JP7365199B2 - Bead ring and tire vulcanization mold - Google Patents

Description

The present invention relates to a bead ring and a tire vulcanization mold.

The pneumatic tire of Patent Document 1 has a large number of ridges on the bottom surface of the bead in order to prevent the bead from falling off the rim. These ridges consist of sloping ridges that fall with respect to the normal to the axis of rotation of the tire.

Japanese Patent Application Publication No. 7-69010

When vulcanizing a pneumatic tire with such ridges, air remains in the recesses provided in the tire vulcanization mold to form the ridges, resulting in dents (bearings) on the surface of the ridges after vulcanization. ) may occur. However, Patent Document 1 does not describe the discharge of air during vulcanization molding.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bead ring and a tire vulcanization mold that can manufacture a pneumatic tire in which the bead portion does not easily fall off the rim, and can suppress the occurrence of bareness on the bottom surface of the bead.

One aspect of the present invention provides an annular bead having a bead bottom molding surface for molding a bead bottom surface extending from a bead heel to a bead toe of a bead portion of a tire, and arranged so that the axial direction coincides with the width direction of the tire. The bead ring is a ring, and the bead ring includes an annular main body and at least one annular split ring disposed inside the main body in the tire width direction, and the bead bottom molding surface includes a ring in the circumferential direction . a plurality of extending recesses are provided, and the bead ring is axially joined to the body and the at least one split ring by a split extending radially inwardly from at least one of the plurality of recesses. The present invention provides a bead ring that is divided into two parts, and is configured such that air in the recessed part can be exhausted through the divided part.

A ridge corresponding to the recess is formed on the bottom surface of the bead of a tire manufactured using the bead ring according to the present invention. When the tire is assembled to the rim, the ridge effectively suppresses movement of the bead portion in the direction of falling off the rim, thereby suppressing the bead portion from falling off the rim. In addition, the bead ring according to the present invention is divided by a dividing part extending radially inward from the concave part, and air in the concave part can be exhausted through the dividing part during vulcanization molding. It is possible to suppress the occurrence of bare spots on the bottom surface of the bead.

The plurality of recesses may be provided side by side in the tire width direction, and the bead bottom molding surface may include a plurality of convex portions formed by the plurality of recesses to have a sawtooth cross section in a cross section perpendicular to the circumferential direction. is provided.

The bead bottom surface of tires manufactured using this bead ring has a serrated ridge formed by the concave and convex portions of the bead bottom molding surface, which effectively prevents the bead from falling off the rim. It can be suppressed.

Each of the plurality of convex portions may extend obliquely outward in the tire width direction with respect to the tire radial direction.

On the bead bottom surface of tires manufactured using this bead ring, a sawtooth-like ridge that extends inward in the tire width direction with respect to the radial direction is formed by the concave and convex portions of the bead bottom molding surface. be done. These ridges are difficult to deform in response to an outward force in the tire width direction, and are easy to deform in response to an inward force in the tire width direction. As a result, after the tire has been assembled to the rim, if the bead part tries to move in the direction in which it will fall off the rim (inward in the tire width direction), the ridge will resist this movement, so the bead part will not fall off the rim. can be effectively suppressed. On the other hand, when assembling the tire to the rim from the inside in the tire width direction, when the bead is moved in the direction of assembly to the rim (outward in the tire width direction), the ridge does not resist this movement, so the tire Easy to assemble onto the rim. As a result, the ease of assembling the tire to the rim is not hindered, and the bead portion does not easily fall off the rim after assembly.

In the bead ring according to one embodiment, the at least one split ring may have a plurality of split rings, and the bead ring has a plurality of split parts extending radially inward from each of the plurality of recesses. The main body and the plurality of split rings may be divided in the axial direction by .

According to the embodiment, since the bead ring is divided into recesses, the depth or shape of each recess can be changed. Thereby, the size or shape of the ridge formed on the tire manufactured using this bead ring can be changed.

Another aspect of the present invention provides a tire vulcanization mold including the above bead ring.

According to the bead ring of the present invention, it is possible to manufacture a tire in which the bead portion does not easily fall off the rim, and it is possible to suppress the occurrence of bareness on the bottom surface of the bead.

