JP7415513B2 - Tire vulcanization mold and tire manufacturing method - Google Patents

Description

The present invention relates to a tire vulcanization mold and a tire manufacturing method that can contribute to making the amount of vulcanization uniform in each part of the tire and shortening the vulcanization time.

The tire vulcanization mold includes upper and lower side molds that mold the side portions of the tire, and a tread mold that molds the tread portion of the tire.

The upper and lower side molds are heated by upper and lower platen plates that support the side molds. The tread mold is heated by an actuator ring that expands and contracts the tread mold. Note that the upper and lower platen plates and actuator ring each have a built-in heat source that is a steam jacket.

However, in tires, the thickness differs depending on each part such as the tread part and the sidewall part. Therefore, when the temperatures of the heat sources built into the platen plate and the actuator ring are the same, a large amount of heating time is required for the thick tread portion, resulting in a problem that the vulcanization time for the tire as a whole becomes longer. At this time, over-vulcanization occurs in the sidewall portion having a small thickness, leading to non-uniformity in the amount of vulcanization.

Therefore, as described in paragraph 0032 of Patent Document 1 below, by setting the heat source temperature of the platen plate lower than the heat source temperature of the actuator ring, the amount of vulcanization of the tire can be made uniform over the entire tire. It is stated that.

Further, the first example of Patent Document 2 below describes that a hollow annular recess is provided on the outer surface of the mold corresponding to the sidewall portion to suppress the transfer of heat from the heat source to the sidewall portion. ing.

Japanese Patent Application Publication No. 2002-172624 Japanese Unexamined Patent Publication No. 58-49232

However, in a vulcanization mold, when the mold is closed, for example, the side mold and the tread mold are in contact with each other and are thermally conductive.

Therefore, as described in Patent Document 1, even when the heat source temperature of the platen plate is set lower than the heat source temperature of the actuator ring, as conceptually shown in FIG. High-temperature heat from A also circulates to side mold b. Therefore, the amount of heat supplied to the sidewall portion Td of the tire increases, and it is difficult to sufficiently suppress unevenness in the amount of vulcanization.

Also, as described in Patent Document 2, when a hollow annular recess (not shown) is provided on the outer surface of the mold corresponding to the sidewall portion Td, high-temperature heat from the heat source A is transferred to the side mold. It also wraps around b. Therefore, although the heat from the heat source B built into the platen plate c is suppressed, the high-temperature heat that circulates from the heat source A is supplied to the sidewall portion Td, so that unevenness in the amount of vulcanization can be sufficiently suppressed. is difficult.

An object of the present invention is to provide a tire vulcanization mold and a tire manufacturing method that can further contribute to uniformity of the amount of tire vulcanization and shortening of vulcanization time.

The present invention includes a first mold part that receives heat from a first heat source, a second mold part that receives heat from a second heat source, and a first mold part and a second mold part that receive heat from a second heat source. and a heat insulating member disposed between the first mold part and the second mold part.

In the tire vulcanization mold according to the present invention, the first mold part is a tread mold for molding a tread part of the tire, and the second mold part is a tread mold for molding a side part of the tire. It is preferable that it is a side mold for.

In the tire vulcanization mold according to the present invention, the temperature of the first heat source is preferably higher than the temperature of the second heat source.

In the tire vulcanization mold according to the present invention, it is preferable that an internal heat insulating member having a lower thermal conductivity than the side mold is disposed inside the side mold.

In the tire vulcanization mold according to the present invention, the tread mold includes a segment having a tread molding surface and a sector shoe that holds the segment from the outside in the tire radial direction, and the heat insulating member includes the segment and the side It is preferable to include a first heat insulating member disposed between the mold and the mold.

In the tire vulcanization mold according to the present invention, the tread mold includes a segment having a tread forming surface, and a sector shoe that holds the segment from the outside in the tire radial direction, and the heat insulating member includes the sector shoe and the sector shoe. It is preferable to include a second heat insulating member disposed between the side mold and the side mold.

The present invention is a tire manufacturing method, which includes a vulcanization step using the tire vulcanization mold described above.

As described above, in the present invention, a heat insulating member with low thermal conductivity is arranged between the first mold part and the second mold part. Thereby, the influence of heat from the second heat source on the first mold part and the influence of heat from the first heat source on the second mold part can be suppressed.

