Vent piece, tire vulcanization mold, and tire manufacturing method

Abstract

To provide a vent piece that does not cause expansion of an exhaust hole and can cope with variations in the diameter dimension of the exhaust hole, a tire vulcanization mold, and a tire manufacturing method.SOLUTION: Provided is a vent piece, which is a cylindrical vent piece 2 that is fitted into an exhaust hole 16 that opens on a molding surface 1 of a tire vulcanization mold and has an exhaust path 21 inside, and in which a slit 3 that extends in a curved manner when viewed in a longitudinal direction LD view is formed on the outer peripheral surface. According to the configuration, the expansion of the exhaust hole 16 is not caused and the variations in the diameter dimension of the exhaust hole 16 can be coped with.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a cylindrical vent piece that is attached to an exhaust hole on the molding surface of a tire vulcanizing mold, a tire vulcanizing mold with the vent piece attached, and a tire manufacturing method using the same. [Background technology]

[0002] A tire curing mold has many exhaust holes on the molding surface that forms the outer surface of the tire. During curing, air between the tire's outer surface and the molding surface is discharged through the exhaust holes, and rubber that flows into the exhaust holes forms rubber protrusions called spews on the tire's outer surface. As described in Patent Documents 1 and 2, it is known to attach cylindrical vent pieces to the exhaust holes for purposes such as adjusting the size of the spews.

[0003] Typically, vent pieces are attached to the exhaust hole by an interference fit. Therefore, repeated attachment and detachment of the vent piece during periodic maintenance can cause the exhaust hole to expand, resulting in the inconvenience of needing to prepare an oversized vent piece. In response to this issue, Patent Document 3 describes a vent plug with radial slits that extend from a central air vent hole, which serves as the exhaust path, to the outer peripheral surface. This vent plug is tightly fixed to the inner surface of the exhaust hole by its own spring effect.

[0004] However, Patent Document 3 explains that the spacing of the radial slits is set so that no gaps are created during installation based on the relationship between the diameter of the exhaust hole and the outer diameter of the vent plug, and that if the radial slits are not completely closed, rubber will protrude from those parts. Therefore, if there is variation in the diameter of the exhaust hole, it is thought that the radial slits may not close completely and rubber may protrude. Such rubber protrusion increases the spew removal resistance and may interfere with tire demolding. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-30402 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-105126 [Patent Document 3] Japanese Patent Application Publication No. 61-252111 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure has been made in consideration of the above-described circumstances, and aims to provide a vent piece, a tire vulcanization mold, and a tire manufacturing method that do not cause expansion of the exhaust hole and can accommodate variations in the diameter dimension of the exhaust hole. [Means for solving the problem]

[0007] The vent piece of the present disclosure is attached to an exhaust hole that opens on the molding surface of a tire vulcanization mold, and is a cylindrical vent piece that has an exhaust passage inside, and has a slit formed on the outer surface that extends in a curved shape when viewed in the longitudinal direction.

[0008] The tire vulcanizing mold of the present disclosure includes the molding surface that contacts the outer surface of the tire set in the cavity, and the above-mentioned vent piece attached to the exhaust hole that opens on the molding surface.

[0009] The tire manufacturing method of the present disclosure includes the steps of setting an unvulcanized tire in a cavity of a tire vulcanization mold equipped with the above-described vent piece, and applying heat and pressure to the tire to vulcanize it. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of a tire vulcanization mold according to the present disclosure. [Figure 2] 1A is a plan view showing a ventlid according to a first embodiment, and FIG. 1B is a side view showing the exterior thereof. [Figure 3] 3A and 3B are plan and cross-sectional views showing the state in which the vent piece of FIG. 2 is attached to the exhaust hole; [Figure 4] 1A is a plan view showing a ventlid according to a second embodiment, and FIG. 1B is a side view showing the exterior thereof. [Figure 5] FIG. 5 is a plan view showing the ventlid of FIG. 4 in a contracted state. [Figure 6] 10A is an external side view, FIG. 10B is a cross-sectional view taken along the line XX, and FIG. 10C is a cross-sectional view taken along the line YY, showing a modified example of the ventlid in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure will be described with reference to the drawings.

