Tire mold

Abstract

To provide a tire mold capable of discharging gas accumulated inside the tire mold through the mating surface of the tread mold and the side mold, while securing the strength required of the side mold.SOLUTION: The tire mold 1 has a mold 2 and a mold 3. The inner surface F31 of the mating surface side of the mold 3 is inclined inwardly, and a through hole 5 is formed in the mold 3 which opens to the mating surface side inner surface F31 and the mating surface Fm3. In the mold 3, a connecting groove 6 leading to the through hole 5 is formed in the clamping surface Fm3. The connecting groove 6 forms a connecting passageway R6 leading to the through hole 5 with the molds 2 and 3 being matched. Further, a recess 7 leading to the connecting groove 5 is formed in the mold 3 on the mating surface Fm3. The recess 7 forms a filling space S7 having a larger volume than the total volume of the through hole 5 and the connecting passage R6 as well as leading to the connecting passage R6 when the molds 2 and 3 are aligned.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a tire mold.

Background Art

[0002] As a conventional tire mold, in a tire mold in which the inner surface on the mating surface side of the tread mold and the side mold forms an inclined surface, in order to discharge the air accumulated on the inner surface on the mating surface side of the tire mold in the normal direction of the mold inner surface, a vent hole that leads the inner surface on the mating surface side of the side mold to the mating surface with the tread mold is formed in the side mold (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the vent hole is a through hole that opens obliquely with respect to the mating surface of the side mold. For this reason, simply providing the vent hole in the side mold causes the mating surface of the tread mold to block the vent hole when the tire mold is clamped.

[0005]

[0006] Therefore, the above-mentioned conventional tire mold is provided with a space called a communication opening that communicates with the vent hole on the mating surface of the tread mold and the side mold. Thus, according to the above-mentioned conventional tire mold, the space can communicate the vent hole to the outside of the tire mold.However, when a recess that forms part of the space is formed on the mating surface of the side mold so that the vent hole is directly connected to the space, the position where the recess is formed on the mating surface F of the side mold needs to be set so that the strength required for the side mold is maintained. For this reason, the configuration of directly connecting the vent hole to the space is not effective.

[0007] An object of the present invention is to provide a tire mold capable of discharging the gas accumulated inside the tire mold through the mating surface between the tread mold and the side mold while ensuring the strength required for the side mold.

Means for Solving the Problems

[0008] (1) The tire mold of the present invention is a tire mold including a tread mold and a side mold, wherein the mating surface side inner surface of the inner surface of the side mold that is continuous with the mating surface with the tread mold is inclined inward as it approaches the mating surface with the tread mold. A through hole is formed in the side mold. One end of the through hole opens to the mating surface side inner surface of the side mold, and the other end of the through hole opens to the mating surface with the tread mold. Further, the side mold has a one end communicating with the other end of the through hole on the mating surface with the tread mold, and a communication groove extending outward in the tire axial direction of the side mold is formed from the one end. The communication groove forms a communication path communicating with the through hole in a state where the tread mold and the side mold are combined. Further, the side mold has a recess formed on the mating surface with the tread mold and communicating with the other end of the communication groove. The recess forms a filling space that communicates with the communication path and has a volume larger than the total volume of the through hole and the communication path in a state where the tread mold and the side mold are combined. According to the tire mold of the present invention, it is possible to discharge the gas accumulated inside the tire mold through the mating surface between the tread mold and the side mold while ensuring the strength required for the side mold.

[0009] (2) In the tire mold of (1) above, it is preferable that the filling space is a closed space closed with respect to the outside of the tire mold in a state where the tread mold and the side mold are combined. In this case, since the gas in the tire mold does not flow out to the outside of the tire mold, the tire mold has excellent heat retention and higher strength.

[0010] (3) In the tire mold of (1) or (2) above, it is preferable that a spring vent is disposed inside the through hole. In this case, a tire with suppressed appearance defects such as sprues can be obtained.

[0011] (4) In any one of the tire molds of (1) to (3) above, it is preferable that the concave portion is disposed at a position 20 mm or more away from the inner end of the mating surface with the tread mold toward the outer side in the tire axial direction. In this case, the strength required for the side mold can be easily obtained.

