JP6807222B2 - Tire vulcanization method - Google Patents

Description

The present invention relates to a method for vulcanizing a tire using a so-called segmented mold.

As a mold used for vulcanizing a pneumatic tire, a so-called segmented mold is known (for example, Patent Documents 1 to 3). The segmented mold comprises a plurality of sectors for forming the tread surface of the tire and a pair of side plates for forming the side surface of the tire. When the tire is vulcanized, a plurality of sectors connected in an annular shape are brought into close contact with the pair of side plates to be in a mold-closed state. After vulcanization, they separate into a mold-opened state, and the vulcanized tire is taken out of the mold.

Such a mold is stored in a container having a plurality of segments holding a sector and a jacket ring arranged on the tire radial outer side of the segments. The outer surface of the segment and the inner surface of the jacket ring engaged with the segment are formed of tapered surfaces having the same inclination as each other, and the segment moves in the tire radial direction as the jacket ring moves up and down. The displacement of the mold between the mold closed state and the mold open state described above, that is, the opening and closing of the mold is executed according to the operation of the container.

In the step of opening the mold to remove the vulcanized tire, the jacket ring is raised to move the segment outward in the tire radial direction and pull the sector away from the tread surface of the tire. At this time, the segment protrudes downward from the jacket ring and rises together with the jacket ring in that state. Along with these, the upper side plate also rises, thereby pulling the side plate away from the side surface of the tire.

The segment and jacket ring, which have risen to a certain height, are moved further away from the tire so as not to interfere with the removal of the tire. There are various types of movements for moving them out, such as rotating them 90 degrees around a horizontal axis, moving them horizontally, or raising them further. In any case, since the state in which the segment protrudes downward from the jacket ring is unstable, the segment is stored inside the jacket ring in the tire radial direction.

However, since the segment when it is stored in the jacket ring is in a state of being hung by its own weight, it may be displaced with respect to the jacket ring due to vibration. The misaligned segment was not stored in the jacket ring in the proper position, and as a result, the sector or segment could be damaged at the site where the unintended contact occurred. From this point of view, a method of suppressing the vibration of the segment before storage is desired, but a specific method suitable for it has not been known.

Japanese Unexamined Patent Publication No. 2008-126457 Japanese Unexamined Patent Publication No. 2011-46069 Japanese Unexamined Patent Publication No. 2014-113717

The present invention has been made in view of the above circumstances, and an object of the present invention is to perform a method of vulcanizing a tire using a segmented mold when the mold is opened in order to take out the vulcanized tire. The purpose is to allow the segments to be properly stored in the jacket ring.

The present inventor investigated the vibration of the segment when it was stored in the jacket ring, and raised the jacket ring, the tire adhered to the mold, particularly the tire adhered to the upper side plate, and the operation (expansion) of the bladder. However, it has been found that it can cause vibration of the segment. The present invention has been made based on such findings, and the above object can be achieved by the following configuration.

The method for smelting a tire according to the present invention is a method for smelting a tire using a mold including a plurality of sectors for molding the tread surface of the tire and a pair of side plates for molding the side surface of the tire. In the method, the mold is housed in a container having a plurality of segments holding the sector and a jacket ring located laterally lateral to the tire of the segment, engaging with the outer surface of the segment. The inner surface of the jacket ring is formed of tapered surfaces having the same inclination as each other, and the segment is configured to move in the tire radial direction as the jacket ring moves up and down. The step of opening the mold in order to take out the tire is to move the segment outward in the tire radial direction by raising the jacket ring, so that the segment protrudes downward from the jacket ring. The first step of raising the tire ring and the second step of raising the jacket ring and the segment together, and stopping the rise of the jacket ring to raise the segment. The third step includes expanding the bladder arranged inside the tire in the first or second step, including a third step of accommodating the segment inside the tire radial of the jacket ring. The bladder is contracted before the jacket ring stops ascending.