1 is a cross-sectional view showing a schematic configuration of a tire vulcanization mold according to a first embodiment of the present invention. 1 is a sectional view showing a schematic configuration of a bead ring according to a first embodiment. FIG. 1 is a sectional view showing main parts of a bead ring according to a first embodiment. FIG. 3 is a cross-sectional view showing main parts of a bead ring according to a second embodiment.

Hereinafter, a bead ring and a tire vulcanization mold according to an embodiment will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a sectional view showing a schematic configuration of a tire vulcanization mold 1 according to the present embodiment, and only one side in the tire radial direction (the right side in FIG. 1) is shown. In addition, in FIG. 1, a pneumatic tire T that is vulcanized and molded in a tire vulcanization mold 1 is also shown by a virtual line (two-dot chain line). The pneumatic tire T is manufactured by setting a green tire in a tire vulcanization mold 1 so that the tire axis faces in the vertical direction and vulcanizing the tire.

As shown in FIG. 1, the tire vulcanization mold 1 includes an annular sector mold 2, a pair of upper and lower side plates 3 located on the inner diameter side, and a pair of upper and lower bead rings located further on the inner diameter side. 4, 4, and a cavity 5 in which the pneumatic tire T is vulcanized and molded is defined inside these. The tire vulcanization mold 1 is configured as a so-called segmented mold.

The inner wall surfaces of the sector mold 2, the side plates 3, 3, and the cavities 5 of the bead rings 4, 4 are vulcanized to form the tread portion T1, sidewall portion T2, and bead portion T3 of the pneumatic tire T, respectively. It is configured as a molding surface.

FIG. 2 is a sectional view showing a schematic configuration of the bead ring 4 of this embodiment. FIG. 2 shows a cross section of the bead ring 4 perpendicular to the circumferential direction. In addition, in FIG. 2, the pneumatic tire T vulcanized and molded in the tire vulcanization mold 1 is also shown by a virtual line (two-dot chain line).

Referring to FIG. 2, the bead ring 4 is arranged so that its axial direction coincides with the tire width direction of the pneumatic tire T set in the tire vulcanization mold 1 (shown in FIG. 1).

The bead ring 4 of this embodiment is divided in the axial direction and is composed of an annular main body 10 and a plurality of (four in this embodiment) divided rings 11 to 14. Furthermore, the bead ring 4 of this embodiment includes a bead bottom forming surface 20 that forms a bead bottom surface T33 between the bead heel T31 and bead toe T32 of the bead portion T3. The bead bottom molding surface 20 is provided with a plurality of (four in this embodiment) recesses 21 to 24.

The split rings 11-14 are stacked on the main body 10. Further, the split rings 11 to 14 are arranged in the order of split rings 11 to 14 from the outside to the inside in the tire width direction. The main body 10 and the split rings 11 to 14 are fixed by, for example, screws (not shown) extending in the axial direction.

The bead ring 4 is divided by dividing portions P1 to P4 extending radially inward from the recesses 21 to 24, respectively. Specifically, the main body 10 and the split ring 11 are separated by a split portion P1 extending radially inward from the recess 21. The split ring 11 and the split ring 12 are separated by a split portion P2 extending radially inward from the recess 22. The split ring 12 and the split ring 13 are separated by a split portion P3 extending radially inward from the recess 23. Further, the split ring 13 and the split ring 14 are separated by a split portion P4 extending radially inward from the recess 24.

Further, the main body 10 and the split rings 11 to 14 are divided in the radial direction by a split portion P5.

The bead bottom molding surface 20 is a part of the outer peripheral surface of the bead ring 4. Specifically, of the outer peripheral surface of the bead ring 4, from the inner edge in the tire width direction (indicated by point A in FIG. 2) to the edge corresponding to the outer edge in the tire width direction of the bead heel T31 ( (shown as point B in FIG. 2).

The four recesses 21 to 24 are provided in the bead bottom molding surface 20 so as to be recessed radially inward. Further, although not shown, four recesses 21 to 24 are provided all around the bead ring 4. The four recesses 21 to 24 are provided in the order of the recesses 21 to 24 from the outside to the inside in the tire width direction.

