Method of manufacturing pneumatic tire

Abstract

To provide a method of manufacturing a pneumatic tire capable of suppressing deformation of the pneumatic tire after vulcanization.SOLUTION: A method of manufacturing a pneumatic tire T1 includes a hanging step of hanging the pneumatic tire T1 after a vulcanization step so that a tire radial direction D2 is aligned with a horizontal direction. A hanging time of the pneumatic tire T1 in the hanging step is 30 seconds or longer and 120 seconds or shorter. According to the method, by setting the hanging time to 30 seconds or longer, the pneumatic tire T1 in a high temperature state is naturally cooled, and when the pneumatic tire T1 is placed in a post step, deformation of the tire due to a self-weight can be suppressed. By setting the hanging time to 120 seconds or shorter, deformation of the pneumatic tire T1 in a hanging state due to a self-weight can be suppressed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a pneumatic tire.

Background Art

[0002] Post-cure inflation in which a vulcanized pneumatic tire is filled with internal pressure and then naturally cooled is generally performed (for example, Patent Document 1). By performing post-cure inflation, the dimensional stability and uniformity of the tire can be improved.

[0003] Before performing post-cure inflation on a vulcanized tire taken out of a mold, it is necessary to blow off the tire fumes. This is to prevent poor appearance of the tire due to partial solidification of the fumes. The tire is taken out of the vulcanizer with the bead portion supported by the chuck of the unloader and is suspended by the chuck until the fumes fly off.

[0004] However, as shown in FIG. 6, when the tire T9 is suspended and waiting, there is a problem that the bead portion 91 and the adjacent sidewall 92 of the tire T9 are deformed (from the solid line shape to the chain line shape) due to the self-weight of the tire T9, and the bead interval Dm9a widens to the interval Dm9b. In recent years, due to the increasing demand for low-fuel-consumption (high rolling resistance performance) tires, the number of tires with low rigidity has increased, and the solution to this problem is desired.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present disclosure is to provide a method for manufacturing a pneumatic tire capable of suppressing deformation of the pneumatic tire after vulcanization.

Means for Solving the Problems

[0007] The method for manufacturing a pneumatic tire of the present disclosure includes a suspension step of suspending the pneumatic tire after the vulcanization step so that the tire radial direction is along the horizontal direction, and the suspension time of the pneumatic tire in the suspension step is 30 seconds or more and 120 seconds or less.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0009] <Pneumatic Tire> First, an example of a pneumatic tire will be described with reference to FIG. 1. In each figure (the same applies to FIGS. 2 to 6), the dimensional ratio in the drawing and the actual dimensional ratio do not necessarily match, and the dimensional ratios between the drawings do not necessarily match either. FIG. 1 is a figure showing a state where a pneumatic tire T1 (hereinafter, also simply referred to as "tire T1") is suspended. In FIG. 1 (the same applies to FIGS. 2 to 4), the tire T1 is drawn in a meridian cross-section.

[0010] In FIG. 1, the first direction D1 indicates the tire axial direction D1 that is parallel to the tire rotation axis of the tire T1, and the second direction D2 indicates the tire radial direction D2 that is the diameter direction of the tire T1. In the tire radial direction D2, the inner side indicates the side close to the tire rotation axis, and the outer side indicates the side far from the tire rotation axis. The tire equatorial plane S is a plane that is orthogonal to the tire rotation axis and is located at the center of the tire T1 in the tire axial direction D1,

[0011] As shown in FIG. 1, the tire T1 includes a pair of bead portions 1, 1, a pair of sidewalls 2, 2 extending outward in the tire radial direction D2 from each of the pair of bead portions 1, 1, and a tread 3 connected to the outer ends in the tire radial direction D2 of each of the pair of sidewalls 2, 2. A tread pattern is formed on the outer side of the tread 3 in the tire radial direction D2.

[0012] <Tire manufacturing apparatus> Next, an example of a tire manufacturing apparatus for manufacturing a pneumatic tire will be described with reference to FIGS. 1 to 4. FIG. 2 is a view showing a state in which the suspended pneumatic tire T1 is conveyed to a post-cure inflation device 12 (hereinafter also referred to as the "PCI device 12") described later, and FIG. 3 is a view showing a state in which the suspended pneumatic tire T1 is lowered onto the PCI device 12. FIG. 4 is a view showing a state in which post-cure inflation is performed on the vulcanized tire T1.