In this method, when the mold is opened in order to take out the vulcanized tire, the jacket ring is stopped from rising and then the segment is raised and stored. Therefore, the segment caused by the jacket ring raising operation. Vibration is suppressed. Further, by expanding the bladder in the first or second stage, the tire is smoothly separated from the upper side plate, and the vibration of the segment caused by the close contact of the tire is also suppressed. Further, since the bladder is contracted by the time the jacket ring stops ascending in the third stage, the vibration of the segment caused by the operation of the bladder is also suppressed. Therefore, according to this method, it is possible to prevent the segment from being displaced due to vibration and to appropriately store the segment in the jacket ring.

It is preferable that the bladder is contracted at the time when the jacket ring starts to rise in the first step. As a result, the load on the container can be reduced and the safety is enhanced.

From the expansion of the bladder to the contraction of the bladder in the first or second step, it is preferable to continuously raise the jacket ring without pausing. As a result, deterioration of the cycle time can be suppressed and the load on the container can be reduced.

In the first step, it is preferable to inflate the bladder with the sector away from the tread surface of the tire and the pair of side plates in contact with the side surfaces of the tire. In this case, since the bladder is expanded at a relatively early stage, it is convenient not to transmit the vibration to the segment. Even if the side plate is in contact with the tire, the sector is separated from the tire, so that the inflated bladder can give some movement or deformation to the tire to promote mold release.

In the second step, the bladder may be expanded after the side plates located above the pair of side plates start to rise. According to such a method, in a situation where the tire is in close contact with the upper side plate, the tire can be pulled away from the side plate by the inflated bladder.

A cross-sectional view schematically showing an example of a tire vulcanizer used for vulcanizing a pneumatic tire. Sectional view showing the state of vulcanizing a tire Cross-sectional view showing the state when the jacket ring starts to rise Cross-sectional view showing the state in which the jacket ring is in the process of rising Cross-sectional view showing a state in which the segment is moved outward in the tire radial direction. Sectional view showing the state where the jacket ring and the segment are raised together. Cross-sectional view showing the state where the segment is stored in the jacket ring Graph showing the mold opening rate of the mold and the change of the internal pressure of the bladder over time

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a tire vulcanizer used for vulcanizing pneumatic tires. This tire vulcanizer includes a mold 1 as a so-called segmented mold, a container 2 in which the mold 1 is stored, and a rubber bag-shaped bladder 3 (not shown in FIG. 1). The tires are set with the tire axial direction facing up and down as described later, and the left direction in FIG. 1 is the outside in the tire radial direction, and the right direction is the inside in the tire radial direction. The bladder 3 expands when a heating and pressurizing medium is supplied, and is pressed against the inner surface of the tire during vulcanization.

The mold 1 includes a plurality of sectors 11 for forming the tread surface of the tire, and a pair of side plates 12 and 13 for forming the side surface of the tire. In the mold clamping state shown in FIG. 1, a plurality of sectors 11 divided in the tire circumferential direction are gathered together and connected in an annular shape, and are in close contact with the side plates 12 and 13. Although not shown, the sector 11 is provided with a protrusion for forming a groove on the tread surface of the tire. A pair of bead rings 14 and 15 for fitting the bead portions of the tire are provided inside the side plates 12 and 13 in the tire radial direction, respectively.

The container 2 has a plurality of segments 21 that hold the sector 11 and a jacket ring 22 that is arranged on the outer side of the segment 21 in the tire radial direction. Generally, one segment 21 holds one sector 11. The jacket ring 22 is provided in an annular shape. The outer peripheral surface of the segment 21 and the inner peripheral surface of the jacket ring 22 that engages with the segment 21 are formed by tapered surfaces having the same inclination as each other, and the segment 21 moves in the tire radial direction as the jacket ring 22 moves up and down. It is configured to move. Each of the tapered surfaces is inclined outward in the tire radial direction toward the lower side.

