JP2024000590A - Tire molds and tires - Google Patents

Abstract

To provide a tire mold and a tire capable of suppressing an occurrence of bareness even when spew remains in a vent hole.SOLUTION: In a tire mold that has a side mold part that molds a sidewall of a tire, the side mold part includes: a circumferential groove extending in a circumferential direction of the tire; a radial groove that extends in a radial direction of the tire and intersects with the circumferential groove; a vent hole provided at an intersection of the circumferential groove and the radial groove; and a bypass of at least one of a grooved first bypass connected to a first part of the circumferential groove located on a first side of the tire circumferential direction across the vent hole and to the radial groove, a grooved second bypass connected to a second part of the circumferential groove located on a second side of the tire circumferential direction across the vent hole and to the radial groove, and a grooved third bypass extending without intersecting the radial groove and connected to the first part and the second part.SELECTED DRAWING: Figure 6

Description

TECHNICAL FIELD This disclosure relates to tire molds and tires.

In tire vulcanization molding, the tread and side surfaces of an unvulcanized tire are pressed against the tire molding surface of a tire mold, and the unvulcanized tire is heated and pressurized. At this time, if the air present between the tire molding surface and the unvulcanized tire is not properly discharged and an air pocket is created, a depression called a bare is generated on the outer surface of the tire.

In order to suppress the occurrence of bare air, a circumferential groove extending in the circumferential direction of the tire and a radial groove extending in the tire radial direction are formed in the side mold part that contacts the side surface of the unvulcanized tire, and these grooves are used for air circulation. It is known that it is used in the route to increase exhaust efficiency (see Patent Document 1 below). A vent hole is provided at the intersection where the circumferential groove and the radial groove intersect, and air that has passed through the circumferential groove and the radial groove is discharged from the vent hole to the outside of the tire mold.

By the way, rubber protrusions (hereinafter referred to as spews) are formed on the outer surface of the tire after vulcanization molding, depending on the vent holes, but when the tire is taken out from the tire mold after vulcanization molding, the spews are torn to pieces. It may remain in the vent hole. At this time, the spew remaining in the vent hole may block communication between the circumferential groove and the radial groove, causing air to accumulate near the intersection of the circumferential groove and the radial groove, resulting in bare air. Ta.

JP 2021-28213 Publication

An object of the present disclosure is to provide a tire mold and a tire that can suppress the occurrence of bareness even when spew remains in the vent hole.

The tire mold of the present disclosure is a tire mold having a side mold part for molding a sidewall of a tire,
The side mold portion includes a circumferential groove extending in the circumferential direction of the tire;
a radial groove extending in the tire radial direction and intersecting the circumferential groove;
a vent hole provided at the intersection of the circumferential groove and the radial groove;
a groove-shaped first bypass connected to a first portion of the circumferential groove disposed on the first side in the tire circumferential direction with the vent hole in between and the radial groove; a groove-shaped second bypass connected to the second portion of the circumferential groove and the radial groove disposed on the second side; at least one of the groove-shaped third bypasses connected to the portion.

Cross-sectional view of the tire mold along the tire meridian cross-section Front view of side mold part III-III cross-sectional view of the side mold part in Figure 2 Enlarged view of IV region in Figure 3 Enlarged view of V area in Figure 3 Enlarged view of the VI area in Figure 2 Diagram showing an example of the cross-sectional shape of a circumferential groove Diagram showing an example of the cross-sectional shape of a radial groove Cross-sectional view showing the side mold part after vulcanization molding Front view of side mold part according to other embodiments Front view of the side mold part according to the second embodiment Front view of side mold part according to other embodiments

<First embodiment>
A first embodiment of a tire mold will be described below with reference to FIGS. 1 to 10. In addition, in each figure (the same applies to Figures 11 and 12), the dimensional ratio in the drawing and the actual dimensional ratio do not necessarily match, and the dimensional ratio between each drawing does not necessarily match. do not have.

