JP2006026925A - Tire vulcanizing method and tire vulcanizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire vulcanizing method for obtaining a tire throughout homogeneous in its degree of vulcanization by eliminating the temperature difference within a bladder at the time of vulcanization by the minimum purge, and a tire vulcanizer. <P>SOLUTION: In the tire vulcanizer equipped with a heating medium supply means 32 for supplying a heating medium into the bladder 6, a pressure medium supply means 33 for supplying a pressure medium into the bladder 6 and the exhaustion means 35 for purging communicating with the bladder 6, a link mechanism 22, which is freely expansible in a tire diameter direction from bladder clamp rings 12 and 16 and arranges temperature sensors 21a and 21b at two different height places in the bladder 6 at the time of vulcanization, and a control part 28 for controlling the exhaustion means 35 for purging on the basis of the temperature difference are provided. When the temperature difference arrives at a predetermined threshold value, a part of a mixed medium is discharged from the bladder 6 and the heating medium or the pressure medium is introduced into the bladder 6 to eliminate the temperature difference in the bladder 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for vulcanizing a tire in a state where a mixed medium of a heating medium and a pressure medium is supplied into a bladder inserted inside the tire, and more specifically, a temperature in the bladder during vulcanization. The present invention relates to a tire vulcanizing method and a tire vulcanizing apparatus in which a difference is eliminated with a minimum purge and a tire having a uniform vulcanization degree is obtained.

  In vulcanizing a tire, after shaping the green tire to the shape of the inner surface of the mold by filling the shaping pressure inside the bladder, the tire is vulcanized with a heating medium and a pressure medium supplied to the bladder. . However, in the method of vulcanizing the tire in a state where a heating medium (steam) is supplied into the bladder and then a pressurized medium (nitrogen gas) is supplied, if the flow of the mixed medium in the bladder stops, A layer mainly composed of steam is formed above the upper layer, while a layer mainly composed of nitrogen gas is formed below the upper layer, resulting in a difference in temperature between the upper and lower sides in the bladder, resulting in a decrease in tire quality and productivity. There is an inconvenience. That is, the degree of vulcanization of the tire differs depending on the position in the vertical direction in the mold, or it is necessary to lengthen the vulcanization time in order to completely vulcanize the insufficiently vulcanized portion.

  In order to eliminate such inconvenience, the mixed medium in the bladder is discharged from the piping with the orifice, and at the same time, the pressurized medium is introduced into the bladder, and so-called gas purge is used to eliminate the upper and lower temperature difference in the bladder. Has been proposed (see, for example, Patent Document 1).

However, if the timing for performing the gas purge is not appropriate, the temperature difference between the upper and lower sides in the bladder cannot be effectively eliminated. That is, if the timing for performing the gas purge is too late, the difference in temperature between the upper and lower sides in the bladder will be enlarged and the quality and productivity of the tire will be reduced. If the number of times of performing the gas purge is excessive, a pressurized medium such as nitrogen gas will be used. Will be wasted. If the vulcanization conditions are always the same, it is possible to set an optimal timing for performing the gas purge in advance. However, since the vulcanization conditions are not always the same, it is necessary to optimize the gas purge timing in accordance with the actual vulcanization conditions.
JP-A-3-212010

  An object of the present invention is to provide a tire vulcanizing method and a tire vulcanizing apparatus that can eliminate a temperature difference in a bladder during vulcanization with a minimum purge and obtain a tire having a uniform vulcanization degree in the vertical direction. There is to do.

  In order to achieve the above object, the tire vulcanizing method of the present invention is a method of vulcanizing a tire in a state where a mixed medium of a heating medium and a pressure medium is supplied into a bladder inserted inside the tire. Two temperatures having different inner heights are detected during vulcanization, and when the temperature difference reaches a predetermined threshold, a part of the mixed medium is discharged from the bladder and the heating medium or the pressurizing at the same time. A medium is introduced into the bladder to eliminate a temperature difference in the bladder.

  Further, the tire vulcanizing apparatus of the present invention for carrying out the tire vulcanizing method includes a heating medium supply means for supplying a heating medium into a bladder inserted inside the tire, and a pressure medium in the bladder. In a tire vulcanizing apparatus comprising a pressurized medium supply means for performing a purge exhaust means communicating with the bladder, a pair of temperature sensors for detecting the temperature in the bladder, and a tire diameter from a bladder clamp ring The purge exhaust based on the difference in temperature detected by the pair of temperature sensors, and a link mechanism that can be expanded in the direction and is installed at two places where the temperature sensors are vulcanized at different heights in the bladder. And a control unit for controlling the means.

