Tire vulcanization method and tire vulcanization device

Abstract

To provide a tire vulcanization method and a tire vulcanization device capable of reducing a use amount of steam and improving the quality of a tire.SOLUTION: Provided is a method in which an unvulcanized tire 1 is inserted into a mold 10, steam is supplied as a heating medium to the inside of a bladder 20 inserted into the tire 1, steam-through is performed within a steam supply time, and the tire 1 is vulcanized in a state in which inert gas is supplied as a pressure medium. In the method, an initial temperature T1 of the inside of a pipe 42 supplying steam into the bladder 20 or of the inside of a pipe 82 discharging steam in the bladder 20 is measured at any time from the start of steam supply to the start of steam-through, and a steam-through execution time is controlled based on the initial temperature T1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for vulcanizing pneumatic tires, and more particularly to a tire vulcanizing method and tire vulcanizing apparatus that can reduce the amount of steam used and improve the quality of tires. [Background technology]

[0002] When manufacturing a pneumatic tire, an unvulcanized tire is inserted into a mold, and steam is supplied as a heat medium to the inside of a bladder inserted in the tire, and then the tire is vulcanized while inert gas is further supplied as a pressure medium. When supplying steam, steam through may be performed for a certain period of time. Steam through is a process in which drainage in the bladder is discharged by simultaneously supplying and discharging steam. Such a vulcanization process is a process in which the tire is shaped, the crosslinking reaction of rubber is performed, and the adhesion reaction between components is performed, and is an important process for achieving the desired tire performance. Therefore, in the vulcanization process, it is necessary to suppress the variation in the amount of vulcanization caused by the temperature of the raw tire, the temperature of the vulcanization device, the thickness of the components, the variation in the vulcanization speed of the compound, and the resulting variation in the physical properties of the compound in order to obtain stable quality. In particular, keeping the heat history given to the tire from the vulcanization device constant leads to improved manufacturing quality and stable tire performance.

[0003] Conventionally, it has been proposed to keep the thermal history of a tire constant by varying the total vulcanization time of the tire using the temperature of the raw tire and the temperature of the mold as reference information (see, for example, Patent Documents 1 to 3). However, such a control method does not fully consider the influence of drainage generated by the steam supplied into the bladder. If drainage is present in the bladder, the temperature inside the bladder decreases, and the total vulcanization amount of the tire tends to decrease, which is a factor that affects the quality of the tire. On the other hand, if the execution time of the steam through is set sufficiently long, the drainage in the bladder can be reliably discharged. However, in this case, there is a problem that steam is consumed more than necessary, resulting in energy waste. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-30322 A [Patent Document 2] JP 2017-213719 A [Patent Document 3] Patent No. 5737331 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a tire vulcanizing method and a tire vulcanizing apparatus which make it possible to reduce the amount of steam used and improve the quality of tires. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the tire vulcanization method of the present invention (first invention) comprises inserting an unvulcanized tire into a mold, supplying steam as a heat medium to the inside of a bladder inserted into the tire, performing steam-through within the time period during which the steam is supplied, and vulcanizing the tire while further supplying an inert gas as a pressure medium, characterized in that at any time point between the start of the steam supply and the start of the steam-through, an initial temperature T1 inside the piping that supplies steam into the bladder or inside the piping that discharges the steam from inside the bladder is measured, and the time period during which the steam-through is performed is controlled based on the initial temperature T1.

[0007] In order to achieve the above-mentioned object, the tire vulcanization method of the present invention (second invention) comprises inserting an unvulcanized tire into a mold, supplying steam as a heat medium to the inside of a bladder inserted into the tire, performing steam-through within the time period during which the steam is supplied, and vulcanizing the tire while further supplying an inert gas as a pressure medium, characterized in that at any time from the start of the steam supply to the start of the steam-through, the temperatures inside the pipe that supplies steam into the bladder and the pipe that discharges the steam from inside the bladder are measured, an initial temperature difference ΔT1 between the two pipes is calculated from the temperatures, and the implementation time of the steam-through is controlled based on the initial temperature difference ΔT1.