[0012] (5) In any one of the tire molds of (1) to (4) above, it is preferable that the through hole is disposed at a position of 8 mm or less along the inner surface on the mating surface side of the side mold from the inner end of the mating surface with the tread mold. In this case, the strength required for the side mold can be easily obtained.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide a tire mold capable of discharging the gas accumulated inside the tire mold through the mating surface between the tread mold and the side mold while ensuring the strength required for the side mold.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0015] With reference to the drawings, a tire mold which is an exemplary embodiment of the present invention will be described.

[0016] In FIG. 1, a tire mold 1 which is an embodiment of the present invention is schematically shown in a half cross-section. FIG. 1 is shown when viewed from a cross-section in the tire axial direction including the tire central axis O1 of a tire (product tire) molded by the tire mold 1 (hereinafter, also referred to as "view in the tire axial direction cross-section").

[0017] Here, the reference sign O1 is the tire central axis. The tire central axis O1 (hereinafter, also simply referred to as "central axis O1") corresponds to the central axis (rotation center axis) of the product tire. Also, the reference sign O2 is the tire radial axis. The tire radial axis O2 (hereinafter, also simply referred to as "tire radial axis O2") is an axis orthogonal to the tire central axis O1. Further, the reference sign PC is the intersection point of the tire central axis O1 and the tire radial axis O2.

[0018] In the following description, the tire axial direction refers to the direction in which the tire central axis O1 extends or a direction parallel to said direction. Among the tire axial directions, the side closer to the intersection point PC is referred to as the inner side in the tire axial direction, and the side farther from the intersection point PC is referred to as the outer side in the tire axial direction. Further, the tire radial direction refers to the direction in which the tire radial axis O2 extends or a direction parallel to said direction. Among the tire radial directions, the side closer to the intersection point PC is referred to as the inner side in the tire radial direction, and the side farther from the intersection point PC is referred to as the outer side in the tire radial direction. Furthermore, the tire circumferential direction refers to the circumferential direction around the tire central axis O1.

[0019] Referring to FIG. 1, the tire mold 1 includes a tread mold 2 and side molds 3. In the present embodiment, the tire mold 1 includes a pair of side molds 3 on the outer side in the tire axial direction.

[0020] In the present embodiment, the inner surface F2 of the tread mold 2 forms the outer shape of the tread portion of the tire and also forms a part of the outer shape of the shoulder portion of the tire. FIG. 1 exemplarily shows, among the inner surface F2 of the tread mold 2, a tread-side inner surface F21 that forms the tread tread surface of the product tire, and a shoulder-side inner surface F22 that forms a part of the outer surface of the shoulder portion of the product tire.

[0021] Also, in the present embodiment, the inner surface F3 of the side mold 3 forms the remaining part of the outer surface of the shoulder portion of the product tire and also forms the outer surface of the sidewall portion of the product tire. FIG. 1 exemplarily shows, among the inner surface F3 of the side mold 3, a shoulder-side inner surface F31 that forms the remaining part of the outer surface of the shoulder portion of the product tire, and sidewall-side inner surfaces F32, F33 that form the outer surface of the sidewall portion of the product tire.

[0022] In addition, in the present embodiment, the tire mold 1 includes a bead mold 4. In the present embodiment, the tire mold 1 includes a pair of bead molds 4 on the outer side in the tire axial direction. In FIG. 1, the bead mold 4 is shown in a state of being fitted to the side mold 3 on the inner side in the tire axial direction of the side mold 3. FIG. 1 exemplarily shows the inner surface F4 of the bead mold 4 that forms the outer surface of the bead portion of the product tire.

[0023] Furthermore, the tread mold 2 includes a side mating surface Fm2. The side mating surface Fm2 is a mating surface with the side mold 3. On the other hand, the side mold 3 includes a tread side mating surface Fm3. The tread side mating surface Fm3 is a mating surface with the tread mold 2. As shown in FIG. 2, the tire mold 1 according to the present embodiment is clamped in a state where the side mating surface Fm2 of the tread mold 2 and the tread side mating surface Fm3 of the side mold 3 are mated.

[0024] The region X in FIG. 2 is shown enlarged in FIG. 3.

