JP2020179532A - Stitching device and stitching method - Google Patents

Abstract

To provide a stitching technique capable of sufficiently suppressing the occurrence of insufficient stitching in a central part and the occurrence of biting and insufficient stitching in a side edge part of a breaker, a tread, and the like regardless of how a tire is.SOLUTION: A stitching device is configured such that: a plurality of sets of pressing means opposed to each other, one set of pressing means including two stitching rollers each of which is inserted and held through one end of a rotary shaft, are provided along the circumferential direction of a 1st cover; the respective pressing rollers of the respective pressing means are configured to move laterally from a center part of a 2nd cover toward a side edge part of the 2nd cover to press the 2nd cover against the 1st cover in synchronization with each other; the two stitching rollers of the one set of pressing means are stitching rollers with the same diameter and different widths; and in the two sets of pressing means adjacent to each other, portions of the pressing surfaces of wide stitching rollers are arranged to overlap each other.SELECTED DRAWING: Figure 2

Description

The present invention relates to a stitching device and a stitching method used in a process of crimping tire components to each other.

When manufacturing pneumatic tires, the 1st cover is molded by pasting an inner or carcass ply on the 1st molding drum, while the 2nd cover is molded by pasting a breaker or tread on the 2nd molding drum. A low cover (raw tire) is molded by expanding the 1st cover into the shape of a tire and attaching it to the 2nd cover (two-stage molding method).

When molding this low cover, a rotating 1st cover is used by using a stitching device configured by connecting two sets of pressing means in order to sufficiently bring the 2nd cover and the 1st cover attached to the 1st cover into close contact with each other. It is common practice to press the 2nd cover upwards (stitching).

FIG. 7 is a top view (a) schematically showing a pressing means in a conventional stitching device, and a view (b) showing a state of stitching. As shown in FIG. 7A, the stitching device is configured by two sets of pressing means. Each of the two sets of pressing means 31 and 32 is configured by inserting two rollers (stitching rollers) having the same diameter and the same width into the rotating shaft. The corners of each stitching roller are chamfered.

The stitching rollers of the two sets of pressing means 31 and 32 are arranged along the circumferential direction of the 1st cover to which the 2nd cover is attached to the outer peripheral surface, and are centered while rotating in accordance with the rotation of the 1st cover. Stitching is performed by moving from the portion toward the outer edge portion in the direction of the white arrow and pressing the 2nd cover against the 1st cover. However, since the stitching rollers used in the pressing means 31 and 32 have chamfered corners, the chamfered corners form a portion N that cannot be pressed in the central portion. As a result, as shown in FIG. 7B, stitching is not performed in the central portion, and air may remain. Then, when vulcanization is performed using the low cover in which air remains in this way, a dent is generated in the central portion of the vulcanized product tire after the air is released, which causes the generation of bears or the gauge distribution. May lead to non-uniformity.

Therefore, in order to prevent such a non-stitched portion, it is possible to press the stitching rollers at right angles, or to shift (offset) the positions of the stitching rollers in the two sets of pressing means. It has been proposed (for example, Patent Document 1).

However, with a stitching roller with right-angled corners, the lack of stitching at the center can be eliminated, but when stitching between the side edge and the shoulder of the low cover, the corners of the stitching roller are treads, etc. There is a risk that it will bite into the surface and damage it, leading to the occurrence of bears.

In addition, although the roller offset can be sufficiently stitched for ordinary passenger car tires, it is deformed even when pressed with a stitching roller for high-rigidity belt structure tires such as racing tires. Since it is difficult to make the tires, there is a possibility that insufficient stitching may occur at the side edge portion and peeling (bron) from the 1st cover may occur.

JP-A-2007-223223

In view of the above-mentioned problems in conventional stitching, the present invention has insufficient stitching in the central portion such as a breaker or tread, and insufficient biting or stitching in the side edge portion regardless of the rigidity of the belt structure. An object of the present invention is to provide a stitching technique capable of sufficiently suppressing the occurrence.

The present inventor has diligently studied the solution to the above problem, found that the above problem can be solved by the invention described below, and has completed the present invention.