In each figure, the tire axial direction D1 is a direction parallel to the tire rotation axis O, which is the rotation center of the tire T, the tire radial direction D2 is the diametrical direction of the tire T, and the tire circumferential direction D3 is a direction parallel to the tire rotation axis O, which is the rotation center of the tire T. , the direction around the tire rotation axis O. Further, the tire equatorial plane S1 is a plane perpendicular to the tire rotation axis O and is located at the center of the tire T in the tire axial direction D1, and the tire meridian plane is a plane perpendicular to the tire rotation axis O. This is a surface that includes the tire and is perpendicular to the tire equatorial plane S1.

In addition, in the tire axial direction D1, the inner side refers to the side closer to the tire equatorial plane S1, and the outer side refers to the side farther from the tire equatorial plane S1. In addition, in the tire radial direction D2, the inner side refers to the side closer to the tire rotation axis O, and the outer side refers to the side farther from the tire rotation axis O.

FIG. 1 shows a cross section of the tire mold TM along the tire meridian plane. This tire mold TM is in a closed state. The unvulcanized tire is set with the tire axial direction D1 facing up and down. In FIG. 1, the right direction is the outside in the tire radial direction, and the left direction is the inside in the tire radial direction.

The tire mold TM includes a tread mold part M1 for molding the tread of the tire T, side mold parts M2 and M3 for molding a pair of sidewalls of the tire T, and bead rings M4 and M5 in contact with a pair of beads of the tire T. Equipped with. Although not shown, the inner surface of the tread mold portion M1 is provided with an uneven shape for forming a tread pattern on the tread of the tire T.

During vulcanization molding, the tread surface of the unvulcanized tire is pressed against the inner surface of the tread mold part M1, and the side surface of the unvulcanized tire is pressed against the inner surfaces of the side mold parts M2 and M3. Circumferential grooves 1 and 2 extending in the tire circumferential direction D3 are provided on the inner surfaces of the side mold parts M2 and M3.

FIG. 2 is a front view of the side mold part M2. FIG. 3 is a sectional view taken along the line III--III of the side mold portion M2 in FIG. 4 is an enlarged view of the IV region in FIG. 3, and FIG. 5 is an enlarged view of the V region in FIG. FIG. 6 is an enlarged view of the VI region in FIG. 2. The structure of the inner surface of the side mold part M3 may be the same as or different from the structure of the inner surface of the side mold part M2, but in this embodiment, it is the same, so the structure of the inner surface of the side mold part M3 is The explanation of is omitted.

As shown in FIG. 2, the side mold part M2 includes circumferential grooves 1 and 2 extending in the tire circumferential direction D3, radial groove 3 extending in the tire radial direction D2, and circumferential grooves 1 and 2 and radial groove 3. and a vent hole 4 provided at the intersection of the two.

The circumferential grooves 1 and 2 are arranged at intervals in the tire radial direction D2, and form an annular band-shaped region. In this annular area, tire size, manufacturing year and week, etc. may be displayed. The width dimension of the band-shaped region, ie, the interval between the circumferential grooves 1 and 2, is preferably 10 mm or more and 40 mm or less, and more preferably 14 mm or more and 30 mm or less.

It is preferable that the circumferential grooves 1 and 2 are arranged radially inward of the tire maximum width position (not shown). Thereby, bareness during vulcanization molding can be effectively suppressed, and the durability of the tire T can be improved. However, the circumferential grooves 1 and 2 may be arranged at any position in the tire radial direction D2. For example, the pair of circumferential grooves 1 and 2 may be arranged so as to sandwich the tire maximum width position. .

In this embodiment, the two circumferential grooves 1 and 2 are provided concentrically around the tire rotation axis O, but the present invention is not limited to this, and even if only one circumferential groove is provided. Often, three or more circumferential grooves may be provided. Further, the circumferential grooves 1 and 2 are formed continuously over the entire circumference in the tire circumferential direction D3, but are not limited to this, and are formed as a circle that is a part of a circle centered on the tire rotation axis O. It may also be formed in an arc shape.

