in the tire axial direction, and a communication path that connects the first hole portion and the exhaust hole to each other. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view illustrating an example of a tire vulcanizing mold according to a first embodiment. [Diagram 2] Plan view of lower bead ring [Diagram 3] Enlarged view of the main part of Figure 1 [Figure 4] 11 is a cross-sectional view of a lower bead ring according to a second embodiment. [Diagram 5] 13 is a cross-sectional view of a lower bead ring according to a third embodiment. [Figure 6] 13 is a cross-sectional view of a lower bead ring according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, one embodiment of a tire vulcanizing mold will be described with reference to Figures 1 to 3. Note that in each figure (as well as Figures 4 to 6), the dimensional ratios in the drawing do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match either.

[0010] In each drawing, the tire axial direction D1 is a direction parallel to the tire rotation axis which is the rotation center of the tire T, the tire radial direction D2 is a diameter direction of the tire T, and the tire circumferential direction is a direction around the tire rotation axis. The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and is located at the center of the tire axial direction D1 of the tire T, and the tire meridian plane is a plane that includes the tire rotation axis and is perpendicular to the tire equatorial plane S1.

[0011] In the tire axial direction D1, the inner side means the side closer to the tire equatorial plane S1, and the outer side means the side farther from the tire equatorial plane S1. In the tire radial direction D2, the inner side means the side closer to the tire rotation axis, and the outer side means the side farther from the tire rotation axis.

[0012] First Embodiment FIG. 1 shows a cross section of a tire vulcanization mold 10 (hereinafter, may be simply referred to as "mold 10") along a tire meridian cross section. This mold 10 is in a closed state. A tire T is set with the tire axial direction D1 facing up and down. In FIG. 1, the right direction is the outer side in the tire radial direction, and the left direction is the inner side in the tire radial direction.

[0013] The mold 10 includes a tread mold portion 11 for molding the tread of the tire T, a lower side mold portion 12 and an upper side mold portion 13 that contact a pair of sidewalls of the tire T from the outer side in the tire axial direction, respectively, and a lower bead ring 14 and an upper bead ring 15 that contact a pair of beads of the tire T from the outer side in the tire axial direction, respectively. Although not shown in the figure, an uneven portion for forming a tread pattern on the tread surface of the tire T is provided on the inner surface of the tread mold portion 11. The lower bead ring 14 and the upper bead ring 15 are arranged spaced apart from each other in the tire axial direction D1.

[0014] A central mechanism 20 of the tire vulcanizing apparatus is disposed on the inner periphery side of the mold 10, more specifically, on the inner periphery side of the lower bead ring 14 and the upper bead ring 15. The central mechanism 20 includes a rubber bag called a bladder 21 for expanding and deforming the tire T. The central mechanism 20 also includes piping (not shown) for supplying and discharging a heating and pressurizing medium such as steam or nitrogen gas to the bladder. Since the central mechanism 20 has a predetermined size, the inner diameter of the lower bead ring 14 and the inner diameter of the upper bead ring 15 are determined accordingly.

[0015] The mold 10 has a molding surface 10a that contacts the outer surface of the set tire T. Although not shown, the molding surface 10a is provided with a large number of exhaust holes (vent holes) that communicate the inside and outside of the mold 10. The exhaust holes are provided on the inner surface of the tread mold portion 11, the inner surfaces of the side mold portions 12 and 13, and the inner surfaces of the bead rings 14 and 15. During vulcanization molding, air between the tire T and the molding surface 10a is exhausted through the exhaust holes. In addition, a suction machine (not shown) is installed outside the mold 10, and is configured to be able to suction the space inside the exhaust holes.

[0016] Fig. 2 is a plan view of the lower bead ring 14. Fig. 3 is an enlarged view of a main part of Fig. 1, and corresponds to a cross section of the lower bead ring 14 taken along the line AA in Fig. 2.

[0017] The lower side mold portion 12 has an axially inner surface 12a and a radially inner surface 12b adjacent to the lower bead ring 14. The lower side mold portion 12 also has an exhaust hole 3 that opens on the axially inner surface 12a. The exhaust hole 3 opens on the outer circumferential side of the axially inner surface 12a. An end of the exhaust hole 3, not shown, leads to the outside of the mold 10 and is connected to a suction machine.