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

[0013] The mold 10 includes a cavity 15 in which the tire T is set, and a molding surface 1 that comes into contact with the outer surface of the tire T set in the cavity 15. The molding surface 1 is provided with an exhaust hole 16 that connects the inside of the mold 10 (i.e., the cavity 15) to the outside. During vulcanization molding, air is discharged between the outer surface of the tire T and the molding surface 1 through the exhaust hole 16. A vent piece 2 is attached to the exhaust hole 16.

[0014] An example of the material for the forming surface 1 is an aluminum material. This aluminum material is a concept that includes not only pure aluminum-based materials but also aluminum alloys, such as Al-Cu-based, Al-Mg-based, Al-Mg-Si-based, Al-Zn-Mg-based, Al-Mn-based, and Al-Si-based materials. An example of the material for the ventlid 2 is a steel material such as stainless steel or S45C.

[0015] The mold 10 includes a tread mold 11 for molding the tire tread, side molds 12 and 13 for molding the tire sidewalls, and bead rings 14 and 14 into which the tire bead portions are fitted. The molding surface 1 includes the inner surface of the tread mold 11 and the inner surfaces of the side molds 12 and 13. Although not shown, the inner surface of the tread mold 11 has projections and depressions for forming the tire tread pattern. While FIG. 1 depicts only one exhaust hole 16 opening on the inner surface of the tread mold 11, in reality, many exhaust holes opening on the inner surfaces of the tread mold 11 and the side molds 12 and 13 are provided.

[0016] The vent piece 2 is attached to an exhaust hole 16 that opens on the molding surface 1. In FIG. 1, it is attached to the exhaust hole 16 on the inner surface of the tread mold 11, but instead of or in addition to this, it is also possible to attach it to an exhaust hole that opens on the inner surface of the side mold 12 and / or side mold 13. Also, in this embodiment, the mold 10 has a structure including the tread mold 11 and a pair of side molds 12, 13, but this is not limited to this, and for example, a mold structure in which the tread mold is divided into two, upper and lower, at the center may also be used.

[0017] [First embodiment of vent piece] A first embodiment of the vent piece of the present disclosure will be described with reference to Figures 2 and 3. Figure 2 shows a vent piece 2a, which is one form of the vent piece 2. The vent piece 2a shown in Figure 2 is not attached to the exhaust hole 16 and is in a natural state with no external force acting on it. The vent piece 2a is formed in a cylindrical shape with an exhaust passage 21 therein. The exhaust passage 21 is formed by a through-hole that passes through the vent piece 2a in the longitudinal direction LD. The exhaust passage 21 is located at the center of the vent piece 2a, and the center line CL of the exhaust passage 21 coincides with the center line of the vent piece 2a.

[0018] FIG. 3 shows the ventlid 2a attached to the exhaust hole 16. The ventlid 2a in FIG. 3(B) is drawn from an external view. In FIG. 3(B), the upper direction is the molding surface side (cavity side), and the lower direction is the opposite molding surface side (opposite cavity side). In the area where the ventlid 2a is attached, the inner surface of the exhaust hole 16 is formed by a cylindrical surface extending with a constant diameter (diameter dimension D2) from the molding surface 1 toward the opposite molding surface side. The longitudinal direction LD of the ventlid 2a coincides with the axial direction of the exhaust hole 16. Although not adopted in this embodiment, a counterbore may be provided on the end surface of the ventlid 2a on the molding surface side to prevent spew cutting during demolding.

[0019] In this vent piece 2a, a slit 3 that extends in a curved shape when viewed in the longitudinal direction LD is formed on the outer peripheral surface. The slit 3 extends from one end 3a that opens on the outer peripheral surface toward the other end 3b, gradually reducing the distance from the exhaust path 21. The portion located on the outer peripheral side of the slit 3 is tapered toward the one end 3a of the slit 3. The outer diameter of the vent piece 2a is reduced by elastically deforming the portion located on the outer peripheral side of the slit 3 radially inward so that the spacing between the slits 3 becomes smaller. By utilizing this, the vent piece 2a can be attached to the exhaust hole 16 without relying on an interference fit.

