JP2019038110A - Tire vulcanizing method and tire vulcanizing apparatus - Google Patents

Abstract

To provide a method and an apparatus for vulcanizing a tire capable of securing the rubber flowing property at the initial stage of vulcanization and suppressing the delay of a vulcanization time by controlling the mold temperature according to the contact state of a green tire and a mold at the time of vulcanization of a tire and improving the appearance quality of a tire.SOLUTION: There is provided a method for vulcanizing a tire using a mold 2 having a molding surface M in contact with a green tire G, wherein the temperature of the mold 2 is controlled according to the contact state of the green tire G and the mold 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tire vulcanizing method and a tire vulcanizing apparatus, and more specifically, by controlling the temperature of a mold according to the contact state between a green tire and a mold at the time of tire vulcanization, the rubber flow at the initial stage of vulcanization TECHNICAL FIELD The present invention relates to a tire vulcanizing method and a tire vulcanizing apparatus capable of ensuring both the property and suppressing the delay of vulcanization time and improving the appearance quality of a tire.

  Generally, when a tire is vulcanized, a green tire is placed in a vulcanizing apparatus, and the green tire is pressed from the inner side toward the inner surface of the mold by a bladder, while the mold is heated from the outside. Is done. Since the shape of the green tire and the profile of the mold (tire shape after vulcanization) are different, the rubber flows in the process of vulcanization and the shape of the product tire is formed. At that time, if the rubber flowability is poor, there is a problem that a gap remains between the mold and the green tire, and the appearance quality of the product tire is impaired.

  On the other hand, it is possible to improve rubber flowability by lowering the temperature of the mold. However, when the temperature of the mold is set low, the time required for the vulcanization process becomes long, so the productivity tends to deteriorate and the rubber flow continues even after the tire shape is sufficiently formed. There is a problem in that the spew formed in the vent becomes excessively long, or overflow occurs from a gap in the mold and the appearance quality of the product tire is impaired. Such inconvenience particularly occurs in a pneumatic tire having a local convex portion in the sidewall portion and a pneumatic tire having a large block in the crown portion. In addition, in the vulcanization method using a rigid core, there is a great demand for rubber flowability, so that it is a problem to be compatible with productivity.

  The upper and lower heat source temperatures interposed between the upper mold and the lower mold for molding the sidewall portion are changed between the first half and the second half of the vulcanization molding cycle. A vulcanization method in which the melting point is higher by 15 ° C. or more than the melting point has been proposed (for example, Patent Document 1). However, in the above vulcanization method, since the heat source temperature in the first half of vulcanization is set to a high temperature, there is a concern that the rubber flowability cannot be sufficiently ensured in the early stage of vulcanization.

JP 2009-214330 A

  The object of the present invention is to control the temperature of the mold according to the contact state between the green tire and the mold at the time of vulcanizing the tire, thereby ensuring both rubber flowability at the initial stage of vulcanization and suppressing the delay of the vulcanization time. In addition, an object of the present invention is to provide a tire vulcanizing method and a tire vulcanizing apparatus that can improve the appearance quality of a tire.

  In order to achieve the above object, the tire vulcanizing method of the present invention is a method of vulcanizing a tire using a mold having a molding surface in contact with a green tire, according to the contact state between the green tire and the mold. Then, the temperature of the mold is controlled.

  Further, the tire vulcanizing apparatus of the present invention is a tire vulcanizing apparatus including a mold having a molding surface that abuts against a green tire, a detection unit that detects a contact state between the green tire and the mold, and the detection And a control device for controlling the temperature of the mold in accordance with the contact state detected by the means.

  In the tire vulcanizing method of the present invention, the temperature of the mold is controlled according to the contact state between the green tire and the mold. For example, at the initial stage of vulcanization, the temperature of the mold (heat source) is lowered. Set to ensure rubber flow and, after the initial vulcanization, set the mold (heat source) to a high temperature to shorten the overall vulcanization time and suppress the vulcanization time delay. Can do. Further, by setting the temperature of the mold (heat source) in this way, unnecessary rubber flow can be eliminated, and the appearance quality of the tire can be improved.