The upper plate 23 is configured to be able to move up and down, and is driven by, for example, a hydraulic device. A side plate 12 located above the pair of side plates 12 and 13 is attached to the lower surface of the upper plate 23. Further, a segment 21 is slidably supported on the lower surface of the upper plate 23 along the tire radial direction. A side plate 13 located below is attached to the upper surface of the lower plate 24. The arm 25 is attached to a guide 26 erected on the upper surface of the upper plate 23 so as to be able to move up and down. The jacket ring 22 is supported by its arm 25 and is configured to be able to move up and down relative to the segment 21.

The jacket ring 22 is engaged with the segment 21 via the sliding rail 27. In the present embodiment, the sliding rail 27 is composed of an engaging groove formed on the tapered surface (inner surface) of the jacket ring 22 and a protrusion formed on the tapered surface (outer surface) of the segment 21. The cross-sectional shape of the sliding rail 27 is not particularly limited, and the positional relationship between the engaging groove and the protrusion may be opposite. When the jacket ring 22 is moved up and down, the segment 21 moves in the tire radial direction with sliding between the tapered surfaces, and the sector 11 held by the segment 21 follows the segment 21.

The mold 1 is configured to be openable and closable between a mold closed state in which the sector 11 and the pair of side plates 12 and 13 are in close contact with each other (see FIGS. 1 and 2) and a mold open state in which they are separated from each other. There is. The displacement of the mold 1 between the mold closed state and the mold open state, that is, the opening and closing of the mold 1, is performed according to the operation of the container 2. Although not shown, the tire vulcanizer includes a drive device for driving the container 2, heating means for heating the sector 11 and the side plates 12 and 13, and control for controlling the operation of each member such as the container 2 and the bladder 3. Sections are provided, and conventionally known configurations can be applied to these sections.

A tire vulcanization method using this mold 1 will be described. First, the unvulcanized tire T is set in the mold 1 in the mold open state (setting process). Next, the mold 1 is placed in the mold closed state, and as shown in FIG. 2, the sector 11 and the pair of side plates 12 and 13 in close contact with each other are pressed against the outer surface of the tire T, and the expanded bladder 3 is pressed against the tire T. The tire T is vulcanized by pressing it against the inner surface of the tire (vulcanization step). In vulcanization, conventionally known vulcanization conditions can be applied. After vulcanization of the tire T, the sector 11 and the pair of side plates 12 and 13 are separated to bring the mold 1 into a mold-opening state (mold-opening step). Then, the tire T after vulcanization is taken out from the mold 1 in the mold-opened state (demolding step).

As will be described later, in the above-mentioned mold opening step, the segment 21 is in a state of protruding downward from the jacket ring 22 (see FIG. 5). Further, after raising them, the segment 21 is housed inside the jacket ring 22 in the tire radial direction. At that time, if vibration is transmitted to the segment 21 hanging from the jacket ring 22, the segment 21 may be misaligned and may not be stored in an appropriate posture. Therefore, in the present embodiment, in order to suppress the vibration of such a segment 21, the step of opening the mold 1 into the mold open state is executed as follows.

That is, in the step of opening the mold 1 in order to take out the vulcanized tire T, first, the jacket ring 22 is raised as shown in FIGS. 3 to 5 from the mold closed state of FIG. As a result, the segment 21 is moved outward in the tire radial direction so that the segment 21 protrudes downward from the jacket ring 22 (first step). At this stage, each sector 11 is expanded in diameter and pulled away from the tread surface of the tire T. In the present embodiment, from the viewpoint of reducing the load on the container 2 and improving the safety, the bladder 3 is contracted when the jacket ring 22 starts to rise in the first stage (see FIG. 3).