Furthermore, the bead ring 4 has exhaust passages E1 to E4 that open to the bead bottom molding surface 20, and an exhaust passage E5 that opens to the inner end surface of the bead ring 4 in the tire width direction. The exhaust passages E1 to E4 and the exhaust passage E5 are in communication. The exhaust passage E1 is formed in the divided portion P1 and opens into the recess 21. Similarly, the exhaust passage E2 is formed in the divided portion P2 and opens into the recess 22. The exhaust passage E3 is formed in the divided portion P3 and opens into the recess 23. The exhaust passage E4 is formed in the divided portion P4 and opens into the recess 24. Further, the exhaust passage E5 is formed in the divided portion P5.

FIG. 3 is a sectional view showing essential parts of the bead ring 4 of this embodiment. FIG. 3 shows a cross section of the bead ring 4 perpendicular to the circumferential direction. In addition, in FIG. 3, the pneumatic tire T that is vulcanized and molded in the tire vulcanization mold 1 is also shown by a virtual line (two-dot chain line).

Referring to FIG. 3, the main body 10 of the present embodiment includes an outer circumferential surface 10a that extends from the outer side in the tire width direction (lower side in FIG. 3) to the inner side (upper side in FIG. 3) while curving inward in the radial direction; It includes a horizontal wall 10b extending radially inward from the inner end in the tire width direction of the outer circumferential surface 10a. The main body 10 also includes a vertical wall 10c extending inward in the tire width direction from the radially inner end of the horizontal wall 10b, and an inner end surface 10d extending radially inward from the tire width inner end of the vertical wall 10c. Equipped with. The main body 10 is formed with a portion cut out by a horizontal wall 10b and a vertical wall 10c, and the dividing rings 11 to 14 are arranged to fill this cutout.

The split ring 11 has an outer circumferential surface 11a that extends radially inward from the outer side in the tire width direction (lower side in FIG. 3) to the inner side (upper side in FIG. 3), and an inner side in the tire width direction of the outer circumferential surface 11a. and an inner end surface 11b extending radially inward from the end side. The split ring 11 has an outer end surface 11c extending radially outward from an outer edge in the tire width direction of the outer circumferential surface 11a, a radially inner edge of the inner end surface 11b, and a radially inner edge of the outer end surface 11c. and an inner circumferential surface 11d that connects.

The outer end surface 11c of the split ring 11 faces the horizontal wall 10b of the main body 10. Further, the outer end surface 11c of the split ring 11 is spaced apart from the horizontal wall 10b of the main body 10. In other words, a gap is formed between the horizontal wall 10b of the main body 10 and the outer end surface 11c of the split ring 11. In this embodiment, a shim (not shown) is provided between the side wall 10b of the main body 10 and the outer end surface 11c of the split ring 11. The distance between the horizontal wall 10b of the main body 10 and the outer end surface 11c of the split ring 11 is adjusted by this shim. Furthermore, the horizontal wall 10b of the main body 10 and the outer end surface 11c of the split ring 11 constitute a split portion P1.

Further, the inner circumferential surface 11d of the split ring 11 faces the vertical wall 10c of the main body 10. The inner peripheral surface 11d of the split ring 11 is spaced apart from the vertical wall 10c of the main body 10. In other words, a gap is formed between the vertical wall 10c of the main body 10 and the inner peripheral surface 11d of the split ring 11. Further, the vertical wall 10c of the main body 10 and the inner circumferential surface 11d of the split ring 11 constitute a part of the split portion P5.

The split ring 12 has an outer circumferential surface 12a that extends radially inward from the outer side in the tire width direction (lower side in FIG. 3) to the inner side (upper side in FIG. 3), and an inner side in the tire width direction of the outer circumferential surface 12a. and an inner end surface 12b extending radially inward from the end side. The split ring 12 has an outer end surface 12c extending radially outward from an outer edge in the tire width direction of the outer circumferential surface 12a, a radially inner edge of the inner end surface 12b, and a radially inner edge of the outer end surface 12c. and an inner circumferential surface 12d that connects.

The outer end surface 12c of the split ring 12 faces the inner end surface 11b of the split ring 11. Further, the outer end surface 12c of the split ring 12 is spaced apart from the inner end surface 11b of the split ring 11. In other words, a gap is formed between the inner end surface 11b of the split ring 11 and the outer end surface 12c of the split ring 12. In this embodiment, a shim (not shown) is provided between the inner end surface 11b of the split ring 11 and the outer end surface 12c of the split ring 12. The distance between the inner end surface 11b of the split ring 11 and the outer end surface 12c of the split ring 12 is adjusted by this shim. Furthermore, the inner end surface 11b of the split ring 11 and the outer end surface 12c of the split ring 12 constitute a split portion P2.