The radial grooves 3 extend radially along the tire radial direction D2. However, the radial groove 3 may extend obliquely with respect to the tire radial direction D2.

For example, 6 to 20 radial grooves 3 are provided, and preferably around 10 radial grooves 3 are provided. In this embodiment, the 20 radial grooves 3 are provided at equal intervals in the tire circumferential direction D3, but the invention is not limited thereto. The distance between the radial grooves 3 does not need to be constant, and the radial grooves 3 may be provided so as to avoid displaying, for example, tire size, manufacturing year, week, etc.

The radial groove 3 intersects the circumferential grooves 1 and 2. Here, when the radial groove 3 intersects the circumferential grooves 1 and 2, it means not only that the radial groove 3 terminates at the circumferential grooves 1 and 2, but also that the radial groove 3 intersects the circumferential grooves 1 and 2. It also includes forms that extend through.

The vent hole 4 is provided at the intersection 30 of the circumferential grooves 1 and 2 and the radial groove 3, as shown in FIG. Depending on the tire size, for example, 10 to 24 vent holes 4 are provided. The vent holes 4 may be provided on the circumferential grooves 1 and 2 other than the intersection portion 30, that is, the vent holes 4 may be provided in greater numbers than the radial grooves 3.

The vent hole 4 is a through hole extending outward in the tire axial direction D1 from the inner surface S2 of the side mold portion M2. The inner diameter 4d (see FIG. 5) of the vent hole 4 is set to, for example, 0.6 to 2.0 mm.

FIG. 9 is a sectional view showing the side mold part M2 after vulcanization molding. When vulcanization is performed in the tire mold TM, air is released from the vent hole 4, and then the rubber of the unvulcanized tire flows into the vent hole 4. As a result, a protruding spew 9 is formed on the sidewall of the tire T taken out from the tire mold TM after vulcanization molding. However, when the tire T is taken out from the tire mold TM, the formed spew 9 may be torn and remain in the vent hole 4. If the spew 9 remains in a state reaching the inner surface S2 of the side mold portion M2 as shown in FIG. 9, the spew 9 blocks communication between the circumferential groove 1 and the radial groove 3. When the next unvulcanized tire is vulcanized and molded in the state shown in FIG. 9, it is difficult for air to escape near the intersection 30 of the circumferential groove 1 and the radial groove 3, and bare air is likely to occur. As a countermeasure to this problem, increasing the number of radial grooves 3 and vent holes 4 may be considered, but this may deteriorate the tire appearance or increase the amount of rubber to be discarded. Furthermore, if the number of radial grooves 3 is increased, it becomes difficult to secure space for displaying tire size, manufacturing year, week, etc. By providing bypasses (first bypass to third bypass), which will be described later, around the intersection 30, the inventor has achieved a solution in which the spew 9 remains in the vent hole 4 without increasing the radial groove 3 or the vent hole 4. It has been found that the occurrence of bears can be suppressed even in cases where

As shown in FIG. 6, the groove-shaped first bypass 51 is connected to the first portions 11, 21 of the circumferential grooves 1, 2 disposed on the first side D31 in the tire circumferential direction with the vent hole 4 in between and the radial groove. Connected to 3. As a result, if the spew 9 remains in the vent hole 4 provided at the intersection 30 of the circumferential grooves 1, 2 and the radial groove 3, and the communication between the circumferential grooves 1, 2 and the radial groove 3 is interrupted, Also, communication between the circumferential grooves 1 and 2 and the radial groove 3 can be ensured by the first bypass 51. As a result, even if the spew 9 remains in the vent hole 4, air in the vicinity of the intersection 30 can escape easily, and the occurrence of bare air can be suppressed.