[0020] In Figure 2(A), the outline of the exhaust hole 16 to which the vent piece 2a is attached is shown by a chain line. The outer peripheral surface of the vent piece 2a in its natural state includes a portion that is positioned more outer than the outline of the exhaust hole 16. In other words, the outer diameter D1 of the vent piece 2a in its natural state is larger than the diameter D2 of the exhaust hole 16. In Figure 3, the vent piece 2a, whose outer diameter has been reduced by elastic deformation, is attached to the exhaust hole 16. The vent piece 2a is held in the exhaust hole 16 by the restoring force of its elastic deformation; in other words, it is attached to the exhaust hole 16 by the spring effect associated with the elastic deformation.

[0021] In this way, the vent piece 2a can be attached to the exhaust hole 16 by the spring effect caused by elastic deformation of the portion located on the outer periphery of the slit 3, so repeated attachment and detachment of the vent piece 2a does not cause the exhaust hole 16 to expand. Furthermore, unlike when a radial slit is used (see Patent Document 3), with this vent piece 2a, it is only necessary to deform the portion located on the outer periphery of the curved slit 3 along the radial direction, so there is no need to connect the slit 3 to the exhaust path 21. Even when the slit is connected to the exhaust path 21 as in the second embodiment described below, a curved slit makes it easier to close despite variations in the diameter of the exhaust hole 16, thereby suppressing the occurrence of rubber protrusion.

[0022] The slit 3 is formed over the entire length of the ventlid 2a. In this embodiment, an example is shown in which the slit 3 extends continuously from the end face on the molding surface side of the ventlid 2a to the end face on the non-molding surface side, but this is not limited to this, and the slit 3 may be divided into one side and the other side in the longitudinal direction LD as in the example of Fig. 6 described later. Furthermore, in this embodiment, an example is shown in which the slit 3 extends parallel to the longitudinal direction LD, but this is not limited to this, and the slit 3 may extend at an angle with respect to the longitudinal direction LD, for example.

[0023] The slit 3 has a curved shape that is concave toward the exhaust path 21 when viewed in the longitudinal direction LD. In other words, the slit 3 has a curved shape that is convex toward the outer peripheral surface located on the outer periphery of the slit 3. With this configuration, the portion located on the outer periphery of the slit 3 becomes thinner as it approaches one end of the slit 3, which is convenient for smooth elastic deformation of that portion. However, the slit 3 may also have a curved shape that is convex in the opposite direction, i.e., toward the exhaust path 21. Furthermore, multiple types of slits with such curved shapes that differ in direction may coexist.

[0024] The slit 3 formed in the vent piece 2a has one end 3a that opens on the outer peripheral surface and the other end 3b that terminates without being connected to the exhaust passage 21. Because the slit 3 is not connected to the exhaust passage 21, rubber that enters the exhaust passage 21 during vulcanization molding will not protrude into the slit 3. Therefore, even if the diameter of the exhaust hole 16 is larger than expected and the slit 3 is not sufficiently closed as a result, rubber will not protrude and the spew removal resistance will not increase. Therefore, the vent piece 2a of this embodiment can more reliably accommodate variations in the diameter of the exhaust hole 16.

[0025] The slits 3 are formed at multiple locations in the circumferential direction around the center line CL of the exhaust passage 21. This allows a spring effect to be exerted at multiple locations in the circumferential direction, making it easier to stabilize the vent piece 2a attached to the exhaust hole 16 and improving the pull-out resistance of the vent piece 2a. The slits 3 are preferably formed at two to four locations in the circumferential direction, and in this embodiment, are formed at three locations in the circumferential direction. The multiple slits 3 preferably have a shape obtained by rotating any one of the slits 3 included therein at a predetermined angle around the center line CL. Furthermore, when the number of slits 3 is N, the predetermined angle is preferably (360 / N)±10 degrees.

[0026] When viewed in the longitudinal direction LD, when an imaginary line extending radially from the center line of the vent piece 2a (i.e., the center line CL of the exhaust passage 21) is drawn at any position, it is preferable that the number of slits 3 intersecting this line be one, as in the present embodiment, or less. With this configuration, the slits 3 are not arranged to overlap in the radial direction between the exhaust passage 21 and the outer peripheral surface, which is advantageous in ensuring the strength of the vent piece 2a.

