JP2021169170A - Method and apparatus for manufacturing pneumatic tire - Google Patents

Abstract

To provide a method and an apparatus for manufacturing a pneumatic tire capable of improving dimensional stability and quality stability.SOLUTION: When performing post-cure inflation on a pneumatic tire T vulcanized in a mold, a width of the pneumatic tire T is detected, and a position of an annular pipe 14 that blows air onto an outer surface of the pneumatic tire T is automatically adjusted based on a width of the pneumatic tire T. Therefore, a pipe drive device 13 that displaces the annular pipe 14 along a tire width direction, a tire width detection device 21 that detects a width of the pneumatic tire T, and a control unit 22 that controls the pipe drive device 13 based on the width of the pneumatic tire T detected by the tire width detection device 21, are provided.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method and an apparatus for manufacturing a pneumatic tire that performs post-cure inflation (PCI), and more specifically, a method and a manufacturing device for a pneumatic tire that can improve dimensional stability and quality stability. Regarding the device.

In the manufacturing process of a pneumatic tire having a carcass layer made of an organic fiber cord, the pneumatic tire is vulcanized in a mold of a vulcanizer, and then the internal pressure is applied to the vulcanized pneumatic tire removed from the mold. Post-cure inflation that naturally cools the pneumatic tire in a state of being filled with the tire is generally performed (see, for example, Patent Documents 1 to 3). Pneumatic tires are still hot immediately after vulcanization and tend to undergo dimensional changes due to heat shrinkage of the carcass cord. Therefore, post-cure inflation should be used to improve the dimensional stability and uniformity of pneumatic tires. Can be done.

Conventionally, in post-cure inflation, an annular pipe having a plurality of air injection holes is arranged so as to surround the pneumatic tire, and air is blown from the annular pipe to the outer surface of the pneumatic tire to cool the pneumatic tire. It is carried out. Here, pneumatic tires having various tire sizes are provided in the post-cure inflation process, but when the tire sizes are different, the position where the air hits differs in the tire width direction according to the tire size. If the cooling points of the pneumatic tire during post-cure inflation are different in this way, the dimensional change due to heat shrinkage of the carcass cord will not be uniform. Further, in the belt cover layer, the intermediate elongation of the band cord extending in the tire circumferential direction and the physical properties of the cap tread rubber layer are likely to vary. Therefore, the position where the air hits differs depending on the tire size, which causes variations in the tire dimensions, which in turn causes variations in the tire quality including uniformity.

JP-A-2007-190808 Japanese Unexamined Patent Publication No. 2008-273095 JP-A-2017-94613

An object of the present invention is to provide a method and an apparatus for manufacturing a pneumatic tire capable of improving dimensional stability and quality stability.

The method for producing a pneumatic tire of the present invention for achieving the above object detects the width of the pneumatic tire when performing post-cure inflation on the pneumatic tire vulcanized in the mold, and the above-mentioned It is characterized in that the position of the annular pipe that blows air onto the outer surface of the pneumatic tire is automatically adjusted based on the width of the pneumatic tire.

Further, the pneumatic tire manufacturing apparatus of the present invention includes a pair of rim plates that are fitted to a pair of bead portions of the pneumatic tire, and a supply path that supplies a pressurizing medium into the pneumatic tire through the rim plates. , A discharge path for discharging the pressure medium in the pneumatic tire through the rim plate, an annular pipe for blowing air on the outer surface of the pneumatic tire, and a pipe drive for displace the annular pipe along the tire width direction. The device includes a tire width detecting device that detects the width of the pneumatic tire, and a control unit that controls the pipe drive device based on the width of the pneumatic tire detected by the tire width detecting device. It is a feature.

In the method for manufacturing a pneumatic tire of the present invention, the width of the pneumatic tire is detected, and the position of the annular pipe that blows air to the outer surface of the pneumatic tire is automatically adjusted based on the width of the pneumatic tire. Since it is possible to effectively and uniformly cool the pneumatic tire regardless of the tire size, it is possible to suppress the dimensional change due to the heat shrinkage of the carcass cord, and to improve the dimensional stability and quality stability of the pneumatic tire. Can be improved.

Further, in the pneumatic tire manufacturing apparatus of the present invention, in addition to the conventional post-cure inflation apparatus configuration, a pipe drive device that displaces an annular pipe for cooling along the tire width direction and a pneumatic tire width are used. The above-mentioned method for manufacturing a pneumatic tire is carried out by providing a tire width detecting device for detecting and a control unit for controlling a pipe drive device based on the width of the pneumatic tire detected by the tire width detecting device. Is possible.

In the present invention, the width of the pneumatic tire can be detected by a camera or a laser sensor. That is, a camera or a laser sensor can be used as the tire width detecting device. According to the camera or the laser sensor, the width of the pneumatic tire can be accurately detected.