Further, the inner peripheral surface 12d of the split ring 12 faces the vertical wall 10c of the main body 10. The inner peripheral surface 12d of the split ring 12 is spaced apart from the vertical wall 10c of the main body 10. In other words, a gap is formed between the vertical wall 10c of the main body 10 and the inner peripheral surface 12d of the split ring 12. Furthermore, the vertical wall 10c of the main body 10 and the inner circumferential surface 12d of the split ring 12 constitute a part of the split portion P5.

The split ring 13 has an outer circumferential surface 13a that extends inward in the tire radial direction from the outer side (lower side in FIG. 3) to the inner side (upper side in FIG. 3) in the tire width direction, and a side surface of the outer circumferential surface 13a in the tire width direction. It has an inner end surface 13b extending radially inward from the inner edge. The split ring 13 has an outer end surface 13c extending radially outward from an outer edge in the tire width direction of the outer circumferential surface 13a, a radially inner edge of the inner end surface 13b, and a radially inner edge of the outer end surface 13c. and an inner circumferential surface 13d that connects.

The outer end surface 13c of the split ring 13 faces the inner end surface 12b of the split ring 12. Further, the outer end surface 13c of the split ring 13 is spaced apart from the inner end surface 12b of the split ring 12. In other words, a gap is formed between the inner end surface 12b of the split ring 12 and the outer end surface 13c of the split ring 13. In this embodiment, a shim (not shown) is provided between the inner end surface 12b of the split ring 12 and the outer end surface 13c of the split ring 13. The distance between the inner end surface 12b of the split ring 12 and the outer end surface 13c of the split ring 13 is adjusted by this shim. Further, the inner end surface 12b of the split ring 12 and the outer end surface 13c of the split ring 13 constitute a split portion P3.

Further, an inner circumferential surface 13d of the split ring 13 faces the vertical wall 10c of the main body 10. The inner peripheral surface 13d of the split ring 13 is spaced apart from the vertical wall 10c of the main body 10. In other words, a gap is formed between the vertical wall 10c of the main body 10 and the inner peripheral surface 13d of the split ring 13. Further, the vertical wall 10c of the main body 10 and the inner circumferential surface 13d of the split ring 13 constitute a part of the split portion P5.

The split ring 14 includes an outer circumferential surface 14a that extends inward in the tire radial direction from the outer side (lower side in FIG. 3) to the inner side (upper side in FIG. 3) in the tire width direction, and a side surface of the outer circumferential surface 14a in the tire width direction. It has an inner end surface 14b extending radially inward from the inner edge. The split ring 14 has an outer end surface 14c extending radially outward from an outer edge in the tire width direction of the outer peripheral surface 14a, a radially inner edge of the inner end surface 14b, and a radially inner edge of the outer end surface 14c. and an inner circumferential surface 14d that connects.

The inner end surface 14b of the split ring 14 is provided flush with the inner end surface 10d of the main body 10. The edge of the outer peripheral surface 14a connected to the inner end surface 14b corresponds to the bead tow T32.

The outer end surface 14c of the split ring 14 faces the inner end surface 13b of the split ring 13. Further, the outer end surface 14c of the split ring 14 is spaced apart from the inner end surface 13b of the split ring 13. In other words, a gap is formed between the inner end surface 13b of the split ring 13 and the outer end surface 14c of the split ring 14. In this embodiment, a shim (not shown) is provided between the inner end surface 13b of the split ring 13 and the outer end surface 14c of the split ring 14. The distance between the inner end surface 13b of the split ring 13 and the outer end surface 14c of the split ring 14 is adjusted by this shim. Further, the inner end surface 13b of the split ring 13 and the outer end surface 14c of the split ring 14 constitute a split portion P4.

Further, the inner peripheral surface 14d of the split ring 14 faces the vertical wall 10c of the main body 10. The inner peripheral surface 14d of the split ring 14 is spaced apart from the vertical wall 10c of the main body 10. In other words, a gap is formed between the vertical wall 10c of the main body 10 and the inner peripheral surface 14d of the split ring 14. Furthermore, the vertical wall 10c of the main body 10 and the inner circumferential surface 14d of the split ring 14 constitute a part of the split portion P5.

