Mold for tire vulcanization molding, tire manufacturing method, and tire

Abstract

This mold M for tire vulcanization molding is configured to produce a tire by vulcanization-molding a green tire T01', and comprises: a flat bead-heel-part molding surface MBh that is configured to mold a bead heel part of the tire; a vent hole MH opened on the bead-heel-part molding surface; and a spring vent MV installed in the vent hole.

Description

Tire vulcanization molding mold, tire manufacturing method, and tire

[0001] The present invention relates to a tire vulcanization mold, a tire manufacturing method, and a tire. This application claims priority to Japanese Patent Application No. 2023-121086, filed on July 25, 2023, the entire contents of which are incorporated herein by reference.

[0002] BACKGROUND ART Conventionally, there have been tire vulcanization molding molds equipped with spring vents (for example, Patent Document 1).

[0003] Patent No. 7189043

[0004] However, in conventional tire vulcanization molding molds, there is a risk that raw rubber from the raw tire will get into the spring vents, causing the spring vents to stick.

[0005] An object of the present invention is to provide a tire vulcanization molding mold, a tire manufacturing method, and a tire that can prevent raw rubber from entering the inside of a spring vent.

[0006] [1] A tire vulcanization molding mold configured to obtain a tire by vulcanizing and molding a green tire, the tire vulcanization molding mold comprising: a flat bead heel portion molding surface configured to mold a bead heel portion of the tire; a vent hole opening to the bead heel portion molding surface; and a spring vent installed in the vent hole.

[0007] [6] A tire manufacturing method including a vulcanization molding step of vulcanizing and molding the green tire using the tire vulcanization molding mold according to [1] to obtain the tire.

[0008] [7] A tire, wherein a bead heel portion of the tire has: a flat bead heel flat surface; and a spring vent mark provided on the bead heel flat surface.

[0009] According to the present invention, it is possible to provide a tire vulcanization molding mold, a tire manufacturing method, and a tire that can prevent raw rubber from entering the inside of a spring vent.

[0010] 1 is a tire widthwise cross-sectional view schematically showing a tire vulcanization molding mold according to one embodiment of the present invention, and is also a drawing for explaining a green tire inflation step and a vulcanization molding step. 1 is a perspective view schematically showing a part of the bead mold portion of FIG. 1 together with a tire widthwise cross-section. 2 is an A-A cross-sectional view schematically showing a part of the bead mold portion of FIG. 2, taken along line A-A in FIG. 2. 3 is a drawing corresponding to FIG. 3 and for explaining a modified example of the bead mold portion. 4 is a tire widthwise cross-sectional view schematically showing the bead mold portion of FIG. 2 when the spring vent is in an open state. 5 is a tire widthwise cross-sectional view schematically showing the bead mold portion of FIG. 2 in the green tire inflation step. 6 is a tire widthwise cross-sectional view schematically showing the bead mold portion of FIG. 2 in the vulcanization molding step. 7 is a tire widthwise cross-sectional view schematically showing a bead portion of a tire according to one embodiment of the present invention obtained after the vulcanization molding step. 8 is a perspective view schematically showing the bead portion of the tire of FIG. 8 together with a tire widthwise cross-section. Fig. 10 is a cross-sectional view taken along line BB of Fig. 9, illustrating the bead portion of the tire of Fig. 9. Fig. 11 is a view corresponding to Fig. 10, illustrating a modified example of the bead portion of the tire. Fig. 12 is a cross-sectional view in the tire width direction, illustrating a tire internal structure that can be applied to a tire according to any embodiment.

[0011] The tire vulcanization molding mold, tire manufacturing method, and tire according to the present invention can be suitably used for any pneumatic tire.

[0012] Hereinafter, embodiments of a tire vulcanization molding mold, a tire manufacturing method, and a tire according to the present invention will be described with reference to the drawings. Common members and parts in the drawings are designated by the same reference numerals.

[0013] 1 is a cross-sectional view in the tire width direction, schematically showing a tire vulcanization-molding mold M according to one embodiment of the present invention. The tire vulcanization-molding mold M is configured to obtain a vulcanized tire T01 (hereinafter simply referred to as "tire T01") according to one embodiment of the present invention by vulcanizing a green tire T01'.

[0014] In this specification, for convenience, the raw tire T01' and the tire T01 may be collectively referred to as "tires T01', T01." In this specification, when describing the tire vulcanization molding mold M, for convenience, regardless of whether or not the tires T01', T01 are present in the tire vulcanization molding mold M, the tire width direction (TWD), tire width direction outer side (TWDO), tire width direction inner side (TWDI), tire radial direction (TRD), tire radial direction outer side (TRDO), tire radial direction inner side (TRDI), tire circumferential direction (TCD), tire equatorial plane (CL), tire center axis (tire rotation axis, O), etc. of the tires T01', T01 molded in the tire vulcanization molding mold M will be simply referred to as "tire width direction (TWD)," "tire width direction outer side (TWDO)," "tire width direction inner side (TWDI)," "tire radial direction (TRD)," "tire radial direction outer side (TRDO)," "tire radial direction inner side (TRDI)," "tire circumferential direction (TCD)," "tire equatorial plane (CL)," "tire center axis (O)," etc. In each drawing, for ease of understanding, the tire width direction TWD, tire width direction outer side TWDO, tire width direction inner side TWDI, tire radial direction TRD, tire radial direction outer side TRDO, tire radial direction inner side TRDI, and tire circumferential direction TCD are indicated by arrows, respectively. For simplicity, illustration of internal components of tires T01′, T01 is omitted in Figures 1, 6, 7, 8, 9, and 12.

[0015] In this embodiment, the tire curing mold M includes multiple mold sections MB, MS, and MT separated from one another and a bladder MD. More specifically, in this embodiment, the tire curing mold M includes a pair of bead mold sections MB located on both sides of the tire equatorial plane CL, a pair of side mold sections MS located on both sides of the tire equatorial plane CL, and a tread mold section MT. The pair of bead mold sections MB have similar configurations, so when describing the bead mold section MB in this specification, unless otherwise specified, it is assumed that each bead mold section MB is being described. The pair of side mold sections MS have similar configurations, so when describing the side mold section MS in this specification, it is assumed that each side mold section MS is being described, unless otherwise specified.

[0016] The bead mold portion MB has a molding surface MBS configured to mold the outer surface T20 of the corresponding one of the pair of bead portions T01b of the tire T01. The bead mold portion MB (and therefore the molding surface MBS) is configured in an annular shape centered on the tire central axis O. The bead mold portion MB may be configured from multiple members separated from each other, or may be configured from a single member.

[0017] The side mold section MS has a molding surface MSS configured to mold the outer surface T20 of the corresponding one of a pair of sidewall sections T01w of the tire T01. The side mold section MS (and therefore the molding surface MSS) is configured in an annular shape centered on the tire central axis O. The side mold section MS may be configured from multiple members separated from each other, or may be configured from a single member.