[0013] The tire manufacturing apparatus 10 includes a vulcanizing device (not shown) for vulcanizing the tire T1 and an unloader 11 for taking out the tire T1 from the vulcanizing device. In the present embodiment, the tire manufacturing apparatus 10 includes a PCI device 12 (see FIG. 2) for cooling while stabilizing the shape of the vulcanized tire T1, but is not limited thereto.

[0014] The vulcanizing apparatus includes a vulcanizing mold and a center mechanism for shaping the shape of the tire T1, and an opening / closing mechanism capable of opening and closing the vulcanizing mold. The vulcanizing mold may be a conventionally known segmented mold or a conventionally known two-piece mold. The center mechanism includes a bladder or the like and is disposed at the center portion of the vulcanizing mold. The opening / closing mechanism is disposed around the vulcanizing mold and is configured to be displaceable between a mold clamping state and a mold opening state.

[0015] The unloader 11 includes an unloader main body 111, a plurality of chucks 112 capable of suspending the tire T1 (in a horizontal orientation) such that the tire diameter direction D2 is along the horizontal direction, and a moving mechanism 113 capable of moving the unloader main body 111 in both the vertical direction and the horizontal direction. The unloader main body 111 is formed in a ring shape so as not to interfere with the center mechanism of the vulcanizing mold when taking out the tire T1. In FIG. 1 (similarly for FIGS. 3 and 4), some of the plurality of chucks 112 are omitted in the drawing.

[0016] The chuck 112 extends downward from the unloader main body 111 and its tip extends radially outward of the unloader main body 111. That is, the chuck 112 is formed in an L shape in a vertical cross-section along the radial direction of the unloader main body 111. When suspending the tire T1, the radial direction of the unloader main body 111 substantially coincides with the tire diameter direction D2.

[0017] The plurality of chucks 112 are arranged in an annular shape at intervals in the circumferential direction of the unloader main body 111. Each chuck 112 is configured to be slidable along the radial direction of the unloader main body 111. Thereby, the plurality of chucks 112 can be expanded in diameter or contracted in diameter. When the plurality of chucks 112 are expanded in diameter, the bead portion 1 of the tire T1 can be supported from the inside in the tire diameter direction D2 to suspend the tire T1. When the plurality of chucks 112 are contracted in diameter, they retract inside the tire diameter direction D2 from the bead portion 1 of the tire T1 to release the tire T1.

[0018] The moving mechanism 113 is configured to be able to move the tire T1, for example, from the vulcanizing mold to the PCI device 12 (see FIG. 2). In the present embodiment, the moving mechanism 113 includes a rotating shaft 113a that can rotate in the horizontal direction, an arm 113b that connects the rotating shaft 113a and the unloader main body 111, and a vertical moving means (not shown) that can move the rotating shaft 113a in the vertical direction, but is not limited thereto. For example, the moving mechanism 113 may have a configuration similar to a conventionally known robot arm.

[0019] As shown in FIG. 2, the PCI device 12 includes a lower rim plate 121 and an upper rim plate 122 that are assembled to the vulcanized tire T1, and an internal pressure loading means (not shown) that supplies gas to the internal space of the tire T1 (see FIG. 4) sealed by the rim plates 121 and 122 to load internal pressure. Thereby, the tire T1 is cooled (expansion cooling) in an expanded state, and the dimensional stability and uniformity of the tire can be improved.

[0020] The rim plates 121 and 122 are formed in a shape that can support the bead portion 1 during the expansion cooling of the tire T1, and are arranged along the horizontal direction. The rim plates 121 and 122 are formed in a circular shape in plan view and contact the outer surface of the bead portion 1 in the tire axis direction D1.

[0021] The lower rim plate 121 is disposed below the PCI device 12 and is supported by a lower support shaft 123 that extends along the vertical direction. The lower support shaft 123 is disposed at the center of the lower rim plate 121. The upper rim plate 122 is disposed above the PCI device 12 and is supported by an upper support shaft 124 that extends along the vertical direction. The upper support shaft 124 is disposed at the center of the upper rim plate 122.