Therefore, for example, when the temperature of the first heat source is set higher than the temperature of the second heat source, the flow of heat to the second mold part is blocked in the first mold part. Therefore, it is possible to increase the amount of vulcanization of the tire part (the part that becomes the vulcanization rate controlling part) that is vulcanized in the first mold part, and it is possible to shorten the vulcanization time of the tire as a whole. Furthermore, the second mold section blocks the inflow of heat from the first mold section. Therefore, the vulcanization temperature and vulcanization amount of the tire part that is vulcanized in the second mold part can be kept low, and together with the above-mentioned shortening of vulcanization time, over-vulcanization can be suppressed. sell.

Furthermore, even when the temperature of the first heat source and the temperature of the second heat source are the same, heat flow is blocked between the first mold part and the second mold part, It becomes less susceptible to the effects of heat from other heat sources. Therefore, for example, when an internal heat insulating member is provided in the second mold part, the effect of the internal heat insulating member, that is, the effect of reducing the vulcanization temperature at the tire part that is vulcanized in the second mold part, and The effect of reducing the amount of vulcanization can be effectively exhibited, and overvulcanization can be suppressed. In addition, in the first mold part, the amount of vulcanization of the tire part (part that becomes the vulcanization rate controlling part) vulcanized in the first mold part can be increased, and the vulcanization time can be shortened. sell.

BRIEF DESCRIPTION OF THE DRAWINGS It is a partial sectional view which shows one Example of the tire vulcanization mold of this invention. It is a partial sectional view showing the main part together with a heat insulating member. FIG. 7 is a partial cross-sectional view showing another example of the heat insulating member. It is a partial sectional view showing still another example of a heat insulating member. It is a partial sectional view showing still another example of a heat insulating member. FIG. 2 is a partial cross-sectional view showing the effect of the tire vulcanization mold of the present invention. FIG. 2 is a partial cross-sectional view conceptually showing the flow of heat in a conventional tire vulcanization mold.

Embodiments of the present invention will be described in detail below.
As shown in FIG. 1, the tire vulcanization mold 1 of this embodiment includes a first mold part 3 that receives heat from a first heat source 2, and a second mold part 3 that receives heat from a second heat source 4. It includes a mold part 5 and a heat insulating member 6 disposed between the first mold part 3 and the second mold part 5. The tire curing mold 1 is held by a container 7 having a first heat source 2 and a second heat source 4.

In this example, a case is shown in which the tire T is vulcanized and molded in a sideways state (a state in which the tire axis i is oriented vertically).

The tire vulcanization mold 1 includes a tread mold 10 for molding the tread portion Ta of the tire T, upper and lower side molds 11U and 11L for molding the side portion Tb of the tire T, and a bead portion Tc of the tire T. It includes upper and lower bead rings 12U and 12L for molding.

In this example, the tread mold 10 constitutes the first mold part 3, and each side mold 11U, 11L constitutes the second mold part 5, respectively. Then, the tire T is vulcanized and molded in a mold closed state Y in which the tread mold 10 and each of the side molds 11U and 11L are butted against each other.

The tread mold 10 includes a plurality of segments 14 divided in the tire circumferential direction, and a plurality of sector shoes 15 that hold each segment 14 from the outside in the tire radial direction. A tread forming surface Sa for forming the tread portion Ta is arranged on the inner circumferential surface of the segment 14.

The segment 14 is replaceably attached to the sector shoe 15. The tread mold 10 expands and contracts in diameter by integrally moving the segments 14 and the sector shoes 15 in and out in the tire radial direction.

The upper and lower side molds 11U and 11L have side molding surfaces Sb for molding the side portions Tb of the tire T. The side portion Tb includes a sidewall portion Td, and in this example, further includes a region Tc1 outside the bead portion Tc in the tire radial direction. Note that a region Tc2 (including the bead bottom surface) that is radially inner of the tire than the outer region Tc1 is formed by a bead ring 12.

The container 7 includes an upper platen plate 16, a lower platen plate 17, and an actuator ring 18.

The upper side mold 11U is fixed to the lower surface of the upper platen plate 16. The upper platen plate 16 is attached to, for example, a lifting platform (not shown) of a mold device, and can move up and down together with the upper side mold 11U. Further, each sector shoe 15 is held on the upper platen plate 16 via guide means (not shown) so as to be movable in and out of the tire radial direction, for example, in a suspended state.

A lower side mold 11L is fixed to the upper surface of the lower platen plate 17. The lower platen plate 17 is supported by, for example, a table stand (not shown) of a mold device.

