Retreading green tire heating device, retreading green tire heating method, and retreading tire manufacturing method

Abstract

This invention provides a retreading tire heating device and method that can focus on heating the raw tread rubber. [Solution] A retreading green tire heating device for heating retreading green tires before vulcanization comprises a heating chamber body 2 that partitions a heating chamber 21, a microwave oscillating unit 3 provided on the inner wall surface of the heating chamber body and configured to irradiate microwaves into the heating chamber, a pair of shielding plates 4 that shield microwaves, and a rotating device 5 configured to rotate the retreading green tire placed in the heating chamber relative to the heating chamber body in the tire circumferential direction. The retreading green tire, in which a pair of side portions of the retreading green tire are covered from both outer sides in the tire width direction by the pair of shielding plates, is rotated in the tire circumferential direction relative to the heating chamber body by the rotating device, while the green tread rubber of the retreading green tire that is not covered by the pair of shielding plates is heated by microwaves irradiated from the microwave oscillating unit.

Description

Technical Field

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[0001] The present invention relates to a green tire heating device for retreading, a method for heating a green tire for retreading, and a method for manufacturing a retread tire.

Background Art

[0002] $Conventionally, there is a method (generally called the "re-mold manufacturing method") of obtaining a retread tire by vulcanizing a green tire for retreading, which is formed by assembling raw tread rubber to a used casing tire, using a vulcanization mold (for example, Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0007] [2] The retreading green tire heating device according to [1], wherein each of the shielding plates is circular.

[0008] [3] The retreading green tire heating device according to [1] or [2], wherein the radius R1 of each shielding plate is approximately equal to the inner diameter R2 of the green tread rubber on the tire side surface of the retreading green tire.

[0009] [4] The rotating device includes a rotating table placed in the heating chamber, The retreading green tire heating device according to any one of [1] to [3], wherein the rotating table is configured to be rotatable relative to the heating chamber body around a predetermined axis of rotation.

[0010] A method for heating retreading green tires before vulcanization, using a retreading green tire heating device described in any one of [5], [1] to [4], A method for heating a retreaded tire, wherein the retreaded tire, in which a pair of side portions of the retreaded tire are covered from both outer sides in the tire width direction by the pair of shielding plates, is rotated relative to the heating chamber in the tire circumferential direction by the rotating device, while heating the raw tread rubber of the retreaded tire that is not covered by the pair of shielding plates with microwaves irradiated from the microwave oscillating unit.

[0011] [6] A method for manufacturing retreaded tires, The assembly step involves assembling raw tread rubber onto a base tire to obtain a retreaded raw tire, and A heating step of heating the retreaded green tire using the retreaded green tire heating method described in [5], A vulcanization step is performed by vulcanizing the retreaded green tire, which has been heated in the heating step, using a vulcanization mold. A method for manufacturing retreaded tires, including the method described above. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a retreading green tire heating device, a retreading green tire heating method, and a retreading tire manufacturing method that can heat the green tread rubber intensively. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic perspective view showing a retreading green tire heating device according to one embodiment of the present invention, together with a retreading green tire. [Figure 2] Figure 1 shows a cross-sectional view in the tire width direction, schematically illustrating the retreading tire heating device and retreading tire in the tire width direction, including the tire axis of the retreading tire. [Modes for carrying out the invention]

[0014] The green tire heating device for retread, the green tire heating method for retread, and the retread tire manufacturing method according to the present invention can be used for manufacturing any type of retread tire (for example, retread tires for trucks and buses, retread tires for passenger cars, etc.), and can be preferably used when manufacturing retread tires by the remold manufacturing method.

[0015] Hereinafter, embodiments of the green tire heating device for retread, the green tire heating method for retread, and the retread tire manufacturing method according to the present invention will be illustratively described with reference to the drawings. The same reference numerals are given to the members and parts common to each figure.

[0016] [[ID=,10]]First, an overview of the retread tire manufacturing method according to an embodiment of the present invention will be described. This retread tire manufacturing method manufactures retread tires by the remold manufacturing method and can be used for manufacturing any type of retread tire (for example, retread tires for trucks and buses, retread tires for passenger cars, retread tires for aircraft, etc.). The retread tire manufacturing method of the present embodiment includes an assembling step, a heating step (FIGS. 1 to 2), and a vulcanizing step.