[0008] In order to achieve the above-mentioned object, the tire vulcanization method of the present invention (third invention) comprises inserting an unvulcanized tire into a mold, supplying steam as a heat medium to the inside of a bladder inserted into the tire, performing steam-through within the time period during which the steam is being supplied, and vulcanizing the tire while further supplying an inert gas as a pressure medium, characterized in that the temperature inside the pipe that supplies steam into the bladder or the inside of the pipe that discharges the steam from the bladder is measured at any time period from the start of the steam supply to the start of the steam-through, an equivalent vulcanization amount U1 to be applied during the time period is calculated from the temperature, and the time period during which the steam-through is performed is controlled based on the equivalent vulcanization amount U1.

[0009] The tire vulcanizing apparatus of the present invention comprises a mold into which an unvulcanized tire is inserted, a bladder inserted into the tire, a steam supply source that supplies steam as a heat medium, a steam supply pipe that guides the steam to the inside of the bladder, an inert gas supply source that supplies an inert gas as a pressure medium, an inert gas supply pipe that guides the inert gas to the inside of the bladder, an exhaust pipe that exhausts the steam and the inert gas in the bladder to the outside of the system, valves that open and close the steam supply pipe, the inert gas supply pipe, and the exhaust pipe, respectively, a temperature sensor that measures the temperature inside the steam supply pipe or the exhaust pipe, and a control unit that controls the vulcanization conditions of the tire, and the control unit is characterized in that it controls the implementation time of the steam through based on the temperature measured by the temperature sensor at any time point or time period from the start of the steam supply to the start of the steam through. Effect of the Invention

[0010] In the tire vulcanization method according to the first invention, the initial temperature T1 inside the pipe supplying steam into the bladder or inside the pipe discharging the steam from the bladder is measured at any time between the start of steam supply and the start of steam through, and the implementation time of steam through is controlled based on the initial temperature T1, so that an appropriate implementation time of steam through can be set for each vulcanization and drainage from the bladder can be efficiently discharged, improving tire quality and stabilizing tire performance. In addition, since an appropriate implementation time of steam through is set for each vulcanization, the amount of steam used can be reduced, leading to reduced energy consumption.

[0011] In the first invention, it is preferable to extend the steam-through implementation time from the standard time when the initial temperature T1 is T-T1>0 with respect to a preset standard temperature T, and to shorten the steam-through implementation time from the standard time when T-T1<0. By performing such control, it is possible to optimize the implementation time of the steam-through, and to achieve both a reduction in the amount of steam used and an improvement in tire quality at a high level.

[0012] In the tire vulcanization method according to the second invention, the temperature inside the pipe supplying steam into the bladder and the temperature inside the pipe discharging the steam from the bladder are measured at any time between the start of steam supply and the start of steam through, the initial temperature difference ΔT1 between the two pipes is calculated from the measured temperature, and the implementation time of the steam through is controlled based on the initial temperature difference ΔT1, so that an appropriate implementation time of the steam through can be set for each vulcanization, and the drainage inside the bladder can be efficiently discharged, thereby improving the quality of the tire and stabilizing the tire performance. Also, since an appropriate implementation time of the steam through is set for each vulcanization, the amount of steam used can be reduced, and energy consumption can be reduced.

[0013] In the second invention, it is preferable to extend the steam-through implementation time from the standard time when the initial temperature difference ΔT1 is ΔT-ΔT1<0 with respect to a preset standard temperature difference ΔT, and to shorten the steam-through implementation time from the standard time when ΔT-ΔT1>0. By performing such control, it is possible to optimize the implementation time of the steam-through, and to achieve both a reduction in the amount of steam used and an improvement in tire quality at a high level.

[0014] In the tire vulcanization method according to the third invention, the temperature inside the pipe supplying steam into the bladder or the temperature inside the pipe discharging the steam from the bladder are measured during any time period between the start of steam supply and the start of steam through, the equivalent vulcanization amount U1 given during the time period is calculated from the temperature, and the steam through execution time is controlled based on the equivalent vulcanization amount U1, so that an appropriate steam through execution time can be set for each vulcanization, and the drainage in the bladder can be efficiently discharged, improving tire quality and stabilizing tire performance. Also, since an appropriate steam through execution time is set for each vulcanization, the amount of steam used can be reduced, and energy consumption can be reduced.

