JP2016137624A - Method for manufacturing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a pneumatic tire, in which a core in a core with tire can be more quickly cooled, and can be vulcanized in a good balance by preventing over-vulcanization of the tire.SOLUTION: A method for manufacturing a pneumatic tire includes: a step to vulcanize in a mold a green tire T1 formed outside a core 1 together with the core 1; a step to take a core 1B with the tire formed by integrating a vulcanized tire T2 and the core 1 out of the mold; and a cooling step to cool the core 1 in the core 1B with the tire taken out of the mold. The cooling step includes a first step in which a coolant is supplied to and circulated in a chamber 20 formed in the core 1, and a second step in which a part of the coolant in the chamber 20 is discharged, and then after a new coolant is replenished in the chamber 20, the coolant in the chamber 20 is circulated therein.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a pneumatic tire, and more particularly to a method for manufacturing a pneumatic tire by vulcanizing a raw tire together with a core.

  Patent Document 1 below proposes a method for manufacturing a pneumatic tire including a step of vulcanizing a raw tire formed on the outside of a core together with a core with a mold. In this manufacturing method, in order to suppress excessive vulcanization of the tire (hereinafter referred to as “overvulcanization”), after vulcanization, a coolant is supplied to the inside of the core with the tire taken out from the mold. The child is cooled.

JP 2013-006367 A

  In the conventional manufacturing method, since the vulcanized tire and the core are in contact with each other for a while, there is a possibility that vulcanization of the inner surface of the tire proceeds until the core is sufficiently cooled. is there. In addition, a part of the refrigerant supplied to the core may stay in the chamber of the core without stirring and become high temperature, and vulcanization on the inner surface of the tire may progress. In order to solve such a problem, it is desired to cool the core faster.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a method for manufacturing a pneumatic tire that can cool the core of the tire-attached core faster and prevent over-vulcanization of the tire. It is said.

  The present invention is a method for producing a pneumatic tire, the step of vulcanizing a raw tire formed on the outside of a core with a mold together with the core, from the mold, A step of taking out the core with the tire integrated with the core, and a cooling step of cooling the core of the taken-out core with the tire, wherein the cooling step is formed inside the core A first step of supplying and circulating a refrigerant into the chamber, and a second step of discharging a part of the refrigerant in the chamber and then replenishing the chamber with a new refrigerant to circulate the refrigerant in the chamber And a process.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that the cooling step is performed the second step a plurality of times.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that the cooling step supplies a refrigerant having a temperature of 25 degrees or less to the chamber.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that a refrigerant filling the chamber is supplied in the first step or the second step.

  In the method for manufacturing a pneumatic tire according to the present invention, the cooling step includes, as the first step, the second step is performed after the refrigerant is circulated in a range of 60 to 180 seconds. desirable.

  In the method for manufacturing a pneumatic tire according to the present invention, the amount of the refrigerant discharged in the second step is preferably 40% to 80% of the amount of the refrigerant stored in the chamber. .

  The method for manufacturing a pneumatic tire according to the present invention includes a step of vulcanizing a raw tire formed on the outside of a core together with a core with a mold, and a vulcanized tire and the core are integrally formed from the mold. A step of taking out the core with tire, and a cooling step of cooling the core with tire taken out.

  The cooling process of the present invention includes a first process of supplying and circulating a refrigerant in a chamber formed inside the core, a part of the refrigerant in the chamber is discharged, and then a new refrigerant is replenished in the chamber. And a second step of circulating the refrigerant in the chamber again.

  In the first step, the refrigerant supplied to the chamber of the core can be circulated, for example, so that the high-temperature refrigerant in contact with the core and the low-temperature refrigerant not in contact with the core can be stirred, and the refrigerant in contact with the core Thus, the efficiency of heat exchange between the core and the refrigerant can be increased.