[0017] In the assembling step (not shown), the raw tread rubber T61 is assembled (attached) to the casing tire T1 to obtain a green tire T for retread (see FIG. 2). The green tire T for retread thus obtained includes the casing tire T1 and the raw tread rubber T61. The casing tire T1 is obtained by removing the tread rubber from a used tire by buffing or the like. The casing tire T1 includes, for example, a pair of bead cores T4, a carcass T2 extending toroidally between the pair of bead cores T4, and a belt T3 disposed on the outer side in the tire radial direction TRD of the crown region of the carcass T2. The entire casing tire T1 (specifically, the rubber constituting the casing tire T1) is vulcanized. In the green tire T for retreading, the green tread rubber T61 is composed of strip-shaped green rubber (unvulcanized rubber) and is disposed on the outer peripheral surface of the tire of the casing tire T1. Consequently, the green tread rubber T61 is disposed on the outer side in the tire radial direction TRD with respect to the belt T3. The green tread rubber T61 is a portion that will constitute the (vulcanized) tread rubber in the retreaded tire obtained after the vulcanization step. The green tire T for retreading includes a tread portion T6, a pair of sidewall portions T51 extending inward in the tire radial direction TRD from both ends of the tread portion T6 in the tire width direction TWD, and a pair of bead portions T52 continuous from the pair of sidewall portions T_{51} inward in the tire radial direction TRD. The tread portion T6 includes the green tread rubber T61, a belt T3 located on the inner side in the tire radial direction TRD with respect to the green tread rubber T61, and the crown region of the carcass T2 located on the inner side in the tire radial direction TRD with respect to the belt T3. The pair of bead portions T52 located on both sides in the tire width direction TWD includes a pair of bead cores T4. The green tire T for retreading includes a pair of side portions T5 on both sides in the tire width direction TWD. On each of both sides in the tire width direction TWD, the side portion T5 is constituted by the sidewall portion T51 and the bead portion T52.

[0018] After the assembling step, in the heating step (FIGS. 1 to 2), the green tire T for retreading obtained in the assembling step is heated using the green tire heating method according to any of the embodiments described in this specification. In the heating step, as will be described later, while suppressing the heating of the casing tire T1, the green tread rubber T61 is preferentially heated.

[0019] After the heating step, in the vulcanization step (not shown), the green tire T for retreading heated in the heating step is vulcanized using a vulcanization mold. In the vulcanization step, a tread pattern is formed on the outer peripheral surface of the tire (and thus the tread surface) of the green tread rubber T61 of the green tire T for retreading by the vulcanization mold, and the green tread rubber T61 is vulcanized to become a vulcanized tread rubber. After the vulcanization step, a retreaded tire (not shown) is obtained.

[0020] Thus, by preheating the raw tread rubber T61, which is made of raw rubber, intensively in the preheating step before the vulcanization step, the quality of the final retread tire can be improved, and the vulcanization time required for the vulcanization step can be shortened.

[0021] The following describes in more detail, with reference to Figures 1 and 2, a method for heating a retreaded green tire according to an embodiment of the present invention, which is carried out in the heating step. This method for heating a retreaded green tire is used to heat a retreaded green tire T before vulcanization (before the vulcanization step) using a retreaded green tire heating device 1 according to any embodiment described herein. The retreaded green tire T is obtained in advance in the assembly step.

[0022] Here, a retreading tire heating device 1 according to one embodiment of the present invention will be described with reference to Figures 1 and 2. The retreading green tire heating device 1 comprises a heating chamber 2, one or more microwave oscillating units 3, a pair of shielding plates 4, and a rotating device 5.