[0015] In the third invention, it is preferable to extend the steam-through execution time from the standard steam-through execution time when the equivalent vulcanization amount U1 is U-U1>0 with respect to a preset standard equivalent vulcanization amount U, and to shorten the steam-through execution time from the standard steam-through execution time when U-U1<0. By performing such control, it is possible to optimize the execution time of the steam-through execution time, and to achieve both a reduction in the amount of steam used and an improvement in tire quality at a high level.

[0016] In the first to third inventions, when multiple vulcanization cycles are repeatedly performed, if the standby time of the vulcanization cycle becomes equal to or exceeds a preset threshold value, the steam-through implementation time can be set equal to or longer than the standard steam-through implementation time in the following one to three vulcanization cycles. When the standby time of the vulcanization cycle becomes equal to or exceeds a preset threshold value, it is assumed that the vulcanization device is in a cold state, and by ensuring sufficient time for steam-through implementation in the following one to three vulcanization cycles, drainage generated due to a long stop can be reliably removed.

[0017] On the other hand, the tire vulcanizing apparatus of the present invention is equipped with a temperature sensor that measures the temperature inside the steam supply pipe or the exhaust pipe, and a control unit that controls the vulcanizing conditions of the tire, and the control unit is configured to control the implementation time of the steam-through based on the temperature measured by the temperature sensor at any time or time period from the start of the steam supply to the start of the steam-through, so that the tire vulcanizing method described above can be implemented. This makes it possible to reduce the amount of steam used and improve the quality of the tires when repeatedly vulcanizing multiple tires. [Brief description of the drawings]

[0018] [Figure 1] 1 is a meridian cross-sectional view showing a tire vulcanizing apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a meridian half cross-sectional view showing a tire vulcanizing apparatus according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a block diagram showing a control system of a tire vulcanizing apparatus according to an embodiment of the present invention. [Figure 4] 1 is a graph showing the change in pipe temperature over time when multiple tires are repeatedly vulcanized in a tire vulcanization method according to an embodiment of the present invention. [Diagram 5] 1 is a graph showing the relationship between pipe temperature and time in a tire vulcanization method according to an embodiment of the present invention. [Figure 6] 11 is another graph showing the relationship between pipe temperature and time in the tire vulcanization method according to the embodiment of the present invention. [Figure 7] 1 is a graph showing the relationship between the equivalent vulcanization amount and the number of vulcanized tires in a tire vulcanization method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings, in which: Figures 1 to 3 show a tire vulcanizing apparatus according to an embodiment of the present invention.

[0020] As shown in Figures 1 and 2, this tire vulcanizing apparatus includes a mold 10 for forming the outer surface of a pneumatic tire 1, a cylindrical bladder 20 inserted inside the pneumatic tire 1, a central mechanism 30 for operating the bladder 20, a heat medium supplying section 40 for supplying steam as a heat medium to the inside of the bladder 20, a pressure medium supplying section 50 for supplying an inert gas as a pressure medium to the inside of the bladder 20, a heating section 60 for heating the mold 10, a driving section 70 for driving the mold 10, and an exhaust section 80 for discharging the steam and inert gas in the bladder 20 to the outside of the system.

[0021] The mold 10 is composed of a lower side plate 11 and an upper side plate 12 for molding the sidewall portion of the pneumatic tire 1, a lower bead ring 13 and an upper bead ring 14 for molding the bead portion of the pneumatic tire 1, and a plurality of sectors 15 for molding the tread portion of the pneumatic tire 1, and the pneumatic tire 1 is vulcanized and molded inside the mold 10. The structure of the mold 10 is not particularly limited, and in addition to a sectional type mold as shown in the figure, a two-split type mold can also be used.