[0018] The tread mold part MT has a molding surface MTS configured to mold the outer surface T20 of the tread portion T01t of the tire T01. The tread mold part MT (and therefore the molding surface MTS) is configured in an annular shape centered on the tire central axis O. The tread mold part MT may be configured from multiple members separated from each other, or may be configured from a single member.

[0019] The bladder MD is made of an elastic material such as rubber, and is configured to mold the inner surface of the tire T01.

[0020] When the tire vulcanization-molding mold M is in a closed state (FIG. 1), the molding surfaces MBS, MSS, and MTS of the mold parts MB, MS, and MT and the molding surface of the bladder MD define a cavity of the tire vulcanization-molding mold M.

[0021] The tire center axis O (and therefore the tire width direction TWD) of the tire vulcanization molding mold M is oriented so as to be parallel to the vertical direction, for example.

[0022] The configuration of the tire vulcanization molding mold M is not limited to that shown in FIG. 1 and may be any configuration.

[0023] FIG. 2 is a perspective view schematically showing a portion of the bead mold portion MB of FIG. 1 together with a tire widthwise cross section. FIG. 5 is a tire widthwise cross section schematically showing the bead mold portion MB of FIG. 2. As shown in FIGS. 1, 2, and 5, the molding surface MBS of the bead mold portion MB of the tire vulcanization mold M has a bead heel portion molding surface MBh, a bead base surface molding surface MBb, and a bead back surface molding surface MBr. The bead heel portion molding surface MBh is configured to mold the bead heel portion T01bh ( FIG. 13 ) of the bead portion T01b of the tire T01. The bead heel portion molding surface MBh connects the bead base surface molding surface MBb and the bead back surface molding surface MBr to each other. In the tire T01, the bead heel portion T01bh connects the bead base surface T01bb and the bead back surface T01br to each other ( FIG. 13 ). The bead base surface molding surface MBb is configured to mold a bead base surface T01bb ( FIG. 13 ) of the bead portion T01b of the tire T01. The bead base surface molding surface MBb extends inward in the tire width direction from the bead heel portion molding surface MBh. In the tire T01, the bead base surface T01bb extends inward in the tire width direction from the bead heel portion T01bh. The bead back surface molding surface MBr is configured to mold a bead back surface T01br ( FIG. 13 ) of the bead portion T01b of the tire T01. The bead back surface molding surface MBr extends outward in the tire radial direction from the bead heel portion molding surface MBh. In the tire T01, the bead back surface T01br extends outward in the tire radial direction from the bead heel portion T01bh.

[0024] The bead heel portion molding surface MBh is flat (eventually a flat surface). In the present embodiment, the bead heel portion molding surface MBh extends linearly toward the inner side in the tire width direction and the inner side in the tire radial direction in the tire width direction cross section ( FIG. 5 ).

[0025] As shown in FIGS. 2 and 5, the bead mold portion MB of the tire vulcanization molding mold M is provided with a vent hole MH and a spring vent MV installed in the vent hole MH.

[0026] One end of the vent hole MH opens to the bead heel molding surface MBh. The vent hole MH penetrates the bead mold portion MB, and the other end communicates with the outside of the bead mold portion MB. In this embodiment, the vent hole MH has a circular shape in plan view ( FIG. 2 ), but may have another shape in plan view.

[0027] The spring vent MV is configured as a valve that can open and close the vent hole MH. The spring vent MV is not limited to the one shown in FIG. 5 and may have any known configuration. As shown in FIG. 5, the spring vent MV includes a housing MVH, a pin MVP, and a spring MVS. The housing MVH is tubular (more specifically, cylindrical in this embodiment), and its outer circumferential surface is fixed to the inner circumferential surface of the vent hole MH. The pin MVP is, for example, rod-shaped and located on the inner circumferential side of the housing MVH. The pin MVP has a head surface MVPt that faces the cavity of the tire curing mold M. The head surface MVPt is a flat surface perpendicular to the central axis MVO of the spring vent MV (which is the same as the central axis of the pin MVP). In this embodiment, the head surface MVPt is circular ( FIG. 2 ), but may have other shapes. The spring MVS is a coil spring and is located between the housing MVH and the pin MVP. The housing MVH, the pin MVP, and the spring MVS are arranged coaxially with each other. The spring vent MV and the vent hole MH are also arranged coaxially with each other.

[0028] FIG. 5 shows the spring vent MV in an open state. As shown in FIG. 5, when the spring vent MV is in an open state, a gap is formed between the housing MVH and the pin MVP, allowing air to flow through the gap into the spring vent MV and, therefore, into the vent hole MH. The pin MVP is biased toward the open state by the spring MVS. FIG. 7 shows the spring vent MV in a closed state. As shown in FIG. 7, when the spring vent MV is in a closed state, the housing MVH and the pin MVP come into contact with each other, eliminating the gap, preventing raw rubber from flowing through the spring vent MV and, therefore, into the vent hole MH.

[0029] A tire manufacturing method according to one embodiment of the present invention includes a green tire inflation step and a vulcanization-molding step. In the green tire inflation step, a pre-assembled green tire T01' is placed in a cavity of a tire vulcanization-molding mold M, and the green tire T01' is expanded by inflating a bladder MD, thereby pressing the green tire T01' against the molding surfaces MBS, MSS, and MTS of the respective mold sections MB, MS, and MT ( FIGS. 1 and 6 ). During this process, the bead portions T01b of the green tire T01' can roll toward the inside in the tire width direction on the molding surface MBS of the bead mold section MB ( FIGS. 1 and 6 ). After the green tire inflation step, in the vulcanization-molding step, the green tire T01' in the cavity of the tire vulcanization-molding mold M is vulcanized using the tire vulcanization-molding mold M, thereby obtaining a vulcanized tire T01 ( FIGS. 7 , 8 , and 9 ).

[0030] The bead heel portion T01bh of the tire T01 has a flat bead heel flat surface T01bf formed by the flat bead heel portion molding surface MBh during the vulcanization molding process ( FIGS. 8 and 9 ). Furthermore, a spring vent mark TVF formed by the spring vent MV (and possibly a vent hole MH) during the vulcanization molding process may remain in the bead heel portion T01bh of the tire T01. In this case, the bead heel portion T01bh of the tire T01 has a spring vent mark TVF provided on the bead heel flat surface T01bf. The spring vent mark TVF may be, for example, convex and have a circular or annular shape in a plan view ( FIG. 9 ).