[0023] The heating chamber body 2 is configured to partition the internal space (hereinafter referred to as "heating chamber 21"). In the heating step, the retreading green tire T, which is to be heated, is placed inside the heating chamber 21 partitioned by the heating chamber body 2. In this embodiment, the heating chamber 2 is roughly box-shaped (roughly rectangular), and one side (the front side in Figure 1) is configured to be openable and closable. In this specification, for the sake of clarity, as shown with the arrows in Figures 1 and 2, the side of the heating chamber 2 that can be opened and closed (the front side in Figure 1) is referred to as the "front," the opposite side as the "rear," the left and right sides when viewing the heating chamber 2 from the front to the rear are referred to as the "left" and "right," respectively, and the upper and lower sides in the vertical direction are referred to as the "up" and "down," respectively. In this embodiment, the heating chamber 2 is roughly box-shaped (roughly rectangular) and has a main body 23 with an open front and a door 24 configured to close the open front surface of the main body 23. The main body 23 and the door 24 may be connected to each other via hinges or the like. When the door 24 closes the open surface of the main body 23, the inner wall surface 22 of the heating chamber 2 partitions the heated chamber 21 into a closed area. In this embodiment, the inner wall surface 22 of the heating chamber 2 includes a lower wall surface 22a facing upward, an upper wall surface 22b facing downward and opposite to the lower wall surface 22a, a left wall surface 22c facing to the right, a right wall surface 22d facing to the left and opposite to the left wall surface 22c, a rear wall surface 22e facing forward, and a front wall surface 22f. The lower wall surface 22a, the upper wall surface 22b, the left wall surface 22c, the right wall surface 22d, and the rear wall surface 22e are provided on the main body 23, and the front wall surface 22f is provided on the door 24. When the closed heating chamber 21 is partitioned (and thus the door 24 closes the open surface of the main body 23), the front wall surface 22f faces backward and opposite to the rear wall surface 22e. However, the shape and configuration of the heating chamber 2 are not limited to this embodiment and may be arbitrary. Preferably, the inner wall surface 22 of the heating chamber 2 is configured to reflect microwaves. This allows microwaves irradiated from the microwave oscillation unit 3 to diffuse more uniformly into the heating chamber 21, thereby suppressing uneven heating of the raw tread rubber T61 of the retreaded tire T. From this viewpoint, the inner wall surface 22 of the heating chamber 2 may be made of, for example, a non-magnetic metal.

[0024] One or more (six in this embodiment) microwave oscillators 3 are each provided on the inner wall surface 22 of the heating chamber body 2 and are configured to irradiate microwaves into the heating chamber 21. The microwaves irradiated from the microwave oscillators 3 are diffused into the heating chamber 21 without directionality. Microwaves are electromagnetic waves with wavelengths of approximately 1 mm to 1 m and frequencies of approximately 300 MHz to 300 GHz. For microwaves irradiated from the microwave oscillator 3, frequencies of 2000 to 3000 MHz are particularly preferred, and for example, 2450 MHz (ISM band) may also be used. The microwave oscillation unit 3 may be, for example, an opening on the inner wall surface 22 of the heating chamber 2 in a waveguide (not shown) connecting a microwave generator (not shown) and the heating chamber 2. The microwave generator (not shown) is configured to generate microwaves and is, for example, composed of a magnetron. The microwave generator is, for example, located outside the heating chamber 21. The waveguide (not shown) is configured to transmit the microwaves generated by the microwave generator into the heating chamber 21. In this embodiment, four microwave oscillating units 3 are provided on the rear wall surface 22e of the heating chamber 2, and two microwave oscillating units 3 are provided (one each) on the left wall surface 22c and the right wall surface 22d of the heating chamber 2. By arranging the microwave oscillating units 3 in this way, the microwaves irradiated from the microwave oscillating units 3 can be diffused more uniformly within the heating chamber 21, thereby suppressing uneven heating of the raw tread rubber T61 of the retreaded raw tire T. However, the number and position of the microwave oscillating units 3 can be arbitrary. The microwave oscillation unit 3 (and by extension, the microwave generator) may be configured to be activated and deactivated by an operator operating an input unit (switch, etc.) (not shown). Or / or, the microwave oscillation unit 3 (and by extension, the microwave generator) may be deactivated automatically by a timer function or the like.

[0025] Each of the pair of shielding plates 4 is plate-shaped and configured to shield microwaves (i.e., to prevent microwaves from passing through). Each shielding plate 4 is made of, for example, stainless steel. Each shielding plate 4 may be flat (and thus flat in shape) as shown in the examples in Figures 1 and 2. Each shielding plate 4 may have one or more (multiple in the examples shown in Figures 1 and 2) through holes 42. Each through hole 42 penetrates the shielding plate 4 in the thickness direction of the shielding plate 4. Each through hole 42 is configured to prevent microwaves from passing through. From this viewpoint, the diameter of each through hole is approximately Φ10 mm in the case of 2.45 GHz. Here, the diameter of the through hole 42 refers to the diameter of the circumscribed circle of the shape (planar shape) formed by the through hole 42 if the shape (planar shape) formed by the through hole 42 is not circular. The shape (planar shape) formed by each through hole 42 can be any shape, such as a circle or polygon. Alternatively, each shielding plate 4 does not need to have a through hole 42.