Further, the groove-shaped second bypass 52 is connected to the second portions 12, 22 of the circumferential grooves 1, 2 and the radial groove 3, which are arranged on the second side D32 in the tire circumferential direction with the vent hole 4 in between. There is. Similarly to the first bypass 51, even if the spew 9 remains in the vent hole 4 provided at the intersection 30 of the circumferential grooves 1 and 2 and the radial groove 3, the second bypass 52 Since communication between the groove 2 and the radial groove 3 can be ensured, the occurrence of bears can be suppressed.

The first bypass 51 and the second bypass 52 extend in an arc shape. However, from the viewpoint of shortening the bypass path, it is preferable that the first bypass 51 and the second bypass 52 extend linearly as shown in FIG. 10.

It is preferable that the first bypass 51 and the second bypass 52 are connected on the radial groove 3. That is, it is preferable that the first bypass 51 and the second bypass 52 are connected to the radial groove 3 at the same position. This allows the first bypass 51 and the second bypass 52 to communicate with each other, making it easier for air to escape.

A connecting portion 51a between the first bypass 51 and the circumferential grooves 1 and 2, a connecting portion 51b between the first bypass 51 and the radial groove 3, a connecting portion 52a between the second bypass 52 and the circumferential grooves 1 and 2, and The connecting portion 52b between the second bypass 52 and the radial groove 3 is preferably arranged within 15 mm from the center of the vent hole 4. By arranging the connecting portions 51a, 51b, 52a, and 52b within 15 mm from the center of the vent hole 4, air near the intersection portion 30 can be effectively vented.

FIG. 7 is a diagram showing an example of the cross-sectional shape of the circumferential groove 1. As shown in FIG. FIG. 8 is a diagram showing an example of the cross-sectional shape of the radial groove 3. As shown in FIG.

The circumferential groove 1 has a triangular cross-sectional shape that tapers in the depth direction, and its tip is formed by a small circular arc. The depth 1d of the circumferential groove 1 with respect to the inner surface S2 of the side mold part M2 is set to, for example, 0.5 to 1.2 mm. The cross-sectional shape and depth of the circumferential groove 2 may be the same as that of the circumferential groove 1. Note that the inner surface S2 is a surface on which the profile surface of the tire T is formed.

The cross-sectional shape of the radial groove 3 is rectangular, and the tip thereof is formed by a small circular arc. The depth 3d of the radial groove 3 with respect to the inner surface S2 of the side mold portion M2 is set to, for example, 0.5 to 1.2 mm. That is, the depth 3d of the radial groove 3 is approximately the same as the depth 1d of the circumferential groove 1.

Note that the cross-sectional shapes of the circumferential grooves 1 and 2 and the radial groove 3 are not particularly limited, and various shapes can be adopted. When these cross-sectional shapes are tapered in the depth direction, for example, triangular, trapezoidal, or semicircular, resistance is less likely to occur when taking out the vulcanized tire T from the tire mold TM.

Further, the cross-sectional shapes of the first bypass 51 and the second bypass 52 are not particularly limited, and may be the same as the circumferential grooves 1 and 2 or the same as the radial groove 3.

The depths of the first bypass 51 and the second bypass 52 based on the inner surface S2 of the side mold part M2 may be different from those of the circumferential grooves 1 and 2 and the radial groove 3, but it is preferable that they be the same. preferable. That is, the depth of the first bypass 51 and the second bypass 52 based on the inner surface S2 of the side mold part M2 is set to, for example, 0.5 to 1.2 mm. However, the widths of the first bypass 51 and the second bypass 52 are the widths of the circumferential grooves 1 and 2 and the radial groove 3 from the viewpoint of making the protrusions formed by the first bypass 51 and the second bypass 52 less noticeable. It is preferable that it be narrower than

Note that a thin groove (not shown) may be formed in the band-shaped region between the circumferential grooves 1 and 2. The depth of this narrow groove is, for example, 0.3 to 0.6 mm, and is preferably smaller than the depth of the circumferential grooves 1 and 2, the radial groove 3, and the bypasses 51 and 52.