The bead bottom molding surface 20 is constituted by the outer circumferential surface 10a of the main body 10, the outer circumferential surfaces 11a, 12a, 13a, 14a of the split rings 11-14, and the outer end surfaces 11c, 12c, 13c, 14c of the split rings 11-13. ing. The bead bottom molding surface 20 is provided across the main body 10 and the split rings 11 to 14.

The recess 21 is provided in the bead bottom molding surface 20 so as to be recessed radially inward. The recess 21 is provided in a substantially triangular shape in the cross section shown in FIG. The recess 21 is defined by the outer peripheral surface 10a of the main body 10 and the outer end surface 11c of the split ring 11. Thereby, the recessed portion 21 is provided so as to gradually become deeper from the outer side (lower side in FIG. 3) to the inner side (upper side in FIG. 3) in the tire width direction.

The recess 22 is provided in the bead bottom molding surface 20 so as to be recessed radially inward. The recess 22 is provided in a substantially triangular shape in the cross section shown in FIG. The recess 22 is defined by the outer circumferential surface 11 a of the split ring 11 and the outer end surface 12 c of the split ring 12 . Thereby, the recessed portion 22 is provided so as to gradually become deeper from the outer side (lower side in FIG. 3) to the inner side (upper side in FIG. 3) in the tire width direction.

The recess 23 is provided in the bead bottom molding surface 20 so as to be recessed radially inward. The recess 23 is provided in a substantially triangular shape in the cross section shown in FIG. The recess 23 is defined by the outer peripheral surface 12a of the split ring 12 and the outer end surface 13c of the split ring 13. Thereby, the recess 23 is provided so as to gradually become deeper from the outside (lower side in FIG. 3) to the inside (upper side in FIG. 3) in the tire width direction.

The recess 24 is provided in the bead bottom molding surface 20 so as to be recessed radially inward. The recess 24 is provided in a substantially triangular shape in the cross section shown in FIG. The recess 24 is defined by the outer peripheral surface 13a of the split ring 13 and the outer end surface 14c of the split ring 14. Thereby, the recessed portion 24 is provided so as to gradually become deeper from the outer side (lower side in FIG. 3) to the inner side (upper side in FIG. 3) in the tire width direction.

In this embodiment, the depths of the recesses 21 to 24 are provided to be different from each other. Specifically, among the recesses 21 to 24 of this embodiment, the recess 21 located innermost in the tire width direction is formed to have the shallowest depth. Among the recesses 21 to 24, the recess 23 is formed to have the deepest depth.

The bead bottom molding surface 20 is provided with a plurality of (four in this embodiment) convex portions 25 to 28 having a sawtooth cross section by providing concave portions 21 to 24 continuously in the tire width direction. ing. These convex portions 25 to 28 are inclined outward in the tire width direction with respect to the radial direction.

The convex portion 25 of this embodiment is constituted by a part of the split ring 11. Specifically, the convex portion 25 is defined by the outer peripheral surface 11a and the outer end surface 11c of the split ring 11. The convex portion 25 is provided so that the amount of protrusion gradually increases from the inside to the outside in the tire width direction.

The convex portion 26 of this embodiment is constituted by a part of the split ring 12. Specifically, the convex portion 26 is defined by the outer peripheral surface 12a and the outer end surface 12c of the split ring 12. The convex portion 26 is provided so that the amount of protrusion gradually increases from the inside to the outside in the tire width direction.

The convex portion 27 of this embodiment is constituted by a part of the split ring 13. Specifically, the convex portion 27 is defined by the outer peripheral surface 13a and the outer end surface 13c of the split ring 13. The convex portion 27 is provided so that the amount of protrusion gradually increases from the inside to the outside in the tire width direction.

The convex portion 28 of this embodiment is constituted by a part of the split ring 14. Specifically, the convex portion 28 is defined by the outer peripheral surface 14a and the outer end surface 14c of the split ring 14. The convex portion 28 is provided so that the amount of protrusion gradually increases from the inside to the outside in the tire width direction.

The bead bottom surface T33 of the pneumatic tire T formed by the bead ring 4 is formed to have a sawtooth cross section by the bead bottom molding surface 20 having an uneven shape having a sawtooth cross section. Specifically, the bead bottom surface T33 of the pneumatic tire T formed by the bead ring 4 is formed with ridges R1 to R4 having sawtooth cross sections corresponding to the recesses 21 to 24, respectively. Each of these ridges R1 to R4 is inclined inward in the tire width direction with respect to the radial direction.