Next, as shown in FIG. 6, the jacket ring 22 is further raised, and the jacket ring 22 and the segment 21 are raised together (second step). At this stage, the upper side plate 12 is also raised along with them, so that the side plate 12 is separated from the side surface of the tire T. The segment 21 shown in FIG. 6 stays on the jacket ring 22 via the stopper of the sliding rail 27, and is in a state of being hung by its own weight, so that it is unstable and vibration is easily transmitted.

Subsequently, by stopping the ascent of the jacket ring 22 and raising the segment 21 as shown in FIG. 7, the segment 21 is housed inside the jacket ring 22 in the tire radial direction (third step). This operation can be executed by stopping the raising operation of the arm 25 and then raising the upper plate 23. By storing the segment 21 after stopping the ascent of the jacket ring 22 in this way, the vibration of the segment 21 caused by the ascending operation of the jacket ring 22 is suppressed.

The mold 1 of FIG. 7 is in a mold-opened state in which the tire T can be taken in and out, but in the present embodiment, after the storage of the segment 21 in the third stage is completed so as not to interfere with the removal of the tire T. Then, the jacket ring 22, the segment 21, and the like are rotated 90 degrees around the horizontal axis, and the jacket ring 22 and the segment 21 are moved away from the tire T (fourth stage). Therefore, the stop of the jacket ring 22 in the third stage is a temporary stop. The movement for moving out may be another mode such as horizontal movement or further raising.

The step of bringing the mold 1 into the mold-opened state includes the first to third steps as described above, and then, as shown in FIG. 4, in the first or second step (in the present embodiment, the first step). The bladder 3 arranged inside the tire T is inflated (at the stage of). Further, as shown in FIG. 5, the bladder 3 is contracted until the jacket ring 22 stops ascending in the third stage. In other words, the bladder 3 expands and contracts between the time when the jacket ring 22 starts to rise in the first stage and the time when the jacket ring 22 stops rising in the third stage. The bladder 3 contracts when the heating and pressurizing medium is discharged.

By expanding the bladder 3 in this way, the release of the tire T is promoted, and the tire T is smoothly separated from the side plate 12. Therefore, the vibration of the segment 21 caused by the adhesion of the tire T to the side plate 12 is suppressed. Further, since the bladder 3 is contracted before the jacket ring 22 stops ascending in the third stage, the vibration of the segment 21 caused by the operation (expansion) of the bladder 3 is also suppressed. Therefore, according to the present embodiment, the segment 21 can be appropriately housed in the jacket ring 22 by preventing the segment 21 from being displaced due to vibration.

In the present embodiment, as shown in FIG. 4, in the first stage, the sector 11 is separated from the tread surface of the tire T and the pair of side plates 12 and 13 are in contact with the side surface of the tire T. Inflate the bladder 3. In this case, since the bladder 3 is expanded at a relatively early stage, it is convenient not to transmit the vibration to the segment 21. Even if the side plates 12 and 13 are in contact with the tire T, since the sector 11 is separated from the tire T, the inflated bladder 3 can give some movement or deformation to the tire T to promote mold release. ..

The graph of FIG. 8 shows the change over time in the mold opening rate of the mold 1 and the internal pressure of the bladder 3. The time on the horizontal axis starts from the time when the jacket ring 22 starts the ascending operation. The mold opening rate on the vertical axis represents the degree of progress of the operation of the jacket ring 22 when the mold closing state is zero and the mold opening state in which the jacket ring 22 has moved out is 100. Therefore, this mold opening rate does not change while the jacket ring 22 is stopped.

At the time when the mold opening process is started, that is, when the jacket ring 22 starts to rise, the internal pressure of the bladder 3 is substantially zero, and the bladder 3 is contracted. The mold opening rate of the mold 1 changes linearly from the start of ascending of the jacket ring 22, and changes linearly again with a period of no change in the middle. During the period in which the mold opening rate changes linearly, the jacket ring 22 is continuously operated. The period during which the mold opening rate does not change corresponds to the third stage in which the jacket ring 22 stops rising, and the segment 21 is housed in the jacket ring 22 at this stage.