[0026] The rotating device 5 is configured to rotate the retreading green tire T, which is placed in the heating chamber 21, relative to the heating chamber body 2 in the tire circumferential direction TCD. Here, when rotating the retreading green tire T relative to the heating chamber body 2 in the tire circumferential direction TCD, for example, the retreading green tire T may be rotated in the tire circumferential direction TCD without moving the heating chamber body 2, or the heating chamber body 2 may be rotated in the tire circumferential direction TCD of the retreading green tire T without moving the retreading green tire T. In this specification, when describing the method for heating retreading green tires or the retreading green tire heating apparatus 1, the tire width direction TWD, tire diameter direction TRD, and tire circumferential direction TCD of the retreading green tire T placed in the heating chamber 21 are simply referred to as "tire width direction TWD," "tire diameter direction TRD," and "tire circumferential direction TCD," respectively. In Figures 1 and 2, for ease of understanding, the tire width direction TWD, tire diameter direction TRD, and tire circumferential direction TCD of the retreading green tire T placed in the heating chamber 21 are indicated by arrows. In this embodiment, the rotating device 5 includes a rotating table 51 placed inside the heating chamber 21. In the heating step, a retreaded green tire T is placed on the rotating table 51. The rotating table 51 is configured to be rotatable relative to the heating chamber 2 around a predetermined axis of rotation 52. The axis of rotation 52 coincides with the central axis of the rotating table 51, and therefore, the rotating table 51 is configured to rotate relative to the heating chamber 2 around the axis of rotation 52. The rotating table 51 may be rotated in the tire circumferential direction TCD without moving the heating chamber 2, or the heating chamber 2 may be rotated in the tire circumferential direction TCD without moving the rotating table 51. The rotating device 5 may further include, in addition to the rotary table 51, a shaft 53 fixed to the rotary table 51, and a motor (not shown) configured to rotate the shaft 53 around a rotation axis 52. In this case, the shaft 53 may extend downward from the rotary table 51, penetrate the inner wall surface 22 of the heating chamber 21, and extend to the outside of the heating chamber 21. The central axis of the shaft 53 coincides with the rotation axis 52. The motor is located, for example, outside the heating chamber 21. The rotating device 5 may be configured to be operated and stopped by an operator operating an input unit (switch, etc.) (not shown). Or / or, the rotating device 5 may be stopped automatically by a timer function or the like. However, the rotating device 5 may have a different configuration from that of this embodiment.

[0027] In the retreading tire heating method (heating step) using the retreading tire heating device 1 described above, first, the pair of side portions T5 of the retreading tire T are covered from both outer sides in the tire width direction TWD by a pair of shielding plates 4 (Figures 1 to 2), and the retreading tire T in this state is set on the rotating device 5. Specifically, in this embodiment, the pair of shielding plates 4 are brought into contact with the pair of side portions T5 of the retreading tire T from both outer sides in the tire width direction TWD, and the retreading tire T in this state is placed on the rotating table 51 of the rotating device 5 together with the pair of shielding plates 4. At this time, as shown in Figures 1 and 2, it is preferable to orient the retreading green tire T so that its tire axis TO is perpendicular to the rotating table 51 (and thus parallel to the rotation axis 52 of the rotating device 5) in order to improve stability. Furthermore, at this time, it is preferable that each shielding plate 4 is oriented so that the central axis of each shielding plate 4 is parallel to the tire axis TO of the retreading green tire T, and it is even preferable that the central axis of each shielding plate 4 is oriented so that it coincides with the tire axis TO of the retreading green tire T (and thus that each shielding plate 4 and the retreading green tire T are concentric). This allows for more uniform heating in the tire width direction TWD and the tire circumferential direction TCD. Furthermore, at this time, it is preferable that each shielding plate 4 is parallel to each other and oriented so that it is parallel to the tire radial direction TRD. Furthermore, as shown in the examples in Figures 1 and 2, the rotation axis 52, the tire axis TO, and the central axes of each shielding plate 4 may be arranged to coincide. In this state, each shielding plate 4 is not positioned outside the tire radial TRD of the retreading green tire T (i.e., it is not located outside the tire radial TRD of the green tread rubber T61). As a result, at least the surface of the retreading green tire T that is outside the tire radial TRD (the outer surface of the tire) is exposed in the heating chamber 21 without being covered by each shielding plate 4. Subsequently, the operator operates the input unit (not shown) to activate the rotating device 5 and the microwave oscillating unit 3 (and thus the microwave generator). As a result, the retreading green tire T, in which a pair of side portions T5 of the retreading green tire T are covered from both outer sides in the tire width direction TWD by a pair of shielding plates 4, is rotated relative to the heating chamber 2 in the tire circumferential direction TCD by the rotating device 5, while the green tread rubber T61 of the retreading green tire T that is not covered by the pair of shielding plates 4 is heated by microwaves irradiated from the microwave oscillating unit 3. More specifically, in this embodiment, during this time, the rotating table 51 of the rotating device 5 rotates (rotates) around the rotation axis 52, and accordingly, the pair of shielding plates 4 and the retreading green tire T placed on it rotate together with the rotating table 51 around the rotation axis 52. Subsequently, the operator, for example, operates the input unit (not shown), or the rotating tool 5 is stopped, and the microwave oscillation unit 3 (and thus the microwave generator) is stopped automatically. This completes the heating of the retreading green tire T, and the retreading green tire heating method (heating step) is completed. In order to prevent the rubber from vulcanizing due to excessive temperature rise, when heating with microwaves, the surface temperature of the retreading green tire T (for example, green tread rubber T61) may be measured periodically or continuously using a thermovision or the like. When the surface temperature reaches a predetermined set temperature (for example, a temperature at which vulcanization does not begin: approximately 80°C), the microwave oscillation unit 3 (and thus the microwave generator) may be stopped to end microwave irradiation.