  On the other hand, in the second step, by discharging a part of the refrigerant in the chamber and then replenishing the chamber with a new refrigerant, for example, a high-temperature refrigerant that stays in the chamber without being stirred in the circulation of the refrigerant, The new low-temperature refrigerant to be replenished in the chamber can be agitated, the temperature of the refrigerant in the chamber can be lowered, and the efficiency of heat exchange between the core and the refrigerant can be increased.

  Therefore, in the manufacturing method of the present invention, the core with the tire can be cooled more quickly, and the overvulcanization on the luminal surface side of the tire can be more reliably suppressed.

It is sectional drawing of the core used with the manufacturing method of this embodiment. It is a bottom view of the core seen from the axial direction. It is the elements on larger scale of the segment of the left side of FIG. It is a schematic diagram of the segment of FIG. 3 for demonstrating a 1st process. (A) is explanatory drawing at the time of circulating a refrigerant | coolant, (B) is explanatory drawing at the time of discharging | emitting a refrigerant | coolant. It is a schematic diagram of the segment of FIG. 3 for demonstrating a 2nd process.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The method for manufacturing a pneumatic tire according to the present embodiment includes a step of vulcanizing a raw tire together with a core with a mold, a step of removing the core with a tire from the mold, and the core of the core with a tire taken out. Cooling process for cooling.

  FIG. 1 shows a cross-sectional view of a core 1 used in the method for manufacturing a pneumatic tire of the present embodiment. FIG. 2 shows a bottom view of the core 1 as viewed from the axial direction. As shown in FIGS. 1 and 2, the core 1 includes, for example, an annular core body 8, a cylindrical inner cylinder 9 that connects the core body 8, and the core body 8 and the inner cylinder 9. A pair of disk-shaped side wall bodies 10U and 10L that hold the two together.

  The core body 8 is composed of a plurality of segments 11 divided in the circumferential direction, and the outer surface thereof is a tire molding surface 8a on which the raw tire T1 is formed.

  The segment 11 includes a first segment 11A in which the circumferential length gradually decreases inward in the radial direction and a second segment 11B in which the circumferential length gradually increases inward in the radial direction. The first segments 11A and the second segments 11B are alternately arranged in the tire circumferential direction.

  On the outside of the core 1, a raw tire T1 is formed in advance. The raw tire T <b> 1 is formed by, for example, an inner liner or a tire constituent member such as a carcass ply that is directly or indirectly attached to the core 1 in accordance with common practice.

  The process of vulcanizing the raw tire T1 is performed by setting the core 1A with the raw tire in a mold (not shown) that is an outer mold and heating. As a result, the raw tire T1 is vulcanized in the cavity between the mold and the core 1, and as a result, the core with tire 1B in which the vulcanized tire T2 and the core 1 are integrated is formed. The

  In the step of taking out the core with tire 1B from the mold, after the mold is opened, for example, the core 1 is held by a transfer device (not shown), and the core with tire 1B is taken out from the mold. As the transfer device, for example, transfer means as described in JP 2014-46645 A is preferably used. The transfer device can hold and move the core 1 through the side walls 10U and 10L. Such a transfer device is also used when setting the core 1A with a raw tire into a mold.

  The cooling step of the present embodiment includes a first step of supplying and circulating a refrigerant to the core 1, and a second step of discharging a part of the refrigerant and then replenishing the new refrigerant to circulate the refrigerant. Including. In the present embodiment, as shown in FIG. 1, the cooling process is performed in a state where the axis of the core with tire 1 </ b> B is vertical.

  In the first step, first, the refrigerant is supplied to the chamber 20 formed inside the core 1. FIG. 3 shows a partially enlarged view of the segment 11 on the left side of FIG. As shown in FIG. 3, each segment 11 of the core 1 has an outer segment portion 16 on the outer side in the radial direction and an inner segment portion 17 adjacent on the inner side in the radial direction. Is formed. In order to form the chamber 20, the outer segment portion 16 includes, for example, a portion formed in a substantially U shape in a sectional view. The outer segment portion 16 and the inner segment portion 17 are fixed via an O-ring or the like, for example. Thereby, the chamber 20 is formed airtight.