[0031] The spring vent MV configured as described above is maintained in an open state by the biasing force of the spring MVS while the green tire T01' is not present in the tire vulcanization mold M (FIG. 5). On the other hand, between the green tire inflation step and the vulcanization molding step (FIGS. 1, 6, and 7), the green tire T01' in the tire vulcanization mold M presses the pin MVP against the biasing force of the spring MVS, causing the pin MVP to come into contact with the housing MVH and enter a closed state. At this time, until just before the spring vent MV enters a closed state, air AR between the green tire T01' and the molding surface MBS in the cavity of the tire vulcanization mold M is discharged to the outside of the tire vulcanization mold M via the spring vent MV and, ultimately, the vent hole MH (FIG. 7). This makes it possible to prevent air from remaining between the raw tire T01' and the molding surface MBS, and in turn makes it possible to prevent the occurrence of shape defects such as bare spots on the outer surface T20 of the tire T01 obtained after the vulcanization molding process.

[0032] In this embodiment, as described above, the vent hole MH in which the spring vent MV is provided opens to the flat bead heel portion molding surface MBh, or in simpler terms, the spring vent MV is embedded in a flat surface. If the spring vent MV were embedded in a curved surface (for example, if the vent hole MH in which the spring vent MV is provided opens to the curved bead heel portion molding surface), when a part of the green tire T01' rolls on the curved surface as the green tire T01' expands during, for example, the green tire inflation process, the raw rubber of the green tire T01' would get caught on the edge of the head surface MVPt of the pin MVP of the spring vent MV, which is still in an open state, and would easily get into the gap between the pin MVP and the housing MVH (and thus into the inside of the spring vent MV). If raw rubber gets into the gap between the pin MVP and the housing MVH, the raw rubber may stick the pin MVP and the housing MVH to each other, potentially impairing the exhaust function of the spring vent MV. The inventors of the present invention have newly discovered that embedding the spring vent MV in a flat surface significantly prevents raw rubber from the raw tire T01' from getting caught on the edge of the head surface MVPt of the pin MVP of the spring vent MV and getting into the gap between the pin MVP and the housing MVH, compared to embedding the spring vent MV in a curved surface. This embodiment effectively prevents raw rubber from the raw tire T01' from getting into the gap between the pin MVP and the housing MVH of the spring vent MV (and ultimately into the interior of the spring vent MV) and causing the spring vent MV to stick. Once sticking occurs, the spring vent MV cannot vent air from the next vulcanization molding, resulting in poor appearance quality, such as the occurrence of bare spots. This in turn improves the durability of the spring bent MV and the tire vulcanization mold M, thereby improving the productivity and appearance quality of tires.Incidentally, the bead base surface T01bb and the bead back surface T01br (FIGS. 8 and 13) of the bead portion T01b of the tire T01 are portions that come into contact with a rim assembled to the tire T01. Therefore, the formation of a protrusion due to a spring vent mark TVF there is undesirable because it could impair fit with the rim (and thus tire internal pressure retention performance, rolling performance, etc.). On the other hand, the bead heel portion T01bh of the bead portion T01b of the tire T01 is a portion that generally does not come into contact with the rim. Therefore, even if a protrusion due to a spring vent mark TVF is formed, it is unlikely to cause problems with fit with the rim. According to this embodiment, the spring vent MV is embedded in the bead heel portion molding surface MBh configured to mold the bead heel portion T01bh. Therefore, even if the spring vent mark TVF is formed by the spring vent MV, it is possible to avoid impairing fit with the rim (and thus tire internal pressure retention performance, rolling performance, etc.).

[0033] In this specification, the extending direction of the bead heel portion molding surface MBh in the tire width direction cross section is referred to as the "bead heel portion molding surface extending direction (MED)" ( FIG. 5 ). Also, in this specification, the extending direction of the bead heel flat surface T01bf in the tire width direction cross section is referred to as the "bead heel flat surface extending direction (TED)" ( FIG. 8 ). From the viewpoint of preventing the raw rubber of the raw tire T01' from getting caught on the edge of the head surface MVPt of the pin MVP of the spring vent MV and getting into the gap between the pin MVP and the housing MVH, it is preferable that, in the tire widthwise cross section of the tire vulcanization mold M, the central axis MVO of the spring vent MV passes through a point on the bead heel portion molding surface MBh that is located closer to the center of the bead heel portion molding surface MBh in the bead heel portion molding surface extending direction MED than both ends of the bead heel portion molding surface MBh in the bead heel portion molding surface extending direction MED, as shown in Fig. 5. It is even more preferable that, in the tire widthwise cross section of the tire vulcanization mold M, the central axis MVO of the spring vent MV passes through the center point of the bead heel portion molding surface MBh in the bead heel portion molding surface extending direction MED, as shown in Fig. 5. From the same viewpoint, it is preferable that, in a tire widthwise cross section of the tire T01, the central axis TVFO of the spring vent mark TVF passes through a point on the bead heel flat surface T01bf that is located closer to the center of the bead heel flat surface T01bf in the bead heel flat surface extending direction TED than both ends of the bead heel flat surface T01bf in the bead heel flat surface extending direction TED, as shown in Fig. 8. It is even more preferable that, in a tire widthwise cross section of the tire T01, the central axis TVFO of the spring vent mark TVF passes through the center point of the bead heel flat surface T01bf in the bead heel flat surface extending direction TED, as shown in Fig. 8. The central axis TVFO of the spring vent mark TVF is the central axis of the shape of the spring vent mark TVF (in the example of Fig. 8, a cylindrical shape).