  In the tire vulcanization method of the present invention, a pressure sensor capable of measuring the contact pressure between the green tire and the mold is used to detect the contact state between the green tire and the mold, and the temperature of the mold is controlled based on the output of the pressure sensor. It is preferable to do. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing method of the present invention, a temperature sensor capable of measuring the mold surface temperature is used to detect the contact state between the green tire and the mold, and the mold temperature is controlled based on the output of the temperature sensor. It is preferable. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanization method of the present invention, a proximity sensor capable of detecting contact with rubber is used to detect the contact state between the green tire and the mold, and the temperature of the mold is controlled based on the output of the proximity sensor. Is preferred. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing method according to the present invention, a separation sensor capable of measuring the distance to the surface of the green tire is used to detect the contact state between the green tire and the mold, and the mold is measured based on the output of the separation sensor. It is preferable to control the temperature. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanization method of the present invention, the amount of rubber flowing into a vent hole provided in the mold is detected in order to detect the contact state between the green tire and the mold, and the temperature of the mold is controlled based on the amount of flow. It is preferable to do. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing method of the present invention, the green tire and the mold are positioned at a position corresponding to any one of the block part of the crown part of the green tire, the rim guard part and the local convex part of the sidewall part in the mold. It is preferable to detect the contact state. This makes it possible to accurately detect the contact state between the green tire and the mold.

  Further, the tire vulcanizing apparatus of the present invention has a detecting means for detecting the contact state between the green tire and the mold, and a control device for controlling the temperature of the mold in accordance with the contact state detected by the detecting means. Therefore, for example, at the initial stage of vulcanization, the temperature of the mold (heat source) is set to a low temperature to ensure rubber flowability, and after the initial stage of vulcanization, the temperature of the mold (heat source) is increased to a high temperature. By setting, the vulcanization time can be shortened as a whole, and the delay of the vulcanization time can be suppressed. Further, by setting the temperature of the mold (heat source) in this way, unnecessary rubber flow can be eliminated, and the appearance quality of the tire can be improved.

  In the tire vulcanizing apparatus of the present invention, it is preferable that the detection means is a pressure sensor capable of measuring the contact pressure with the green tire, and the control device controls the temperature of the mold based on the output of the pressure sensor. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing apparatus of the present invention, it is preferable that the detection means is a temperature sensor capable of measuring the surface temperature of the mold, and the control apparatus controls the temperature of the mold based on the output of the temperature sensor. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing apparatus of the present invention, it is preferable that the detection means is a proximity sensor capable of detecting contact with rubber, and the control device controls the temperature of the mold based on the output of the proximity sensor. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing apparatus of the present invention, the detection means is a separation sensor that can measure the distance to the surface of the green tire, and the control device preferably controls the temperature of the mold based on the output of the separation sensor. . This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing apparatus of the present invention, the detection means is a detector that detects the amount of rubber flowing into the vent hole provided in the mold, and the control device controls the temperature of the mold based on the output of the detector. It is preferable to do. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the tire vulcanizing apparatus of the present invention, the detecting means is disposed at a position corresponding to any one of the block portion of the crown portion of the green tire, the rim guard portion and the local convex portion of the sidewall portion in the mold. It is preferable. This makes it possible to accurately detect the contact state between the green tire and the mold.

  In the present invention, the temperature of the mold means the temperature of the heat source disposed outside the mold, and controls the temperature of the heat source.

It is sectional drawing which shows the metal mold | die of the tire vulcanizer which consists of embodiment of this invention. In the tire vulcanization method of the present invention, the heat source temperature, the surface temperature of the mold, the pressure measured at a position corresponding to the local convex portion formed on the sidewall of the green tire in the mold, and the internal pressure of the bladder It is a graph which shows the relationship with elapsed time. In the conventional tire vulcanization method, the heat source temperature, the mold surface temperature, the pressure measured at the position corresponding to the local convex part formed on the sidewall of the green tire in the mold, and the internal pressure and course of the bladder It is a graph which shows the relationship with time. It is a perspective sectional view showing an example of a pneumatic tire in which a local convex part is formed in a sidewall part.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a tire vulcanizing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the tire vulcanizing apparatus 1 includes a mold 2 for molding a green tire G.

  The mold 2 has a configuration divided into a plurality of parts in the vertical direction, and a pair of upper and lower side plates 3 and 3 for forming a sidewall portion of the green tire G and a bead portion of the green tire G are formed. The upper bead ring 4A and the lower bead ring 4B, and a plurality of sector molds 5 for molding the tread portion of the green tire G are configured. The mold 2 is configured to vulcanize and mold a green tire G loaded in the cavity with the rotation axis in the vertical direction. At the time of vulcanization, a rubber bladder 6 formed in a cylindrical shape is inserted inside the green tire G.