It is a meridian cross-sectional view which shows the manufacturing apparatus (post-cure inflation apparatus) of the pneumatic tire which concerns on embodiment of this invention. It is a figure which shows schematic operation of the annular pipe in the manufacturing method of the pneumatic tire of FIG.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a pneumatic tire manufacturing apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the pneumatic tire manufacturing apparatus includes a pair of rim plates 1 and 2 fitted to a pair of bead portions of a pneumatic tire T arranged so that the tire central axis is in the vertical direction. , Support shafts 3 and 4 for driving these rim plates 1 and 2 in the vertical direction, a supply path 5 for supplying the pressurizing medium M into the pneumatic tire T through the lower rim plate 1, and the upper rim plate 2. It is provided with a discharge path 6 for discharging the pressurizing medium M in the pneumatic tire T through the tire T. The pneumatic tire T may be arranged so that its central axis is in the horizontal direction. The rim plates 1 and 2 are configured to close the hollow portion of the pneumatic tire T by fitting with the bead portion of the pneumatic tire T. The supply path 5 and the discharge path 6 may be formed on either side of the rim plates 1 and 2, and may be a common flow path. Air is preferably used as the pressurizing medium M, but other gases or liquids can also be used.

A support beam 11 extending in the horizontal direction is arranged above the pneumatic tire T supported by the rim plates 1 and 2, and a plurality of support rods 12 are arranged so as to hang down from the support beam 1. There is. Two annular pipes 14 are attached to the support rod 12 via a pipe drive device 13. The pipe drive device 13 is composed of a pair of upper and lower rods 13a that are connected to the annular pipe 14 and extend in the tire width direction, and a drive unit 13b that advances and retreats these rods 13a along the longitudinal direction of the rods 13a. The annular pipe 14 is displaced along the tire width direction by advancing and retreating. Each annular pipe 14 extends so as to surround the pneumatic tire T, and is provided with a plurality of air injection holes 15 on the inner peripheral side thereof. The annular pipe 14 is connected to an air supply source (not shown), and during post-cure inflation, cooling air is injected from the air injection hole 15 toward the outer surface of the pneumatic tire T.

Further, a tire width detecting device 21 for detecting the width of the pneumatic tire T is provided on one of the annular pipes 14, and the width of the pneumatic tire T detected by the tire width detecting device 21 is input to the control unit 22. It is supposed to be done. It is preferable to use a camera or a laser sensor as the tire width detecting device 21. In the case of a camera, the width of the pneumatic tire T can be detected from the captured image. On the other hand, in the case of the laser sensor, the width of the pneumatic tire T can be detected based on the cutting condition of the laser light. According to the camera or the laser sensor, the width of the pneumatic tire T can be accurately detected, and the output data can be used as it is for control. The control unit 22 controls the pipe drive device 13 based on the width of the pneumatic tire T detected by the tire width detection device 21. The width of the pneumatic tire T can be measured as a whole, but when the center position of the pipe drive device 13 and the center position of the pneumatic tire T match, the pneumatic tire It may be sufficient to only detect the end position of T in the tire width direction. That is, it is possible to determine the position of the pair of annular pipes 14 in the tire width direction so as to be symmetrical with respect to the center position of the pneumatic tire T with reference to the end position of the pneumatic tire T in the tire width direction. be.

Next, a method of manufacturing the pneumatic tire T by using the above-mentioned pneumatic tire manufacturing apparatus will be described. First, the pneumatic tire T is vulcanized in a vulcanizer (not shown), and then the vulcanized pneumatic tire T removed from the mold of the vulcanizer is subjected to a post-cure inflation step. That is, as shown in FIG. 1, the pair of rim plates 1 and 2 are fitted into the pair of bead portions of the pneumatic tire T, and the exhaust passage 6 is closed and the supply passage 5 is added to the pneumatic tire T. The pressure medium M is supplied. On the other hand, the width of the pneumatic tire T is detected by the tire width detection device 21, and the control unit 22 controls the pipe drive device 13 based on the width of the pneumatic tire T detected by the tire width detection device 21. The position of the annular pipe 14 is automatically adjusted based on the width of the pneumatic tire T. For example, the position of the annular pipe 14 can be adjusted so that the air injection hole 15 of the annular pipe 14 is near the shoulder portion of the pneumatic tire T.

After adjusting the position, cooling air is blown from the air injection hole 15 of the annular pipe 14 toward the outer surface of the pneumatic tire T. In this way, post-cure inflation for the pneumatic tire T is started. Further, when the post-cure inflation is terminated, the pressurizing medium M in the pneumatic tire T is discharged from the discharge path 6, and the pair of rim plates 1 and 2 are separated from the bead portion of the pneumatic tire T.

FIG. 2 schematically shows the operation of the annular pipe. As shown in FIG. 2, when post-cure inflation is performed on the pneumatic tire T1 having a relatively small width and the pneumatic tire T2 having a relatively large width, a pair of annular pipes 14 for the narrow pneumatic tire T1. Is placed at position P1, and for the wide pneumatic tire T2, a pair of annular pipes 14 are placed at position P2.