[0034] In the tire vulcanization mold M, the central axis MVO of the spring vent MV may be parallel to the perpendicular line MBhL of the bead heel portion molding surface MBh, as in the example shown in FIG. 5 . In this case, the angle θM between the central axis MVO of the spring vent MV and the perpendicular line MBhL of the bead heel portion molding surface MBh is 0°. Furthermore, the head surface MVPt of the spring vent MV is parallel to the bead heel portion molding surface MBh. This effectively prevents the raw rubber of the raw tire T01′ from getting caught on the edge of the head surface MVPt of the pin MVP of the spring vent MV and entering the gap between the pin MVP and the housing MVH. Alternatively, in the tire vulcanization mold M, the central axis MVO of the spring vent MV may be inclined at an acute angle with respect to the perpendicular line MBhL of the bead heel portion molding surface MBh, as in another example shown in FIG. 12 . In this case, it is preferable that the angle θM between the central axis MVO of the spring vent MV and the perpendicular line MBhL of the bead heel portion molding surface MBh is (greater than 0° and) 8° or less. This also effectively prevents the raw rubber from entering the gap between the pin MVP of the spring vent MV and the housing MVH. In this case, it is preferable that, in the tire width direction cross section, the angle formed by the head surface MVPt of the spring vent MV on the acute side with respect to the tire radial direction is larger than the angle formed by the bead heel portion molding surface MBh on the acute side with respect to the tire radial direction, as in the example shown in Figure 12. As a result, compared to the example of Figure 5 where the head surface MVPt of the spring vent MV is parallel to the bead heel portion molding surface MBh, the portion of the head surface MVPt of the spring vent MV that is outer in the tire width direction than the central axis MVO of the spring vent MV is inclined in a direction away from the raw tire T01' in the tire vulcanization molding mold M (i.e., in the direction of lying down).Therefore, when the bead portion T01b of the raw tire T01' rolls toward the inside in the tire width direction on the bead heel portion molding surface MBh during the raw tire inflation process, the raw rubber of the raw tire T01' is less likely to get caught on the edge of the head surface MVPt of the pin MVP of the spring vent MV, and ultimately, it is possible to prevent the raw rubber from penetrating into the spring vent MV.From a similar perspective, in the tire T01, the central axis TVFO of the spring vent mark TVF may be parallel to the perpendicular line T01bfL of the bead heel flat surface T01bf, as in the example shown in Fig. 8 . In this case, the angle θT formed between the central axis TVFO of the spring vent mark TVF and the perpendicular line T01bfL of the bead heel flat surface T01bf is 0°. Furthermore, the tip surface TVFt of the spring vent mark TVF is parallel to the bead heel flat surface T01bf. Alternatively, although not shown in the drawings, in the tire T01, the central axis TVFO of the spring vent mark TVF may be inclined so as to form an acute angle with respect to the perpendicular line T01bfL of the bead heel flat surface T01bf. In this case, it is preferable that the angle θT between the central axis TVFO of the spring vent mark TVF and the perpendicular line T01bfL of the bead heel flat surface T01bf be (greater than 0°) and 8° or less. In this case, although not shown, it is preferable that the angle on the acute side of the tip surface TVFt of the spring vent mark TVF with respect to the tire radial direction in the tire width direction cross section of the tire, which is greater than the angle on the acute side of the bead heel flat surface T01bf with respect to the tire radial direction, is greater than the angle on the acute side of the bead heel flat surface T01bf with respect to the tire radial direction. Here, the tip surface TVFt of the spring vent mark TVF refers to the surface of the surface of the spring vent mark TVF that is located at the tip of the direction in which the spring vent mark TVF protrudes from the bead heel flat surface T01bf. At least a portion of the tip surface TVFt of the spring vent mark TVF is formed by the head surface MVPt of the spring vent MV ( FIG. 7 ).

[0035] As shown in the example of Figure 5, in the tire vulcanization mold M, it is preferable that the diameter of the head surfaces MVPt of the pins MVP of the spring vents MV is shorter than the length of the bead heel portion molding surface MBh in the bead heel portion molding surface extending direction MED in the tire widthwise cross section. This makes it less likely that the raw rubber of the raw tire T01' will get caught on the edges of the head surfaces MVPt of the pins MVP of the spring vents MV when the bead portions T01b of the raw tire T01' roll on the bead heel portion molding surface MBh during the raw tire inflation process, thereby preventing the raw rubber from penetrating into the spring vents MV. Note that, when the head surfaces MVPt are non-circular in plan view, the diameter of the head surfaces MVPt of the pins MVP of the spring vents MV refers to the diameter of the circumscribed circle of the shape formed by the head surfaces MVPt. From the same viewpoint, in the tire T01, it is preferable that the diameter of the tip surface TVFt of the spring vent mark TVF is shorter than the length of the bead heel flat surface T01bf in the bead heel flat surface extending direction TED in the tire width direction cross section, as in the example shown in Fig. 8. Note that, when the tip surface TVFt is non-circular in plan view, the diameter of the tip surface TVFt of the spring vent mark TVF refers to the diameter of a circumscribing circle of the shape formed by the tip surface TVFt.

[0036] 6 , during the green tire inflation process, while the bead portion T01b of the green tire T01′ rolls toward the inside in the tire width direction on the molding surface MBS of the bead mold portion MB, the shape of the bead portion T01b of the green tire T01′ differs from the shape of the molding surface MBS of the bead mold portion MB, and therefore a gap exists between them. If the head surfaces MVPt of the pins MVP of the spring vents MV are configured not to face this gap, particularly in the portion on the bead back surface molding surface MBr side in the bead heel portion molding surface extending direction MED, during the green tire inflation process, when the bead portion T01b of the green tire T01′ rolls toward the inside in the tire width direction on the molding surface MBS of the bead mold portion MB, the raw rubber of the green tire T01′ is less likely to get caught on the edge of the head surfaces MVPt of the pins MVP of the spring vents MV, and ultimately, it is possible to prevent the raw rubber from entering the inside of the spring vents MV. From this perspective, as shown in the example of Fig. 6, in the tire vulcanization molding mold M, it is preferable that the end MVPta of the head surface MVPt of the pin MVP of the spring vent MV, which is on the bead backside molding surface MBr side in the bead heel portion molding surface extending direction MED, is located at the same position as the end T01'a, in the bead heel portion molding surface extending direction MED, of the portion of the green tire T01' that comes into contact with the bead heel portion molding surface MBh while the bead portion T01b of the green tire T01' rolls on the bead heel portion molding surface MBh toward the inside in the tire width direction during the green tire inflation step, or is located closer to the bead base surface molding surface MBb in the bead heel portion molding surface extending direction MED. From the same perspective, it is preferable that the diameter of the head surface MVPt of the pin MVP of the spring vent MV in the tire vulcanization molding mold M is 3.5 mm or less. From the same viewpoint, in the tire T01, it is preferable that the diameter of the tip surface TVFt of the spring vent mark TVF is 3.5 mm or less.

[0037] In the tire vulcanization molding mold M, the further the spring vent MV is embedded in the vent hole MH (the opposite side to the cavity of the tire vulcanization molding mold M), the farther it is from the raw tire T01', so that during the raw tire expansion process, while the bead portion T01b of the raw tire T01' rolls on the bead heel portion molding surface MBh, the raw rubber of the raw tire T01' is less likely to get caught on the edge of the head surface MVPt of the pin MVP of the spring vent MV. From this perspective, it is preferable that the spring vent MV, when the spring vent MV is in a closed state ( FIG. 7 ), has a center point MVPtc of the head surface MVPt of the pin MVP of the spring vent MV located on the bead heel portion molding surface MBh (i.e., on the opening surface of the vent hole MH that faces the bead heel portion molding surface MBh), or located further back in the vent hole MH than the bead heel portion molding surface MBh as in the example of Fig. 7 , and it is more preferable that the spring vent MV is located further back in the vent hole MH than the bead heel portion molding surface MBh as in the example of Fig. 7. In other words, it is preferable that the spring vent MV is configured so that, when the spring vent MV is in a closed state, the center point MVPtc of the head surface MVPt of the pin MVP of the spring vent MV is located at a depth of 0 mm or more from the bead heel portion molding surface MBh, and it is more preferable that the center point MVPtc is located at a depth of more than 0 mm from the bead heel portion molding surface MBh. On the other hand, if the spring vent MV is embedded too far back in the vent hole MH, the protruding height of the spring vent mark TVF formed by the spring vent MV will be excessively high, which may impair the aesthetics of the tire T01 or cause the spring vent mark TVF to come into contact with the rim assembled to the tire T01, impairing the fit with the rim. From this perspective, it is preferable that the spring vent MV be configured so that, when the spring vent MV is closed, the center point MVPtc of the head surface MVPt of the spring vent MV pin MVP is located at a depth of 0.5 mm or less from the bead heel portion molding surface MBh. Note that the depth is measured along the central axis MVO of the spring vent MV.From the same viewpoint, in the tire T01, it is preferable that the center point TVFtc ( FIG. 8 ) of the tip surface TVFt of the spring vent mark TVF is located on the bead heel flat surface T01bf or located at a position protruding from the bead heel flat surface T01bf as in the example of Fig. 8, and it is more preferable that it is located at a position protruding from the bead heel flat surface T01bf as in the example of Fig. 8. In other words, it is preferable that the spring vent mark TVF is configured so that the center point TVFtc of the tip surface TVFt of the spring vent mark TVF is located at a height of 0 mm or more from the bead heel flat surface T01bf, and it is more preferable that it is configured so that it is located at a height of more than 0 mm from the bead heel flat surface T01bf. On the other hand, it is preferable that the spring vent mark TVF is configured so that the center point TVFtc of the tip surface TVFt of the spring vent mark TVF is located at a height of 0.5 mm or less from the bead heel flat surface T01bf, where the height is measured along the central axis TVFO of the spring vent mark TVF.