  The chamber 20 is in communication with one end 21 a of the first flow path 21, one end 22 a of the second flow path 22, and one end 23 a of the third flow path 23. For example, the one end 23 a of the third flow path 23 is located above the one end 21 a of the first flow path 21 and is located below the one end 22 a of the second flow path 22.

  The other ends 21 b, 22 b, and 23 b of the first flow path 21, the second flow path 22, and the third flow path 23 of the present embodiment are opened on the lower surface of the inner segment portion 17, for example. In FIG. 3, only one is shown as each of the other ends 21b, 22b, and 23b. However, as shown in FIG. 2, these are provided at different positions in the tire circumferential direction.

  As shown in FIG. 3, the first inlet / outlet 35 of the cooling means 33 provided outside the core 1 is connected to the other end 21 b of the first flow path 21. A second entrance / exit 36 of the cooling means 33 is connected to the other end 22 b of the second flow path 22. Similarly, the third inlet / outlet 37 of the cooling means 33 is connected to the other end 23 b of the third flow path 23.

  The cooling means 33 controls, for example, supply and circulation of the temperature-controlled refrigerant. The cooling means 33 supplies the refrigerant, the suction device 39 that sucks the air and the refrigerant in the chamber 20, and the compressed air. The air supply device 40 to be supplied is included. The suction device 39 is connected to the first entrance 35 and the second entrance 36, for example. The refrigerant supply machine 38 and the air supply machine 40 are connected to the 3rd entrance / exit 37, for example so that switching is possible. As the refrigerant of the present embodiment, for example, a fluid such as an antifreeze or water is used, but a gas such as helium may be used.

  In the first step, first, the connection between the first flow path 21 and the first entrance / exit 35 is blocked. Next, the cooling means 33 supplies the refrigerant into the chamber 20 through the third flow path 23 and discharges the air in the chamber 20 through the second flow path 22. Thereby, a refrigerant | coolant is supplied in the chamber 20 (refer the schematic of FIG. 4).

  As shown in FIGS. 3 and 4, one end 22 a of the second flow path 22 communicates with the uppermost portion of the chamber 20, for example. One end 22 a of the second flow path 22 of the present embodiment communicates with an air reservoir 25 that locally protrudes above the chamber 20. According to such a configuration, more air in the chamber 20 can be discharged, and the chamber 20 can be filled with more refrigerant 41. The air reservoir 25 of a more preferable aspect is locally provided on the inner side in the tire radial direction of the chamber 20 in order to increase the efficiency of heat exchange between the core 1 and the refrigerant 41 in the chamber 20. In a more preferable aspect, the ceiling surface 20 </ b> U of the chamber 20 connected to the air reservoir 25 is formed with an upward slope toward the air reservoir 25. Thereby, the air in the chamber 20 travels through the ceiling surface 20U and accumulates in the air reservoir 25.

  In the first step, as shown in FIG. 5A, for example, when the refrigerant 41 continues to be supplied to the chamber 20 via the third flow path 23, the refrigerant 41 It reaches one end 22 a and is discharged to the outside of the chamber 20 through the second flow path 22. For example, the discharged refrigerant 41 is returned to the refrigerant supplier 38 via the suction device 39 and cooled in the refrigerant supplier 38. The cooled refrigerant 41 is supplied to the chamber 20 through the third flow path 23. Thereby, the refrigerant 41 is circulated along a normal path including the chamber 20. When the refrigerant 41 is discharged from the chamber 20 while supplying the refrigerant 41 to the chamber 20, for example, the new refrigerant 41 is supplied from the outside to the refrigerant supplier 38, and the refrigerant 41 is transferred from the suction device 39 to the outside. A mode of discharging may be used.