The tire mold TM described above has the above-mentioned circumferential grooves 1 and 2, radial groove 3, vent hole 4, bypass (first bypass 51, first The structure is similar to a normal tire mold except for providing two bypasses 52), and any conventionally known materials, shapes, structures, etc. can be employed in the present disclosure.

<Second embodiment>
Next, a second embodiment of the tire mold TM will be described with reference to FIG. 11. In addition, in FIG. 11, parts with the same reference numerals as those in FIGS. 1 to 10 represent elements having substantially the same configuration or substantially the same function (action) as in the first embodiment, and the description thereof is as follows. Don't repeat.

The side mold parts M2 and M3 according to the present embodiment include a groove-shaped third bypass 53 that extends without intersecting the radial groove 3 and is connected to the first portion 11 and the second portion 12. Thereby, even if the spew 9 remains in the vent hole 4, communication between the first portion 11 and the second portion 12 can be ensured by the third bypass 53, so that occurrence of bare air can be suppressed. Note that, regarding the radial groove 3, communication with the circumferential groove 2 is ensured by a first bypass 51 and a second bypass 52.

The connecting portions 53a and 53b between the third bypass 53 and the circumferential groove 1 are preferably arranged within 15 mm from the center of the vent hole 4. By arranging the connecting portions 53a and 53b within 15 mm from the center of the vent hole 4, air near the intersection 30 can be effectively vented.

[1]
As described above, the tire mold TM according to the first or second embodiment is a tire mold TM having side mold parts M2, M3 for molding the sidewall of the tire T, and the side mold parts M2, M3 are Circumferential grooves 1 and 2 that extend in the tire circumferential direction D3, radial grooves 3 that extend in the tire radial direction D2 and intersect with the circumferential grooves 1 and 2, and intersections of the circumferential grooves 1 and 2 and the radial grooves 3. 30, and a groove connected to the first portions 11, 21 of the circumferential grooves 1, 2 and the radial groove 3, which are arranged on the first side D31 in the tire circumferential direction with the vent hole 4 in between. a groove-shaped first bypass 51 connected to the second portion 12.22 of the circumferential grooves 1 and 2 and the radial groove 3 disposed on the second side D32 in the tire circumferential direction with the vent hole 4 in between; 2 bypasses 52, and at least one of a groove-shaped third bypass 53 that extends without intersecting the radial groove 3 and is connected to the first portion 11 and the second portion 12.

According to this configuration, even if the spew 9 remains in the vent hole 4, the occurrence of bears can be suppressed.

[2]
In the tire mold TM of [1] above, it is preferable that the first bypass 51 and the second bypass 52 extend linearly.

According to this configuration, the bypass path can be shortened and exhaust efficiency can be increased.

[3]
In the tire mold TM of [1] or [2] above, the first bypass 51 and the second bypass 52 are preferably connected on the radial groove 3.

According to this configuration, the first bypass 51 and the second bypass 52 communicate with each other, making it easier for air to escape.

[4]
In any one of the tire molds TM of [1] to [3] above, at least one bypass among the first bypass 51, the second bypass 52, and the third bypass 53, and the circumferential grooves 1 and 2 or the radial groove The connecting portions 51a, 51b, 52a, 52b, 53a, and 53b with the vent hole 4 are preferably arranged within 15 mm from the center of the vent hole 4.

According to this configuration, air near the intersection 30 can be effectively removed.

[5]
Further, the tire T is vulcanized and molded using any one of the tire molds TM of [1] to [4] above.

Although the embodiments of the present disclosure have been described above based on the drawings, it should be understood that the specific configuration is not limited to these embodiments. The scope of the present disclosure is indicated not only by the description of the embodiments described above but also by the claims, and further includes all changes within the meaning and scope equivalent to the claims.