[0022] The PCI device 12 includes a vertical moving means (not shown) that can move the upper support shaft 124 in the vertical direction. The upper support shaft 124 is lifted (retracted) by the vertical moving means so as not to interfere with the unloader 11 during the movement (transport) of the tire T1, and descends after placing the tire T1 on the lower rim plate 121 (see FIG. 3) and retracting the unloader 11 (see FIG. 4).

[0023] <Method for manufacturing a pneumatic tire> Next, a method for manufacturing a pneumatic tire according to the present embodiment will be described with reference to FIGS. 1 to 4.

[0024] The method for manufacturing the pneumatic tire T1 of the present embodiment includes a suspension step of suspending the tire T1 after the vulcanization step so that the tire diameter direction D2 is along the horizontal direction. In the vulcanization step, after setting the pre-vulcanization tire T1 in the open mold vulcanizing mold, the vulcanizing mold is closed to vulcanize the tire T1. Thereafter, in the vulcanization step, the vulcanizing mold is opened to make the vulcanized tire T1 removable. In the vulcanization step, conventionally known vulcanization conditions can be applied.

[0025] In the suspension step, among the pair of bead portions 1, 1, the bead portion 1 located above is supported from below. In the suspension step, the bead portion 1 located below is not supported, and the tire T1 hangs by its own weight.

[0026] The suspension step includes a removal step of removing the vulcanized tire T1 from the open mold vulcanizing mold, a standby step of waiting in a suspended state of the vulcanized tire T1 after the removal step, and a transfer step of transferring the vulcanized tire T1 to a subsequent process after the standby step.

[0027] In the removal step, the vulcanized tire T1 is removed from the open mold vulcanizing mold using the unloader 11. Specifically, the moving mechanism 113 moves the unloader main body 111 above the central mechanism of the vulcanizing mold and coaxially with the vulcanized tire T1, and then lowers it. At this time, the chuck 112 moves to the inner side in the radial direction of the unloader main body 111, and the tip of the chuck 112 is located inside the tire diameter direction D2 than the bead portion 1. Next, the chuck 112 is moved to the outer side in the radial direction of the unloader main body 111. Thereby, the bead portion 1 can be supported by the chuck 112. Finally, the moving mechanism 113 raises the unloader main body 111 to remove the vulcanized tire T1 from the vulcanizing mold.

[0028] In the standby process, the vulcanized tire T1 is suspended to wait in order to blow off the fumes generated from the tire T1. The standby position of the tire T1 in the standby process is between the vulcanizing mold and the device used in the subsequent process or on the device. In the present embodiment, the subsequent process is the post-cure inflation process (hereinafter also referred to as the "PCI process"), and the device used in the PCI process is the PCI device 12, but it is not limited thereto. The fumes contain, for example, compounding agents such as vulcanizing agents, vulcanization accelerators, plasticizers, and anti-aging agents. By blowing off the fumes in the standby process, it is possible to suppress the appearance defect of the tire caused by the solidification of a part of the fumes. The standby time of the tire T1 at the standby position is the time when the tire T1 is stationary at the standby position.

[0029] In the conveying process, the suspended tire T1 is conveyed from the standby position to the device used in the subsequent process. In the present embodiment, as shown in FIGS. 2 and 3, the tire T1 suspended at the standby position is moved between the lower rim plate 121 and the upper rim plate 122 and coaxially therewith (see FIG. 2), and then the tire T1 is lowered (see FIG. 3). Then, after the tire T1 is placed on the lower rim plate 121, the chuck 112 is moved radially inward of the unloader body 111 to release the suspended state of the tire T1, and the unloader 11 is retracted from the PCI device 12.

[0030] The suspension time of the tire T1 in the suspension process is 30 seconds or more. According to such a method, the tire T1 is naturally cooled, and it is possible to suppress the deformation of the tire T1 due to its own weight when the tire T1 is placed in the subsequent process. Specifically, as shown in FIG. 3, when the bead portion 1 of the tire T1 is placed on the lower rim plate 121, it is possible to suppress the deformation of the bead portion 1 and the adjacent sidewall 2 due to the weight of the tire T1 and the narrowing of the bead interval Dm1 (see FIG. 1). This is because the tire T1 immediately after vulcanization has a high temperature and is soft.