  As described above, in the first step, by circulating the refrigerant 41 supplied to the chamber 20 of each core 1, for example, the high-temperature refrigerant 41 that contacts the core 1 and the low temperature that does not contact the core 1. The refrigerant 41 can be stirred, the temperature of the refrigerant 41 in contact with the core 1 is lowered, the efficiency of heat exchange between the core 1 and the refrigerant 41 is increased, and the cooling of the core 1 is promoted.

  Although the temperature of the refrigerant | coolant 41 is not specifically limited, For example, it is preferable that it is 25 degrees C or less. When the temperature of the refrigerant 41 is higher than 25 ° C., there is a possibility that the cooling time of the core 1 may be prolonged, and as a result, the inner surface of the tire may be excessively vulcanized. On the other hand, when the excessively cold refrigerant 41 is supplied to the core 1, the service life of the core 1 may be shortened, and the temperature of the refrigerant 41 is preferably 5 ° C. or more, for example.

  In the first step of the preferred embodiment, the refrigerant 41 is circulated and supplied in a range of 60 to 180 seconds, for example, in order to maintain the refrigerant 41 in the chamber 20 of the core 1 at a low temperature.

  FIG. 6 shows a schematic diagram of the segment 11 for explaining the second step. As shown in FIG. 6, in the second step, the first flow path 21 and the first entrance / exit 35 are connected. On the other hand, the connection of the third flow path 23 is switched to the air supply unit 40 (or outside air may be used) via the third entrance 37.

  In the second step, first, as shown in FIG. 5B, the refrigerant 41 in the chamber 20 is discharged through the first flow path 21. The discharged refrigerant 41 is discharged to the outside through, for example, a suction device 39. In addition, the discharged | emitted refrigerant | coolant 41 may be returned to the refrigerant | coolant supply machine 38 via the suction device 39, for example, and may be stored. In addition, the refrigerant 41 is discharged, and air is supplied to the chamber 20 from the air supply unit 40 via the third flow path 23. This supply of air may be performed via the second flow path 22, for example.

  Next, in the second step, the connection of the first inlet / outlet 35 is connected to the refrigerant supplier 38. On the other hand, the second entrance 36 is connected to the suction machine 39. As a result, as shown in FIGS. 4 and 5A, new refrigerant 41 is replenished into the chamber 20 again through the first flow path 21, and the air in the chamber 20 flows into the second flow. It is discharged via the path 22. Thereafter, the refrigerant 41 is circulated along a normal path including the chamber 20.

  In the second step described above, a part of the refrigerant 41 in the chamber 20 is discharged, and then, the chamber 20 is replenished with a new refrigerant 41. For example, the corner of the chamber 20 is not stirred in the circulation of the refrigerant 41. The high-temperature refrigerant 41 staying in the section or the like and the refrigerant replenished to the chamber 20, for example, the lower-temperature refrigerant 41 can be stirred, the temperature of the refrigerant 41 in the chamber 20 can be lowered, and heat exchange between the core 1 and the refrigerant 41 Can increase the efficiency. Therefore, in the manufacturing method of the present embodiment, the core 1 of the tire-equipped core 1B can be cooled more quickly, and overvulcanization on the inner cavity surface side of the tire can be more reliably suppressed.

  In a more preferred embodiment, the second step is repeated a plurality of times. By repeating the second step, the refrigerant 41 staying in the chamber 20 without being agitated by the circulation of the refrigerant 41 can be more reliably agitated with the newly refilled refrigerant 41. For example, the core 1 is sufficiently cooled. Until this is done, the refrigerant 41 can always be kept at a low temperature.

  In order to exhibit the above-mentioned action more effectively, in the second step, the refrigerant 41 is circulated and supplied in the range of 60 to 180 seconds. When the second step is repeated a plurality of times, the time for which the refrigerant 41 is circulated is, for example, as the core 1 is cooled in order to maintain a large temperature difference between the core 1 and the refrigerant 41. Therefore, it is desirable to shorten it sequentially.