The actuator ring 18 is supported so as to be vertically movable relative to the tread mold 10 via another lifting platform (not shown). A cone surface 18S is arranged on the inner peripheral surface of the actuator ring 18. As the actuator ring 18 moves downward, the cone surface 18S slides on the inclined surface 15S of each sector shoe 15, and pushes each sector shoe 15 inward in the tire radial direction until it reaches the mold closed state Y.

The first heat source 2 is built into the actuator ring 18 . Further, a second heat source 4 is built into the upper and lower platen plates 16 and 17, respectively.

As the first heat source 2 and the second heat source 4, in this example, a jacket that is heated by supplying a high-temperature thermal fluid such as steam is employed. A thermal fluid from a thermal fluid supply means (not shown) such as a boiler is supplied to each jacket while being circulated. In this example, separate thermal fluid supply means are connected to the first heat source 2 and the second heat source 4, and the temperature of the first heat source 2 is set to be higher than the temperature of the second heat source 4. be done.

Thereby, heat from the first heat source 2 built into the actuator ring 18 is transmitted to the tread forming surface Sa through the sector shoes 15 and the segments 14. Similarly, heat from the second heat source 4 built in the upper platen plate 16 is transmitted to the side molding surface Sb through the upper side mold 11U, and is transmitted to the second heat source 4 built in the lower platen plate 17. Heat from the heat source 4 is transmitted to the side molding surface Sb through the lower side mold 11L.

In the tire vulcanization mold 1 of this embodiment, a heat insulating member 6 is disposed between the tread mold 10 (first mold part 3) and the side molds 11U and 11L (second mold part 5). be done. The heat insulating member 6 is formed of a member having a lower thermal conductivity than the tread mold 10 (first mold part 3) and the side mold (second mold part 5).

As a result, as shown in FIG. 6, the influence of heat from the second heat source 4 on the tread mold 10 and the influence of heat from the first heat source 2 on the side molds 11U and 11L can be reduced. can. Heat flow from the first and second heat sources 2, 4 is indicated by arrows.

Therefore, when the temperature of the first heat source 2 is set higher than the temperature of the second heat source 4 as in this example, in the tread mold 10, the outflow of heat to the side molds 11U and 11L is suppressed. Therefore, the amount of vulcanization of the tread portion Ta vulcanized in the tread mold 10 can be increased, and the vulcanization time of the tire as a whole can be shortened.

In the side molds 11U and 11L, the inflow of heat from the tread mold 10 is suppressed. Therefore, the vulcanization temperature and amount of vulcanization of the side portions Tb that are vulcanized in the side molds 11U and 11L can be kept low, and together with the shortening of the vulcanization time, over-vulcanization of the side portions Tb can be suppressed. Can be suppressed.

As shown in FIG. 2 as a representative of the lower part of the tire vulcanization mold 1, in this example, the heat insulating member 6 includes a first heat insulating member 20 and a second heat insulating member 21. be done.

The first heat insulating member 20 is arranged between the segment 14 and the side molds 11U and 11L. The first heat insulating member 20 is formed of a member having a thermal conductivity lower than that of the segments 14 and lower than that of the side molds 11U and 11L.

In this example, the segments 14 are formed of the same aluminum material (aluminum, aluminum alloy, etc.) as in the past, considering the workability of the tread forming surface Sa. On the other hand, the sector shoe 15, the side molds 11U, 11L, and the bead rings 12U, 12L are made of the same ferrous material (iron, steel, etc.) as in the past, considering strength and cost. The thermal conductivity of aluminum-based materials is about 100 to 200 (W/m·K), and the thermal conductivity of iron-based materials is about 50 to 60 (W/m·K). Therefore, the first heat insulating member 20 may be made of, for example, a stainless steel material with a thermal conductivity of about 10 to 20 (W/m·K), or a ceramic material (for example, zirconia) with a thermal conductivity lower than that of the stainless steel material. can be suitably adopted.

The first heat insulating member 20 is fixed to an end surface 14S on the inner peripheral surface side of the segment 14 and on the outer side in the tire axial direction than the tread forming surface Sa. In this example, the first heat insulating member 20 is attached to the recess 30 provided in the end surface 14S. At this time, the inner surface 20S of the first heat insulating member 20 in the tire radial direction protrudes beyond the end surface 14S, and when the mold is closed, the first heat insulating member 20 extends over the outer circumferential surface 11S of the side mold 11U, 11L in the tire radial direction. come into contact with. This blocks heat flow between the segment 14 and the side molds 11U and 11L. Note that at a position of the end surface 14S other than the first heat insulating member 20, the end surface 14S and the outer circumferential surface 11S are spaced apart, and an air layer 22 is formed. This air layer 22 blocks heat inflow and outflow more effectively. The air layer 22 is formed so as to be maintained even during thermal expansion during vulcanization. Note that even when the air layer 22 is not formed, the contact area between the end surface 14S and the outer circumferential surface 11S is reduced by the first heat insulating member 20, so that the inflow and outflow of heat can be suppressed.