[0025] In the tire mold 1, the mating surface side inner surface (F31) of the inner surface F3 of the side mold 3 that is continuous with the tread side mating surface Fm3 is inclined inward as it goes toward the tread side mating surface Fm3.

[0026] In the present embodiment, the mating surface side inner surface of the side mold 3 is the shoulder side inner surface F31 of the side mold 3. As shown in FIG. 3, the shoulder side inner surface F31 is inclined inward in the tire axial direction as it goes toward the outer side in the tire radial direction in a cross-sectional view in the tire axial direction. Also, in the present embodiment, the tread side mating surface Fm3 of the side mold 3 extends in the tire axial direction in a cross-sectional view in the tire axial direction as shown in FIG. 3.

[0027] The side mold 3 is formed with a through hole 5. One end 5a of the through hole 5 opens to the mating surface side inner surface of the side mold 3, that is, the shoulder side inner surface F31. On the contrary, the other end 5b of the through hole 5 opens to the mating surface with the tread mold 2, that is, the tread side mating surface Fm3.

[0028] In the present embodiment, the through hole 5 extends in the normal direction of the shoulder side inner surface F31 of the side mold 3. That is, in the present embodiment, the through hole 5 extends perpendicular to the shoulder side inner surface F31. In the present embodiment, as shown in FIG. 3, the through hole 5 extends linearly on the plane of the cross section in the tire axial direction. In this case, the through hole 5 communicates with the filling space S7 described later at the shortest distance. However, the through hole 5 can be extended obliquely in the circumferential direction (the direction perpendicular to the drawing in FIG. 3) so as to intersect the cross section in the tire axial direction. Also, the through hole 5 can be meandered in the circumferential direction. That is, the path of the through hole 5 is not particularly limited. Further, in the present embodiment, the cross section perpendicular to the extending direction of the through hole 5, that is, the cross-sectional shape of the flow path of the through hole 5 is circular. However, the cross-sectional shape of the flow path of the through hole 5 can be elliptical, polygonal, or the like.

[0029] Also, the side mold 3 has one end 6a communicating with the other end 5b of the through hole 5 on the mating surface with the tread mold 2, that is, the tread side mating surface Fm3, and a communication groove 6 is formed extending outward in the tire axial direction from the one end 6a. As shown in FIG. 3, the communication groove 6 forms a communication path R6 communicating with the through hole 5 in a state where the tread mold 2 and the side mold 3 are mated.

[0030] In this embodiment, as shown in FIG. 1, the communication groove 6 is a groove formed in the tread mating surface Fm3. As shown in FIG. 1, the communication groove 6 is open to the tread mating surface Fm3 of the side mold 3. In this embodiment, as shown in FIG. 1, in the tire axial direction cross section, the communication groove 6 extends linearly in the tire axial direction. In this embodiment, as shown in FIG. 1, the communication groove 6 extends linearly on the plane of the tire axial direction cross section. In this case, the communication groove 6 communicates with the filling space S7 to be described later at the shortest distance. However, the communication groove 6 can extend obliquely in the circumferential direction (the direction perpendicular to the drawing plane of FIG. 3) so as to intersect the tire axial direction cross section. Also, the communication groove 6 can be meandered in the circumferential direction. That is, the path of the communication groove 6 is not particularly limited either.

[0031] Furthermore, FIG. 4 schematically shows the flow path cross-sectional shape of the communication path R6. In FIG. 4, the straight portion on the upper side of the drawing of the communication path R6 (communication groove 6) corresponds to the tread mating surface Fm3 of the side mold 3. FIG. 4 shows the height of the communication path R6, that is, the depth d of the communication groove 6. Also, FIG. 4 shows the width of the communication path R6, that is, the width w of the communication groove 6. In this embodiment, as shown in FIG. 4, the communication groove 6 is a U-shaped groove. The U-shaped groove is a groove whose cross-sectional shape (flow path cross-sectional shape) is U-shaped. In this embodiment, the groove bottom of the communication groove 6 is formed by a curved surface formed by a curve with a radius of curvature r in the flow path cross-sectional view in terms of the flow path cross section as shown in FIG. 4. The depth d [mm] of the communication groove 6 can be, for example, 0.5 ≦ d ≦ 1.2. Also, the radius of curvature r [mm] can be 0.5 ≦ r ≦ 1.0. However, the communication path R6 can be a groove other than the U-shaped groove. For example, the communication groove 6 can be a V-shaped groove. The V-shaped groove is a groove whose cross-sectional shape (flow path cross-sectional shape) is V-shaped. When the communication groove 6 is a groove other than the U-shaped groove, the width w [mm] of the communication groove 6 can be, for example, 2.5 ≦ w ≦ 3.5.

