JP2006062213A - Method and apparatus for preheating green tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the vulcanization time of a run-flat green tire 11 in which a reinforcing rubber layer 16 is arranged on the inner surface side of a side wall part 14 and to prevent over-vulcanization in a bead part 13, etc. <P>SOLUTION: Since the middle part of the side wall part 14 in which the reinforcing rubber layer 16 having an approximately crescent cross section is formed, i.e. a thick rubber wall part 18 of the thickest rubber wall, is heated by radiation heat from a heater lamp 35 arranged at a position opposite to the thick rubber wall part 18, the thick rubber wall part 18 which is vulcanized last is preheated in advance of heating, so that the advance of vulcanization in the thick rubber wall part 18 is made approximately equivalent to that in the bead part 13, etc., to shorten the vulcanization time and to prevent the over-vulcanization of the bead part 13, etc. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a preheating method and apparatus for preheating a raw tire by heating a thick rubber part.

As a conventional raw tire preheating method and apparatus, for example, those described in Patent Document 1 below are known.
JP 2004-130653 A

  This is disposed on the outside of the tread portion of the raw tire held by the holding mechanism and detachably holding the raw tire in a predetermined posture, and applies a high-frequency magnetic field to the raw tire from the outside The induction heating mechanism that induction-heats the metal member embedded in the raw tire with the high-frequency magnetic field, and the bead portion that is delayed in temperature rise by induction heating of the metal member and the outside of the shoulder portion, respectively, the bead And a plurality of radiant heaters for radiant heating intensively from the outside with respect to the shoulder portion and the shoulder portion.

    Here, in recent years, as a run-flat tire that can ensure safe running even if the tire internal pressure leaks, a pneumatic tire with a reinforcing rubber layer having a substantially crescent-shaped cross section disposed on the inner surface side of the sidewall portion has been proposed. However, since the thickest part of the reinforcing rubber layer is located in the central portion of the sidewall portion of such a pneumatic tire, the rubber becomes the thickest in the pneumatic tire at the central portion. That is, the rubber is thicker than the beads and shoulders.

  And in order to manufacture the run flat tire as described above, it is necessary to vulcanize the raw tire, but after applying the pre-heated one described in Patent Document 1 as it is, the above vulcanization is performed. In this way, the rubber thick part is not preheated unlike the bead part and the shoulder part, although the rubber part is thicker than other parts including the bead part and the shoulder part. The progress is significantly delayed from the bead part and the shoulder part, and as a result, a long time is required for the rubber thick part to reach a predetermined degree of vulcanization. Moreover, when the vulcanization time is increased as described above, there is a problem that the bead portion and the shoulder portion may be over-vulcanized.

  The present invention can reduce the vulcanization time of a raw tire in which a reinforcing rubber layer is disposed on the inner surface side of the sidewall portion, and can prevent over-vulcanization at a bead portion or the like. It is an object to provide a preheating method and apparatus.

    The purpose of this is, first, by providing a reinforcing rubber layer having a substantially crescent-shaped cross section on the inner surface side of the sidewall portion, so that a thick rubber portion is provided in the central portion of the sidewall portion. A step of disposing an inner radiant heat source at a position facing the rubber thick part inside the tire, and preheating the raw tire by heating the rubber thick part of the raw tire from the inside by radiant heat from the inner radiant heat source. Can be achieved by a method for preheating a raw tire comprising a process,

  Secondly, a reinforcing rubber layer having a substantially crescent-shaped cross section is disposed on the inner surface side of the sidewall portion, so that the outer side of the raw tire provided with a thick rubber portion at the center portion of the sidewall portion, A raw material comprising a step of disposing an outer radiant heat source at a position facing the thick rubber part and a step of preheating the raw tire by heating the thick rubber part of the raw tire from the outside by radiant heat from the outer radiant heat source. Can be achieved by the tire preheating method,

