JP2020066211A - Tire vulcanization mold - Google Patents

Abstract

To provide a tire-vulcanizing metal mold capable of exhibiting excellent exhaust performance even in a thin bead ring.SOLUTION: A lower-side bead ring 14 mounted to a tire-vulcanizing metal mold has an exhaust hole 2 from an inlet part 2a opened in a bead heal-forming part 17 brought into contact with a bead heal in a bead part of a tire T to an outlet part 2b opened in an outer peripheral surface 14g of a ring facing the outside of the tire in a radial direction. The exhaust hole 2 includes: a first hole part 21 linearly extending from the inlet part 2a toward an inner peripheral surface 14n of a ring facing the inside of the tire in the radial direction; a second hole part 22 linearly extending from the outlet part 2b toward the inner peripheral surface 14n thereof; and a connecting part 23 for connecting the first hole part 21 and the second hole part 22 mutually, wherein no opening is formed in the inner peripheral surface 14n.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a tire vulcanizing mold provided with a bead ring that contacts a bead portion of a tire.

  Conventionally, in a tire vulcanizing mold, a large number of exhaust holes are provided on a molding surface for molding an outer surface of a tire. The exhaust hole communicates with the inside and the outside of the mold and discharges air between the outer surface of the tire and the molding surface during vulcanization molding, thereby preventing the occurrence of dent scratches called bare. Further, the space inside the exhaust hole is sucked from the outside of the mold by a suction device to enhance the exhaust performance.

  FIG. 5 shows an example of the lower bead ring 80 provided in the tire vulcanizing mold. The lower bead ring 80 has a bead heel molded portion 81 that is in contact with the bead heel of the bead portion of the tire T. The bead heel molding portion 81 is largely curved as compared with other portions, and air tends to accumulate during vulcanization molding. Therefore, the inlet portion 8a of the exhaust hole 8 is set in the bead heel forming portion 81. The exhaust hole 8 is provided so as to extend from the inlet portion 8a opened at the bead heel molding portion 81 to the outlet portion 8b opened at the lower side surface 80s of the lower bead ring 80. Such an exhaust hole is disclosed in Patent Document 1, for example.

  By the way, the central mechanism of the tire vulcanizing device is arranged on the inner peripheral side of the bead ring. The central mechanism includes a rubber bag called a bladder and piping for supplying and discharging the heating / pressurizing medium. Since the central mechanism has a predetermined size, the inner diameter of the bead ring is defined accordingly. As a result, when the inner diameter of the tire (corresponding to the rim diameter) is small, a thin bead ring 90 having a small thickness Tb is used as shown in FIG. The thickness Tb is obtained as the distance in the tire radial direction from the bead heel molding portion 91 to the ring inner peripheral surface 90n.

  Since the exhaust hole 9 is provided in a direction substantially normal to the bead heel molding portion 91, the exhaust hole 9 cannot be opened on the lower side surface 90s in the thin bead ring 90, and is opened on the ring inner peripheral surface 90n. I will let you. Therefore, that is, the exhaust hole 9 is provided so as to extend from the inlet portion 9a opened at the bead heel molding portion 91 to the outlet portion 9b opened at the ring inner peripheral surface 90n. However, since the above-described central mechanism is arranged on the inner peripheral side of the bead ring 90, it becomes difficult to connect the suction device to the exhaust hole 9. Therefore, the exhaust performance was not sufficient, and there was room for further improvement.

JP, 2008-89827, A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a tire vulcanizing mold capable of exhibiting excellent exhaust performance even with a thin bead ring.

  The above object can be achieved by the present invention as described below. That is, the tire vulcanization mold according to the present invention is a tire vulcanization mold including a lower bead ring and an upper bead ring that respectively come into contact with a pair of bead portions of the tire from outside in the tire width direction, and the lower bead ring. And, at least one of the upper bead ring has an exhaust hole from an inlet portion opened at a bead heel molding portion in contact with a bead heel of the bead portion, to an outlet portion opened at a ring outer peripheral surface facing outward in the tire radial direction, The exhaust hole has a first hole portion linearly extending from the inlet portion toward a ring inner peripheral surface facing inward in a tire radial direction, and a first hole portion linearly extending from the outlet portion toward the ring inner peripheral surface. The hole includes two holes and a connecting portion that connects the first hole and the second hole to each other, and is not opened on the inner peripheral surface of the ring.

  In this tire vulcanizing mold, the exhaust hole provided in the bead ring extends from the inlet opening at the bead heel molding portion to the outlet opening at the ring outer peripheral surface, but not at the ring inner peripheral surface. Therefore, even with a thin bead ring as shown in FIG. 6, a suction device can be connected to the exhaust hole, and excellent exhaust performance can be exhibited.