[0038] In the bead mold portion MB of the tire vulcanization mold M, only one set of the above-mentioned spring vent MV and vent hole MH may be provided on each side of the tire equatorial plane CL, or multiple sets of spring vents MV and vent holes MH may be provided arranged at intervals from each other in the tire circumferential direction as shown in FIG. 2 . In the latter case, the number of sets of spring vents MV and vent holes MH provided on each side of the tire equatorial plane CL is preferably 32 or less. Similarly, in the bead portion T01b of the tire T01, only one spring vent mark TVF may be provided on each side of the tire equatorial plane CL, or multiple spring vent marks TVF may be provided arranged at intervals from each other in the tire circumferential direction as shown in FIG. 9 . In the latter case, the number of spring vent marks TVF provided on each side of the tire equatorial plane CL is preferably 32 or less.

[0039] The tire vulcanization molding mold M may have one or more grooves MBG on the molding surface MBS of the bead mold portion MB, as shown in Fig. 2. For example, the tire vulcanization molding mold M may have, as the groove MBG, one or more connecting grooves MBGa on the molding surface MBS of the bead mold portion MB, which connect the plurality of vent holes MH (and thus the spring vents MV). It is preferable that the connecting groove MBGa extends along the tire circumferential direction as shown in Fig. 2, but it may have any other extending form. And / or, the tire vulcanization molding mold M may have, on the molding surface MBS of the bead mold portion MB, one or more inner circumferential side branch grooves MBGb as grooves MBG, one end of which is connected to the vent hole MH (and thus the spring vent MV) or the connecting groove MBGa and the other end of which is located on the tire radially inner edge MBei of the molding surface MBS of the bead mold portion MB. The inner circumferential side branch groove MBGb preferably extends along the tire radial direction as shown in FIG. 2 , but may have any other extending form. And / or, the tire vulcanization molding mold M may have, on the molding surface MBS of the bead mold portion MB, one or more outer peripheral side branch grooves MBGc as grooves MBG, one end of which is connected to the vent hole MH (and thus the spring vent MV) or the connecting groove MBGa and the other end of which is located on the tire radially outer edge MBeO of the molding surface MBS of the bead mold portion MB. The outer peripheral side branch groove MBGc preferably extends along the tire radial direction as shown in FIG. 2 , but may have any other extending form. By providing the grooves MBG, air that accumulates on the molding surface MBS of the bead mold section MB at positions other than the vent holes MH (and thus the spring vents MV) during the green tire inflation process and vulcanization molding process can be moved along the grooves MBG to the vent holes MH (and thus the spring vents MV) and discharged to the outside of the bead mold section MB via the vent holes MH (and thus the spring vents MV). Furthermore, in the inner peripheral side branch grooves MBGb and the outer peripheral side branch grooves MBGc, it is also possible to discharge air from the tire radially inner edge MBei and the tire radially outer edge MBeo of the molding surface MBS of the bead mold section MB.The cross-sectional shape of the groove MBG may be semicircular (e.g., semicircular with a radius of 0.5 mm) as shown in FIG. 3 , or may be V-shaped (e.g., V-shaped with a depth of 0.5 mm) as shown in another example in FIG. 4 , or may be any other shape. Similarly, the tire T01 may have one or more ridges T01bR on the outer surface T20 of the bead portion T01b as shown in FIG. 9 . The ridge T01bR is formed by the groove MBG. For example, the tire T01 may have one or more connecting ridges T01bRa on the outer surface T20 of the bead portion T01b as the ridge T01bR, connecting multiple spring vent traces TVF together. The connecting ridge T01bRa preferably extends along the tire circumferential direction as shown in FIG. 9 , but may have any other extension form. The connecting ridge T01bRa is formed by the connecting groove MBGa. And / or, the tire T01 may have one or more inner circumferential side branch ridges T01bRb as ridges T01bR on the outer surface T20 of the bead portion T01b, one end of which is connected to the spring vent mark TVF or the connecting ridge T01bRa and the other end of which is located on the tire radially inner edge T01bei of the outer surface T20 of the bead portion T01b. The inner circumferential side branch ridge T01bRb preferably extends along the tire radial direction as shown in FIG. 9 , but may have any other extension form. The inner circumferential side branch ridge T01bRb is formed by the inner circumferential side branch groove MBGb. And / or, the tire T01 may have one or more outer peripheral side branch ridges T01bRc as ridges T01bR on the outer surface T20 of the bead portion T01b, the outer peripheral side branch ridges T01bRc having one end connected to the spring vent mark TVF or the connecting ridge T01bRa and the other end located at a predetermined tire radial position T01beo on the outer surface T20 of the bead portion T01b, the outer peripheral side branch ridges T01bRc being located outward in the tire radial direction from the spring vent mark TVF. It is preferable that the outer peripheral side branch ridge T01bRc extends along the tire radial direction as shown in FIG. 9 , but the outer peripheral side branch ridges T01bRc may have any other extending form.The predetermined tire radial position T01beo corresponds to the tire radially outer edge MBeo ( FIG. 2 ) of the molding surface MBS of the bead mold section MB, and thus corresponds to the boundary between the molding surface MBS of the bead mold section MB and the molding surface MSS of the side mold section MS ( FIG. 1 ). Therefore, a convex or concave shape extending in the tire circumferential direction may be formed at the predetermined tire radial position T01beo. The outer peripheral side branch ridge T01bRc is formed by the outer peripheral side branch groove MBGc. The cross-sectional shape of the ridge T01bR may be semicircular (e.g., semicircular with a radius of 0.5 mm) as shown in FIG. 10 , or may be V-shaped (e.g., V-shaped with a height of 0.5 mm) as shown in another example in FIG. 11 , or may be any other shape.