  In this way, the temperature in two places with different heights in the bladder is detected at the time of vulcanization, and when the temperature difference reaches a predetermined threshold, purging with a heating medium or a pressure medium is performed. The temperature difference in the bladder can be eliminated with a minimum purge, and a tire with a uniform vulcanization degree can be obtained. That is, the purge timing can be optimized according to the actual vulcanization conditions.

  Further, according to the tire vulcanizing apparatus, a pair of temperature sensors detect two temperatures at different heights in the bladder during vulcanization, and control is performed by the control unit when the temperature difference reaches a predetermined threshold value. When the purge means for purging is purged, the temperature difference in the bladder during vulcanization can be eliminated with a minimum purge, and a tire with a uniform vulcanization degree can be obtained.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view showing a tire vulcanizing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the tire vulcanizing apparatus includes a lower mold 1 and an upper mold 2 for forming a sidewall portion of a tire, and a lower bead ring 3 and an upper bead for forming a tire bead portion. A ring 4 and a plurality of sectors 5 for molding a tire tread are provided, and the tire T is vulcanized and molded in these molds. At the time of vulcanization, the bladder 6 is inserted inside the tire T.

  A drive shaft 7 slidable in the vertical direction is installed at the center of the mold. A lower bladder clamp ring 12 is disposed below the drive shaft 7 with various ring-shaped members 8, 9, 10, 11 interposed therebetween. The lower bladder clamp ring 12 holds the lower end portion of the bladder 6 together with the lower bead ring 3. The ring-shaped member 9 is formed with at least one intake hole 9a and at least one exhaust hole 9b for connecting the inside and the outside of the bladder 6. On the other hand, an upper bladder clamp ring 16 is fixed to the upper portion of the drive shaft 7 via a bolt 13, a cap 14, and a holder 15. The upper bladder clamp ring 16 holds the upper end portion of the bladder 6 together with the auxiliary ring 17.

  In the above tire vulcanizing apparatus, the pair of upper and lower bladder clamp rings 12 and 16 are installed at two locations that are expandable in the tire radial direction and have different heights in the bladder 6 during vulcanization. A link mechanism 22 is attached. The link mechanism 22 includes a pair of upper and lower pedestals 23 a and 23 b fixed to the bladder clamp rings 12 and 16, bent swing arms 24 a and 24 b that are swingably attached to the pedestals 23 a and 23 b, and a swing A joint arm 25 that connects the intermediate portions of the arms 24a and 24b to each other, and flexible spring arms 26a and 26b attached to the distal ends of the swing arms 24a and 24b are provided. The temperature sensors 21a and 21b are attached to the tip ends of the spring arms 26a and 26b.

  Further, a wiring 27 is connected to the temperature sensors 21a and 21b, and the wiring 27 is drawn to the outside through the lower bladder clamp ring 12. The detection results from the temperature sensors 21 a and 21 b are supplied to the control unit 28 via the wiring 27.

  FIG. 2 is a sectional view showing the link mechanism 22 extracted. As shown in FIG. 2, when the mold is closed and the distance between the bladder clamp rings 12 and 16 is reduced, the swing arms 24a and 24b protrude outward in the tire radial direction, and the temperature sensors 21a and 21b are connected to the bladder. It arrange | positions in two places where the height in 6 differs. In this embodiment, the swing arms 24a and 24b are curved outward in the tire axial direction, and the temperature sensors 21a and 21b are disposed at the highest position and the lowest position in the bladder 6, respectively. On the other hand, the swing arms 24a and 24b are retracted inward in the tire radial direction when the distance between the bladder clamp rings 12 and 16 is widened with the mold opened. In this state, the tire T can be easily taken in and out.

  FIG. 3 is an explanatory view schematically showing piping of the tire vulcanizing apparatus. As shown in FIG. 3, a shaping gas supply source 31b is connected to the intake hole 9a via a valve 31a, a heating medium supply source 32b is connected via a valve 32a, and a pressurized medium supply is supplied via a valve 33a. A source 33b is connected. The valve 32a and the heating medium supply source 32b constitute a heating medium supply means 32 and supply a heating medium such as steam. The heating medium is a medium that mainly shares heating, but may contribute to pressurization. About a heating medium, it is good to set temperature to the range of 175-207 degreeC, and set a pressure to 0.8-1.7 MPa. On the other hand, the valve 33a and the pressurized medium supply source 33b constitute a pressurized medium supply means 33, and supply a pressurized medium such as nitrogen gas. The pressurizing medium is a medium that mainly applies pressurization, but may contribute to heating. About a pressurization medium, it is good to set temperature to the range of 20-60 degreeC, and set a pressure to 1.0-2.5 MPa.