A longitudinal sectional view schematically showing an example of a tire vulcanizing mold according to the present invention. Top view of lower bead ring Enlarged view of the main part of Figure 1 Enlarged view of the main part of FIG. Sectional view of the lower bead ring included in a typical tire vulcanization mold Cross section of thin bead ring (lower bead ring)

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross section of a tire vulcanizing mold 10 (hereinafter, may be simply referred to as “mold 10”) along a tire meridian section. The mold 10 is in a mold closed state. The tire T is set with the tire width direction facing up and down. In FIG. 1, the left direction is the tire radial direction outer side, and the right direction is the tire radial direction inner side.

  The mold 10 includes a tread mold portion 11 that molds a tread portion of the tire T, a lower side mold portion 12 and an upper side mold portion 13 that are in contact with a pair of sidewall portions of the tire T from outside in the tire width direction, and a tire. The pair of T bead portions includes a lower bead ring 14 and an upper bead ring 15 that are in contact with each other from outside in the tire width direction. Although not shown, the inner surface of the tread mold portion 11 is provided with an uneven portion for forming a tread pattern on the tread surface of the tire T. The lower bead ring 14 and the upper bead ring 15 are arranged apart from each other in the tire width direction.

  A central mechanism of a tire vulcanizing device (not shown) is arranged on the inner peripheral side of the mold 10, more specifically on the inner peripheral side of the lower bead ring 14. The central mechanism includes a rubber bag called a bladder for expanding and deforming the tire T. Further, the central mechanism is provided with a pipe for supplying / discharging a heating / pressurizing medium such as steam or nitrogen gas to / from the bladder. Since the central mechanism has a predetermined size, the inner diameter of the lower bead ring 14 (and the inner diameter of the upper bead ring 15) is defined accordingly.

  The mold 10 includes a molding surface 1 that contacts the outer surface of the tire T set in the cavity 16. Although not shown, the molding surface 1 is provided with a large number of exhaust holes that connect the inside (cavity 16) of the mold 10 to the outside. 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. At the time of vulcanization molding, air between the tire T and the molding surface 1 is exhausted through the exhaust hole. Further, a suction device (not shown) is installed outside the die 10 so that the space inside the exhaust hole can be sucked.

  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 taken along the line AA of FIG. 2 regarding the lower bead ring 14. The lower bead ring 14 has a ring outer peripheral surface 14g facing outward in the tire radial direction and a ring inner peripheral surface 14n facing inward in the tire radial direction. The ring outer peripheral surface 14g includes a lower side surface 14s facing outward in the tire width direction. The inner surface of the lower bead ring 14 is smoothly connected to the inner surface of the lower side mold portion 12 along the profile of the outer surface of the tire T. The inner surface of the lower bead ring 14 is integrally formed without being divided.

  The lower bead ring 14 has an exhaust hole 2 extending from an inlet portion 2a opened at a bead heel forming portion 17 in contact with a bead heel of a bead portion to an outlet portion 2b opened at a ring outer peripheral surface 14g. As shown in FIG. 2, the exhaust holes 2 are provided at a plurality of locations (12 locations in this embodiment) in the tire circumferential direction. The exhaust hole 2 includes a first hole portion 21 linearly extending from the inlet portion 2a toward the ring inner peripheral surface 14n, and a second hole portion 22 linearly extending from the outlet portion 2b toward the ring inner peripheral surface 14n. , And a connection portion 23 that connects the first hole portion 21 and the second hole portion 22 to each other. The exhaust hole 2 is not opened at the ring inner peripheral surface 14n.

  The lower bead ring 14 used in the present embodiment is a thin bead ring having a relatively small thickness, and the extension line of the first hole portion 21 does not pass through the lower side surface 14 s of the lower bead ring 14 inside the ring. Reach the peripheral surface 14n. However, since the exhaust hole 2 extends from the inlet portion 2a opened at the bead heel molding portion 17 to the outlet portion 2b opened at the ring outer peripheral surface 14g, and is not opened at the ring inner peripheral surface 14n, such a thin bead is formed. Even if it is a ring, a suction device can be connected to the exhaust hole 2, and excellent exhaust performance can be exhibited.

  The first hole portion 21 is provided in a direction substantially normal to the surface of the bead heel forming portion 17, and is inclined inward in the tire radial direction from the inlet portion 2a toward the tire width direction outside. The length of the first hole portion 21 is preferably larger than the assumed length of the spew, for example, 12 mm or more. The spew is a rubber protrusion formed by inflow of unvulcanized rubber on the outer surface of the tire during vulcanization molding. The second hole portion 22 is inclined inward in the tire width direction from the outlet portion 2b toward the tire radial direction inner side, and is connected to the first hole portion 21 at the connecting portion 23. The exhaust hole 2 is provided in an L shape or a V shape bent at the connection portion 23.

  The first hole portion 21 and the second hole portion 22 are each formed by a circular hole having a circular cross section. In the present embodiment, the second hole 22 has a larger diameter than the first hole 21, but the diameter is not limited to this. Further, in the present embodiment, the angle formed by the first hole portion 21 and the second hole portion 22 is an acute angle, but it is not limited to this. Further, in the present embodiment, a device such as a vent plug is not attached to the inlet portion 2a of the exhaust hole 2, but the present invention is not limited to this, and for example, a tubular vent for the purpose of reducing the length of the spew. The piece may be attached to the inlet portion 2a.