[0040] In each example described in this specification, the tire T01 may have any internal structure. An example of the internal structure of the tire T01 will be described below with reference to Fig. 13. Fig. 13 is a drawing for explaining an example of a tire internal structure that can be applied to the tire T01 according to any embodiment of the present invention, and is a tire widthwise cross-sectional view that schematically shows a tire half portion of the tire T01 (a portion of the tire T01 on one side with respect to the tire equatorial plane CL) in a cross section in the tire width direction.

[0041] As shown in FIG. 13 , the tire T01 according to each embodiment of the present invention includes a tread portion T01t, a pair of sidewall portions T01w extending radially inward from both ends of the tread portion T01t in the tire width direction, and a pair of bead portions T01b provided at the radially inner ends of each sidewall portion T01w. When the tire T01 is mounted on a rim, the bead portions T01b are configured to contact the rim on the radially inner side and the radially outer side. In the tread portion T01t, a tread rubber T07 is located on the radially outer side of the belt T06. The tread rubber T07 forms a tread surface T01tS, which is the radially outer surface of the tread portion T01t. A tread pattern is formed on the tread surface T01tS. Any tread pattern may be provided on the tread surface T01tS.

[0042] In the example shown in FIG. 13, a tire T01 includes a pair of bead cores T02, a pair of bead fillers T03, a carcass T05, a belt T06, a tread rubber T07, a side rubber T08, and an inner liner T09.

[0043] Each bead core T02 is embedded in a corresponding bead portion T01b. The bead core T02 includes a plurality of bead wires coated with rubber. The bead wires may be made of metal (e.g., steel) or organic fibers such as polyester, nylon, rayon, and aramid. The bead wires may be made of, for example, monofilament or stranded wire.

[0044] Each bead filler T03 is located radially outward of the corresponding bead core T02. The bead filler T03 extends tapered toward the radially outward direction of the tire. The bead filler T03 is made of rubber.

[0045] The carcass T05 straddles the pair of bead cores T02 and extends in a toroidal shape. The carcass T05 is composed of one or more carcass plies T05p (one in the example of FIG. 1). Each carcass ply T05p includes one or more carcass cords and a coating rubber that covers the carcass cords. The carcass cords can be formed of monofilaments or twisted wires. The carcass cords may be made of metal (e.g., steel) or organic fibers such as polyester, nylon, rayon, or aramid. The carcass T05 preferably has a radial structure, but may also have a bias structure.

[0046] The belt T06 is disposed radially outward of the crown portion of the carcass T05. The belt T06 includes one or more belt plies T06p (two layers in the example of FIG. 1). Each belt ply T06p includes one or more belt cords and a coating rubber that covers the belt cords. The belt cords may be formed of monofilaments or twisted wires. The belt cords may be made of metal (e.g., steel) or organic fibers such as polyester, nylon, rayon, or aramid.

[0047] The side rubber T08 is located in the sidewall portion T01w. The side rubber T08 constitutes the outer surface of the sidewall portion T01w on the outer side in the tire width direction. The side rubber T08 is located more outward in the tire width direction than the carcass T05. The side rubber T08 is located more outward in the tire width direction than the bead filler T03. The side rubber T08 is formed integrally with the tread rubber T07.

[0048] The inner liner T09 is disposed on the tire inner side of the carcass T05, and may be laminated on the tire inner side of the carcass T05, for example. The inner liner T09 is made of, for example, a butyl-based rubber having low air permeability. Butyl-based rubbers include, for example, butyl rubber and its derivative, halogenated butyl rubber. The inner liner T09 is not limited to butyl-based rubber, and may be made of other rubber compositions, resins, or elastomers.

[0049] Although not shown in the drawings, the tire T01 may or may not include a cushion rubber between the carcass T05 and the tread rubber T07 in the tire radial direction. The cushion rubber may be located near the end of the belt T06 in the tire width direction.

[0050] As shown in FIG. 13, the tire T01 may include a rubber chafer T11 at a portion of each bead portion T01b that is configured to come into contact with the rim.

[0051] As shown in Fig. 13 , the tire T01 may include one or more wire chafers T14 (one in the example of Fig. 13 ) around each bead core T02. The wire chafer T14 may be arranged on the opposite side of the carcass T05 from the bead core T02, as in the example of Fig. 13 . The wire chafer T14 is made of metal (e.g., steel). Although not shown, the tire T01 may include one or more nylon chafers around each bead core T02. The nylon chafer may be arranged on the opposite side of the carcass T05 from the bead core T02, as in the example of Fig. 13 . The nylon chafer is made of nylon.

[0052] Although not shown in the drawings, the tire T01 may have a hat rubber between the bead filler T03 and the side rubber T08 in the tire width direction in each tire half portion.

[0053] As shown in FIG. 13 , the tire T01 may include an RF tag 10 as a communication device. The RF tag 10 includes an IC chip and an antenna. The RF tag 10 may be sandwiched between multiple identical or different components that constitute the tire T01, for example. This facilitates attachment of the RF tag 10 during tire production, thereby improving the productivity of tires T01 equipped with the RF tag 10. As shown in the example of FIG. 13 , the RF tag 10 may be sandwiched between a bead filler T03 and another component adjacent to the bead filler T03, for example. The RF tag 10 may be embedded in any of the components that constitute the tire T01. This reduces the load on the RF tag 10 compared to when the RF tag 10 is sandwiched between multiple components that constitute the tire T01. This improves the durability of the RF tag 10. In this example, the RF tag 10 may be embedded in a rubber component such as a tread rubber T07 or a side rubber T08. It is preferable that the RF tag 10 is not disposed at a position that is a boundary between members with different rigidities in the periphery length direction, which is a direction along the tire outer surface in a cross-sectional view in the tire width direction. In this way, the RF tag 10 is not disposed at a position where strain is likely to concentrate due to a difference in rigidity. Therefore, the load applied to the RF tag 10 can be reduced. This improves the durability of the RF tag 10. In this example, it is preferable that the RF tag 10 is not disposed at a position that is, for example, a boundary between an end of the carcass T05 and a member adjacent to the end of the carcass T05 (e.g., a side rubber T08, etc.) in a cross-sectional view in the tire width direction. The number of RF tags 10 is not particularly limited. The tire T01 may include only one RF tag 10, or two or more RF tags 10. Here, the RF tag 10 is described as an example of a communication device, but a communication device different from the RF tag 10 may also be used.