  A main blow pipe 34b is connected to the exhaust hole 9b via a valve 34a, a purge blow pipe 35b is connected via a valve 35a, and a vacuum 36b is connected via a valve 36a. In addition, an orifice 35c is provided on the upstream side of the valve 35a to reduce the flow rate. The valve 34a and the main blow pipe 34b constitute the main exhaust means 34, and exhaust after vulcanization. The valve 35a, the purge blow pipe 35b, and the orifice 35c constitute a purge exhaust means 35 for exhausting the purge. The valve 36a and the vacuum 36b constitute deaeration means 36, and perform pressure reduction for contracting the inside of the bladder 6 when the tire T is taken out after vulcanization.

  Opening and closing of the valves 31a to 36a is controlled by the control unit 28 described above. In particular, the timing of the purge by the purge exhaust means 35 is controlled based on the temperature difference detected by the pair of temperature sensors 21a and 21b. That is, purging is performed when the temperature difference reaches a predetermined threshold value.

  Next, a tire vulcanizing method using the above-described tire vulcanizing apparatus will be described. First, the unvulcanized tire T is shaped by the bladder 6 and then the mold is closed. At this time, the temperature sensors 21 a and 21 b are arranged at two locations in the bladder 6 where the heights in the vertical direction are different by the link mechanism 22. Next, a high-temperature and high-pressure heating medium (steam) is supplied from the heating medium supply source 32b into the bladder 6, and the mold is heated by a heating means (not shown) to start vulcanization. After a predetermined time has elapsed, a pressurized medium (nitrogen gas) higher in pressure than the heating medium is supplied from the pressurized medium supply source 33b into the bladder 6 at room temperature.

  When the mixed medium of the heating medium (steam) and the pressurized medium (nitrogen gas) is supplied into the bladder 6 as described above, when the flow of the mixed medium stops, the steam is mainly disposed above the internal space of the bladder 6. Is formed, and a layer mainly composed of nitrogen gas is formed therebelow, and a temperature difference between the upper and lower sides is generated in the bladder 6.

  In the tire vulcanizing apparatus, the pair of temperature sensors 21a and 21b detect two temperatures at different heights in the bladder 6 during vulcanization, and when the temperature difference reaches a predetermined threshold, The valve 35a of the purge exhaust means 35 is opened by the instruction. Thereby, a part of the mixed medium is discharged from the inside of the bladder 6 through the purge blow pipe 35b, and at the same time, a heating medium (steam) or a pressurized medium (nitrogen gas) is introduced into the bladder 6 to perform a gas purge, The temperature difference in the bladder 6 is eliminated. Such gas purge is repeated every time the temperature difference reaches a predetermined threshold in the vulcanization process.

  The threshold value of the temperature difference in the bladder 6 is preferably set smaller as the vulcanization temperature increases. That is, the influence on the degree of vulcanization due to the temperature difference is relatively small when the vulcanization temperature is low, but the influence on the degree of vulcanization due to the temperature difference becomes large when the vulcanization temperature is high. Therefore, if the threshold value of the temperature difference is set smaller as the vulcanization temperature increases, the influence on the vulcanization degree due to the temperature difference can be effectively eliminated.

  According to the tire vulcanizing method, a temperature difference in the bladder 6 during vulcanization can be eliminated, and a tire having a uniform vulcanization degree can be obtained. In other words, even if the temperature in the apparatus varies due to the initial vulcanization or vulcanization interruption, the purge timing is controlled using the temperature measured in the bladder 6, so that the temperature variation in the apparatus is reduced. Improve and get high quality tires. Further, since the number of purges can be minimized based on the temperature difference generated in the bladder 6, the amount of heating medium (steam) or pressurized medium (nitrogen gas) used can be reduced. Furthermore, since the temperature difference in the bladder 6 is eliminated in a timely manner, the vulcanization time for completely vulcanizing the insufficiently vulcanized portion can be set short, and the tire productivity can be improved.

  According to the tire vulcanizing apparatus, the following effects can be expected. For example, when the bladder surface temperature at the time of tire removal is limited due to tire quality, the bladder surface temperature is estimated using the detection temperatures of the temperature sensors 21a and 21b, and the bladder surface temperature is optimized with a minimum purge. be able to.

  Further, in the vulcanization using steam and nitrogen gas in the bladder 6, room temperature nitrogen gas is supplied for the pressure drop to maintain the internal pressure in the bladder 6. Under normal conditions, the pressure drop is small and the temperature drop in the bladder 6 is small. However, if there is an internal pressure leak, the mixed gas in the bladder 6 is replaced with nitrogen gas at room temperature, resulting in under cure. On the other hand, since the temperature sensors 21a and 21b measure the temperature in the bladder 6 in the tire vulcanizer, it is possible to detect an extreme temperature drop.