According to the above-described method for manufacturing a pneumatic tire, the width of the pneumatic tire T is detected, and the position of the annular pipe 14 that blows air onto the outer surface of the pneumatic tire T is automatically determined based on the width of the pneumatic tire T. By adjusting to, it becomes possible to effectively and uniformly cool the pneumatic tire T regardless of the tire size, so that the dimensional change due to heat shrinkage of the carcass cord can be suppressed and the dimensions of the pneumatic tire T can be suppressed. Stability can be improved. Further, it is possible to suppress the variation in the intermediate elongation of the band cord and the variation in the uniformity, and improve the quality stability of the pneumatic tire T.

In manufacturing pneumatic tires for passenger cars, the tire manufacturing methods of Conventional Examples 1 and 2 and Examples 1 and 2 in which only the structure and tire size of the annular pipe for cooling in post-cure inflation were different were carried out, and 120, respectively. Manufactured a book pneumatic tire.

In Conventional Example 1, the position of the annular pipe for cooling is fixed, and a pneumatic tire having a tire size of 195 / 65R15 is targeted. In Conventional Example 2, the position of the annular pipe for cooling is fixed, and a pneumatic tire having a tire size of 225 / 60R18 is targeted. In Example 1, a structure was adopted in which the position of the annular pipe for cooling was automatically adjusted based on the width of the pneumatic tire, and a pneumatic tire having a tire size of 195 / 65R15 was targeted. In the second embodiment, a structure is adopted in which the position of the annular pipe for cooling is automatically adjusted based on the width of the pneumatic tire, and a pneumatic tire having a tire size of 225 / 60R18 is targeted.

The test tires obtained by the above-mentioned method for manufacturing a pneumatic tire were evaluated for dimensional stability, uniformity, and intermediate elongation of the band cord by the following evaluation methods, and the results are shown in Table 1.

Dimensional stability:
The profile of each test tire was measured, and the standard deviation of the profile measurement values was obtained for each of Conventional Examples 1 and 2 and Examples 1 and 2. The evaluation result is shown by an index with Conventional Example 1 as 100. The smaller the index value, the better the dimensional stability.

Uniformity:
The radial force variation (RFV) of each test tire was measured, and the standard deviation of the RFV value was determined for each of Conventional Examples 1 and 2 and Examples 1 and 2. The evaluation result is shown by an index with Conventional Example 1 as 100. The smaller the index value, the better the uniformity.

Band cord intermediate elongation:
The band cord of the belt cover layer was collected from the shoulder portion of each test tire, the intermediate elongation thereof was measured, and the standard deviation of the intermediate elongation of the band cord was obtained for each of Conventional Examples 1 and 2 and Examples 1 and 2. rice field. The evaluation result is shown by an index with Conventional Example 1 as 100. The smaller the index value, the smaller the variation in the intermediate elongation of the band code.

As can be seen from Table 1, the tires obtained by the method of Example 1 have improved dimensional stability and uniformity in comparison with the conventional example 1, and have less variation in the intermediate elongation of the band cord. Met. Further, in the conventional example 2 in which the tire size is larger than that in the conventional example 1, the relative position of the annular pipe with respect to the pneumatic tire is inappropriate, so that the result is worse than that in the conventional example 1. On the other hand, in Example 2 in which the tire size was the same as in Conventional Example 2, the same result as in Example 1 was obtained.

1, 2, Rim plate 3, 4 Support shaft 5 Supply path 6 Discharge path 11 Support beam 12 Support rod 13 Pipe drive device 13a Rod 13b Drive section 14 Circular pipe 15 Air injection hole 21 Tire width detection device 22 Control section M Pressurized medium T, T1, T2 Pneumatic tires

Claims (6)

When performing post-cure inflation on a pneumatic tire vulcanized in a mold, the width of the pneumatic tire is detected, and the position of the annular pipe that blows air onto the outer surface of the pneumatic tire is the position of the pneumatic tire. A method of manufacturing a pneumatic tire, which is characterized by automatically adjusting based on the width of the tire. The method for manufacturing a pneumatic tire according to claim 1, wherein the width of the pneumatic tire is detected by a camera. The method for manufacturing a pneumatic tire according to claim 1, wherein the width of the pneumatic tire is detected by a laser sensor. A pair of rim plates that fit into a pair of bead portions of a pneumatic tire, a supply path that supplies a pressurizing medium into the pneumatic tire through the rim plate, and pressurization in the pneumatic tire through the rim plate. A discharge path for discharging the medium, an annular pipe that blows air onto the outer surface of the pneumatic tire, a pipe drive device that displaces the annular pipe along the tire width direction, and a tire that detects the width of the pneumatic tire. A pneumatic tire manufacturing apparatus including a width detecting device and a control unit that controls the pipe driving device based on the width of the pneumatic tire detected by the tire width detecting device. The pneumatic tire manufacturing device according to claim 4, wherein the tire width detecting device is a camera. The pneumatic tire manufacturing apparatus according to claim 4, wherein the tire width detecting apparatus is a laser sensor.

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