[0022] The central mechanism 30 is composed of a center post 31 that is disposed at the center of the pneumatic tire 1 and configured to be freely raised and lowered in the vertical direction, a lower clamp ring 32 that is disposed so as to be connected to the lower bead ring 13, a cylinder 33 that is disposed between the lower clamp ring 32 and the center post 31, an upper clamp ring 34 that is fixed to the top of the center post 31, and an auxiliary ring 35 that is attached to the upper clamp ring 34. The cylinder 33 is formed with a medium supply path (not shown) for supplying a heat medium and a pressure medium into the bladder 20 and a medium discharge path (not shown) for discharging the heat medium and the pressure medium from the bladder 20.

[0023] The lower end of the bladder 20 is held between the lower bead ring 13 and the lower clamp ring 32, and the upper end of the bladder 20 is held between the upper clamp ring 34 and the auxiliary ring 35. In the vulcanized state as shown in Fig. 1, the bladder 20 is in a state in which it expands toward the outside in the radial direction of the pneumatic tire 1, but when the pneumatic tire 1 is removed from within the mold 10 after vulcanization, the upper clamp ring 34 moves upward, and the bladder 20 is removed from the inside of the pneumatic tire 1 accordingly.

[0024] The heat medium supplying unit 40 is composed of a steam supply source 41 that supplies steam adjusted to a predetermined temperature and pressure as a heat medium, a steam supply pipe 42 that guides the steam to the inside of the bladder 20, and a valve 43 provided in the middle of the steam supply pipe 42. For example, the temperature of the steam is set in the range of 190°C to 220°C, and the pressure of the steam is set in the range of 1760 kPa to 1980 kPa. On the other hand, the pressure medium supplying unit 50 is composed of an inert gas supply source 51 that supplies an inert gas (e.g., nitrogen gas) adjusted to a predetermined temperature and pressure as a pressure medium, an inert gas supply pipe 52 that guides the inert gas to the inside of the bladder 20, and a valve 53 provided in the middle of the inert gas supply pipe 52. For example, the pressure of the inert gas is set to be higher than the pressure of the steam and is in the range of 2180 kPa to 2220 kPa. The heat medium supplied from the heat medium supply unit 40 and the pressure medium supplied from the pressure medium supply unit 50 are introduced into the bladder 20 via the central mechanism 30. The pneumatic tire 1 is pressed from the inside against the inner surface of the mold 10 during vulcanization based on the pressure of the heat medium and pressure medium.

[0025] The heating section 60 is composed of a lower platen 61 attached to the lower side plate 11, an upper platen 62 attached to the upper side plate 12, and a jacket 63 attached to the sector 15. The mold 10 is heated by the heating section 60, whereby the pneumatic tire 1 is vulcanized.

[0026] The drive unit 70 of the mold 10 is configured as follows. The lower side plate 11, together with the lower bead ring 13, is fixed to a lower support plate 71 via the lower platen 61. The upper side plate 12, together with the upper bead ring 14, is fixed to an upper support plate 72. A closing plate 74 equipped with a drive shaft 73 is connected to the center of the upper support plate 72. Therefore, by driving the drive shaft 73 in the vertical direction, the upper side plate 12 and the upper bead ring 14 move in the vertical direction.

[0027] A segment 75 is attached to the back side of each sector 15. The segment 75 is configured to be slidable along a rail formed on the jacket 63, and the sliding surface between the segment 75 and the jacket 63 is inclined with respect to the vertical direction. The jacket 63 is fixed to the drive plate 76 via the upper platen 62. Therefore, by driving the drive plate 76 in the vertical direction, the jacket 63 moves in the vertical direction, and the segment 75 and the sector 15 move in the tire radial direction and the tire axial direction in accordance with the movement of the jacket 63. A slide plate 77 is disposed between the segment 75 and the lower platen 61 to facilitate the movement of the segment 75 in the tire radial direction.

[0028] The exhaust section 80 is composed of an exhaust pipe 82 that guides the steam and inert gas in the bladder 20 to the outside of the system, and a valve 83 provided in the middle of the exhaust pipe 82. The heat medium and pressure medium in the bladder 20 pass through the inside of the central mechanism 30 and are exhausted to the outside of the system via the exhaust section 80.