  The lower end portion of the bladder 6 is sandwiched between the lower bead ring 4B and the lower clamp ring 7B, and the upper end portion of the bladder 6 is located between the upper clamp ring 7A and the auxiliary ring 8 configured to be movable in the vertical direction. It is sandwiched between. Therefore, when the mold is closed, the upper clamp ring 7A is arranged at the lower position to allow the bladder 6 to expand. On the other hand, when the mold is opened, the upper clamp ring 7A is moved to the upper position so that the bladder is moved from the inside of the green tire G. 6 is drawn out.

  The tire vulcanizing apparatus is provided with a medium supply means (not shown) for introducing a heating and pressing medium into the bladder 6, and the bladder 6 is vulcanized based on the pressure of the heating and pressing medium. The green tire G is pressed from the inside toward the inner surface of the mold 2. As the heating medium, for example, steam can be used, and as the pressurizing medium, for example, an inert gas such as nitrogen gas or steam can be used.

  A heat source 9 is disposed as a heating means outside the pair of upper and lower side plates 3 and 3 and the sector mold 5. The structure of these heat sources 9 is not particularly limited. For example, a structure in which a cavity is provided inside and a heating medium such as steam is introduced into the cavity can be adopted.

  The tire vulcanizing apparatus includes a detection unit 10 that detects a contact state between the green tire G and the mold 2, and a control that controls the temperature of the mold 2 (heat source 9) according to the contact state detected by the detection unit 10. Device 11.

  The detection means 10 is installed in the vicinity of the molding surface M of the mold 2 and can be arranged at an arbitrary location on the mold 2. For example, a pressure sensor that can measure the contact pressure with the green tire G can be used as the detection means 10. In addition, a temperature sensor that can measure the surface temperature of the mold 2 and a contact with rubber can be detected. A proximity sensor, a separation sensor that can measure the distance to the surface of the green tire G, or a detector that detects the amount of rubber flowing into the vent hole provided in the mold 2 can be used. Any device is configured to control the temperature of the mold 2 based on the output of the device. In the embodiment of FIG. 1, a pressure sensor is adopted as the detection means 10, and the pressure sensor is installed at a position (two places in total) in contact with the sidewall portion of the green tire G in the mold 2.

  When the pressure sensor is used, it is preferable to install the pressure sensor on a local convex portion of the block portion of the crown portion, the rim guard portion or the sidewall portion, which is a portion where the contact between the mold 2 and the green tire G is slow. Moreover, the pressure sensor should just be installed in the mold 2 at least one place. When controlling the temperature of the mold 2 in accordance with the output of such a pressure sensor, for example, the temperature is lowered when the pressure sensor output at the initial stage of vulcanization is small, and the temperature is increased when the output is large. Control.

  When any one of the temperature sensor, the proximity sensor, the separation sensor, and the detector is used, an object is to detect a contact range between the green tire G and the mold 2 by the sensor or the detector. If the contact area between the green tire G and the mold 2 can be grasped, the temperature of the mold 2 can be controlled without using a pressure sensor. These sensors or detectors are preferably installed at a plurality of locations of the mold 2, and furthermore, the plurality of sensors or detectors are evenly arranged with respect to the entire molding surface M of the mold 2. More preferably. When controlling the temperature of the mold 2 according to the output of such various sensors or detectors, for example, when the contact area between the green tire G and the mold 2 at the initial stage of vulcanization is small, the temperature is lowered and the contact is made. The temperature is controlled so as to increase as the area increases.

  The temperature sensor detects a temperature change at the time of contact between the mold 2 and the green tire G. When the mold 2 and the green tire G come into contact with each other, a temperature drop is detected.

  The proximity sensor detects contact between the green tire G and the molding surface M of the mold 2. As the proximity sensor, for example, a non-contact type or contact type proximity sensor such as an eddy current type or a capacitance type can be used. Also, a mechanical proximity sensor that detects the stroke of a spring vent attached to the exhaust hole of the mold can be used.

  The separation sensor measures the distance between the surface of the green tire G and the molding surface M of the mold 2. As the separation sensor, for example, a laser sensor, an infrared sensor, an ultrasonic sensor, an image sensor, or the like can be used.

  A detector that detects the amount of rubber flowing into the vent hole measures the length of spew formed on the tire surface after vulcanization, when the rubber flows into the vent hole of the mold 2 during vulcanization. When the mold 2 and the green tire G come into contact with each other, the spew length is detected.