[0032] Also, referring to FIG. 3, in the present embodiment, the area of the cross section orthogonal to the extending direction of the communication passage R6, that is, the flow path cross-sectional area of the communication passage R6, is different from the flow path cross-sectional area of the through hole 5. For example, the communication passage R6 can be an enlarged flow path by making the flow path cross-sectional area of the communication passage R6 larger than the flow path cross-sectional area of the through hole 5. Also, for example, the communication passage R6 can be a throttled flow path by making the flow path cross-sectional area of the communication passage R6 smaller than the flow path cross-sectional area of the through hole 5.

[0033] In the present embodiment, the flow path cross-sectional shape of the through hole 5 is the same throughout the extending direction of the through hole 5. However, the flow path cross-sectional shape (flow path cross-sectional area) of the through hole 5 can be formed so as to expand as it goes toward the outer side in the tire axial direction, that is, as it goes toward the communication passage R6. Also, the through hole 5 can be formed so that the flow path cross-sectional shape shrinks as it goes toward the outer side in the tire axial direction. That is, in the present embodiment, the flow path cross-sectional shape of the through hole 5 can be expanded or shrunk as it goes toward the outer side in the tire axial direction.

[0034] Also, in the present embodiment, the flow path cross-sectional shape of the communication passage R6 is also the same throughout the extending direction of the communication passage R6. However, the flow path cross-sectional shape (flow path cross-sectional area) of the communication passage R6 can be formed so as to expand as it goes toward the filling space S7 described later, that is, as it goes toward the outer side in the tire axial direction. Also, the communication passage R6 can be formed so that the flow path cross-sectional shape shrinks as it goes toward the outer side in the tire axial direction. That is, in the present embodiment, the flow path cross-sectional shape of the communication passage R6 can be expanded or shrunk as it goes toward the outer side in the tire axial direction.

[0035] Furthermore, for example, referring to FIG. 3, the side mold 3 has a mating surface with the tread mold 2, i.e., a tread-side mating surface Fm3, and a recess 7 that communicates with the other end 6b of the communication groove 6 is formed therein. The recess 7 forms a filling space S7 that communicates with the communication passage R6 and has a volume larger than the total volume of the through-hole 5 and the communication passage R6 when the tread mold 2 and the side mold 3 are mated. Here, in the present embodiment, "the volume of the filling space S7 is larger than the total volume of the through-hole 5 and the communication passage R6" means that, taking the through-hole 5 and the communication groove 6 communicating with the through-hole 5 as one set, the volume of one filling space S7 communicating with the one set is larger than the total volume of the through-hole 5 and the communication passage R6 of the one set.

[0036] In the present embodiment, the filling space S7 is a space filled with gas accumulated inside the tire mold 1 (cavity space). In the present embodiment, among the gases accumulated between the unvulcanized rubber for tire molding and the inner surface (cavity surface) of the tire mold 1, the gas accumulated between the inner surface (F22, F31) of the tire mold 1 that forms the shoulder portion of the product tire and the unvulcanized rubber is exhausted and filled into the filling space S7 through the through-hole 5 and the communication passage R6 from one end 5a of the through-hole 5.

[0037] In the present embodiment, the area of the cross-section orthogonal to the extending direction of the filling space S7, i.e., the flow path cross-sectional area of the filling space S7, is different from the flow path cross-sectional area of the communication passage R6. The filling space S7 is formed as an enlarged space by making the flow path cross-sectional area of the filling space S7 larger than the flow path cross-sectional area of the communication passage R6.

[0038] In the present embodiment, the cross-sectional shape (cross-sectional area) of the filling space S7 is the same throughout the extending direction of the filling space S7. However, the cross-sectional shape of the filling space S7 can be formed so as to expand as it goes toward the outside in the tire axial direction. Further, the filling space S7 can be formed so that the cross-sectional shape thereof shrinks as it goes toward the outside in the tire axial direction. That is, in the present embodiment, the cross-sectional shape of the filling space S7 can be expanded or shrunk as it goes toward the outside in the tire axial direction.