The exhaust passage E1 is defined by the horizontal wall 10b of the main body 10 and the outer end surface 11c of the split ring 11. In other words, the exhaust passage E1 is a gap formed between the horizontal wall 10b of the main body 10 and the outer end surface 11c of the split ring 11. Further, the exhaust passage E1 opens into the recess 21.

The exhaust passage E2 is defined by the inner end surface 11b of the split ring 11 and the outer end surface 12c of the split ring 12. In other words, the exhaust passage E2 is a gap formed between the inner end surface 11b of the split ring 11 and the outer end surface 12c of the split ring 12. Further, the exhaust passage E2 opens into the recess 22.

The exhaust passage E3 is defined by the inner end surface 12b of the split ring 12 and the outer end surface 13c of the split ring 13. In other words, the exhaust passage E3 is a gap formed between the inner end surface 12b of the split ring 12 and the outer end surface 13c of the split ring 13. Further, the exhaust passage E3 opens into the recess 23.

The exhaust passage E4 is defined by the inner end surface 13b of the split ring 13 and the outer end surface 14c of the split ring 14. In other words, the exhaust passage E4 is a gap formed between the inner end surface 13b of the split ring 13 and the outer end surface 14c of the split ring 14. Furthermore, the exhaust passage E4 opens into the recess 24.

The exhaust passage E5 is defined by the vertical wall 10c of the main body 10 and the inner peripheral surfaces 11d, 12d, 13d, and 14d of the split rings 11-14. In other words, the exhaust passage E1 is a gap formed between the vertical wall 10c of the main body 10 and the inner peripheral surfaces 11d, 12d, 13d, and 14d of the split rings 11-14.

According to this configuration, the following effects are achieved.

(1) On the bead bottom surface T33 of the pneumatic tire T manufactured using the bead ring 4 according to the present invention, ridges R1 to R4 (see FIG. 3) having sawtooth cross sections corresponding to the recesses 21 to 24 are formed. Ru. When the pneumatic tire T is assembled on a rim (not shown) and a force is applied to the pneumatic tire T from the outside in the tire width direction, the bead portion T3 moves inward in the width direction and falls off the rim. Sometimes. In contrast, in the present invention, the ridges R1 to R4 suppress the movement of the bead portion T3 in the direction in which it falls off the rim, so it is possible to suppress the bead portion T3 from falling off the rim. In addition, since the bead ring 4 is divided by the divided parts P1 to P4 extending radially inward from the recessed parts 21 to 24, air in the recessed parts 21 to 24 flows through the divided parts P1 to P4 during vulcanization molding. The bead bottom surface T33 of the pneumatic tire T after vulcanization molding can be suppressed from being exposed.

(2) Furthermore, the bead bottom surface T33 of the pneumatic tire T manufactured using the bead ring 4 according to the present embodiment has a diameter formed by the concave portions 21 to 24 and convex portions 25 to 28 of the bead bottom molding surface 20. Sawtooth-shaped ridges R1 to R4 are formed that extend inwardly in the tire width direction with respect to the direction. These ridges R1 to R4 are difficult to deform in response to an outward force in the tire width direction, and are easy to deform in response to an inward force in the tire width direction. As a result, after the pneumatic tire T is assembled to the rim, when the bead portion T3 tries to move in the direction of falling off the rim (inward in the width direction of the tire), the ridges R1 to R4 resist this movement. Falling off of the bead portion T3 from the rim can be effectively suppressed. On the other hand, when assembling the pneumatic tire T to the rim from the inside in the tire width direction, when the bead part T3 is moved in the direction of assembly to the rim (outward in the tire width direction), the ridges R1 to R4 move due to this movement. Since the pneumatic tire T does not resist, the pneumatic tire T can be easily assembled to the rim. As a result, the ease of assembling the pneumatic tire T to the rim is not hindered, and the bead portion T3 does not easily fall off from the rim after assembly.

(3) Also, since the bead ring 4 is divided into recesses 21 to 24, by changing the shape of the main body 10 and the divided rings 11 to 14, the depth or shape of each of the recesses 21 to 24 can be changed. can. Thereby, the size or shape of the ridges R1 to R4 formed on the pneumatic tire T manufactured using the bead ring 4 can be changed.