  The control device 11 is connected to each heat source 9 and is configured to control the temperature of the heat source 9. For example, in one cycle from the start of vulcanization to the end of vulcanization, the temperature of the heat source 9 is controlled to be constant or changed. The temperature of the heat source 9 is preferably set to 140 ° C. to 170 ° C. at a low temperature at the initial stage of vulcanization and set to 170 ° C. to 190 ° C. at a high temperature after the initial stage of vulcanization.

  The tire vulcanizing apparatus can be configured to measure the surface temperature of the mold 2 (the temperature at the molding surface M of the mold 2). Although the measuring method is not specifically limited, For example, it can measure by installing a temperature measuring device in the vicinity of the molding surface M of the mold 2.

  When the green tire G is vulcanized using the above-described tire vulcanizing apparatus, the green tire G is put into the mold 2, the bladder 6 is inserted inside the green tire G, and the inside of the bladder 6 is inserted by the medium supply means. The green tire G is vulcanized by introducing a heating and pressurizing medium to the mold and heating the mold 2 from the outside by the heat source 9. In the present invention, in the vulcanization process, when the green tire G is heated from the outside, the temperature of the heat source 9 is controlled according to the contact state between the green tire G and the mold 2.

  The method for controlling the temperature of the heat source 9 will be described in detail in comparison with a conventional tire vulcanization method. 2 and 3 show the heat source temperature, the surface temperature of the mold, and the local area formed on the sidewall of the green tire in the mold in each of the tire vulcanizing method of the present invention and the conventional tire vulcanizing method. The relationship between the pressure measured at the position corresponding to the convex part and the internal pressure of the bladder and the elapsed time is shown. 2 and 3, the vertical axis represents pressure P and temperature T, and the horizontal axis represents elapsed time t. Further, the heat source temperature is Tp (the upper dashed line in the figure), the mold surface temperature is Tm (the upper solid line in the figure), and the pressure measured at the position corresponding to the convex portion in the mold is Ps. (The dashed line in the lower part of the figure), and the internal pressure of the bladder is Pi (solid line in the lower part of the figure).

  2 and 3 show a tire vulcanization method of the present invention and a conventional tire vulcanization in a pneumatic tire 20 in which a plurality of local protrusions 22 are formed on the sidewall portion 21 as shown in FIG. The results of vulcanization by each of the vulcanization methods are shown. When the pneumatic tire 20 is vulcanized, a pressure sensor is installed at a position corresponding to the convex portion 22 of the pneumatic tire 20 in the mold, and the pressure of the convex portion is shown. Ps was measured. In FIGS. 2 and 3, the pressure Ps of the convex portion and the internal pressure Pi of the bladder become the same pressure after a lapse of a predetermined time, and change in a consistent state on the graph.

  In the conventional tire vulcanizing method shown in FIG. 3, the heat source temperature Tp is maintained at a relatively low temperature (temperature T1) in one cycle from the start of vulcanization to the end of vulcanization, and the heat source temperature Tp is maintained at the temperature T1 after time t1. It remains constant. This time t1 is when rubber flows into the concave portion of the mold corresponding to the convex portion and the concave portion begins to be filled with rubber. The surface temperature Tm of the mold decreases due to contact with the green tire immediately after the start of vulcanization, but gradually increases, and after reaching the temperature T1, the temperature T1 is maintained. In this case, since the heat source temperature Tp is maintained at a low temperature, the rubber flowability is improved, while the entire vulcanization time is increased and the productivity is deteriorated.

  On the other hand, in the tire vulcanization method of the present invention shown in FIG. 2, in one cycle from the start of vulcanization to the end of vulcanization, the heat source temperature Tp is maintained at a low temperature at the initial stage of vulcanization, and then the convex portion The temperature is raised according to the pressure Ps, and the heat source temperature Tp is set stepwise. Specifically, the heat source temperature Tp is maintained at the temperature T1 immediately after the start of vulcanization, but is raised to the temperature T2 after the time t1, and thereafter maintained at the temperature T2. The surface temperature Tm of the mold 2 decreases due to contact with the green tire immediately after the start of vulcanization, but gradually increases and exceeds the temperature T1 and reaches a peak in the later stage of vulcanization. Thus, by setting the heat source temperature Tp to a low temperature at the initial stage of vulcanization, the rubber flowability at the initial stage of vulcanization is secured, and at the time t1 when the rubber begins to fill the concave portion of the mold 2 corresponding to the convex portion. After that (after the initial stage of vulcanization), the overall vulcanization time is shortened by setting the temperature higher.