[0039] In the present embodiment, the filling space S7 is a closed space closed with respect to the outside of the tire mold 1 in a state where the tread mold 2 and the side mold 3 are combined.

[0040] In the present embodiment, one end 7a of the recess 7 communicates with the other end 6b of the communication groove 6, and the other end 7b of the recess 7 is closed by a step 3a protruding outward in the tire radial direction. In the present embodiment, the outer step surface (tread side step surface) of the step 3a in the tire radial direction forms the same plane as the tread side mating surface Fm3 of the side mold 3. Thereby, in the present embodiment, the outside in the tire axial direction of the filling space S7 is closed by the step 3a of the side mold 3 as shown in FIG. 3. Specifically, in the present embodiment, the outside in the tire axial direction of the filling space S7 is closed by the tread side step surface of the step 3a of the side mold 3 as the side mating surface Fm2 of the tread mold 2 and the tread side mating surface Fm3 of the side mold 3 in a state where the tread mold 2 and the side mold 3 are combined. Thereby, in the present embodiment, the filling space S7 is a closed space closed with respect to the outside of the tire mold 1. Therefore, in the present embodiment, the gas discharged into the filling space S7 is not discharged to the outside of the tire mold 1. As a result, heated gas is stored in the filling space S7.

[0041] FIG. 5 schematically shows one of the two side molds 3 in an assembled state over the entire circumferential direction of the tire. Note that in FIG. 5, only one through-hole 5 connected to the communication groove 6 is shown, and the other through-holes 5 are shown omitted. As shown in FIG. 5, in the present embodiment, the recess 7 is an annular recess that extends over the entire circumference in the circumferential direction around the tire axial direction axis O1. As a result, the communication groove 6 formed in the tread-side mating surface Fm3 of the side mold 3 communicates with the recess 7 regardless of the position in the circumferential direction. In this case, when arranging the communication groove 6 around the tire axial direction axis O1, the degree of freedom in the arrangement position of the communication groove 6 can be provided. Further, when the recess 7 is annular, the connection with the communication groove 6 (installation of the communication groove 6) becomes easy. In particular, as shown in FIG. 5, when there are a plurality of sets each including a through-hole 5 and a communication groove 6 communicating with the through-hole 5, the degree of freedom in arranging the communication groove 6 is improved, and the communication groove 6 can also be easily installed. However, the recess 7 can be provided intermittently in the circumferential direction without being provided annularly.

[0042] FIG. 6 schematically shows an example of a spring vent applicable to the tire mold 1.

[0043] In the tire mold 1, it is preferable that a vent piece as a check valve is arranged inside the through-hole 5. In the present embodiment, a spring vent 10 as a vent piece is arranged inside the through-hole 5. Examples of the spring vent 10 include a spring vent manufactured by "glebus alloys".

[0044] In this embodiment, the spring vent 10 includes a shaft valve 11, a housing 12, and a spring 13. In this embodiment, the shaft valve 11 is housed inside the housing 12. The lower end portion of the shaft valve 11 functions as a valve body 11a for opening and closing an opening A1 formed at the lower end of the housing 12. The spring 13 is housed inside the housing 12 together with the shaft valve 11. The spring 13 biases the shaft valve 11 toward the inside of the tire mold 1 (the upper side in the drawing of FIG. 6). As a result, in this embodiment, as shown in FIG. 6, the shaft valve 11 is maintained in a state where the valve body 11a of the shaft valve 11 closes the opening A1 of the housing 12. That is, in this embodiment, the spring vent 10 closes the inside of the through hole 5 in its initial state. On the other hand, when the pressure of the gas accumulated inside the tire mold 1 increases, the shaft valve 11 moves toward the side mating surface Fm2 of the tread mold 2 (the lower side in the drawing of FIG. 6) against the biasing force of the spring 13 due to the pressure of the gas. Thereby, the valve body 11a of the shaft valve 11 can open the opening A1 of the housing 12. Therefore, when the pressure of the gas accumulated inside the tire mold 1 rises above a certain level, the spring vent 10 can discharge the gas from the through hole 5 to the filling space S7 through the communication path R6.