[0031] The hanging time refers to the time when the tire T1 is in a suspended state. Specifically, it is the time from when it is removed from the vulcanization mold until it is set in the device (PCI device 12) used in the subsequent process. That is, the hanging time is the time from when the tire T1 is separated from the vulcanization mold in the extraction process until the chuck 112 is moved in the conveying process to release the suspended state of the tire T1.

[0032] The hanging time is 120 seconds or less. According to such a method, it is possible to suppress the deformation of the suspended tire T1 due to its own weight. Specifically, as shown in FIGS. 1 and 2, it is possible to suppress the deformation of the bead portion 1 supported by the chuck 112 and the adjacent sidewall 2 due to the weight of the tire T1 and the widening of the bead interval Dm1. Further, by performing the PCI process, which is a subsequent process, before the temperature of the tire T1 drops significantly, it is possible to make the bead interval Dm1 of the manufactured tire T1 closer to uniform. The hanging time is more preferably 90 seconds or less, and even more preferably 75 seconds or less.

[0033] By suppressing the deformation of the tire T1 by setting the hanging time to be 30 seconds or more and 120 seconds or less, the uniformity (homogeneity) of the tire T1 can be ensured, and manufacturing defects of the tire T1 can be suppressed. The method for manufacturing the tire T according to the present embodiment is particularly effective for tires with low rigidity. Specifically, the method for manufacturing the tire T according to the present embodiment is particularly effective for tires with a minimum thickness of the sidewall 2 of 8.1 mm or less.

[0034] When the ambient temperature is 10°C or more and less than 25°C, the hanging time is preferably less than 45 seconds. According to such a method, in an ambient temperature range where the temperature of the tire T1 easily drops, the hanging time of the tire T1 can be shortened, and the deformation of the suspended tire T1 due to its own weight can be suppressed. The ambient temperature is measured, for example, by a temperature sensor installed in the PCI device 12.

[0035] The hanging time is preferably 45 seconds or more when the ambient temperature is 25°C or higher and 40°C or lower. By such a method, even in an ambient temperature range where it is difficult for the temperature of the tire T1 to drop, the tire T1 is naturally cooled, and it is possible to suppress the tire T1 from deforming due to its own weight when the tire T1 is placed in a subsequent process.

[0036] The hanging time is preferably 60 seconds or less when the ambient temperature is 25°C or higher and 40°C or lower. By such a method, the hanging time of the tire T1 can be shortened, and it is possible to suppress the tire T1 in the hanging state from deforming due to its own weight.

[0037] The tire height of the tire T1 is preferably 185 mm or more. Thereby, for a tire with a large tire height, since the sidewall 2 is likely to deform during hanging, by manufacturing using the manufacturing method of the tire T1 according to the present embodiment, the deformation of the tire T1 can be effectively suppressed. The tire height is the height of the tire cross-section and can be calculated by (outer diameter of the tire - rim diameter) / 2. The outer diameter of the tire T1 is the outer diameter when the tire T1 is viewed with a line of sight parallel to the rotation axis.

[0038] The tire width of the tire T1 is preferably 265 mm or more. The tire width is the width in the tire axial direction D1 between the outermost portions located in the tire axial direction D1.

[0039] Each dimension of the tire is a value measured in a no-load state where the tire is mounted on a standard rim and filled with the standard internal pressure. The standard rim is the rim defined for each tire in the standard system including the standards on which the tire is based. For example, it is the standard rim in JATMA, and the "Measuring Rim" in TRA and ETRTO. The standard internal pressure is the air pressure defined for each tire in the standard system including the standards on which the tire is based. In the case of tires for trucks and buses and light trucks, it is the maximum air pressure in JATMA, the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in TRA, and the "INFLATION PRESSURE" in ETRTO. In the case of passenger car tires, it is usually 180 kPa, but in the case of tires marked with Extra Load or Reinforced, it is 220 kPa.

[0040] In this embodiment, the post-process of the suspension process is the PCI process. In the PCI process, as shown in FIG. 4, the upper rim plate 122 is lowered from above the tire T1 placed on the lower rim plate 121, and the internal space of the tire T1 is sealed by the lower rim plate 121 and the upper rim plate 122. Then, a gas is supplied to the internal space of the tire T1 by the internal pressure loading means, and the tire T1 is cooled in an inflated state.