[0029] In the tire vulcanizing apparatus described above, temperature sensors 91, 92 are installed inside the steam supply pipe 42 and inside the exhaust pipe 82, respectively. The temperature sensors 91, 92 measure the temperature inside the steam supply pipe 42 or the exhaust pipe 82 at any time or time period from the start of steam supply to the start of steam through. Either one of the temperature sensors 91, 92 may be installed, or both may be installed. The temperature sensor 91 that measures the internal temperature of the steam supply pipe 42 is disposed downstream of the valve 43 of the heat medium supply section 40. On the other hand, the temperature sensor 92 that measures the internal temperature of the exhaust pipe 82 is disposed upstream of the valve 83 of the exhaust section 80.

[0030] 3, the control unit 100 is configured to control the driving of the central mechanism 30, the opening and closing of the valve 43 of the heat medium supply unit 40, the opening and closing of the valve 53 of the pressure medium supply unit 50, the heating of the heating unit 60, the driving of the drive unit 70 that drives the mold 10, the opening and closing of the valve 83 of the exhaust unit 80, and the like, to carry out a series of vulcanization steps. In particular, the control unit 100 inputs the temperatures detected by the temperature sensors 91, 92 at any time or time period from the start of the steam supply to the start of the steam through, and controls the implementation time S1 of the steam through based on the temperatures.

[0031] When vulcanizing the pneumatic tire 1 using the tire vulcanizer described above, the unvulcanized pneumatic tire 1 is placed in the mold 10, the bladder 20 is inserted inside the pneumatic tire 1 by operating the central mechanism 30, and steam supplied from the heat medium supply unit 40 is supplied to the inside of the bladder 20 by operating the valve 43 while the valve 83 is closed. At that time, steam through is performed by temporarily opening the valve 83 within the steam supply time Sm. Next, the inert gas supplied from the pressure medium supply unit 50 is introduced into the inside of the bladder 20 by operating the valve 53, and the mold 10 is heated from the outside by the heating unit 60, thereby vulcanizing the pneumatic tire 1.

[0032] When multiple tires 1 are repeatedly vulcanized, the pipe temperatures of the steam supply pipe 42 and the exhaust pipe 82 detected by the temperature sensors 91, 92 change as shown in Fig. 4. Fig. 4 shows the temperature change when three vulcanization cycles are repeatedly performed, a long waiting period is allowed, and then four more vulcanization cycles are repeatedly performed.

[0033] In the first tire vulcanization method, as shown in FIG. 5, at any time from the start of steam supply to the start of steam through, the initial temperature T1 inside the pipe 42 that supplies steam into the bladder 20 or the pipe 82 that discharges the steam from the bladder 20 is measured. Here, the initial temperature T1 is measured at one minute after the start of steam supply. In FIG. 5, the standard time So for steam through is set within the steam supply time Sm. Then, the control unit 100 controls the implementation time S1 of the steam through based on the initial temperature T1. As a result, the implementation time S1 of the steam through appropriate for each vulcanization can be set, and the drain in the bladder 20 can be efficiently discharged, thereby improving the quality of the tire and stabilizing the tire performance. In addition, since the implementation time S1 of the steam through appropriate for each vulcanization is set, the amount of steam used can be reduced, and energy consumption can be reduced.

[0034] In the first tire vulcanization method, as a specific control method by the control unit 100, when the initial temperature T1 is T-T1>0 with respect to a preset standard temperature T, the steam-through execution time S1 (seconds) is extended from the standard time So (seconds) of the steam-through, and when T-T1<0, the steam-through execution time S1 (seconds) is shortened from the standard time So (seconds) of the steam-through. By performing such control, the steam-through execution time S1 can be optimized, and both the reduction of the amount of steam used and the improvement of the tire quality can be achieved at a high level. The standard temperature T is not particularly limited, but can be selected from the range of, for example, 175°C to 210°C in order to provide an ideal thermal history. For example, T=207°C is exemplified. The steam-through standard time So is preferably set in the range of 6 seconds to 300 seconds.