[0018] The lower bead ring 14 has a bead heel molding surface 14a that contacts the bead heel of the bead, a bladder contact surface 14b that contacts the inflated bladder 21, an outer peripheral surface 14c facing outward in the tire radial direction, an inner peripheral surface 14d facing inward in the tire radial direction, and an outer side surface 14e facing outward in the tire axial direction. The inner surface of the lower bead ring 14 smoothly connects to the inner surface of the lower side mold portion 12 along the profile of the outer surface of the tire T.

[0019] In addition, a corner 14f consisting of the outer peripheral surface 14c and the outer side surface 14e is formed by a chamfered slope. When the lower bead ring 14 is fitted to the lower side mold portion 12, the outer peripheral surface 14c comes into close contact with the tire radial inner side surface 12b, the outer side surface 14e comes into close contact with the tire axial inner side surface 12a, and a circumferential gap 14g extending along the tire circumferential direction is provided facing the corner 14f. The exhaust hole 3 of the lower side mold portion 12 is connected to the circumferential gap 14g.

[0020] The lower bead ring 14 has an exhaust path 4 that extends from an inlet 4a provided on the bladder contact surface 14b to an outlet 4b provided at a corner portion 14f. The outlet 4b communicates with the exhaust hole 3 of the lower side mold portion 12. As shown in Fig. 2, the exhaust path 4 is provided at multiple locations (12 locations in this embodiment) in the circumferential direction of the tire.

[0021] The exhaust path 4 includes a linear first hole portion 41 extending from the bladder contact surface 14b toward the outside in the tire axial direction, and a communication path 42 that connects the first hole portion 41 and the exhaust hole 3 to each other.

[0022] The first hole 41 is formed as a circular hole having a circular cross section. The first hole 41 opens at the bladder contact surface 14b to form an inlet 4a. The first hole 41 also has an opening 41a that opens at the outer surface 14e. The opening 41a is adjacent to the axially inner surface 12a of the lower side mold portion 12.

[0023] The first hole 41 is provided in a direction substantially normal to the bladder contact surface 14b. The first hole 41 may extend from the inlet 4a toward the outside in the tire axial direction in the normal direction of the bladder contact surface 14b, but preferably extends at an incline toward the outside in the tire radial direction with respect to the normal direction of the bladder contact surface 14b. The angle θ between the normal direction of the bladder contact surface 14b and the extension direction of the first hole 41 is preferably 15° or less, and is 5° in this embodiment.

[0024] The communication path 42 is formed by a groove 43 formed on the outer surface 14e, which extends from the opening 41a of the first hole portion 41 toward the outer periphery of the lower bead ring 14. The groove 43 extends along the tire radial direction D2 and opens at the corner portion 14f. The opening of the groove 43 serves as the outlet 4b.

[0025] The outlet 4b is set at the corner 14f, and the exhaust path 4 (communication path 42) communicates with the circumferential gap 14g. The lower side mold section 12 is provided with an exhaust hole 3 that communicates with the circumferential gap 14g. By providing such a circumferential gap 14g, the exhaust path 4 and the exhaust hole 3 are appropriately communicated with each other even if they are misaligned in the tire circumferential direction. Therefore, although the exhaust path 4 and the exhaust hole 3 appear on the same cross section in FIG. 3, this is not limiting.

[0026] The lower bead ring 14 used in this embodiment is a thin bead ring having a relatively small thickness, and the opening 41a of the first hole portion 41 is located at a position blocked by the tire axial inner surface 12a of the lower side mold portion 12, but by providing a communication path 42 (groove 43) extending from the opening 41a, the first hole portion 41 and the exhaust hole 3 are communicated with each other. As a result, even with a thin bead ring, the air between the inner surface of the tire T and the bladder 21 can be exhausted to the outside through the exhaust path 4 and the exhaust hole 3. Furthermore, by using a suction machine connected to the exhaust hole 3, excellent exhaust performance can be achieved.