  Thirdly, an inner radiant heat source capable of generating radiant heat and a reinforcing rubber layer having a substantially crescent-shaped cross section on the inner surface side of the sidewall portion are arranged so that a thick rubber wall is formed at the center portion of the sidewall portion. An arrangement means for disposing the inner radiant heat source at a position facing the rubber thick portion inside the raw tire by relatively moving the raw tire provided with a portion and the inner radiant heat source, With the raw tire preheating device that preheats the raw tire by heating the thick rubber part of the raw tire from the inside by radiant heat from the inner radiant heat source, it can be achieved,

  Fourthly, an outer radiant heat source capable of generating radiant heat and a reinforcing rubber layer having a substantially crescent-shaped cross section on the inner surface side of the sidewall portion are disposed, so that a thick rubber wall is formed at the center portion of the sidewall portion. An arrangement means for disposing the outer radiant heat source at a position facing the rubber thick portion outside the raw tire by relatively moving the raw tire provided with a portion and the outer radiant heat source, This can be achieved by a raw tire preheating device that preheats the raw tire by heating the thick rubber portion of the raw tire from the outside by radiant heat from the outside radiant heat source.

  In this invention, the rubber thick wall portion of the green tire is heated by radiant heat from the inner or outer radiant heat source disposed at a position facing the thick rubber portion where the rubber is the thickest. The rubber thick-walled part where the progress of the rubber is most delayed is preheated prior to vulcanization, and this makes the progress of vulcanization in the rubber thick-walled part almost the same as the bead part and the shoulder part, reducing the vulcanization time, It is also possible to prevent over-vulcanization of the bead part and the shoulder part.

  Here, when the thick rubber part is heated by the inner radiant heat source disposed inside the green tire, the inner surface of the thick rubber part is heated to a high temperature. Since most of the periphery of the inner surface of the meat part is covered with the raw tire, heat is not dissipated from the inner surface of the thick rubber part to the surroundings by radiation, and air is not contained in the raw tire. Since there is almost no flow, heat is hardly taken away from the inner surface of the thick rubber part by air, and heat is trapped in the thick rubber part, and the heating efficiency is easily improved.

Moreover, if comprised as described in Claim 3, a heating (preheating) time can be shortened easily.
Moreover, if comprised as described in Claim 4, a rubber | gum thick part can be heated uniformly.
Furthermore, if it comprises as described in Claim 7, a rubber | gum thick part can be heated rapidly and reliably.
According to the eighth aspect of the present invention, the radiant heat from the inner radiant heat source can be confined between the reflecting plates, whereby the rubber thick part can be heated quickly and reliably.

Embodiment 1 of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 11 denotes a green tire that has been molded by a molding drum (not shown). The green tire 11 includes a pair of bead portions 13 each having a bead core 12 embedded therein, and a radial direction extending from the bead portions 13. It is composed of a pair of sidewall portions 14 that extend outward, and a substantially cylindrical tread portion 15 that connects the outer ends in the radial direction of the sidewall portions 14.

  Here, a reinforcing rubber layer 16 made of a relatively hard rubber is disposed on the inner surface side of the sidewall portion 14, but the reinforcing rubber layer 16 has a substantially crescent-shaped cross section, and the bead portion 13 and As the tread portion 15 approaches the center portion of the sidewall portion 14, the wall thickness gradually increases. As a result, when the raw tire 11 is vulcanized, it becomes a run-flat tire that can ensure safe running even if the tire internal pressure leaks.

  Here, the bead portion 13 of the raw tire 11 and the shoulder portion 17 located at the boundary portion between the sidewall portion 14 and the tread portion 15 are relatively thick in rubber in the raw tire 11 (gauge). Is a thick part, and the part where the progress of vulcanization is delayed. On the other hand, the central portion of the sidewall portion 14 provided with the reinforcing rubber layer 16 as described above (near the thickest portion of the reinforcing rubber layer 16) is thicker than the bead portion 13 and the shoulder portion 17. That is, the rubber is the thickest in the raw tire 11 and constitutes the rubber thick portion 18. Further, the central portion in the thickness direction of the thick rubber portion 18 is a portion where the progress of vulcanization is most delayed because the heat of vulcanization is hardly transmitted compared to other portions.