[0054] The RF tag 10 may be disposed, for example, in the tread portion T01t of the tire T01. In this manner, the RF tag 10 is not damaged by a side cut of the tire T01. The RF tag 10 may be disposed, for example, in the tread center portion in the tire width direction. The tread center portion is a position where flexure is less likely to concentrate in the tread portion T01t. In this manner, the load applied to the RF tag 10 can be reduced. This improves the durability of the RF tag 10. In addition, it is possible to prevent differences in communication with the RF tag 10 from both outer sides of the tire T01 in the tire width direction. In this example, the RF tag 10 may be disposed, for example, within a range of half the tread width centered on the tire equatorial plane CL in the tire width direction. The RF tag 10 may be disposed, for example, at a tread edge in the tire width direction. If the position of a reader that communicates with the RF tag 10 is predetermined, the RF tag 10 may be disposed, for example, at one tread edge closer to the reader. In this example, the RF tag 10 may be arranged, for example, within a range of ¼ of the tread width in the tire width direction, with the tread end as the outer end.

[0055] The RF tag 10 may be positioned closer to the tire cavity than the carcass T05, which includes one or more carcass plies T05p spanning the bead portions T01b. This arrangement makes the RF tag 10 less susceptible to damage from external impacts to the tire T01, side cuts, nail penetration, and other damage. As an example, the RF tag 10 may be positioned in close contact with the tire cavity-side surface of the carcass T05 (see point P31 in FIG. 13 ). As another example, if there is another component closer to the tire cavity than the carcass T05, the RF tag 10 may be positioned between the carcass T05 and the other component located closer to the tire cavity than the carcass T05. An example of another component located closer to the tire cavity than the carcass T05 is the inner liner T09 that forms the tire inner surface. As another example, the RF tag 10 may be attached to the tire inner surface facing the tire cavity (see point P32 in FIG. 13 ). By configuring the RF tag 10 to be attached to the inner surface of the tire, it is easy to attach the RF tag 10 to the tire T01 and to inspect and replace the RF tag 10. In other words, it is possible to improve the ease of attachment and maintenance of the RF tag 10. Furthermore, by attaching the RF tag 10 to the inner surface of the tire, it is possible to prevent the RF tag 10 from becoming the core of tire failure, compared to a configuration in which the RF tag 10 is embedded in the tire T01. Furthermore, when the carcass T05 includes multiple carcass plies T05p and there is a position where multiple carcass plies T05p are overlapped, the RF tag 10 may be disposed between the overlapped carcass plies T05p.

[0056] The RF tag 10 may be arranged, for example, in the tread portion T01t of the tire T01, radially outward of a belt T06 including one or more belt plies T06p. As one example, the RF tag 10 may be arranged radially outward of the belt T06 and in close contact with the belt T06 (see point P44 in FIG. 13 ). As another example, in the case where a belt reinforcing layer T04 is provided, the RF tag 10 may be arranged radially outward of the belt reinforcing layer T04 and in close contact with the belt reinforcing layer T04 (see point P45 in FIG. 13 ). As another example, the RF tag 10 may be embedded in the tread rubber T07 radially outward of the belt T06 (see point P41 in FIG. 13 ). By arranging the RF tag 10 radially outward of the belt T06 in the tread portion T01t of the tire T01, communication with the RF tag 10 from the outside of the tire T01 in the tire radial direction is less likely to be hindered by the belt T06. This improves communication with the RF tag 10 from the outside of the tire T01 in the tire radial direction. Alternatively, the RF tag 10 may be arranged, for example, radially inward of the belt T06 in the tread portion T01t of the tire T01. In this manner, the outer side of the RF tag 10 in the tire radial direction is covered by the belt T06, making the RF tag 10 less susceptible to damage from impacts from the tread surface, nail penetration, and the like. As an example, the RF tag 10 may be arranged between the belt T06 and the carcass T05, which is located radially inward of the belt T06 in the tire radial direction, in the tread portion T01t of the tire T01 (see point P42 in FIG. 13 ). Furthermore, when the belt T06 includes a plurality of belt plies T06p, the RF tag 10 may be disposed between any two belt plies T06p in the tread portion T01t of the tire T01 (see point P43 in FIG. 13 ). In this manner, the outer side of the RF tag 10 in the tire radial direction is covered with one or more belt plies T06p, making the RF tag 10 less susceptible to damage from impacts from the tread surface, nail penetration, and the like.

[0057] The RF tag 10 may be disposed, for example, in a position of the sidewall portion T01w or the bead portion T01b of the tire T01. The RF tag 10 may be disposed, for example, in one sidewall portion T01w or one bead portion T01b that is closer to a reader capable of communicating with the RF tag 10 (see points P6 and P62 in FIG. 13 ). This arrangement improves communication between the RF tag 10 and the reader. As an example, the RF tag 10 may be disposed between the carcass T05 and the side rubber T08 or between the tread rubber T07 and the side rubber T08 (see point P61 in FIG. 13 ). The RF tag 10 may be disposed, for example, between the tire's maximum width position and the tread surface position in the tire radial direction. This arrangement improves communication with the RF tag 10 from the outside of the tire T01 in the tire radial direction, compared to a configuration in which the RF tag 10 is disposed radially inward of the tire's maximum width position. The RF tag 10 may be positioned, for example, radially inward of the position where the tire has the widest width. In this manner, the RF tag 10 is positioned near the bead portion T01b, which has high rigidity. Therefore, the load applied to the RF tag 10 can be reduced. This improves the durability of the RF tag 10. As an example, the RF tag 10 may be positioned adjacent to the bead core T02 in the tire radial direction or tire width direction. Strain is less likely to concentrate near the bead core T02. Therefore, the load applied to the RF tag 10 can be reduced. This improves the durability of the RF tag 10. In particular, it is preferable that the RF tag 10 be positioned radially inward of the position where the tire has the widest width and radially outward of the bead core T02 of the bead portion T01b. In this manner, the durability of the RF tag 10 can be improved, and communication between the RF tag 10 and a reader is less likely to be obstructed by the bead core T02, thereby improving the communication performance of the RF tag 10. In addition, when the side rubber T08 is composed of multiple rubber members of the same or different types adjacent to each other in the tire radial direction, the RF tag 10 may be sandwiched and positioned between the multiple rubber members that make up the side rubber T08.

[0058] The RF tag 10 may be disposed sandwiched between the bead filler T03 and a member adjacent to the bead filler T03. This allows the RF tag 10 to be disposed in a position where strain is less likely to be concentrated due to the placement of the bead filler T03. Therefore, the load on the RF tag 10 can be reduced. This improves the durability of the RF tag 10. The RF tag 10 may be disposed sandwiched between the bead filler T03 and the carcass T05, for example. The portion of the carcass T05 that sandwiches the RF tag 10 together with the bead filler T03 may be located either on the outer side of the bead filler T03 in the tire width direction or on the inner side of the bead filler T03 in the tire width direction. When the portion of the carcass T05 that sandwiches the RF tag 10 together with the bead filler T03 is located on the outer side of the bead filler T03 in the tire width direction, the load on the RF tag 10 due to impact or damage from the outside of the tire T01 in the tire width direction can be further reduced. This can further improve the durability of the RF tag 10. The bead filler T03 may have a portion disposed adjacent to the side rubber T08. In such a case, the RF tag 10 may be disposed sandwiched between the bead filler T03 and the side rubber T08. The bead filler T03 may have a portion disposed adjacent to the rubber chafer T11. In such a case, the RF tag 10 may be disposed sandwiched between the bead filler T03 and the rubber chafer T11.