[0028] In the retreading green tire heating device 1 and retreading green tire heating method (heating step) according to the above-described embodiment, as described above, with a pair of side portions T5 of the retreading green tire T covered from both outer sides in the tire width direction TWD by a pair of shielding plates 4, the green tread rubber T61 of the retreading green tire T that is not covered by the pair of shielding plates 4 is heated by microwaves irradiated from the microwave oscillating unit 3. As a result, the pair of shielding plates 4 prevent microwaves from the microwave oscillating unit 3 from hitting the pair of side portions T5 of the retreaded green tire T, thereby preventing the pair of side portions T5 from being heated by microwaves, while the green tread rubber T61, which is not covered by the pair of shielding plates 4, can be heated intensively by microwaves (i.e., only the green tread rubber T61 can be heated in effect). In this way, by preheating the green tread rubber T61, which is made of raw rubber, intensively in the preheating step before the vulcanization step, the quality of the final retreaded tire can be improved, and the vulcanization time required for the vulcanization step can be shortened. In addition, heating of the already vulcanized base tire T1 among the retreaded green tires T can be prevented, thereby avoiding deterioration of durability and other issues caused by heating of the base tire T1. Furthermore, since the retreading green tire T is heated while being rotated relative to the heating chamber 2 in the tire circumferential TCD by the rotating device 5, the green tread rubber T61 of the retreading green tire T can be heated more uniformly in the tire circumferential TCD, and consequently, uneven heating of the green tread rubber T61 in the tire circumferential TCD can be suppressed. This also improves the quality of the final retreaded tire.

[0029] Each shielding plate 4 preferably has a circular planar shape, as shown in the examples in Figures 1 and 2. This ensures that when each shielding plate 4 is arranged concentrically with the retreaded green tire T, as shown in Figures 1 and 2, the TRD position of the outer edge 41 of each shielding plate 4 relative to the retreaded green tire T is uniform across the entire circumference of the tire. As a result, each shielding plate 4 can uniformly cover each side portion T5 of the retreaded green tire T across the entire circumference of the tire, allowing the green tread rubber T61 of the retreaded green tire T to be heated more uniformly in the circumferential TCD during the heating step. However, each shielding plate 4 may have a planar shape other than a circle (e.g., a polygon). It is preferable that the shielding plates 4 have the same shape and dimensions. This allows for more uniform heating in the tire width direction TWD.