  21 is a loader as an arrangement means for disposing a heater lamp at a position facing the rubber thick portion 18 inside the raw tire 11 by relatively moving a heater lamp described later and the raw tire 11. The loader 21 has a movable base 22 that can be moved in a three-dimensional direction, that is, up and down, front and rear, and left and right by a moving mechanism (not shown). A plurality of downwardly extending gripping claws 23 are supported on the lower end of the movable base 22, and these gripping claws 23 are arranged at equal distances in the circumferential direction and are shown in the movable base 22 It is possible to expand and contract by synchronously moving in the radial direction by a moving mechanism that is not. Further, a locking portion 24 that protrudes outward in the radial direction is formed at the lower end of the gripping claws 23.

  When the raw tire 11 is stored horizontally in the storage station, the lower end portion of the gripping claw 23 in the reduced diameter state is loosely fitted into the upper bead portion 13 of the raw tire 11 from above. Thereafter, when the gripping claws 23 move synchronously outward in the radial direction, the lower ends of the gripping claws 23 come into contact with the inner periphery (bead toe inner periphery) of the upper bead portion 13. When the loader 21 is raised in this state, the locking portion 24 comes into contact with the inner surface of the upper bead portion 13 and is caught by the upper bead portion 13, whereby the raw tire 11 is gripped by the loader 21. Next, as the loader 21 moves, the raw tire 11 is transported from the storage station to the preheating station Y, preheated in the preheating station Y for a predetermined time, and then carried into the vulcanizer of the vulcanization station. Sulfur is performed.

  Reference numeral 28 denotes a flat base installed in the preheating station Y, and a lower end of a vertical post 30 extending in the vertical direction is rotatably supported by a bearing 29 attached to the upper surface of the base 28. . As a result, the vertical post 30 can rotate around the central axis (vertical axis) of the vertical post 30 while being supported by the bearing 29. 31 is a horizontal connecting plate fixed to the upper end of the vertical post 30, this connecting plate 31 has a polygon, for example, an octagonal shape, the diameter of the circumscribed circle is the inner diameter of the bead portion 13 of the green tire 11 Smaller diameter.

  Reference numeral 34 denotes a plurality of (eight) swing arms whose base end portions are rotatably connected to the outer edge portion of the connecting plate 31 via pins 32, and these swing arms 34 are spaced equidistantly in the circumferential direction. And can swing up and down around the base end (pin 32). A heater lamp 35 made of a halogen lamp or the like as an inner radiant heat source is attached to the tip of each swing arm 34. When the plurality of heater lamps 35 are energized, they generate high-temperature radiant heat and are irradiated with heat rays. Heat the area quickly. Here, when these heater lamps 35 are located in the raw tire 11, most of the raw tire 11 including the rubber thick portion 18 is effective from the inside prior to vulcanization by the radiant heat from the heater lamp 35. The vulcanization process is accelerated more than at normal temperature.

  38 is a slide ring that is externally fitted to the vertical post 30 below the connection plate 31 so as to be movable up and down. The slide ring 38 has a plurality of (the same number of swing arms 34) connection links that are equidistant from each other in the circumferential direction. The lower end part of 39 is connected so that rotation is possible. These connecting links 39 are inclined so as to go outward in the radial direction as they go upward, and their upper ends are connected to the central portion in the longitudinal direction of the swing arm 34 so as to be rotatable. As a result, when the slide ring 38 moves to the lower limit shown by the phantom line in FIG. 1, the swing arm 34 swings to the drooping position, while when the slide ring 38 moves to the lift limit shown by the solid line, the swing arm 34 becomes horizontal. Swing to position.