[0045] However, the through hole 5 is a through hole that opens obliquely with respect to the tread side mating surface Fm3 of the side mold 3. For this reason, just providing the through hole 5 in the side mold 3 may cause the side mating surface Fm2 of the tread mold 2 to block the through hole 5 when the tire mold 1 is clamped.

[0046] Therefore, if a filling space S7 communicating with the through hole 5 is provided on the mating surface between the tread mold 2 and the side mold 3, the through hole 5 can be communicated with the filling space S7 without blocking the through hole 5. As a result, the gas accumulated inside the tire mold 1 is discharged to the filling space S7 through the through hole 5.

[0047] However, when the filling space S7 is directly connected to the through-hole 5, a recess 7 that forms a part of the filling space S7 is formed in the tread-side mating surface Fm3 of the side mold 3. In this case, the side mold 3, particularly the shoulder-side inner surface F31 of the side mold 3, cannot maintain the strength required for the side mold 3. Therefore, the configuration of directly connecting the through-hole 5 to the filling space S7 is not effective.

[0048] On the other hand, as shown in FIG. 3, the tire mold 1 according to the present embodiment includes a through-hole 5 that passes from the shoulder-side inner surface F31 to the tread-side mating surface Fm3 in the side mold 3. Thereby, in the interior of the tire mold 1, a portion corresponding to the inclined surface of the tire shoulder portion where gas is likely to accumulate can be communicated with the mating surfaces (Fm2, Fm3) of the tread mold 2 and the side mold 3. Further, the tire mold 1 includes a communication groove 6 that communicates with the through-hole 5 on the tread-side mating surface Fm3 of the side mold 3. The communication groove 6 forms a communication path R6 that communicates with the through-hole 5 in a state where the tread mold 2 and the side mold 3 are mated. Thereby, the through-hole 5 can be communicated to the outside in the tire axial direction along the mating surfaces (Fm2, Fm3) of the tread mold 2 and the side mold 3. Furthermore, the tire mold 1 includes a recess 7 that communicates with the communication groove 6 and has a volume larger than the total volume of the through-hole 5 and the communication path R6 on the tread-side mating surface Fm3 of the side mold 3. The recess 7 forms a filling space S7 that communicates with the communication path R6 and has a volume larger than the total volume of the through-hole 5 and the communication path R6 on the outside in the tire axial direction with respect to the communication path R6 in the mating surfaces (Fm2, Fm3) of the tread mold 2 and the side mold 3. Thereby, the recess 7 that forms the filling space S7 having a volume larger than that of the through-hole 5 communicates with the through-hole 5 via the communication groove 6 without being directly connected to the through-hole 5.

[0049] That is, according to the tire mold 1, the filling space S7 having a volume larger than that of the through hole 5 is formed at the position of the tread side mating surface Fm3 of the side mold 3, which is separated from the through hole 5 without being directly connected to the through hole 5. In this case, the side mold 3, particularly the shoulder side inner surface F31 of the side mold 3, the filling space S7 is more separated from the shoulder side inner surface F31 than when the filling space S7 is directly connected to the through hole 5, so that the strength of the side mold 3 can be increased. Therefore, according to the tire mold 1, while ensuring the strength required for the side mold 3, it is possible to discharge the gas accumulated inside the tire mold 1 through the mating surfaces (Fm2, Fm3) of the tread mold 2 and the side mold 3.

[0050] Also, as shown in FIG. 3, in the tire mold 1, the filling space S7 is a closed space closed with respect to the outside of the tire mold 1 in a state where the tread mold 2 and the side mold 3 are combined. In this case, in the mold clamping state, there is no gas passage communicating the through hole 5 with the outside of the tire mold 1. Therefore, in this case, since the gas in the tire mold 1 does not flow out to the outside of the tire mold 1, it has excellent heat retention, and since no extra flow path leading to the outside is required, the tire mold has higher strength.