[0035] In the second tire vulcanization method, as shown in FIG. 6, at any time from the start of steam supply to the start of steam through, the temperature Ti inside the pipe 42 that supplies steam into the bladder 20 and the temperature To inside the pipe 82 that discharges the steam from the bladder 20 are measured, and the initial temperature difference ΔT1 (ΔT1=Ti-To) between the two pipes is calculated from these temperatures Ti and To. Here, the initial temperature difference ΔT1 is measured one minute after the start of steam supply. In FIG. 6, the standard time So for steam through is set within the steam supply time Sm. Then, the control unit 100 controls the implementation time S1 of the steam through based on the initial temperature difference ΔT1. As a result, the implementation time S1 of the steam through appropriate for each vulcanization can be set, and the drain in the bladder 20 can be efficiently discharged, thereby improving the quality of the tire and stabilizing the tire performance. In addition, since the implementation time S1 of the steam through appropriate for each vulcanization is set, the amount of steam used can be reduced, and energy consumption can be reduced.

[0036] In the second tire vulcanization method, as a specific control method by the control unit 100, when the initial temperature difference ΔT1 is ΔT-ΔT1<0 with respect to the preset standard temperature difference ΔT, the steam-through execution time S1 (seconds) is extended from the standard time So (seconds) of the steam-through, and when ΔT-ΔT1>0, the steam-through execution time S1 (seconds) is shortened from the standard time So (seconds) of the steam-through. By performing such control, the steam-through execution time S1 can be optimized, and reduction in the amount of steam used and improvement in tire quality can be achieved at a high level. The standard temperature difference ΔT is not particularly limited, but can be selected from the range of, for example, 1°C to 5°C in order to provide an ideal thermal history. For example, ΔT=2°C is exemplified.

[0037] In the third tire vulcanization method, the temperature inside the pipe 42 that supplies steam into the bladder 20 or the temperature inside the pipe 82 that discharges the steam from the bladder 20 is measured in any time period from the start of steam supply to the start of steam through, and the equivalent vulcanization amount U1 given in that time period is calculated from the temperature. For example, FIG. 7 shows the equivalent vulcanization amount U1 (min) at 160°C given in the time period from the start of steam supply to one minute later. The equivalent vulcanization amount U1 corresponds to the amount of heat given in that time period. In continuous vulcanization, the equivalent vulcanization amount U1 given in the above time period varies for each vulcanization. Then, the control unit 100 controls the implementation time S1 of the steam through based on the equivalent vulcanization amount U1. As a result, the implementation time S1 of the steam through appropriate for each vulcanization can be set, and the drain in the bladder 20 can be efficiently discharged, so that the quality of the tire can be improved and the tire performance can be stabilized. In addition, since the implementation time S1 of the steam through appropriate for each vulcanization is set, the amount of steam used can be reduced, and energy consumption can be reduced.

[0038] In the third tire vulcanization method, as a specific control method by the control unit 100, when the equivalent vulcanization amount U1 is a preset standard equivalent vulcanization amount U, when U-U1>0, the steam-through execution time S1 (seconds) is extended from the standard steam-through time So (seconds), and when U-U1<0, the steam-through execution time S1 (seconds) is shortened from the standard steam-through time So (seconds). By performing such control, the steam-through execution time S1 can be optimized, and reduction in steam usage and improvement in tire quality can be achieved at a high level. The standard equivalent vulcanization amount U is not particularly limited, but can be selected from the range of 3 minutes to 7 minutes when the equivalent vulcanization amount at 160°C is used as an index to provide an ideal thermal history. For example, U=4.7 minutes is exemplified.

[0039] In the above-mentioned first to third tire vulcanization methods, when a vulcanization cycle is repeatedly performed a plurality of times, if the standby time of the vulcanization cycle is equal to or longer than a preset threshold value, the steam-through implementation time can be set equal to or longer than the standard steam-through implementation time in the following one to three vulcanization cycles. When the standby time of the vulcanization cycle is equal to or longer than a preset threshold value, it is assumed that the vulcanization device is in a cold state, and by ensuring a sufficient implementation time of the steam-through in the following one to three vulcanization cycles, it is possible to reliably remove drainage generated due to a long-term stop. The threshold value of the standby time of the vulcanization cycle can be set to any value of, for example, 30 minutes or more. For example, 30 minutes is exemplified as the threshold value.