[0041] (Modification of the method for manufacturing a pneumatic tire) (A) In the suspension process, the lower part of the suspended tire T1 may be supported by a support member. Thereby, the force applied to the suspended part (bead portion 1) of the tire T1 can be dispersed, and the deformation of the tire T1 can be suppressed. Examples of the support member include a plate member and a net-like member. The lower part of the tire T1 is the outer surface of the bead portion 1 and / or the sidewall 2 adjacent thereto, which is located below the tire T1 in the suspended state.

[0042] The supporting force by the supporting member is preferably 40% or more and 60% or less of the self-weight (vertical load) of the tire T1. The support of the tire T1 by the supporting member is performed in the standby process (standby position). In the standby process, the bead part 1 located above among the pair of bead parts 1, 1 is supported from below by the chuck 112, and the bead part 1 located below among the pair of bead parts 1, 1 and / or the outer surface of the sidewall 2 adjacent thereto are in a state of being supported by the supporting member.

[0043] (B) It is preferable that the supporting member in A above is the lower rim plate 121 of the PCI device 12. Thereby, the effect of suppressing the deformation of the tire T1 can be enhanced by using an existing device. In this case, in the standby process in the hanging process, the tire T1 is conveyed onto the PCI device 12, and the tire T1 is made to standby in a state where the bead part 1 located below is in contact with the lower rim plate 121 (see FIG. 3). Thus, a part of the conveying process may be included in the standby process.

[0044] (C) In the standby process, a device for blowing air onto the suspended tire T1 may be used. Thereby, the time (standby time) for blowing off the oil fume from the tire T1 can be shortened, and the hanging time of the tire T1 can be shortened. As a result, the deformation of the tire T1 due to hanging can be suppressed well.

[0045] (D) In the standby process, a device for sucking out the air containing the oil fume around the suspended tire T1 may be used. The device is attached to, for example, the unloader main body 111. Thereby, the time (standby time) for blowing off the oil fume from the tire T1 can be shortened, and the hanging time of the tire T1 can be shortened. As a result, the deformation of the tire T1 due to hanging can be suppressed well.

Example

[0046] Next, the example in this embodiment will be described.

[0047] By the method for manufacturing a pneumatic tire according to this embodiment, a vulcanization process, a hanging process, and a PCI process were performed to manufacture 19 tires, and the bead interval (see symbol Dm1 in FIG. 1) of each tire (Examples 1 to 19) was measured. The size of the manufactured tire was 265 / 70R18, and the hanging process was performed in an environment with an ambient temperature of 30°C. The bead interval was measured simply with a major without mounting on a regular rim.

[0048] Table 1 and FIG. 5 show the relationship between the hanging time and the bead interval in Examples 1 to 19.

[0049]

Table 1

[0050] As shown in Table 1 and FIG. 5, when the hanging time was 30 seconds, in Example 3, the bead interval was smaller than that in other examples. On the other hand, in Example 4, the bead interval was larger than that in other examples. This is presumably because the hanging process was performed in an environment with an ambient temperature of 30 degrees, making it difficult for the temperature of the tire after vulcanization to drop by natural cooling. By hanging the tire in a high-temperature state and placing it on the hanging and PCI devices, the bead portion and the sidewall adjacent thereto were deformed, resulting in a change in the bead interval.

[0051] When the hanging time was 60 seconds, compared with the cases where the hanging time was 30 seconds or 120 seconds, the bead intervals of Examples 5 to 13 were relatively close. This is presumably because even in an environment with an ambient temperature of 30 degrees, the tire in a high-temperature state was naturally cooled, and the deformation of the bead portion and the sidewall adjacent thereto was small. Also, it is considered that by performing the PCI process before the temperature of the tire dropped significantly, the bead intervals could be made closer to being uniform.

[0052] When the hanging time was 120 seconds, in Example 14, the bead interval was relatively smaller than that in other examples. On the other hand, in Example 16, the bead interval was relatively larger than that in other examples. This is presumably because the PCI process was carried out at a lower tire temperature compared to the cases where the hanging time was 30 seconds or 60 seconds, resulting in a smaller shape improvement effect by the PCI process.

[0053] From these results, it was found that when the ambient temperature was 30°C, 60 seconds was the most suitable among 30 seconds, 60 seconds, and 120 seconds for the hanging time.