  In order to cool the core 1 more quickly, in the second step, the amount of the refrigerant 41 discharged from the chamber 20 is in the range of 40% to 80% of the amount of the refrigerant 41 stored in the chamber 20. Is desirable. When the discharged refrigerant 41 is less than 40%, the refrigerant in the chamber 20 may not be sufficiently stirred, and the temperature of the refrigerant 41 in the chamber 20 may not be sufficiently lowered with newly refilled refrigerant. is there. On the other hand, when the amount of the refrigerant 41 to be discharged is more than 80%, the temperature of the refrigerant 41 in the chamber 20 temporarily increases while the new refrigerant is replenished in the chamber 20, and the cooling efficiency of the core 1 May decrease. In addition, when the second step is repeated a plurality of times, it is desirable that the amount of the refrigerant 41 discharged from the chamber 20 is sequentially decreased. Thereby, the heat exchange loss accompanying discharge | emission of a refrigerant | coolant can be made small as much as possible.

  The second step of the present embodiment is desirably performed until, for example, the temperature of the core 1 reaches about 35 to 45 degrees. Since the core 1 cooled in this way is thermally contracted, the tire can be easily removed from the core 1B with a tire.

  In the present embodiment, when the core 1 is sufficiently cooled by one or more second steps, a step of discharging the refrigerant 41 from the chamber 20 of the core 1 is performed. In this step, for example, the third flow path 23 is connected to the air supply device 40 via the second inlet / outlet 36. Thereby, compressed air is supplied into the chamber 20 through the third flow path 23, and the refrigerant 41 in the chamber 20 is effectively discharged from the first flow path 21.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to these embodiment, It can deform | transform and implement in a various aspect.

By the manufacturing method of the present invention, a pneumatic tire based on the specifications in Table 1 was prototyped and its performance was tested. In addition, the tire of the comparative example was prototyped by a manufacturing method including a cooling process in which the refrigerant was circulated in the chamber of the core with tire after vulcanization.
Common specifications and test methods are as follows.
Tire size: 245 / 45R18
Core temperature at the start of the cooling process: 155 degrees Core temperature at the end of the cooling process: 35 degrees Refrigerant circulation time in the first process: 100 seconds

<Uniformity of vulcanization amount>
The rubber physical property of each part of the sample tire was measured, and the vulcanization amount of each tire part was compared based on the measured rubber physical property, and the uniformity of the vulcanization amount in the entire tire was evaluated. The evaluation is shown in three stages of good, good, and bad that make the uniformity of the vulcanization amount of the tire of Example 1 good.

  As a result of the test, it can be confirmed that the tire of the example is suppressed in terms of over-vulcanization of the tire and vulcanized in a well-balanced manner as compared with the tire of the comparative example.

1 core 1B core with tire 20 chamber T1 raw tire T2 tire

Claims (6)

A pneumatic tire manufacturing method comprising:
Vulcanizing the raw tire formed on the outside of the core together with the core with a mold;
A step of taking out a core with a tire in which a vulcanized tire and the core are integrated from the mold; and
A cooling step of cooling the core of the core with a tire taken out,
The cooling step includes a first step of supplying and circulating a refrigerant in a chamber formed inside the core;
And a second step of discharging a part of the refrigerant in the chamber and then replenishing the chamber with a new refrigerant to circulate the refrigerant in the chamber.   The said cooling process is a manufacturing method of the pneumatic tire of Claim 1 which implements a said 2nd process in multiple times.   The method for manufacturing a pneumatic tire according to claim 1, wherein the cooling step supplies a refrigerant having a temperature of 25 degrees or less to the chamber.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein a refrigerant that fills the chamber is supplied in the first step or the second step.   5. The pneumatic tire according to claim 1, wherein, in the cooling step, the second step is performed after the refrigerant is circulated in a range of 60 to 180 seconds as the first step. Production method.   The pneumatic tire according to any one of claims 1 to 5, wherein in the second step, the amount of the refrigerant discharged is 40% to 80% of the amount of the refrigerant stored in the chamber. Production method.

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