  As described above, in the present invention, the tire vulcanizer 1 detects the contact state between the green tire G and the mold 2, and the temperature of the mold 2 according to the contact state detected by the detection unit 10. For example, in the initial stage of vulcanization, the temperature of the mold 2 (heat source 9) is set to a low temperature to ensure rubber flowability, and after the initial stage of vulcanization. Can set the temperature of the mold 2 (heat source 9) to a high temperature to shorten the entire vulcanization time and suppress the delay of the vulcanization time. Further, by setting the temperature of the mold 2 (heat source 9) in this way, the rubber flowability is improved, and at the same time, the spew formed in the vent becomes excessively long, and the gap between the molds is increased. Since the occurrence of overflow is suppressed, the appearance quality of the product tire can be improved.

  In the tire vulcanizing method and the tire vulcanizing apparatus described above, the vulcanizing method using a bladder has been described, but the present invention can also be applied to a vulcanizing method using a rigid core.

DESCRIPTION OF SYMBOLS 1 Tire vulcanizer 2 Mold 3 Side plate 4 Bead ring 4A Upper bead ring 4B Lower bead ring 5 Sector mold 6 Bladder 7 Clamp ring 7A Upper clamp ring 7B Lower clamp ring 8 Auxiliary ring 9 Heat source 10 Detection means 11 Control Equipment G Green tire M Molding surface

Claims (14)

  In the method of vulcanizing a tire using a mold having a molding surface that comes into contact with the green tire, the temperature of the mold is controlled in accordance with the contact state between the green tire and the mold. Sulfur method.   In order to detect the contact state between the green tire and the mold, a pressure sensor capable of measuring a contact pressure between the green tire and a temperature of the mold is controlled based on an output of the pressure sensor. The tire vulcanizing method according to claim 1.   Using a temperature sensor capable of measuring the surface temperature of the mold to detect the contact state between the green tire and the mold, and controlling the temperature of the mold based on the output of the temperature sensor; The tire vulcanizing method according to claim 1.   A proximity sensor capable of detecting contact with rubber is used to detect a contact state between the green tire and the mold, and the temperature of the mold is controlled based on an output of the proximity sensor. Item 2. The tire vulcanization method according to Item 1.   In order to detect the contact state between the green tire and the mold, a separation sensor capable of measuring the distance to the surface of the green tire is used, and the temperature of the mold is controlled based on the output of the separation sensor. The tire vulcanizing method according to claim 1.   In order to detect the contact state between the green tire and the mold, the amount of rubber flowing into a vent hole provided in the mold is detected, and the temperature of the mold is controlled based on the amount of flow. The tire vulcanizing method according to claim 1.   A contact state between the green tire and the mold is detected at a position corresponding to any one of a block portion of the crown portion of the green tire, a rim guard portion and a local convex portion of the sidewall portion of the mold. The tire vulcanizing method according to any one of claims 1 to 6.   In a tire vulcanizing apparatus including a mold having a molding surface that abuts against a green tire, a detection unit that detects a contact state between the green tire and the mold, and the detection unit according to the contact state detected by the detection unit A tire vulcanizing apparatus comprising a control device for controlling the temperature of a mold.   The said detection means is a pressure sensor which can measure the contact pressure with the said green tire, The said control apparatus controls the temperature of the said metal mold | die based on the output of the said pressure sensor. Tire vulcanizer.   The said detection means is a temperature sensor which can measure the surface temperature of the said metal mold | die, The said control apparatus controls the temperature of the said metal mold | die based on the output of the said temperature sensor. Tire vulcanizer.   The tire adding device according to claim 8, wherein the detecting means is a proximity sensor capable of detecting contact with rubber, and the control device controls the temperature of the mold based on an output of the proximity sensor. Sulfur equipment.   The detection means is a separation sensor capable of measuring a distance to the surface of the green tire, and the control device controls the temperature of the mold based on an output of the separation sensor. The tire vulcanizer according to claim 8.   The detection means is a detector that detects the amount of rubber flowing into a vent hole provided in the mold, and the control device controls the temperature of the mold based on the output of the detector. The tire vulcanizing apparatus according to claim 8.   The detection means is arranged at a position corresponding to any one of the block part of the crown part of the green tire, the rim guard part and the local convex part of the sidewall part in the mold. The tire vulcanizer according to any one of claims 8 to 13.

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