[0054] [1] As described above, the method for manufacturing a pneumatic tire according to the present embodiment includes a hanging step of hanging the pneumatic tire after the vulcanization step so that the tire radial direction is along the horizontal direction, and the hanging time of the pneumatic tire in the hanging step is 30 seconds or more and 120 seconds or less.

[0055] According to such a method, by setting the hanging time to 30 seconds or more, the tire in the high-temperature state is naturally cooled, and it is possible to suppress the tire from deforming due to its own weight when the tire is placed in the subsequent process. By setting the hanging time to 120 seconds or less, it is possible to suppress the tire in the hanging state from deforming due to its own weight.

[0056] [2] In the method for manufacturing a pneumatic tire according to [1] above, it is preferable that the hanging time is less than 45 seconds when the ambient temperature is 10°C or more and less than 25°C.

[0057] According to such a method, in an ambient temperature range where the temperature of the tire easily drops, the hanging time of the tire can be shortened, and the deformation of the tire can be effectively suppressed.

[0058] [3] In the method for manufacturing a pneumatic tire according to the above [1] or [2], it is preferable that the hanging time is 45 seconds or more and 60 seconds or less when the ambient temperature is 25°C or higher and 40°C or lower.

[0059] According to such a method, by setting the hanging time to 45 seconds or more, the tire can be naturally cooled even in an ambient temperature range where it is difficult for the tire temperature to drop, and it is possible to suppress the tire from deforming due to its own weight when the tire is placed in a subsequent process. By setting the hanging time to 60 seconds or less, the hanging time of the tire can be shortened, and it is possible to suppress the tire in the hanging state from deforming due to its own weight.

[0060] [4] In the method for manufacturing a pneumatic tire according to any one of the above [1] to [3], it is preferable that the tire height of the pneumatic tire is 185 mm or more.

[0061] According to such a method, it is possible to effectively suppress the deformation of a tire whose sidewall is likely to deform in the hanging process.

[0062] [5] In the method for manufacturing a pneumatic tire according to any one of the above [1] to [4], in the hanging process, the lower part of the pneumatic tire in the hanging state may be supported by a support member.

[0063] According to such a method, the force applied to the hanging part of the tire can be dispersed, and the deformation of the tire can be suppressed.

[0064] [6] In the method for manufacturing a pneumatic tire according to the above [5], it is preferable that the support member is the lower rim plate of the post-cure inflation device.

[0065] According to such a method, the effect of suppressing the deformation of the tire can be enhanced by using an existing device.

[0066] Note that the method for manufacturing a pneumatic tire is not limited to the configurations and methods of the above-described embodiments, nor is it limited to the above-described effects. Also, the method for manufacturing a pneumatic tire can of course be variously modified within a range not departing from the gist of the present invention. For example, it goes without saying that one or more of the configurations and methods according to the above-described various modification examples can be arbitrarily selected and adopted in the configurations and methods according to the above-described embodiments.

Explanation of Signs

[0067] T1... pneumatic tire, 1... bead portion, 2... sidewall, 3... tread, 10... tire manufacturing apparatus, 11... unloader, 111... unloader body, 112... chuck, 113... moving mechanism, 113a... rotating shaft, 113b... arm, 12... post-cure inflation device, 121... lower rim plate, 122... upper rim plate, 123... lower support shaft, 124... upper support shaft

Claims

1. A manufacturing method of a pneumatic tire including a suspension step of suspending the pneumatic tire after the vulcanization step so that the tire radial direction is along the horizontal direction, wherein the suspension time of the pneumatic tire in the suspension step is 30 seconds or more and 120 seconds or less.

2. The manufacturing method of the pneumatic tire according to Claim 1, wherein the suspension time is less than 45 seconds when the ambient temperature is 10°C or more and less than 25°C.

3. The manufacturing method of the pneumatic tire according to Claim 1, wherein the suspension time is 45 seconds or more and 60 seconds or less when the ambient temperature is 25°C or more and 40°C or less.

4. The manufacturing method of the pneumatic tire according to Claim 1, wherein the tire height of the pneumatic tire is 185 mm or more.

5. In the suspension step, the lower part of the pneumatic tire in the suspended state is supported by a support member. The manufacturing method of the pneumatic tire according to any one of Claims 1 to 4.

6. The manufacturing method of the pneumatic tire according to Claim 5, wherein the support member is a lower rim plate of a post-cure inflation device.

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