  FIG. 4 is a sectional view showing a tire vulcanizing apparatus according to another embodiment of the present invention. In this embodiment, the structure of the link mechanism is different from that of the above embodiment. That is, the swing arms 24a, 24b and the spring arms 26a, 26b constituting the link mechanism 22 are short, and as a result, the temperature sensors 21a, 21b attached to the tip ends of the spring arms 26a, 26b are used for the tire T during vulcanization. It is installed near the bead part.

  As described above, the positions of the temperature sensors 21a and 21b are not particularly limited as long as both positions are different from each other in the vertical direction. In this embodiment, since the swing arms 24a and 24b and the spring arms 26a and 26b are made short, there is an advantage that the tire T and the temperature sensors 21a and 21b hardly interfere with each other at the time of releasing.

  A pneumatic tire having a tire size of 195 / 65R15 was vulcanized using the tire vulcanizing apparatus shown in FIG. As the heating medium, steam having a temperature of 201 ° C. and a pressure of 1.5 MPa was used, and as the pressurizing medium, nitrogen gas having a temperature of 25 ° C. (room temperature) and a pressure of 2.0 MPa was used. From the start of vulcanization to about 1 minute 30 seconds, only 1.5 MPa steam is supplied into the bladder, and thereafter, steam and nitrogen gas are mixed to an internal pressure of 2.0 MPa. After a minute, vulcanization was completed and the mixed gas was exhausted from the bladder.

The purge control was performed according to the flowchart shown in FIG. That is, after the start of vulcanization timer measures the temperature T _B of the temperature T _A and the lower position of the upper position in the bladder, the vulcanization time is a to 4 minutes 2 minutes the temperature difference (T _A -T _B ) Was 6 ° C. or higher, gas purge was performed for 6 seconds (steps S1 to S3). Further, when the vulcanization time was 4 minutes to 7 minutes and the temperature difference (T _A −T _B ) became 4 ° C. or more, gas purge was performed for 6 seconds (steps S4 to S5). Further, if the cure time is a temperature difference be more than 7 minutes (T _A -T _B) is equal to or higher than 2 ° C., and to perform gas purge 6 seconds (step S6~S7).

  FIG. 6 is a graph showing the relationship between the temperature difference inside the bladder in the tire vulcanization step and the vulcanization time. As shown in FIG. 6, the upper and lower temperature difference in the bladder tends to gradually increase with time, but when the temperature difference reaches a predetermined threshold, purging is performed without exceeding the threshold. It changed.

It is sectional drawing which shows the tire vulcanizing apparatus which consists of embodiment of this invention. It is sectional drawing which extracts and shows the link mechanism in the tire vulcanizer of FIG. It is explanatory drawing which shows roughly the piping of the tire vulcanizer of FIG. It is sectional drawing which shows the tire vulcanizing apparatus which consists of other embodiment of this invention. It is a flowchart which shows an example of the purge control in this invention. It is a graph which shows the relationship between the temperature difference in the upper and lower sides in a bladder in the tire vulcanization process by purge control of FIG. 5, and vulcanization time.

Explanation of symbols

6 Bladder 12 Lower bladder clamp ring 16 Upper bladder clamp ring 21a, 21b Temperature sensor 22 Link mechanism 28 Control unit 32 Heating medium supply means 33 Pressurized medium supply means 35 Purge exhaust means

Claims (2)

In a method of vulcanizing a tire in a state where a mixed medium of a heating medium and a pressure medium is supplied into a bladder inserted inside the tire, two temperatures in the bladder having different heights are detected during vulcanization. When the temperature difference reaches a predetermined threshold, a part of the mixed medium is discharged from the bladder, and at the same time, the heating medium or the pressure medium is introduced into the bladder to reduce the temperature difference in the bladder. Tire vulcanization method to eliminate. A heating medium supplying means for supplying a heating medium into a bladder inserted inside the tire; a pressurized medium supplying means for supplying a pressurized medium into the bladder; and a purge exhaust means communicating with the bladder. In the tire vulcanizing apparatus, a pair of temperature sensors for detecting the temperature in the bladder and a bladder clamp ring can be expanded in the tire radial direction, and the height of the temperature in the bladder during vulcanization is increased. A tire vulcanizer provided with link mechanisms installed at two different locations and a control unit that controls the purge exhaust means based on a temperature difference detected by the pair of temperature sensors.

Images