It is possible to apply the structure adopted in each of the above embodiments to any other embodiment. The specific configuration of each part is not limited to the embodiment described above, and various modifications can be made without departing from the spirit of the present disclosure.

Note that the tire mold TM is not limited to the configuration of the embodiment described above, nor is it limited to the effects described above. Further, it goes without saying that the tire mold TM may be modified in various ways without departing from the gist of the present invention. For example, each configuration, each method, etc. of the plurality of embodiments described above may be arbitrarily adopted and combined (each configuration, each method, etc. of one embodiment may be combined with the configuration, method, etc. of another embodiment). Furthermore, it is possible to arbitrarily select one or more of the configurations, methods, etc. related to the various modification examples described below and adopt them to the configurations, methods, etc. related to the embodiments described above. Of course.

In the tire mold TM according to the embodiment described above, the first bypass 51 and the second bypass 52 are connected on the radial groove 3. However, the tire mold TM is not limited to such a configuration. For example, the bypass connected to the circumferential groove 1 and the radial groove 3 is only one of the first bypass 51 or the second bypass 52, and the bypass connected to the circumferential groove 2 and the radial groove 3 is the first bypass 51. Alternatively, only one of the second bypasses 52 may be used.

Furthermore, in the embodiment shown in FIG. 12, for one radial groove 3, a first bypass 51 is provided on the outside in the tire radial direction D2, and a second bypass 52 is provided on the inside in the tire radial direction D2. . According to this configuration, in the tire T after vulcanization molding, the protrusions formed by the first bypass 51 and the second bypass 52 are arranged at different positions in the tire radial direction D2 and the tire circumferential direction D3, so that It is possible to prevent the rigidity from becoming too high in some parts in the tire radial direction D2 and the tire circumferential direction D3, and the rigidity balance of the entire tire is improved.

1... Circumferential groove, 1d... Depth of circumferential groove, 2... Circumferential groove, 3... Radial groove, 3d... Depth of radial groove, 4... Bent hole, 4d... Inner diameter of vent hole, 9... Spew, 11... First part of the circumferential groove, 12... Second part of the circumferential groove, 21... First part of the circumferential groove, 22... Second part of the circumferential groove, 30... Intersection, 51... Second part of the circumferential groove. 1 bypass, 51a... Connection part, 51b... Connection part, 52... Second bypass, 52a... Connection part, 52b... Connection part, 53... Third bypass, 53a... Connection part, 53b... Connection part, TM... Tire mold, M1...Tread mold part, M2...Side mold part, M3...Side mold part, M4...Bead ring, M5...Bead ring, S2...Inner surface of side mold part, T...Tire, S1...Tire equatorial plane, O...Tire Rotating axis, D1... Tire axial direction, D2... Tire radial direction, D3... Tire circumferential direction, D31... Tire circumferential direction first side, D32... Tire circumferential direction second side

Claims (5)

A tire mold having a side mold part for molding a sidewall of a tire,
The side mold portion includes a circumferential groove extending in the circumferential direction of the tire;
a radial groove extending in the tire radial direction and intersecting the circumferential groove;
a vent hole provided at the intersection of the circumferential groove and the radial groove;
a groove-shaped first bypass connected to a first portion of the circumferential groove disposed on the first side in the tire circumferential direction with the vent hole in between and the radial groove; a groove-shaped second bypass connected to the second portion of the circumferential groove and the radial groove disposed on the second side; at least one of the groove-shaped third bypasses connected to the tire mold. The tire mold according to claim 1, wherein the first bypass and the second bypass extend linearly. The tire mold according to claim 1, wherein the first bypass and the second bypass are connected on the radial groove. A connecting portion between at least one of the first bypass, the second bypass, and the third bypass and the circumferential groove or the radial groove is arranged within 15 mm from the center of the vent hole. , The tire mold according to claim 1. A tire vulcanized and molded using the tire mold according to any one of claims 1 to 4.