[0040] In the above-mentioned first to third tire vulcanization methods, it is preferable that the steam supply time Sm is constant. This makes it possible to avoid a decrease in productivity due to fluctuations in the vulcanization time. Therefore, it is possible to reduce the amount of steam used and improve the quality of the tire without decreasing the productivity of the tire 1. EXAMPLES

[0041] In a method for vulcanizing a pneumatic tire (tire size: 205 / 55R16) in which an unvulcanized tire is inserted into a mold, steam is supplied as a heat medium to the inside of a bladder inserted into the tire, steam is passed through within the time that the steam is supplied, and an inert gas is further supplied as a pressure medium, a tire vulcanization method of Comparative Example 1 and Examples 1 to 3 was carried out in which the control method of the vulcanization conditions was different when continuously carrying out the vulcanization process of 1000 tires each. In this case, the steam supply time Sm was set to 2.5 minutes, and the standard time So of steam passing was set to 0.1 minutes.

[0042] In Comparative Example 1, the steam-through execution time S1 was constant (0.1 min). In Example 1, the initial temperature T1 inside the pipe supplying steam into the bladder was measured at any time from the start of steam supply to the start of steam-through, and the steam-through execution time S1 was controlled based on the initial temperature T1. In Example 2, the temperature inside the pipe supplying steam into the bladder and the temperature inside the pipe discharging the steam from the bladder were measured at any time from the start of steam supply to the start of steam-through, the initial temperature difference ΔT1 between the two pipes was calculated from these temperatures, and the steam-through execution time S1 was controlled based on the initial temperature difference ΔT1. In Example 3, the temperature inside the pipe supplying steam into the bladder was measured at any time from the start of steam supply to the start of steam-through, the equivalent vulcanization amount U1 given in the time period was calculated from the temperature, and the steam-through execution time S1 was controlled based on the equivalent vulcanization amount U1. However, in Examples 1 to 3, when multiple vulcanization cycles were repeatedly performed, if the waiting time of a vulcanization cycle exceeded a preset threshold value (30 minutes), the steam-through execution time S1 was set to the same as the standard steam-through time So for the subsequent three vulcanization cycles.

[0043] Regarding the above-mentioned tire vulcanization method, the amount of steam used and the rolling resistance of the tire were evaluated by the following evaluation methods. The results are shown in Table 1.

[0044] Steam usage For each tire vulcanization method, the amount of steam used when vulcanizing 1,000 tires was determined. The evaluation results were expressed as an index with the comparative example being 100. The smaller the index value, the less steam used. The smaller the amount of steam used, the less carbon dioxide emissions in the tire manufacturing process.

[0045] Rolling resistance: The tires obtained by each tire vulcanization method were mounted on a wheel with a rim size of 16×7J and mounted on an indoor drum test machine (drum diameter: 1707 mm), and the rolling resistance was measured when the tires were driven at a speed of 80 km / h while being pressed against the drum with a load equivalent to 80% of the maximum load capacity at the air pressure described in the JATMA Yearbook 2022 edition at 210 kPa. The rolling resistance of each tire was then indexed by setting the average value of the rolling resistance in Comparative Example 1 to 100, and the standard deviation σ of the rolling resistance in each tire vulcanization method was obtained. The smaller the standard deviation σ, the more stable the rolling resistance.