  Reference numeral 41 denotes a vertically extending fluid cylinder attached to the upper surface of the base 28, and the tip of the piston rod 42 of the fluid cylinder 41 is connected to the slide ring 38 via a bracket 43. As a result, when the fluid cylinder 41 is operated and the piston rod 42 is retracted to the stroke end, the slide ring 38 moves to the lower limit, and when it protrudes to the stroke end, the slide ring 38 moves to the upper limit. Here, when the connecting plate 31 is located in the raw tire 11, when the slide ring 38 rises from the descending limit to the ascending limit and the swing arm 34 swings from the suspended position to the horizontal position, the heater lamp 35 Moves synchronously radially outward and upward along an arc centered on the pin 32 and approaches the thick rubber portion 18.

  When the heater lamp 35 moves synchronously to the outer end in the radial direction, the rubber thick wall 18 closest to the thick rubber portion 18 (the central portion of the sidewall portion 14 provided with the reinforcing rubber layer 16) is opposed to the thick rubber portion. The most radiant heat is applied to the portion 18. As a result, the thickest rubber thick portion 18 in the thickness direction central portion is heated to substantially the same temperature as the other bead portions 13 and the shoulder portion 17 in the thickness direction central portion. The thick rubber portion 18 can be vulcanized in a short time to a predetermined degree of vulcanization without over-vulcanizing the shoulder portion 17.

  The swing arm 34, the slide ring 38, the connecting link 39, and the fluid cylinder 41 described above constitute an approach means 46 that allows the heater lamp 35 to move toward the rubber thick portion 18 by synchronously moving the heater lamp 35 radially outward. Here, in order to arrange the heater lamp 35 inside the raw tire 11, the diameter of the circumscribed circle of the heater lamp 35 must be smaller than the inner diameter of the bead portion 13. However, the heater lamp 35 is rubber at this position. It is far away from the thick part 18. However, if the approach means 46 as described above is provided, the heater lamp 35 can be easily brought close to the rubber thick part 18, and thus the rubber thick part 18 can be heated quickly and reliably. .

  49 is an external gear fixed to the vertical post 30 between the bearing 29 and the slide ring 38, and this external gear 49 is attached to the output shaft 51 of the motor 50 fixed to the upper surface of the base 28. The external gear 52 is engaged. Here, when the heater lamp 35 is disposed in the raw tire 11, the motor 50 is operated and the external gear 49, the vertical post 30, the connecting plate 31, and the swing arm 34 are moved with respect to the non-rotating raw tire 11. When the heater lamp 35 is integrally rotated relatively around the axis of the raw tire 11, the heat rays from the heater lamp 35 are evenly applied to each part of the rubber thick part 18, and thereby the rubber thick part 18 is evenly distributed. Can be heated. The external gear 49, the motor 50, and the external gear 52 described above constitute rotation means 53 that relatively rotates the raw tire 11 and the heater lamp 35 around the axis of the raw tire 11.

Next, the operation of the first embodiment will be described.
When preheating the raw tire 11, first, the movable base 22 is moved to a position directly above the raw tire 11 that is stored at room temperature in a horizontal position in a storage station, and then the movable base 22 is lowered to reduce the diameter. The lower end portion of the gripping claw 23 in the state is inserted into the upper bead portion 13 from above. Next, the gripping claw 23 is moved synchronously outward in the radial direction until the lower end of the gripping claw 23 comes into contact with the inner periphery of the upper bead portion 13, and then the movable base 22 is raised so that the locking portion 24 is The raw tire 11 is gripped by the loader 21 in contact with the inner surface. At this time, in the preheating station Y, since the piston rod 42 of the fluid cylinder 41 is retracted to the stroke end, the swing arm 34 is stopped at the hanging position, and the diameter of the circumscribed circle of the heater lamp 35 is the bead portion 13. It is smaller than the inner diameter.