Note that when the first heat insulating member 20 is fixed to the side molds 11U and 11L, the first heat insulating member 20 comes into contact with the soft segment 14 made of an aluminum-based material every time the mold is closed. This results in the disadvantage that the segment 14 is damaged prematurely.

The second heat insulating member 21 is disposed between the sector shoe 15 and the side molds 11U and 11L. In this example, the second heat insulating member 21 has a disk shape and is attached to the recess 31 provided in the outer peripheral surface 11S of the side molds 11U and 11L in the tire radial direction. The second heat insulating member 21 protrudes outward in the tire radial direction from the outer circumferential surface 11S, and comes into contact with the inner end surface 15ES of the sector shoe 15 in the tire radial direction when the mold is closed. This blocks heat flow between the sector shoe 15 and the side molds 11U and 11L.

In this example, an internal heat insulating member 25 is arranged inside the side molds 11U and 11L. Specifically, a hollow portion 26 is provided in the side molds 11U and 11L, and the internal heat insulating member 25 is filled in the hollow portion 26. As the internal heat insulating member 25, a gas, a fluid, or a solid may be appropriately used as long as it has a lower thermal conductivity than the side molds 11U and 11L. For example, various synthetic resins can be used as the solid material, and in particular, heat-resistant rubber materials are preferably used. Note that metal materials such as stainless steel can also be used, air can be used as the gas, and oil or the like can be used as the fluid.

This internal heat insulating member 25 is disposed at a position facing a portion K of the side portion Tb of the tire T where the rubber thickness is relatively thin (usually a portion centered on the tire maximum width position in the side portion Tb).

The internal heat insulating member 25 suppresses the heat from the second heat source 4 from being transmitted to the portion K where the rubber thickness is thin. Thereby, the effect of reducing the vulcanization temperature and the effect of reducing the amount of vulcanization in the thin portion K can be effectively exhibited, and overvulcanization in the thin portion K can be suppressed.

The tire vulcanization mold 1 of this embodiment can exhibit the following effects when the temperature of the first heat source 2 and the temperature of the second heat source 4 are set to the same temperature.

The heat insulating member 6 blocks heat from flowing in and out between the tread mold 10 and the side molds 11U and 11L. Therefore, when the internal heat insulating member 25 is provided in the side molds 11U and 11L, the vulcanization temperature and the amount of vulcanization are effectively reduced in the thinner rubber portion K of the side portion Tb. and overvulcanization is suppressed. Moreover, in the tread mold 10, since the heat from the first heat source 2 is difficult to escape to the outside, the amount of vulcanization of the tread portion Ta, which is the vulcanization rate-limiting portion, can be increased, and the vulcanization time can be shortened.

Another embodiment of the heat insulating member 6 is shown in FIG. In this example, the heat insulating member 6 is composed of a first heat insulating member 20. In this case as well, the above effect can be achieved because heat flow is blocked between the segment 14 and the side molds 11U and 11L. Separately

FIG. 4 shows yet another embodiment of the heat insulating member 6. In this example, the heat insulating member 6 is composed of the second heat insulating member 21, and heat flow is blocked between the sector shoe 15 and the side molds 11U and 11L. In this case, it is preferable to form an air layer 28 by separating the end surface 14S and the outer peripheral surface 11S. The air layer 28 is formed so as to be maintained even during thermal expansion during vulcanization.

FIG. 5 shows yet another embodiment of the heat insulating member 6. In this example, the side molds 11U and 11L are each divided into a first part 35 that molds the sidewall part Td of the side part Tb, and a second part 36 that molds the outer region Tc1 of the bead part Tc. be done. The first portion 35 is formed of a member having a thermal conductivity lower than that of the segment 14, the sector shoe 15, and the second portion 36.

In this example, the segment 14 and the second portion 36 are made of an aluminum-based material, and the sector shoe 15 is made of an iron-based material. Further, the first portion 35 is formed of a member having a lower thermal conductivity than the segment 14, the sector shoe 15, and the second portion 36, such as a stainless steel material.