[0027] As shown in Figure 2(A), an imaginary line is drawn from the center line of the vent piece 2a (i.e., the center line CL of the exhaust passage 21) through the other end 3b of the slit 3 to the outer peripheral surface, and the length on this line from the exhaust passage 21 to the other end 3b is defined as L1, and the length from the exhaust passage 21 to the outer peripheral surface is defined as L2. In this case, from the viewpoint of ensuring elastic deformation of the portion located on the outer peripheral side of the slit 3, it is preferable that the length L1 be 60% or less of the length L2. Furthermore, from the viewpoint of ensuring the strength of the vent piece 2a itself, it is preferable that the length L1 be 20% or more of the length L2.

[0028] From the viewpoint of ensuring elastic deformation of the portion of the slit 3 located on the outer periphery, the opening angle θ of the slit 3 is preferably 60 degrees or more, and more preferably 90 degrees or more. When multiple slits 3 are formed, the opening angle θ is preferably (360 / N)±10 degrees. Furthermore, from the viewpoint of ensuring the strength of the vent piece 2a itself, the opening angle θ is preferably 180 degrees or less, and more preferably 150 degrees or less. The opening angle θ is determined as the angle formed by a pair of straight lines connecting the center line of the vent piece 2a (i.e., the center line CL of the exhaust passage 21) and both ends of the slit 3 (one end 3a and the other end 3b).

[0029] It is also possible to use linear or bent slits instead of the curved slits 3. However, it is desirable to use curved slits 3 as in this embodiment from the viewpoint of forming slits 3 of an appropriate length in the limited region between the exhaust passage 21 and the outer peripheral surface and allowing the portion located on the outer peripheral side of the slits 3 to smoothly elastically deform.

[0030] [Second embodiment of vent piece] Next, a second embodiment of the ventlid of the present disclosure will be described with reference to Figures 4 to 6. A ventlid 2b as the second embodiment can be configured similarly to the ventlid 2a as the first embodiment, except for the configuration described below, so commonalities will be omitted and differences will be mainly described. Configurations already described in the first embodiment will be assigned the same reference numerals, and duplicate explanations will be omitted.

[0031] FIG. 4 shows a vent piece 2b, which is one form of the vent piece 2. The vent piece 2b shown in FIG. 4 is in a natural state with no external force acting on it. In the vent piece 2b, a slit 4 is formed on the outer peripheral surface, extending in a curved manner when viewed in the longitudinal direction LD. The slit 4 extends from one end 4a opening on the outer peripheral surface toward the other end 4b, gradually reducing the distance from the exhaust path 21. The portion of the slit 4 located on the outer peripheral side tapers toward the one end 4a of the slit 4. The portion of the slit 4 located on the inner peripheral side tapers toward the other end 4b of the slit 4 and overlaps radially with the portion of the slit 4 located on the outer peripheral side.

[0032] By elastically deforming the slits 4 to reduce the spacing between them, the outer diameter of the vent piece 2b becomes smaller, and the vent piece 2b can be reduced in diameter, for example, as shown in FIG. 5(A). Therefore, the spring effect associated with elastic deformation allows the vent piece 2b to be attached to the exhaust hole 16, and repeated attachment and detachment of the vent piece 2b does not cause the exhaust hole 16 to expand. Furthermore, because the slits 4 are curved, the slits 4 are easy to close, as shown in the example of FIG. 5(B), even if the diameter of the exhaust hole 16 is larger than expected. In this way, the slits 4 are easy to close even when the diameter of the exhaust hole 16 varies, thereby reducing the occurrence of rubber protrusion.

[0033] The slit 4 has a curved shape that is concave toward the exhaust passage 21 when viewed in the longitudinal direction LD. At the same time, the wall surface 4w on the outer circumferential side of the slit 4 smoothly connects to the inner surface of the exhaust passage 21. The slit 4 formed in the vent piece 2b has one end 4a that opens on the outer circumferential surface and the other end 4b that is connected to the exhaust passage 21. In this example, the slit 4 is connected to the exhaust passage 21, but as described above, rubber protrusion is unlikely to occur, so it can also accommodate variations in the diameter dimension of the exhaust hole 16. When viewed in the longitudinal direction LD, the slit 4 is formed in one circumferential position around the center line CL of the exhaust passage 21.