As shown in FIG. 8, the internal pressure of the bladder 3 is temporarily high when a delay of several seconds (for example, 1 to 2 seconds) has passed since the jacket ring 22 started to rise. In the vicinity of the peak where the internal pressure is high, the bladder 3 expands as shown in FIG. 4, whereby the tire T is surely separated from the side plate 12. The re-expansion of the bladder 3 may be short, for example set to 3-4 seconds. At the beginning of the period when the mold opening rate does not change, the internal pressure of the bladder 3 is sufficiently low, which means that the bladder 3 is contracted by the time the jacket ring 22 stops rising in the third stage. Represents.

In the graph of FIG. 8, while the internal pressure of the bladder 3 is temporarily high, the mold opening rate changes linearly. As described above, in the present embodiment, the jacket ring 22 is continuously raised without pausing from the expansion to the contraction of the bladder 3 in the first or second stage. As a result, deterioration of the cycle time can be suppressed, and the load on the container 2 can be reduced.

In the present embodiment, as shown in FIG. 4, an example in which the bladder 3 is expanded in a state where the pair of side plates 12 and 13 are in contact with the side surface of the tire T is shown, but instead of this, in the second stage. , The bladder 3 may be inflated after the side plate 12 located above the pair of side plates 12 and 13 starts to rise. In that case, the expansion and contraction of the bladder 3 is performed in the process of transitioning from the state shown in FIG. 5 to the state shown in FIG.

The tire vulcanization method according to the present invention is a normal tire vulcanization method, except that when the tire is vulcanized using the segmented mold, the step of opening the mold is performed as described above. The method is the same, and any conventionally known process or apparatus can be applied to the present invention.

The present invention is not limited to the above-described embodiment, and various improvements and changes can be made without departing from the spirit of the present invention.

1 Mold 2 Container 3 Bladder 11 Sector 12 Side plate 13 Side plate 14 Bead ring 15 Bead ring 21 Segment 22 Jacket ring 23 Upper plate 24 Lower plate 25 Arm 26 Guide 27 Sliding rail T Tire

Claims (5)

In a method of vulcanizing a tire using a mold including a plurality of sectors for molding a tread surface of a tire and a pair of side plates for molding the side surface of the tire.
The mold is stored in a container having a plurality of segments holding the sector and a jacket ring arranged on the tire radial outer side of the segment.
The outer surface of the segment and the inner surface of the jacket ring engaged with the outer surface are formed of tapered surfaces having the same inclination as each other, and the segment moves in the tire radial direction as the jacket ring moves up and down. Is configured to
The process of opening the mold to remove the vulcanized tire is
A first step of moving the segment outward in the tire radial direction by raising the jacket ring so that the segment protrudes downward from the jacket ring.
A second step of raising the jacket ring further and raising the jacket ring and the segment together.
A third step of accommodating the segment inside the jacket ring in the tire radial direction by stopping the ascent of the jacket ring and raising the segment is included.
A tire characterized in that the bladder arranged inside the tire is inflated in the first or second step, and the bladder is contracted before the jacket ring stops ascending in the third step. Vulcanization method. The method for vulcanizing a tire according to claim 1, wherein the bladder is contracted at the time when the jacket ring starts to rise in the first step. The rise of the jacket ring is suspended from the expansion of the bladder in the first or second step until the bladder is contracted by the time the jacket ring stops rising in the third step. The method for vulcanizing a tire according to claim 1 or 2, which is carried out continuously without any effort. Any one of claims 1 to 3 in which in the first step, the bladder is inflated with the sector away from the tread surface of the tire and the pair of side plates in contact with the side surfaces of the tire. The method for vulcanizing a tire according to item 1. The method for vulcanizing a tire according to any one of claims 1 to 3, wherein in the second step, the bladder is expanded after the side plates located above the pair of side plates start to rise. ..

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