  Next, after operating the loader 21 and transporting the gripping raw tire 11 to the position just above the preheating station Y, the loader 21 is moved downward, so that the connecting plate 31 and the heater lamp 35 are moved to the raw tire 11. Invade inside from below. Next, when the piston rod 42 of the fluid cylinder 41 protrudes to the stroke end and the slide ring 38 is moved to the upper limit, the swing arm 34 is pushed by the connecting link 39 and swings from the suspended position to the horizontal position. As a result, the heater lamp 35 is disposed in the raw tire 11 at a position facing the thick rubber portion 18 and is synchronously moved radially outward along an arc centered on the pin 32 to thereby increase the thick rubber thickness. It is closest to the part 18 and heating to the thick rubber part 18 is quick and reliable.

  Next, when the heater lamp 35 is energized, high-temperature radiant heat is generated from the heater lamp 35, and the region irradiated with the heat rays (most part of the inner surface of the raw tire 11) is heated prior to vulcanization. At this time, since the heater lamp 35 is closest to the rubber thick portion 18 as described above, the inner surface of the rubber thick portion 18 where the progress of vulcanization is most delayed is heated to a high temperature prior to vulcanization, As a result, the progress of vulcanization in the thick rubber portion 18 is substantially the same as that of the bead portion 13 and the shoulder portion 17, and the vulcanization time is shortened, and over-vulcanization of the bead portion 13 and the shoulder portion 17 is prevented. You can also

  As described above, since the rubber thick portion 18 is heated from the inside by the radiant heat from the heater lamp 35 disposed at the position facing the rubber thick portion 18 inside the raw tire 11, the rubber thick portion 18 Although the inner surface is heated to a high temperature, since the periphery of the inner surface of these thick rubber portions 18 is mostly covered with the raw tire 11, radiation from the inner surface of the thick rubber portion 18 is caused by radiation. The heat is not dissipated so much, and since there is almost no air flow inside the raw tire 11, heat is hardly taken away from the inner surface of the thick rubber part 18 by the air. Heat accumulates in the thick rubber part 18 and the temperature easily rises to improve the heating efficiency.

  Simultaneously with the energization of the heater lamp 35, the motor 50 of the rotating means 53 operates to rotate the heater lamp 35 about the axis of the raw tire 11 (the central axis of the vertical post 30). Then, when a predetermined time has elapsed from the start of heating, the power supply to the heater lamp 35 is cut off, while the operation of the motor 50 is stopped, and the piston rod 42 of the fluid cylinder 41 is retracted to the stroke end, and the swing arm 34 is Swing down to the hanging position. Thereafter, the preheated green tire 11 is conveyed from the preheating station Y to the vulcanization station by the loader 21, and vulcanized by the vulcanizer of the vulcanization station. At this time, since the rubber thick portion 18 having the slowest vulcanization speed is preheated by the heater lamp 35, the progress of the vulcanization is promoted more than at normal temperature, and the vulcanization time is shortened to improve the productivity. .

  Here, FIG. 2 shows temperature changes at the inner surface, the outer surface, and the central portion in the thickness direction of the thick rubber portion 18 when heated by the radiant heat from the heater lamp 35 as described above. When heating by the heater lamp 35 is started at time T1, the temperatures of the inner surface, the outer surface, and the central portion in the thickness direction of the thick rubber portion 18 increase as indicated by curves L1, L2, and L3, respectively. Thereafter, when time T2 is reached, heating by the heater lamp 35 is finished, and thereafter, the raw tire 11 is conveyed by the loader 21 to the vulcanizing device of the vulcanizing station from time T2 to time T3. For this reason, the temperature of the said part is falling gradually.