[0046] [Table 1]

[0047] As can be seen from Table 1, in the tire vulcanization methods of Examples 1 to 3, compared with Comparative Example 1, the amount of steam used was reduced and the quality of the tires was improved. [Explanation of symbols]

[0048] 1. Pneumatic tires 10. Mold 20 Bladder 30 Central mechanism 40 Heat medium supply section 41 Steam source 42 Steam supply pipe 43 Valve 50 Pressure medium supply section 51 Inert gas supply source 52 Inert gas supply piping 53 Valve 60 Heating section 70 Drive unit 80 Exhaust section 82 Exhaust pipe 83 Valve 91,92 Temperature Sensor 100 Control section

Claims

1. A method for vulcanizing an unvulcanized tire by inserting an unvulcanized tire into a mold, supplying steam as a heat medium to the inside of a bladder inserted into the tire, performing steam-through within the time period during which the steam is supplied, and vulcanizing the tire while further supplying an inert gas as a pressure medium, characterized in that an initial temperature T1 of the inside of a pipe that supplies steam into the bladder or the inside of a pipe that discharges steam from inside the bladder is measured at any time from the start of the steam supply to the start of the steam-through, and the time period during which the steam-through is performed is controlled based on the initial temperature T1.

2. The tire vulcanization method according to claim 1, characterized in that when the initial temperature T1 is T-T1>0 with respect to a preset standard temperature T, the implementation time of the steam-through is extended from the standard time of the steam-through, and when T-T1<0, the implementation time of the steam-through is shortened from the standard time of the steam-through.

3. A method for vulcanizing an unvulcanized tire in a mold, supplying steam as a heat medium to the inside of a bladder inserted into the tire, performing a steam-through within a time period during which the steam is supplied, and vulcanizing the tire while further supplying an inert gas as a pressure medium, characterized in that at any time period from the start of the steam supply to the start of the steam-through, the temperatures inside a pipe that supplies steam into the bladder and the inside of a pipe that discharges the steam from inside the bladder are measured, an initial temperature difference ΔT1 between the two pipes is calculated from the temperatures, and the time during which the steam-through is performed is controlled based on the initial temperature difference ΔT1.

4. The tire vulcanization method according to claim 3, characterized in that when the initial temperature difference ΔT1 is ΔT-ΔT1<0 with respect to a preset standard temperature difference ΔT, the implementation time of the steam-through is extended from the standard time of the steam-through, and when ΔT-ΔT1>0, the implementation time of the steam-through is shortened from the standard time of the steam-through.

5. A method for vulcanizing an unvulcanized tire by inserting an unvulcanized tire into a mold, supplying steam as a heat medium to the inside of a bladder inserted into the tire, performing a steam-through within the time period during which the steam is supplied, and vulcanizing the tire while further supplying an inert gas as a pressure medium, the method comprising the steps of: measuring the temperature inside a pipe that supplies steam into the bladder or the temperature inside a pipe that discharges the steam from inside the bladder during any time period from the start of the steam supply to the start of the steam-through; calculating an equivalent vulcanization amount U1 to be applied during the time period from the temperature; and controlling the time period during which the steam-through is performed based on the equivalent vulcanization amount U1.

6. A tire vulcanization method as described in claim 5, characterized in that when the equivalent vulcanization amount U1 is U-U1>0 with respect to a predetermined standard equivalent vulcanization amount U, the execution time of the steam-through is extended from the standard time of the steam-through, and when U-U1<0, the execution time of the steam-through is shortened from the standard time of the steam-through.

7. A tire vulcanization method as described in any one of claims 1 to 6, characterized in that when repeatedly performing multiple vulcanization cycles, if the waiting time of a vulcanization cycle becomes equal to or longer than a predetermined threshold value, the implementation time of the steam-through in the subsequent one to three vulcanization cycles is set to be equal to or longer than the standard time of the steam-through.

8. a steam supply source for supplying steam as a heat medium; a steam supply pipe for directing the steam to the inside of the bladder; an inert gas supply source for supplying an inert gas as a pressure medium; an inert gas supply pipe for directing the inert gas to the inside of the bladder; an exhaust pipe for discharging the steam and the inert gas in the bladder to the outside of a system; valves for opening and closing the steam supply pipe, the inert gas supply pipe, and the exhaust pipe, respectively; a temperature sensor for measuring a temperature inside the steam supply pipe or the exhaust pipe; and a control unit for controlling the vulcanization conditions of the tire, wherein the control unit controls a duration of the steam through based on a temperature measured by the temperature sensor at any time or time period from the start of the steam supply to the start of the steam through.

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