[0059] The RF tag 10 may be disposed, for example, sandwiched between the rubber chafer T11 and the side rubber T08 (see point P82 in FIG. 13 ). By doing so, the RF tag 10 can be disposed in a position where the placement of the rubber chafer T11 makes it difficult for distortion to concentrate. This reduces the load applied to the RF tag 10. This improves the durability of the RF tag 10. The RF tag 10 may be disposed, for example, sandwiched between the rubber chafer T11 and the carcass T05 (see point P81 in FIG. 13 ). By doing so, it is possible to reduce the load applied to the RF tag 10 due to impact or damage from the rim. This improves the durability of the RF tag 10.

[0060] The RF tag 10 may be sandwiched between the wire chafer T14 and another adjacent member on the inner or outer side of the wire chafer T14 in the tire width direction. This makes it difficult for the position of the RF tag 10 to fluctuate when the tire deforms. This reduces the load applied to the RF tag 10 when the tire deforms. This improves the durability of the RF tag 10. The other adjacent member on the inner or outer side of the wire chafer T14 in the tire width direction may be, for example, a rubber member such as a rubber chafer T11 (see point P102 in FIG. 13 ). The other adjacent member on the inner or outer side of the wire chafer T14 in the tire width direction may also be, for example, a carcass T05 (see point P101 in FIG. 13 ).

[0061] A belt reinforcing layer T04 may be further provided on the radially outer side of the belt T06. For example, the belt reinforcing layer T04 may be formed by winding a belt reinforcing layer cord made of polyethylene terephthalate continuously in a spiral shape in the tire circumferential direction. Here, the belt reinforcing layer cord may be 6.9 × 10 －２The belt reinforcement layer T04 may be formed by applying an adhesive treatment under a tension of 29.4 N / tex or more, and may have an elastic modulus of 2.5 mN / dtex% or more when measured at 160°C under a load of 29.4 N. Furthermore, the belt reinforcement layer T04 may be disposed so as to cover the entire belt T06 or so as to cover only both ends of the belt T06. Furthermore, the winding density per unit width of the belt reinforcement layer T04 may vary depending on the position in the width direction. This makes it possible to reduce road noise and flat spots without reducing high-speed durability.

[0062] The tire vulcanization molding mold, tire manufacturing method, and tire according to the present invention can be suitably used for any pneumatic tire.

[0063] M: tire curing mold, MB: bead mold portion (mold portion), MBS: molding surface, MBei: tire radially inner edge of the molding surface, MBeo: tire radially outer edge of the molding surface, MBh: bead heel portion molding surface, MBhL: perpendicular to the bead heel portion molding surface, MBb: bead base surface molding surface, MBr: bead back surface molding surface, MBG: groove, MBGa: connecting groove, MBGb: inner peripheral side branch groove, MBGc: outer peripheral side branch groove, MED: extension direction of the bead heel portion molding surface, MS: side mold portion (mold portion), MSS: molding surface, MT: tread mold portion (mold portion), MTS: molding surface, MD: bladder, MH: vent hole, MV: spring vent, MVP: pin, MVPt: head surface, MVPtc: center point of the head surface, MVPta: end of the head surface on the bead back surface molding surface side in the extending direction of the bead heel portion molding surface, MVS: spring, MVH: housing, MVO: central axis of the spring vent, T01': raw tire, T01'a: end of a portion of the raw tire that comes into contact with the bead heel portion molding surface on the bead back surface molding surface side in the extending direction of the bead heel portion molding surface, T01: tire, T01t: tread portion, T01tS: tread contact surface, T01w: sidewall portion, T01b: bead portion, T01bei: inner edge in the tire radial direction of the outer surface of the bead portion, T01beo: predetermined position in the tire radial direction on the outer surface of the bead portion, T01bh: bead heel portion, T01bf: bead heel flat surface, T01bfL: perpendicular to the bead heel flat surface TVF: spring vent mark, TVFt: tip surface, TVFtc: center point of tip surface, TVFO: central axis of spring vent mark, T01bb: bead base surface, T01br: bead back surface, T01bR: ridge, T01bRa: connecting ridge, T01bRb: inner peripheral side branch ridge, T01bRc: outer peripheral side branch ridge, TED: extension direction of bead heel flat surface, T02: bead core, T03: bead filler, T04: belt reinforcing layer, T05: carcass, T05p: carcass ply, T06: belt, T06p: belt ply, T07: tread rubber, T08: side rubber, T09: inner liner, T11: rubber chafer, T14: wire chafer, T20: outer surface of tire, 10: RF tag,CL: tire equatorial plane, O: tire center axis (tire rotation axis), TW: tire width direction, TWDO: tire width direction outer side, TWDI: tire width direction inner side, TRD: tire radial direction, TRDO: tire radial direction outer side, TRDI: tire radial direction inner side, TCD: tire circumferential direction, AR: air

Claims

1. A tire vulcanization molding mold configured to obtain a tire by vulcanizing and molding a green tire, the tire vulcanization molding mold comprising: a flat bead heel portion molding surface configured to mold a bead heel portion of the tire; a vent hole opening into the bead heel portion molding surface; and a spring vent installed in the vent hole.

2. The tire vulcanization molding mold according to claim 1, wherein the angle between the central axis of the spring vent and the perpendicular to the bead heel portion molding surface is 0° to 8°.

3. A tire vulcanization molding mold as described in claim 1, wherein the diameter of the head surface of the spring vent pin is shorter than the length of the bead heel portion molding surface in the tire width direction cross section of the tire vulcanization molding mold.

4. The tire vulcanization molding mold according to claim 1, wherein the head diameter of the spring vent pin is 3.5 mm or less.

5. A tire vulcanization molding mold as described in claim 1, wherein the spring vent is configured so that, when the spring vent is in a closed state, the center point of the head surface of the spring vent pin is located at a depth of 0 to 0.5 mm from the bead heel portion molding surface.

6. A tire manufacturing method including a vulcanization molding step of obtaining the tire by vulcanizing the green tire using the tire vulcanization molding mold according to any one of claims 1 to 5.

7. A tire, wherein a bead heel portion of the tire has a flat bead heel flat surface, and a spring vent mark provided on the bead heel flat surface.

8. The tire according to claim 7, wherein the spring vent mark is convex and has a circular or annular shape in a plan view.

Images