[0030] From the perspective of suppressing the heating of the pair of side portions T5 by microwaves and preferentially heating the green tread rubber T61 by microwaves, it is preferable that, as much as possible, the pair of side portions T5 are covered with the pair of shielding plates 4 from both sides in the tire width direction TWD so that the microwaves do not hit them, and the green tread rubber T61 is not covered with the pair of shielding plates 4 from both sides in the tire width direction TWD so that the microwaves hit it. From such a perspective, it is preferable that the radius R1 (FIG. 2) of each shielding plate 4 is substantially equal to the inner diameter R2 (FIG. 2) of the green tread rubber T61 on the tire side surface T7 of the green tire T for retreading. Here, the inner diameter R2 of the green tread rubber T61 on the tire side surface T7 of the green tire T for retreading is the distance in the tire radial direction TRD from the inner end in the tire radial direction TRD of the green tread rubber T61 when looking at the tire side surface T7 (the outer surface on the outer side in the tire width direction TWD) of the green tire T for retreading to the tire axis TO. Specifically, for example, it is preferable that the absolute value of the difference between R1 and R2 is 5 mm or less, and more preferably 2 mm or less. Also, it is preferable that R1 ≤ R2, and for example, it is preferable that R1 < R2. Note that when the shape (planar shape) formed by the shielding plate 4 is non-circular, the radius R1 of the shielding plate 4 refers to the radius of the circumscribed circle of the shape formed by the shielding plate 4.

[0031] The thickness of each shielding plate 4 is preferably, for example, 2 mm or more, and considering weight, an aluminum material is a suitable material.

Industrial Applicability

[0032] The retreading green tire heating device, retreading green tire heating method, and retreading tire manufacturing method according to the present invention can be used to manufacture any type of retreading tire (for example, retreading tires for trucks and buses, retreading tires for passenger cars, retreading tires for aircraft, etc.), and can be preferably used when manufacturing retreading tires by a remolding method. [Explanation of symbols]

[0033] 1: Green tire heating device for retreading, 2: heating chamber, 21: heating chamber, 22: Inner wall surface, 22a: Lower wall surface, 22b: Upper wall surface, 22c: Left wall surface, 22d: Right wall surface, 22e: Rear wall surface, 22f: Front wall surface, 23: Main body, 24: Door section, 3: Microwave oscillator section, 4: Shielding plate, 41: Outer edge, 42: Through hole, 5: Rotating mechanism, 51: Rotating table, 52: Rotating axis, 53: Shaft, T: Raw tire for retreading, T1: Base tire, T2: Carcass, T3: Belt, T4: Bead core, T5: Side section, T51: Sidewall section, T52: Bead section, T6: Tread section, T61: Raw tread rubber, T7: Tire sidewall, T8: Boundary, TO: Tire axis, TWD: Tire width direction, TRD: Tire diameter direction, TCD: Tire circumference direction

Claims

1. A retreading green tire heating device for heating retreading green tires before vulcanization, A heating chamber body configured to partition the heating chamber, A microwave oscillating unit is provided on the inner wall surface of the heating chamber and configured to irradiate microwaves into the heating chamber, A pair of shielding plates configured to block microwaves, A rotating device is configured to rotate a retreaded tire placed in the heating chamber relative to the heating chamber body in the tire circumferential direction, Equipped with, A retread tire heating device is configured to heat the raw tread rubber of the retread tire that is not covered by the pair of shielding plates by microwaves irradiated from the microwave oscillating unit, while rotating the retread tire, in which a pair of side portions of the retread tire are covered from both outer sides in the tire width direction by the pair of shielding plates, relative to the heating chamber body in the tire circumferential direction using the rotating device.

2. Each of the shielding plates is circular, as described in claim 1, for a retreaded green tire heating device.

3. The retreading green tire heating device according to claim 1, wherein the radius R1 of each shielding plate is approximately equal to the inner diameter R2 of the green tread rubber on the tire side surface of the retreading green tire.

4. The rotating device includes a rotating table placed in the heating chamber, The retreading green tire heating device according to claim 1, wherein the rotating table is configured to be rotatable relative to the heating chamber body about a predetermined axis of rotation.

5. A method for heating a retreaded green tire before vulcanization, using a retreaded green tire heating device described in any one of claims 1 to 4, A method for heating a retreaded tire, wherein the retreaded tire, in which a pair of side portions of the retreaded tire are covered from both outer sides in the tire width direction by the pair of shielding plates, is rotated relative to the heating chamber in the tire circumferential direction by the rotating device, while heating the raw tread rubber of the retreaded tire that is not covered by the pair of shielding plates with microwaves irradiated from the microwave oscillating unit.

6. A method for manufacturing retreaded tires, The assembly step involves assembling raw tread rubber onto a base tire to obtain a retreaded raw tire, and A heating step of heating the retreaded green tire using the retreaded green tire heating method described in claim 5, A vulcanization step is performed by vulcanizing the retreaded green tire, which has been heated in the heating step, using a vulcanization mold. A method for manufacturing retreaded tires, including the method described above.

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