(4) Furthermore, since shims (not shown) are provided in each of the divided portions P1 to P4, the passage area of the exhaust passages E1 to E5 is sufficiently increased compared to a case where no shims are provided. Since this is ensured, it is possible to suppress the occurrence of bare on the bead bottom surface T33 of the pneumatic tire T after vulcanization molding.

(Second embodiment)
The bead ring 104 of the second embodiment has the same configuration as the bead ring 4 of the first embodiment (shown in FIG. 2) except for the number and shape of the split rings. In the second embodiment, components similar to those in the first embodiment are denoted by the same reference numerals as in the first embodiment, and detailed description thereof will be omitted.

FIG. 4 is a sectional view showing essential parts of the bead ring 104 of the second embodiment. FIG. 4 shows a cross section of the bead ring 104 perpendicular to the circumferential direction. In addition, in FIG. 4, the pneumatic tire T to be vulcanized and molded in the tire vulcanization mold 1 is also shown by a virtual line (two-dot chain line).

Referring to FIG. 4, the bead ring 104 of this embodiment is divided in the axial direction and is composed of an annular main body 10 and a divided ring 111. The main body 10 and the split ring 111 are fixed by, for example, a screw (not shown) extending in the axial direction. Furthermore, the bead ring 104 of this embodiment includes a bead bottom forming surface 120 that forms a bead bottom surface T33 between the bead heel T31 and bead toe T32 of the bead portion T3. The bead bottom molding surface 120 is provided with a plurality of (four in this embodiment) recesses 121 to 124. In addition, the bead bottom molding surface 120 is provided with concave portions 121 to 124 continuously in the tire width direction, thereby forming a plurality of convex portions 125 to 128 (four in this embodiment) having a sawtooth cross section. It is provided. These convex portions 125 to 128 are inclined outward in the tire width direction with respect to the radial direction.

The bead ring 104 is divided by a dividing portion P11 extending radially inward from the recess 121. In other words, the main body 10 and the dividing ring 111 are divided by the dividing part P11 extending radially inward from the recess 121.

Further, the main body 10 and the split ring 111 are divided in the radial direction by a split portion P15.

The bead ring 104 also has an exhaust passage E11 that opens to the bead bottom molding surface 120, and an exhaust passage E15 that opens to the inner end surface in the tire width direction. The exhaust passage E11 and the exhaust passage E15 are in communication. The exhaust passage E11 is formed in the divided portion P11 and opens into the recess 121. Further, the exhaust passage E15 is formed in the divided portion P15.

The split ring 111 has an outer circumferential surface 111a that extends from the inner side in the tire width direction (the upper side in FIG. 4) to the outer side (the lower side in the tire radial direction) toward the outer side in the tire radial direction, and the tire width of the outer circumferential surface 111a. It has an inner end surface 111b extending radially inward from the end side on the inner side in the direction. The split ring 111 has an outer end surface 111c extending radially outward from an outer edge in the tire width direction of the outer peripheral surface 111a, a radially inner edge of the inner end surface 111b, and a radially inner edge of the outer end surface 111c. and an inner circumferential surface 111d that connects.

The outer end surface 111c of the split ring 111 faces the horizontal wall 10b of the main body 10. Further, the outer end surface 111c of the split ring 111 is spaced apart from the horizontal wall 10b of the main body 10. In other words, a gap is formed between the horizontal wall 10b of the main body 10 and the outer end surface 111c of the split ring 111. In this embodiment, a shim (not shown) is provided between the horizontal wall 10b of the main body 10 and the outer end surface 111c of the split ring 111. This shim adjusts the distance between the horizontal wall 10b of the main body 10 and the outer end surface 111c of the split ring 111. Furthermore, the horizontal wall 10b of the main body 10 and the outer end surface 111c of the dividing ring 111 constitute a divided portion P11.

Further, the inner peripheral surface 111d of the split ring 111 faces the vertical wall 10c of the main body 10. The inner peripheral surface 111d of the split ring 111 is spaced apart from the vertical wall 10c of the main body 10. In other words, a gap is formed between the vertical wall 10c of the main body 10 and the inner peripheral surface 111d of the split ring 111. Further, the vertical wall 10c of the main body 10 and the inner circumferential surface 111d of the dividing ring 111 constitute a divided portion P15.