  At time T3, the green tire 11 is rapidly heated to the vulcanization temperature by the high-temperature and high-pressure vulcanization medium, and vulcanization is started. Here, FIG. 2 shows the thickness of the thick rubber portion 18 when the raw tire 11 stored at room temperature is transported to the vulcanizer by the loader 21 without preheating and then vulcanized at the same time T3. The temperature change at the center in the vertical direction is shown by curve L4. When these curves L3 and L4 are compared, the temperature rises to the vulcanization temperature earlier by time M when preheating is performed, and the vulcanization time is shortened. I understand what I can do.

    FIG. 3 is a diagram showing a second embodiment of the present invention. In this embodiment, the vertical post 30, the connecting plate 31, the heater lamp 35, the approaching means 46, and the rotating means 53 in the first embodiment are omitted to eliminate heating from the inside of the raw tire 11, while the base 28 A fixed post 54 extending in the vertical direction is provided on the upper surface of the fixed plate 54, and an outer heater 57 having a substantially bowl shape as an outer radiant heat source is attached to the upper end of the fixed post 54 via an intermediate plate 56, and the lower end of the movable base 22 An outer heater 59 having a substantially bowl shape as an outer radiant heat source is attached to the outer periphery of the part via an intermediate ring 58.

  Here, the outer heaters 57 and 59 extend along the lower side and the upper side wall part 14 of the raw tire 11, respectively, and are arranged at positions facing the thick rubber part 18, and generate radiant heat. For example, it is composed of a far infrared ceramic heater or the like. In this way, the outer heaters 57 and 59 are arranged outside the raw tire 11 and the thick rubber portion 18 is heated from the outside by radiant heat from the outer heaters 57 and 59 as in the first embodiment. The vulcanization time of the raw tire 11 can be shortened, and over-vulcanization at the bead portion 13 can be prevented. Other configurations and operations are the same as those in the first embodiment.

    FIG. 4 is a diagram showing Embodiment 3 of the present invention. In this embodiment, in addition to that of the first embodiment, an outer heater 57 having a substantially bowl shape as an outer radiant heat source is attached to a vertical post 30 immediately above the external gear 49 via an intermediate plate 56, and is movable. An outer heater 59 having a substantially bowl shape as an outer radiant heat source is attached to the outer periphery of the lower end of the base 22 via an intermediate ring 58. Here, the outer heaters 57 and 59 extend along the lower side and the upper side wall part 14 of the raw tire 11, respectively, and are arranged at positions facing the thick rubber part 18, and generate radiant heat. For example, it is composed of a far infrared ceramic heater or the like. In this way, the outer heaters 57 and 59 are also arranged outside the raw tire 11, and the thick rubber portion 18 is heated from the inside and outside by both the heater lamp 35 inside the raw tire 11 and the outside heaters 57 and 59 outside. By doing so, the heating (preheating) time can be easily shortened.

    Further, in this embodiment, the access means 46 is omitted, while the vertical post 30 on the axial direction one side (lower side) and the vertical post 30 on the other axial side (upper side) from the heater lamp 35, that is, the axial direction of the heater lamp 35. Reflecting plates 62 and 63 extending in parallel are provided on both sides. Here, the reflecting plates 62 and 63 have reflecting surfaces on the inner surfaces facing each other, and their outer edge portions are inclined so as to expand toward the outer side in the radial direction. As a result, the radiant heat from the heater lamp 35 is confined between the reflectors 62 and 63, and then concentrated from the outer edge portion toward the thick rubber portion 18, so that heating is fast and reliable.

    In the above-described embodiment, the bare heater lamp 35 is used as the inner radiant heat source. However, in the present invention, a lamp device having a reflecting mirror such as a parabolic mirror is opposed to the rubber thick portion 18. The thick rubber portion 18 may be intensively heated by radiant heat from the lamp device. Further, in the above-described embodiment, by moving the loader 21, the gripped raw tire 11 is conveyed around the heater lamp 35, and thereby the heater lamp 35 is arranged inside the raw tire 11. However, in the present invention, when the raw tire 11 is gripped by the stationary loader 21, the heater lamp 35 is raised to enter the raw tire 11, thereby A heater lamp 35 may be arranged.