[0034] 4, in a natural state where no external force is acting, it is preferable that the spacing of the slits 4 gradually decreases toward the exhaust passage 21. With this configuration, when the ventlid 2b is reduced in diameter by elastic deformation, the slits 4 are more likely to close on the side closer to the exhaust passage 21, which is advantageous in preventing rubber from protruding from the exhaust passage 21.

[0035] The slit 4 is formed over the entire length of the ventlid 2b. In this embodiment, an example is shown in which the slit 4 extends continuously from the end face on the molding surface side of the ventlid 2b to the end face on the non-molding surface side, but this is not limited to this, and the slit 4 may be divided into one side and the other side in the longitudinal direction LD, as in the modified example shown in Fig. 6. The length of each of the divided slits 4 is preferably 50% or more of the entire length of the ventlid 2b. Furthermore, in this embodiment, an example is shown in which the slit 4 extends parallel to the longitudinal direction LD, but this is not limited to this, and the slit 4 may extend at an angle with respect to the longitudinal direction LD, for example.

[0036] [Tire manufacturing method] A tire manufacturing method using a mold 10 equipped with a vent piece 2 includes the steps of setting an unvulcanized tire T in a cavity 15 of the mold 10 and applying heat and pressure to the tire T to vulcanize it. The tire T expands and deforms due to the expansion of a rubber bag called a bladder, and its outer surface presses against the molding surface 1. During this process, air between the tire and the molding surface 1 is discharged to the outside through the exhaust path 21 of the vent piece 2. As described above, because the vent piece 2 is attached to the exhaust hole 16 of the molding surface 1, it does not cause the exhaust hole 16 to expand, and can also accommodate variations in the diameter of the exhaust hole 16.

[0037] [1] As described above, the vent piece 2 of the present disclosure is attached to the exhaust hole 16 opening on the molding surface 1 of the tire vulcanizing mold 10, and is a cylindrical vent piece 2 having an exhaust path 21 inside, with the slit 3 (or slit 4) formed on the outer circumferential surface, extending in a curved manner when viewed in the longitudinal direction LD.

[0038] With this configuration, the vent piece 2 can be attached to the exhaust hole by the spring effect caused by elastic deformation of the portion located on the outer periphery of the slit 3 (or slit 4), so repeated attachment and detachment of the vent piece 2 does not cause the exhaust hole 16 to expand. Moreover, there is no need to connect the slit 3 to the exhaust path 21, and even if the slit 4 is connected to the exhaust path 21, rubber is unlikely to protrude, so it can accommodate variations in the diameter of the exhaust hole 16.

[0039] [2] In the ventlid 2 of [1] above, the slit 3 (or slit 4) preferably has a curved shape that is concave toward the exhaust path 21 when viewed in the longitudinal direction LD. With this configuration, the portion located on the outer periphery of the slit 3 (or slit 4) becomes thinner as it approaches one end of the slit 3 (or slit 4), which is convenient for smooth elastic deformation of that portion.

[0040] [3] The vent piece 2 of [1] or [2] above may be a vent piece 2a in which the slit 3 has one end 3a that opens on the outer peripheral surface and the other end 3b that terminates without being connected to the exhaust passage 21. With this configuration, since the slit 3 is not connected to the exhaust passage 21, no rubber protrusion occurs, and it is possible to more reliably accommodate variations in the diameter of the exhaust hole 16.

[0041] [4] In the ventpiece 2 (ventpiece 2a) of [3] above, it is preferable that the slits 3 are formed at multiple locations in the circumferential direction around the center line CL of the exhaust passage 21. With this configuration, a spring effect can be exerted at multiple locations in the circumferential direction, making it easier to stabilize the ventpiece 2 attached to the exhaust hole 16 and improving the removal resistance of the ventpiece 2.