[0027] <Second embodiment> Fig. 4 is a cross-sectional view of the lower bead ring 14 according to the second embodiment, and corresponds to a cross section taken along the line AA in Fig. 2 with respect to the lower bead ring 14. The second embodiment is the same as the first embodiment except for the lower bead ring 14, and therefore detailed description thereof will be omitted.

[0028] The first hole 41 opens at the bladder contact surface 14b to form an inlet 4a. The first hole 41 extends linearly from the bladder contact surface 14b toward the outside in the tire axial direction and terminates at a terminal end 41e inside the lower bead ring 14.

[0029] The first hole 41 is provided in a direction substantially normal to the bladder contact surface 14b. The first hole 41 extends from the inlet 4a toward the tire axially outward in the normal direction of the bladder contact surface 14b, but is not limited thereto. As in the first embodiment, the first hole 41 may extend inclined toward the tire radial direction outward with respect to the normal direction of the bladder contact surface 14b.

[0030] The communication path 42 is formed by a second hole 44 that extends linearly from the end 41e of the first hole 41 toward the outer periphery of the lower bead ring 14 and opens at the outer surface 14e (corner 14f). The opening of the second hole 44 serves as the outlet 4b.

[0031] The first hole 41 and the second hole 44 are each formed by a circular hole having a circular cross section. In the second embodiment, the second hole 44 is formed to have a larger diameter than the first hole 41, but this is not limited to this. Also, in the second embodiment, the angle formed between the first hole 41 and the second hole 44 is an obtuse angle, but this is not limited to this.

[0032] As described above, the tire vulcanizing mold 10 according to the first embodiment and the second embodiment has the following features: The tire has a tread mold portion 11 for forming a tread of the tire T, a side mold portion 12 for contacting a sidewall of the tire T from an outer side in the tire axial direction, and a bead ring 14 for contacting a bead of the tire T from an outer side in the tire axial direction, The side mold portion 12 has an exhaust hole 3 that opens on an axially inner surface 12a of the tire adjacent to the bead ring 14, The bead ring 14 has a linear first hole portion 41 extending from the bladder contact surface 14b that contacts the inflated bladder 21 toward the outside in the tire axial direction, and a communication path 42 that connects the first hole portion 41 and the exhaust hole 3 to each other.

[0033] According to this configuration, the first hole portion 41 and the exhaust hole 3 are communicated with each other by the communication path 42. As a result, even in the case of a thin bead ring 14, the air between the inner surface of the tire T and the bladder 21 can be discharged to the outside through the first hole portion 41, the communication path 42, and the exhaust hole 3.

[0034] In the tire vulcanizing mold 10 according to the first embodiment, the first hole portion 41 has an opening 41a that opens to the tire axially outer side surface 14e of the bead ring 14, The communication path 42 is constituted by a groove 43 formed on the axially outer side surface 14e of the bead ring 14, extending from the opening 41a toward the outer periphery of the bead ring 14.

[0035] According to this configuration, for example, the first hole portion 41 is formed as a single through hole using a drill or the like, and then a groove 43 is formed in the outer surface 14e from the opening 41a of the first hole portion 41 toward the outer periphery of the bead ring 14, thereby easily forming the exhaust path 4 consisting of the first hole portion 41 and the communicating path 42.

[0036] In the tire vulcanizing mold 10 according to the second embodiment, the first hole portion 41 has an end portion 41e that ends inside the bead ring 14, The communication path 42 is formed by a second hole portion 44 that extends linearly from the terminal end portion 41e toward the outer periphery of the bead ring 14 and opens at an axially outer side surface 14e of the bead ring 14.

[0037] According to this configuration, the exhaust path 4 consisting of the first hole portion 41 and the second hole portion 44 is configured as one continuous hole, and further the length of the exhaust path 4 can be shortened, resulting in excellent exhaust performance.

[0038] The tire vulcanizing mold 10 is not limited to the configuration of the above-mentioned embodiment, and is not limited to the above-mentioned action and effect. Of course, the tire vulcanizing mold 10 can be modified in various ways without departing from the gist of the present invention. For example, the configurations and methods of the above-mentioned embodiments may be arbitrarily adopted and combined, and one or more of the configurations and methods of the various modified examples described below may be arbitrarily selected and adopted in the configurations and methods of the above-mentioned embodiment.