At this time, the segment 14 and the sector shoe 15 can be considered as the first mold part 3 that receives heat from the first heat source 2, and the second part 36 can be considered as the second mold part 3 that receives heat from the second heat source 4. It can be regarded as the mold part 5 of In addition, the first part 35 has a lower thermal conductivity than the first mold part 3 and the second mold part 5, and has a lower thermal conductivity than the first mold part 3 and the second mold part 5. It can be considered as a heat insulating member 6 disposed between them.

In this case, the heat from the first heat source 2 is suppressed from flowing out from the tread mold 10, and the amount of vulcanization of the tread portion Ta, which is the vulcanization rate-limiting section, is increased, and the vulcanization time can be shortened. can. In addition, since the heat from the second heat source 4 is difficult to be transmitted to the sidewall portion Td, which is the thin rubber portion K, due to the heat insulating member 6 (first portion 35), excessive heat is generated in the thin rubber portion K. Can suppress sulfur.

Heat from the second heat source 4 is effectively transmitted to the outer region Tc1 of the bead portion Tc via the second portion 36 having high thermal conductivity. The heat from the second heat source 4 is also transmitted to the inner region Tc2 of the bead portion Tc through the second portion 36 and bead rings 12L, 12U. In other words, insufficient vulcanization of the bead portion Tc, which is a portion where the rubber is relatively thick, can be suppressed.

Although particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments, and can be modified and implemented in various ways. Note that the tire T is formed by a tire manufacturing method including a vulcanization process using the tire vulcanization mold 1 described above.

A tire vulcanization mold having the structure shown in FIG. 1 was prototyped based on the specifications shown in Table 1. Then, the vulcanization time and vulcanization amount ratio when vulcanizing a pneumatic tire (205/55R16) using the prototype tire vulcanization mold were evaluated. The test method is as follows.

(1) Vulcanization time:
The time required for the vulcanization amount of each part of the tire to reach the required vulcanization amount was calculated using a computer simulation (simulation based on the "heat transfer calculation method between a mold and a green tire" described in JP 2018-122527A). ).
- Examples A1 and A2 were evaluated using an index with the vulcanization time of Comparative Example A1 as 100.
- Example B1 was evaluated using an index with the vulcanization time of Comparative Example B1 as 100.
The smaller the value, the shorter the vulcanization time and the better the productivity.

(2) Vulcanization amount ratio:
The amount of vulcanization Q1 in the shoulder portion of the tread portion and the amount of vulcanization Q2 in the center portion of the sidewall portion (the portion including the tire maximum width position) are calculated from the calculation results of the above computer simulation, and the ratio Q2/ Comparison was made in Q1. The closer the vulcanization amount ratio (Q2/Q1) is to 1, the more excellent the uniformity of vulcanization is.

As shown in the table, it can be confirmed that the example products can achieve a uniform amount of tire vulcanization and shorten the vulcanization time.

1 Tire vulcanization mold 2 First heat source 3 First mold part 4 Second heat source 5 Second mold part 6 Heat insulating member 10 Tread mold 10S Tread molding surfaces 11U, 11L Side mold 14 Segment 15 Sector shoe 20 First heat insulating member 21 Second heat insulating member 25 Internal heat insulating member T Tire Ta Tread part Tb Side part

Claims (5)

a first mold part that receives heat from a first heat source;
a second mold part that receives heat from a second heat source;
A heat insulating member having a lower thermal conductivity than the first mold part and the second mold part, and disposed between the first mold part and the second mold part. including
The first mold part is a tread mold for molding a tread part of a tire,
The second mold part is a side mold for molding a side part of the tire,
The tread mold includes a segment having a tread molding surface, and a sector shoe that holds the segment from the outside in the tire radial direction,
The heat insulating member includes a first heat insulating member disposed between the segment and the side mold,
the first heat insulating member is fixed to an end surface of the segment on the inner peripheral surface side ;
Tire vulcanization mold. The tire vulcanization mold according to claim 1, wherein the temperature of the first heat source is higher than the temperature of the second heat source. The tire vulcanization mold according to claim 1 or 2 , wherein an internal heat insulating member having a lower thermal conductivity than the side mold is disposed inside the side mold. The tire vulcanization mold according to any one of claims 1 to 3 , wherein the heat insulating member includes a second heat insulating member disposed between the sector shoe and the side mold. A tire manufacturing method comprising a vulcanization step using the tire vulcanization mold according to any one of claims 1 to 4 .

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