[0042] [5] The vent piece 2 of [1] or [2] above may be a vent piece 2b in which the slit 4 has one end 4a that opens on the outer peripheral surface and the other end 4b that is connected to the exhaust path 21. With this configuration, compared to a structure in which the slit extends in the radial direction, the slit 4 is more likely to close in spite of variations in the diameter dimension of the exhaust hole 16, thereby suppressing the occurrence of rubber protrusion.

[0043] [6] In the vent piece 2 (vent piece 2b) of [5] above, in a natural state where no external force is acting, it is preferable that the spacing of the slits 4 gradually decreases toward the exhaust passage 21. With this configuration, when the vent piece 2b is reduced in diameter by elastic deformation, the slits 4 are more likely to close on the side closer to the exhaust passage 21, which is advantageous in preventing rubber from protruding.

[0044] [7] The tire vulcanizing mold 10 of the present disclosure includes a molding surface 1 that contacts the outer surface of a tire T set in a cavity 15, and any one of the vent pieces 2 [1] to [6] above that is attached to an exhaust hole 16 that opens on the molding surface 1. This configuration does not cause the exhaust hole 16 to expand, and can accommodate variations in the diameter of the exhaust hole 16.

[0045] The tire vulcanizing mold 10 of the present disclosure is equivalent to a normal tire vulcanizing mold, except that the vent piece 2 attached to the exhaust hole 16 is configured as described above, and any of the conventionally known shapes, materials, mechanisms, etc. can be adopted.

[0046] [8] The tire manufacturing method of the present disclosure includes the steps of setting an unvulcanized tire T in the cavity 15 of a tire vulcanizing mold 10 equipped with any one of the vent pieces 2 described above [1] to [6], and vulcanizing the tire T by applying heat and pressure. This method does not cause expansion of the exhaust hole 16, and can also accommodate variations in the diameter of the exhaust hole 16.

[0047] The tire manufacturing method of the present disclosure is the same as a normal tire manufacturing method, except that the vent piece 2 as described above is attached to the exhaust hole 16 of the tire vulcanization mold 10, and any of the conventionally known steps and vulcanization conditions can be adopted.

[0048] Although the embodiments of the present disclosure have been described above, it should be understood that the specific configurations are not limited to these embodiments. The scope of the present disclosure is not limited to the above-described embodiments, but is indicated by the claims, and further includes all modifications within the meaning and scope equivalent to the claims.

[0049] The vent piece, tire vulcanization mold, and tire manufacturing method of the present disclosure are not limited to the above-described embodiments, and various improvements and modifications are possible within the scope of the spirit thereof. Furthermore, the configurations adopted in the first and second embodiments described above can be adopted in any combination. [Explanation of symbols]

[0050] 1 Molding surface 2 Vent Pieces 2a Vent piece (first embodiment) 2b Vent piece (second embodiment) 3 slits 4 slits 10 Tire curing mold 16 Exhaust vent 21 Exhaust duct

Claims

1. A cylindrical vent piece is attached to an exhaust hole that opens on the molding surface of a tire vulcanization mold, has an exhaust passage therein, and has a slit formed on its outer peripheral surface that extends in a curved manner when viewed in the longitudinal direction, The slit has one end that opens at the outer peripheral surface and the other end that terminates without being connected to the exhaust path.

2. The vent piece according to claim 1, wherein the slits are formed at a plurality of locations in a circumferential direction around a center line of the exhaust passage.

3. A cylindrical vent piece is attached to an exhaust hole that opens on the molding surface of a tire vulcanization mold, has an exhaust passage therein, and has a slit formed on its outer peripheral surface that extends in a curved manner when viewed in the longitudinal direction, the slit has one end that opens at the outer peripheral surface and the other end that is connected to the exhaust path, In a natural state where no external force is acting, the spacing between the slits gradually decreases toward the exhaust path.

4. A tire vulcanizing mold comprising: the molding surface that contacts the outer surface of a tire set in a cavity; and the vent piece according to any one of claims 1 to 3 that is attached to the exhaust hole that opens on the molding surface.

5. A tire manufacturing method comprising the steps of setting an unvulcanized tire in a cavity of a tire vulcanizing mold equipped with the vent piece according to any one of claims 1 to 3, and applying heat and pressure to the tire to vulcanize it.

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