[0039] <Third embodiment> Fig. 5 is a cross-sectional view of the lower bead ring 14 according to the third embodiment, and corresponds to a cross section taken along the line AA in Fig. 2 with respect to the lower bead ring 14. The third embodiment is the same as the first embodiment except for the lower bead ring 14, and therefore detailed description thereof will be omitted.

[0040] The lower bead ring 14 is composed of a main body portion 141 and a ring portion 142. The ring portion 142 is formed by dividing a corner portion formed by an inner circumferential surface 14d and an outer circumferential surface 14e of the lower bead ring 14. That is, the ring portion 142 is fitted to the inner circumferential side of the main body portion 141 and to the outside in the tire axial direction.

[0041] The lower bead ring 14 has a first dividing surface 143 extending along the tire radial direction D2 and the tire circumferential direction, and a second dividing surface 144 extending along the tire axial direction D1 and the tire circumferential direction. The first dividing surface 143 and the second dividing surface 144 divide the lower bead ring 14 into a main body portion 141 and a ring portion 142. The main body portion 141 and the ring portion 142 are connected by screws or the like.

[0042] In the ring portion 142, a corner portion defined by the first divided surface 143 and the second divided surface 144 is cut out to have a rectangular cross section. As a result, when the ring portion 142 is fitted into the main body portion 141, a cavity 145 extending around the entire circumference of the ring portion 142 is provided on the outer circumferential side of the axially inner surface of the ring portion 142.

[0043] The first hole portion 41 extends linearly from the bladder contact surface 14b toward the tire axially outward to the first divided surface 143 and opens into the cavity 145. The second hole portion 44 extends linearly from the cavity 145 toward the outer periphery of the lower bead ring 14. Therefore, the cavity 145 can be said to be an end portion 41e of the first hole portion 41.

[0044] The first hole 41 and the second hole 44 communicate with a cavity 145, and by providing the cavity 145, the first hole 41 and the second hole 44 communicate with each other appropriately even if they are misaligned in the tire circumferential direction. This makes it easy to process the first hole 41 and the second hole 44. Note that, although the first hole 41 and the second hole 44 appear on the same cross section in FIG. 5, this is not limiting.

[0045] As described above, in the tire vulcanizing mold 10 of the third embodiment, the bead ring 14 is composed of a main body portion 141 and a ring portion 142 that is fitted onto the inner side of the main body portion 141 and onto the outer side in the tire axial direction, and the terminal end 41e of the first hole portion 41 is composed of a cavity 145 that extends around the entire circumference of the ring portion 142 formed on the outer side of the inner surface of the ring portion 142 in the tire axial direction.

[0046] According to this configuration, even if the first hole portion 41 and the second hole portion 44 are misaligned in the tire circumferential direction, they are properly connected to each other, making it easy to process the first hole portion 41 and the second hole portion 44.

[0047] <Fourth embodiment> Fig. 6 is a cross-sectional view of the lower bead ring 14 according to the fourth embodiment, and corresponds to a cross section taken along the line AA in Fig. 2 with respect to the lower bead ring 14. The fourth embodiment has the same configuration as the first embodiment except for the lower bead ring 14, and therefore detailed description thereof will be omitted.

[0048] The lower bead ring 14 includes a third hole portion 45 extending from the terminal end 41e of the first hole portion 41 in the same direction as the first hole portion 41 and opening at the outer surface 14e, a fourth hole portion 46 extending from the terminal end 41e of the first hole portion 41 in the same direction as the second hole portion 44 and opening at the inner surface 14d, and a plug 47 that blocks the third and fourth hole portions 45, 46.

[0049] The first hole 41 and the third hole 45 are formed as one through hole by a drill. The second hole 44 and the fourth hole 46 are formed as one through hole by a drill so as to intersect with the through holes constituting the first hole 41 and the third hole 45. The intersection of these two through holes can be said to be the terminal end 41e of the first hole 41.

[0050] The opening of the third hole 45 is countersunk, and a plug 47 is detachably attached to the countersunk opening. Similarly, the opening of the fourth hole 46 is countersunk, and a plug 47 is detachably attached to the countersunk opening.