  When the exhaust hole 2 is provided in the lower bead ring 14, the first hole portion 21 and the second hole portion 22 intersecting with the first hole portion 21 are provided as through holes by drills, respectively, and then the ring inner peripheral surface 14n Both openings may be closed by, for example, welding. The same applies to the case where the second hole portion 22 is added to the existing lower bead ring (see FIG. 6) provided with the conventional exhaust hole and the exhaust hole 2 opened at the ring outer peripheral surface 14g is provided. FIG. 3 shows an example in which the welded portions 24, 25 produced by such welding (build-up welding) are provided on the ring inner peripheral surface 14n.

  As shown in FIGS. 3 and 4, the ring outer peripheral surface 14g is provided in a stepped shape via the lower side surface 14s. Further, the inner peripheral surface 12n of the lower side mold part 12 is provided in a stepped shape with the upper side surface 12u corresponding to the stepped shape of the ring outer peripheral surface 14g. The step-shaped corner 14c of the ring outer peripheral surface 14g is formed by a chamfered slope. When the lower bead ring 14 is fitted to the lower side mold part 12, the ring outer peripheral surface 14g is in close contact with the inner peripheral surface 12n, the lower side surface 14s is in close contact with the upper side surface 12u, and extends along the tire circumferential direction. A circumferential gap 18 is provided facing the corner 14c.

  The outlet portion 2b is set to a corner portion 14c, and the exhaust hole 2 (the second hole portion 22 thereof) communicates with the circumferential gap 18. The lower side mold part 12 is provided with an exhaust hole 3 communicating with the circumferential gap 18. The not-shown end of the exhaust hole 3 communicates with the outside of the mold 10 and is connected to a suction device. By interposing such a circumferential gap 18, even if the exhaust holes 2 and the exhaust holes 3 are displaced in the tire circumferential direction, the exhaust path is appropriately configured. Therefore, although the exhaust hole 2 and the exhaust hole 3 appear on the same cross section in FIGS. 3 and 4, the present invention is not limited to this.

  The method of manufacturing a tire using the mold 10 includes a step of setting an unvulcanized tire in the cavity 16 of the mold 10 and subjecting the unvulcanized tire to heating and pressurization for vulcanization. The tire is expanded and deformed by the expansion of the bladder, and its outer surface is pressed against the molding surface 1. In the process, air between the tire and the molding surface 1 is discharged to the outside. The air around the inner surface of the lower bead ring 14 is exhausted through the exhaust holes 2 and 3. Since the exhaust hole 2 has the outlet portion 2b on the ring outer peripheral surface 14g and is not open on the ring inner peripheral surface 14n, the space inside the exhaust hole 2 can be sucked by the suction device to enhance the exhaust performance.

  The exhaust hole 2 as described above may be provided in at least one of the lower bead ring 14 and the upper bead ring 15. Therefore, in the present embodiment, an example in which the exhaust hole 2 as described above is provided in the lower bead ring 14 has been shown, but instead of or in addition to this, it is possible to provide it in the upper bead ring 15. .

  In the present embodiment, the mold structure including the tread mold section 11 and the pair of side mold sections 12 and 13 has been exemplified, but the present invention is not limited to this, and for example, the tread mold section is vertically divided into two parts. It may be a mold structure.

  The tire vulcanizing mold described above is the same as a normal tire vulcanizing mold except that the exhaust hole provided in the bead ring is configured as described above, and any conventionally known shape, material, mechanism or the like is used. It can be adopted in the present invention.

  The present invention is not limited to the embodiments described above, and various improvements and modifications can be made without departing from the spirit of the present invention.

1 Molding Surface 2 Exhaust Hole 2a Inlet 2b Outlet 10 Tire Vulcanizing Mold 11 Tread Mold 12 Lower Side Mold 13 Upper Side Mold 14 Lower Bead Ring 14g Ring Outer Surface 14n Ring Inner Surface 14s Lower Side 15 Upper Bead Ring 16 Cavity 17 Bead Heel Molded Part 21 First Hole 22 Second Hole 23 Connection

Claims (1)

In a tire vulcanization mold including a lower bead ring and an upper bead ring that respectively contact a pair of bead portions of a tire from the tire width direction outer side,
Exhaust from at least one of the lower bead ring and the upper bead ring to an outlet opening at the outer peripheral surface of the ring facing the radial outside of the tire from an inlet opening at the bead heel molding that contacts the bead heel of the bead portion. Have holes,
The exhaust hole has a first hole portion linearly extending from the inlet portion toward a ring inner peripheral surface facing inward in a tire radial direction, and a first hole portion linearly extending from the outlet portion toward the ring inner peripheral surface. A tire vulcanizing mold, comprising two holes and a connecting part that connects the first hole and the second hole to each other and is not opened on the inner peripheral surface of the ring.

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