[0051] Incidentally, in the tire mold 1 according to the present embodiment, a spring vent 10 is disposed inside the through hole 5. The spring vent 10 functions as a check valve for discharging only the gas accumulated inside the tire mold 1. In this case, a tire with suppressed appearance defects such as sprues can be obtained. Also, it is preferable that the spring vent 10 does not project obliquely from the through hole 5 into the tire mold 1 in terms of the aesthetic appearance of the product tire. On the other hand, according to the tire mold 1, the through hole 5 can be extended in the normal direction of the inner surface F31 on the shoulder side of the side mold 3. That is, in the present embodiment, the through hole 5 can be extended perpendicular to the inner surface F31 on the shoulder side. For this reason, according to the present embodiment, the spring vent 10 can also be extended perpendicular to the inner surface F31 on the shoulder side. Therefore, according to the present embodiment, the spring vent 10 does not project obliquely from the through hole 5 into the tire mold 1, and the product tire has excellent aesthetic appearance.

[0052] Further, in the tire mold 1 according to the present embodiment, it is preferable that the recess 7 formed in the tread side mating surface Fm3 of the side mold 3 is disposed at a position 20 mm or more away from the inner end of the mating surface with the tread mold 2, that is, the outer side from the inner end of the tread side mating surface Fm3 of the side mold 3.

[0053] More specifically, as shown in FIG. 3, in the present embodiment, the recess 7 is disposed at a position separated by a dimension L1 in the tire axial direction outward from the inner end 3e in the tire axial direction of the tread side mating surface Fm3 of the side mold 3. In the present embodiment, the dimension L1 is the distance in the tire axial direction between the inner end 3e in the tire axial direction of the tread side mating surface Fm3 and one end 7a (the other end 6b of the communication groove 6) of the recess 7. In the present embodiment, the dimension L1 is a dimension of 20 mm or more.

[0054] When the concave portion 7 is arranged at a position more than 20 mm away from the inner end (3e) of the tread-side mating surface Fm3 of the side mold 3 as in the present embodiment, for example, while arranging the spring vent 10 inside the through hole 5, the strength required for the side mold 3 can be easily obtained.

[0055] Further, in the tire mold 1 according to the present embodiment, it is preferable that the through hole 5 is arranged at a position 8 mm or less along the inner surface on the mating surface side of the side mold 3, that is, along the inner surface F31 on the shoulder side from the inner end of the mating surface with the tread mold 2, that is, the inner end of the tread-side mating surface Fm3 of the side mold 3.

[0056] As shown in FIG. 3, in the present embodiment, the through hole 5 is arranged at a position separated by a dimension L2 in the tire radial direction along the inner surface F31 on the shoulder side from the inner end 3e in the tire axial direction of the tread-side mating surface Fm3 of the side mold 3. In the present embodiment, the dimension L2 is the distance (in this example, the straight-line distance) measured along the inner surface F31 on the shoulder side between the inner end 3e in the tire axial direction of the tread-side mating surface Fm3 and one end 5a of the through hole 5. Specifically, as shown in FIG. 3, the dimension L2 is the distance between the inner end 3e in the tire axial direction of the tread-side mating surface Fm3 and the edge of one end 5a of the through hole 5 that is closer to the tread-side mating surface Fm3. In the present embodiment, the dimension L2 is a dimension of at most 8 mm. More preferably, the dimension L2 is 5 to 6 m.

[0057] When the through hole 5 is arranged at a position 8 mm or less along the inner surface on the mating surface side of the side mold 3, that is, along the inner surface F31 on the shoulder side from the inner end of the tread-side mating surface Fm3 of the side mold 3 as in the present embodiment, for example, while arranging the spring vent 10 inside the through hole 5, the strength required for the side mold 3 can be easily obtained.

[0058] FIG. 7 is a cross-sectional view schematically showing a main part of a tire mold according to another embodiment of the present invention, corresponding to the region X in FIG. 2. Note that parts substantially the same as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0059] Referring to FIG. 7, in the present embodiment, the step 3a of the side mold 3 protrudes toward the tread mold 2 side, that is, radially outward of the tire, so as to form a step on the tread-side mating surface Fm3 of the side mold 3. On the other hand, the tread mold 2 is provided with a step 2a for accommodating the step 3a of the side mold 3. That is, the step 2a of the tread mold 2 is recessed radially outward of the tire. As a result, in the present embodiment, the outer side in the tire axial direction of the filling space S7 is more reliably closed by the contact portion between the radially inner mating surface Fm21 of the step 2a of the tread mold 2 and the radially outer mating surface Fm31 of the step 3a of the side mold 3, and the contact portion between the axially inner mating surface Fm22 of the step 2a of the tread mold 2 and the axially outer mating surface Fm32 of the step 3a of the side mold 3. Therefore, in the present embodiment, the gas discharged into the filling space S7 is not reliably discharged to the outside of the tire mold 1.