The recess 121 is provided in the bead bottom molding surface 120 so as to be recessed radially inward. The recess 121 is provided in a substantially triangular shape in the cross section shown in FIG. The recess 121 is defined by the outer peripheral surface 10a of the main body 10 and the outer end surface 111c of the split ring 111. As a result, the recessed portion 121 is provided so as to gradually become deeper from the outer side (lower side in FIG. 4) to the inner side (upper side in FIG. 4) in the tire width direction.

The recesses 122 to 124 are provided in the bead bottom molding surface 120 so as to be recessed radially inward. Specifically, the recesses 122 to 124 are provided on the outer peripheral surface 111a of the split ring 111. The recesses 122 to 124 are provided so as to gradually become deeper from the outer side (lower side in FIG. 4) to the inner side (upper side in FIG. 4) in the tire width direction.

The convex portions 125 to 128 are provided on the bead bottom forming surface 120 so as to protrude outward in the radial direction. Specifically, the protrusions 125 to 128 are provided on the outer peripheral surface 111a of the split ring 111. The protrusions 125 to 128 are provided so that the amount of protrusion gradually increases from the inner side (upper side in FIG. 4) to the outer side (lower side in FIG. 4) in the tire width direction.

The second embodiment provides the same effects as the first embodiment.

Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be implemented with various changes within the scope of the present invention.

For example, in the first and second embodiments, shims are inserted in the dividing portions so that adjacent divided rings are spaced apart from each other; however, the present invention is not limited to this, and each divided ring is , the split portion may abut adjacent split rings. In this case, it is preferable that a groove or the like extending from the recess to the outside of the main body is formed in the opposing surfaces of adjacent split rings, so that an exhaust passage is formed in the split portion.

For example, in the first embodiment and the second embodiment, four recesses are formed, but the present invention is not limited to this, and the number of recesses may be one or more. Further, the shape, size, and position of the recess on the bead bottom molding surface may be changed as appropriate.

1 Tire vulcanization mold 2 Sector mold 3 Side plate 4 Bead ring 10 Main body 10a Outer peripheral surface 10b Horizontal wall 10c Vertical wall 10d Inner end surface 11-14 Split ring 11a Outer peripheral surface 11b Inner end surface 11c Outer end surface 11d Inner peripheral surface 12a Outer peripheral surface 12b Inner end surface 12c Outer end surface 12d Inner peripheral surface 13a Outer peripheral surface 13b Inner end surface 13c Outer end surface 13d Inner peripheral surface 14a Outer peripheral surface 14b Inner end surface 14c Outer end surface 14d Inner peripheral surface 20 Bead bottom molding surface 21-24 Concave portion 25-28 Convex portion E1 ～E5 Exhaust passage P1～P5 Split part T Pneumatic tire T1 Tread part T2 Sidewall part T3 Bead part T31 Bead heel T32 Bead toe T33 Bead bottom

Claims (5)

An annular bead ring having a bead bottom forming surface for forming a bead bottom surface extending from a bead heel to a bead toe of a bead portion of a tire, and arranged so that the axial direction coincides with the tire width direction ,
The bead ring is
a ring-shaped body;
at least one annular split ring disposed on the inner side in the tire width direction with respect to the main body;
Equipped with
The bead bottom molding surface is provided with a plurality of recesses extending in the circumferential direction ,
The bead ring is axially divided into the main body and the at least one split ring by a split portion extending radially inward from at least one of the plurality of recesses , and the bead ring is axially divided into the main body and the at least one split ring through the split portion. and a bead ring configured to be able to exhaust air within the recess. The plurality of recesses are arranged side by side in the tire width direction,
The bead ring according to claim 1, wherein the bead bottom molding surface is provided with a plurality of convex portions each having a sawtooth cross section in a cross section perpendicular to the circumferential direction by the plurality of concave portions. The bead ring according to claim 2, wherein each of the plurality of convex portions extends obliquely outward in the tire width direction with respect to the tire radial direction. the at least one split ring has a plurality of split rings;
Any one of claims 1 to 3, wherein the bead ring is axially divided into the main body and the plurality of split rings by a plurality of split parts extending radially inward from each of the plurality of recesses. The bead ring according to item 1. A tire vulcanization mold comprising the bead ring according to any one of claims 1 to 4.

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