[0051] As described above, in the tire vulcanizing mold 10 of the fourth embodiment, the bead ring 14 is configured to include a third hole portion 45 extending from the terminal end 41e of the first hole portion 41 in the same direction as the first hole portion 41 and opening at the tire axial outer surface 14e of the bead ring 14, a fourth hole portion 46 extending from the terminal end 41e of the first hole portion 41 in the same direction as the second hole portion 44 and opening at the inner surface 14d of the bead ring 14, and a plug 47 that blocks the third and fourth hole portions 45, 46.

[0052] According to this configuration, when cleaning the first hole 41 and the second hole 44, the first hole 41 and the second hole 44 can be easily cleaned by removing the plug 47.

[0053] (1) It is sufficient that at least one of the lower bead ring 14 and the upper bead ring 15 has the exhaust path 4 as described above. Therefore, in the above embodiment, an example was shown in which the exhaust path 4 as described above is provided in the lower bead ring 14, but instead of or in addition to this, it is also possible to provide it in the upper bead ring 15.

[0054] (2) In the above-described embodiment, a mold structure having a tread mold portion 11 and a pair of side mold portions 12, 13 was exemplified. However, this is not limited to this, and for example, a mold structure divided into two parts, upper and lower, at the center of the tread mold portion may also be used.

[0055] (3) The above-described tire vulcanizing mold is equivalent to a normal tire vulcanizing mold, except that the exhaust paths and exhaust holes provided in the bead ring and side mold portion are configured as described above, and any of the conventionally known shapes, materials, mechanisms, etc. can be adopted in the present invention. [Explanation of symbols]

[0056] 3...exhaust hole, 4...exhaust path, 4a...inlet, 4b...outlet, 10...tire curing mold, 11...tread mold portion, 12...lower side mold portion, 12a...tire axial inner surface, 13...upper side mold portion, 14...lower bead ring, 14a...bead heel molding surface, 14b...bladder contact surface, 14c...outer peripheral surface, 14d...inner peripheral surface, 14e...outer surface, 14f...corner portion, 14 g...circumferential gap, 15...upper bead ring, 20...center mechanism, 21...bladder, 41...first hole, 41a...opening, 41e...terminal end, 42...communication path, 43...groove, 44...second hole, 45...third hole, 46...fourth hole, 47...plug, 141...main body, 142...ring, 145...cavity, D1...tire axial direction, D2...tire radial direction, T...tire

Claims

1. A tire tread mold portion for forming a tire tread, a side mold portion contacting a sidewall of the tire from an outer side in the tire axial direction, and a bead ring contacting a bead of the tire from an outer side in the tire axial direction, the side mold portion has an exhaust hole that opens to an axially inner surface of the tire adjacent to the bead ring, the bead ring includes a linear first hole portion extending from a bladder contact surface that is in contact with the inflated bladder toward an outer side in the tire axial direction, and a communication path that connects the first hole portion and the exhaust hole to each other, the first hole has an end portion that terminates inside the bead ring, the communication path is composed of a second hole portion that extends linearly from the terminal end portion inside the bead ring toward the outer periphery of the bead ring and opens at an outer surface of the bead ring in the tire axial direction.

2. the first hole portion has an opening portion that opens to an axially outer surface of the bead ring, 2. The tire vulcanizing mold according to claim 1, wherein the communication path is constituted by a groove formed in an axially outer surface of the bead ring, the groove extending from the opening toward an outer periphery of the bead ring.

3. The bead ring is composed of a main body portion and a ring portion that is fitted to an inner circumferential side of the main body portion and an outer side in the axial direction of the tire, 2. The tire vulcanizing mold according to claim 1, wherein an end portion of the first hole portion is constituted by a cavity extending around the entire circumference of the ring portion, the cavity being formed on an outer circumferential side of an axially inner surface of the ring portion.

4. 2. The tire vulcanization mold according to claim 1, wherein the bead ring comprises: a third hole portion extending from a terminal end of the first hole portion in the same direction as the first hole portion and opening on an outer surface of the bead ring in the tire axial direction, a fourth hole portion extending from a terminal end of the first hole portion in the same direction as the second hole portion and opening on an inner surface of the bead ring, and a plug that closes the third and fourth hole portions.

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