[0060] The above description is an exemplary embodiment of the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be variously modified within the scope described in the claims.

[0061] For example, in the side mold 3 according to each of the above embodiments, the through hole 5, and thus the communication groove 6 (communication path R6), can be at least one or more. Specifically, for example, 24 communication grooves 6 can be arranged at intervals in the circumferential direction around the tire central axis O1. Also, for example, 8 to 16 communication grooves 6 can be arranged at intervals in the circumferential direction. The communication grooves 6 can be arranged at arbitrary intervals in the circumferential direction. Also, the communication grooves 6 can be arranged at equal intervals in the circumferential direction.

[0062] Also, in each of the above embodiments, the filling space S7 is a closed space that is closed with respect to the outside of the tire mold 1 in a state where the tread mold 2 and the side mold 3 are combined. However, the filling space S7 can be an open space that is open with respect to the outside of the tire mold 1 in a state where the tread mold 2 and the side mold 3 are combined.

Explanation of Signs

[0063] 1: Tire mold, 2: Tread mold, 2a: Step of tread mold, 3: Side mold, 3a: Step of side mold, 4: Bead mold, 5: Through hole, 5a: One end of through hole, 5b: The other end of through hole, 6: Communication groove, 6a: One end of communication groove, 6b: The other end of communication groove, 7: Recess, 7a: One end of recess, 7b: The other end of recess, 10: Spring vent, 11: Shaft valve, 12: Housing, 13: Spring, F2: Inner surface of tread mold, F21: Inner surface of tread side of tread mold, F22: Inner surface of shoulder side of tread mold, F3: Inner surface of side mold, F31: Inner surface of shoulder side of side mold, F32, F33: Inner surfaces of sidewall side of side mold, F4: Inner surface of bead mold, Fm2: Side mating surface of tread mold (mating surface of tread mold), Fm21: Tire diameter direction inner mating surface of step of tread mold, Fm22: Tire axis direction inner mating surface of step of tread mold, Fm3: Tread side mating surface of side mold (mating surface of side mold), Fm31: Tire diameter direction outer mating surface of step of side mold, Fm32: Tire axis direction outer mating surface of step of side mold, O1: Tire center axis, O2: Tire diameter direction axis, R6: Communication path, S7: Filling space

Claims

1. A tire mold comprising a tread mold and a side mold, wherein the mating surface side inner surface of the inner surface of the side mold that is continuous with the mating surface with the tread mold is inclined inward as it approaches the mating surface with the tread mold; a through hole is formed in the side mold, one end of the through hole opens to the mating surface side inner surface of the side mold, and the other end of the through hole opens to the mating surface with the tread mold; also, the side mold has, on the mating surface with the tread mold, a communication groove that has one end communicating with the other end of the through hole and extends outward in the tire axial direction of the side mold from the one end, and the communication groove forms a communication path communicating with the through hole when the tread mold and the side mold are mated; furthermore, the side mold has, on the mating surface with the tread mold, a recess communicating with the other end of the communication groove, and the recess forms a filling space that communicates with the communication path and has a volume larger than the total volume of the through hole and the communication path when the tread mold and the side mold are mated, the tire mold.

2. The tire mold according to claim 1, wherein the filling space is a closed space closed with respect to the outside of the tire mold when the tread mold and the side mold are mated.

3. The tire mold according to claim 1 or 2, wherein a spring vent is disposed inside the through hole.

4. The tire mold according to claim 1 or 2, wherein the recess is disposed at a position 20 mm or more away from the inner end of the mating surface with the tread mold in the tire axial direction outside.

5. The tire mold according to claim 1 or 2, wherein the through hole is disposed at a position 8 mm or less along the mating surface side inner surface of the side mold from the inner end of the mating surface with the tread mold.

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