  Furthermore, in the above-described embodiment, while the raw tire 11 is stationary (non-rotating), the heater lamp 35 is rotated around the axis of the raw tire 11. However, in the present invention, the heater lamp 35 is stationary. On the other hand, the raw tire 11 may be rotated around the axis of the raw tire 11 while being gripped by the loader 21.

  The present invention can be applied to the industrial field of preheating raw tires.

It is a partially broken front view which shows Example 1 of this invention. It is a graph showing the state of the temperature change in a rubber thick part. It is a partially broken front view which shows Example 2 of this invention. It is a partially broken front view which shows Example 3 of this invention.

Explanation of symbols

11 ... Raw tire 14 ... Side wall
16 ... Reinforced rubber layer 18 ... Rubber thick part
21 ... Arrangement means 35 ... Inside radiant heat source
46 ... Approaching means 57, 59 ... Outside radiant heat source
62, 63 ... reflector

Claims (8)

    By providing a reinforcing rubber layer having a substantially crescent-shaped cross section on the inner surface side of the sidewall portion, the rubber thick portion is provided inside the raw tire in which the rubber thick portion is provided in the central portion of the sidewall portion. And a step of preheating the raw tire by heating the rubber thick portion of the raw tire from the inside by the radiant heat from the inner radiant heat source. Raw tire preheating method.     The reinforcing rubber layer having a substantially crescent-shaped cross section is disposed on the inner surface side of the sidewall portion, so that the thick rubber portion on the outer side of the raw tire in which the thick rubber portion is provided in the central portion of the sidewall portion. And a step of preheating the raw tire by heating the rubber thick portion of the raw tire from the outside by radiant heat from the outer radiant heat source. Raw tire preheating method.     An outer radiant heat source is further arranged outside the raw tire at a position facing the rubber thick part, and the rubber thick part of the raw tire is heated from inside and outside by radiant heat from both the inner and outer radiant heat sources. The raw tire preheating method according to claim 1.     The raw tire preheating method according to claim 1, wherein when the thick rubber portion is heated by radiant heat from the inner radiant heat source, the inner radiant heat source and the raw tire are relatively rotated about the axis of the raw tire.     An inner radiant heat source capable of generating radiant heat and a reinforcing rubber layer having a substantially crescent-shaped cross section are disposed on the inner surface side of the sidewall portion, so that a thick rubber portion is provided at the center portion of the sidewall portion. The inner radiant heat source is disposed at a position facing the rubber thick portion inside the raw tire by relatively moving the raw tire and the inner radiant heat source. The raw tire preheating apparatus is characterized in that the raw tire is preheated by heating the thick rubber portion of the raw tire from the inside by the radiant heat of the raw tire.     An outer radiant heat source capable of generating radiant heat and a reinforcing rubber layer having a substantially crescent-shaped cross section are disposed on the inner surface side of the sidewall portion, thereby providing a thick rubber portion at the center of the sidewall portion. The outer radiant heat source is disposed relatively to the outer radiant heat source so as to dispose the outer radiant heat source at a position facing the rubber thick portion outside the raw tire. The raw tire preheating device is characterized in that the raw tire is preheated by heating the thick rubber portion of the raw tire from the outside by radiant heat.     The raw tire preheating according to claim 5, wherein a plurality of the inner radiant heat sources are provided apart from each other in the circumferential direction, and an approach means is provided for moving the inner radiant heat sources synchronously to the radially outer side so as to approach the thick rubber portion. apparatus.     6. The preheating apparatus for a raw tire according to claim 5, wherein a pair of reflecting plates whose inner surfaces are reflecting surfaces are installed on both axial sides of the inner radiant heat source, and radiant heat is confined between the reflecting plates.

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