The invention according to claim 1
The 1st cover and the 2nd cover are crimped by pressing the outer surface of the 2nd cover, which is attached to the outer peripheral surface of the 1st cover expanded in the shape of a tire and rotates together with the 1st cover, by using a pressing means. It is a stitching device that makes you
Each of the two stitching rollers is inserted and held at one end of the rotation shaft, and a set of pressing means arranged so as to face each other is provided along the circumferential direction of the 1st cover. Provided,
The stitching rollers of the pressing means of each set press the 2nd cover against the 1st cover by moving laterally from the central portion to the side edge portion of the 2nd cover in synchronization with each other. Configured to
The two stitching rollers of the set of pressing means are stitching rollers having the same diameter but different widths.
The stitching device is characterized in that the stitching rollers are arranged so that a part of the pressing surfaces of the wide stitching rollers overlap each other in the two adjacent sets of the pressing means.

The invention according to claim 2
The stitching device according to claim 1, wherein two sets of the pressing means are provided along the circumferential direction of the 1st cover.

The invention according to claim 3
The stitching device according to claim 1 or 2, wherein each of the stitching rollers is a stitching roller whose corners are chamfered.

The invention according to claim 4
The stitching device according to claim 3, wherein the chamfering process is an R process.

The invention according to claim 5
In the two sets of adjacent pressing means, the total width of the pressing means is T, and the distances from the side surface of each wide stitching roller to the end of the pressing surface on the narrow stitching roller side are W1 and W2. The stitching device according to any one of claims 1 to 4, wherein the stitching device satisfies the following formula.
W1 + W2> T

The invention according to claim 6
The method according to any one of claims 1 to 5, wherein the amount of overlapping of the pressing surfaces of the wide stitching rollers in the two adjacent sets of the pressing means is 5 to 20 mm. It is a stitching device.

The invention according to claim 7
The outer surface of the 2nd cover which is attached to the outer peripheral surface of the 1st cover expanded in the shape of a tire and rotates together with the 1st cover by using the stitching device according to any one of claims 1 to 6. Is a stitching method in which the 1st cover and the 2nd cover are crimped by pressing with a pressing means.
The stitching device is arranged on the outer peripheral surface of the 2nd cover along the circumferential direction of the 1st cover.
The 2nd cover is pressed against the 1st cover by moving the stitching rollers of the pressing means of each set laterally from the central portion to the side edge portion of the 2nd cover in synchronization with each other. This is a stitching method characterized by the fact that.

The invention according to claim 8 is
The stitching method according to claim 7, wherein the low cover of a racing tire is stitched.

According to the present invention, it is possible to sufficiently suppress the occurrence of insufficient stitching in the central portion such as a breaker or tread, and the occurrence of biting or insufficient stitching in the side edge portion regardless of the rigidity of the belt structure. Stitching techniques can be provided.

It is a side view which shows typically two sets of pressing means provided in the stitching apparatus which concerns on one Embodiment of this invention. It is a front view which shows typically two sets of pressing means provided in the stitching apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows typically two sets of pressing means provided in the stitching apparatus which concerns on one Embodiment of this invention. It is a figure which shows the state of arrangement of each stitching roller in two sets of pressing means provided in the stitching apparatus which concerns on this embodiment. It is a figure explaining the stitching method which concerns on this Embodiment. It is a figure which shows the state of performing the pressing in two in a row using two sets of pressing means. It is the top view (a) which shows typically the pressing means in the conventional stitching apparatus, and the figure (b) which shows the state of stitching.

Hereinafter, the present invention will be described with reference to the drawings based on the embodiments. In the following, a stitching device provided with two sets of pressing means will be described as an example, but the same can be considered even if three or more sets of pressing means are provided.

1. 1. Stitching device FIGS. 1 to 3 are a side view (FIG. 1), a front view (FIG. 2), and a perspective view schematically showing two sets of pressing means provided in the stitching device according to the present embodiment, respectively. It is a figure (FIG. 3).

In FIGS. 1 to 3, 1 is a stitching device, 11 is a first pressing means, and 12 is a second pressing means. The first pressing means 11 is composed of a stitching roller 11a inserted through the rotating shaft 11c and a stitching roller 11b inserted through the rotating shaft 11d, and the second pressing means 12 is inserted through the rotating shaft 12c. It is composed of a stitching roller 12a and a stitching roller 12b inserted through a rotating shaft 12d, and each stitching roller is rotatably supported by each of the inserted rotating shafts. The rotating shafts 11c and 12c are connected by a clamp 21, and the rotating shafts 11d and 12d are also connected by a clamp (not shown).

As shown in FIGS. 1 to 3, also in the present embodiment, the stitching device is configured by providing two sets of pressing means composed of two stitching rollers as in the conventional case. However, in the present embodiment, the widths of the two stitching rollers in each pressing means are different from each other, and the widths of the two adjacent sets of pressing means facing each other are also different. There is.

That is, the first pressing means 11 is composed of a wide stitching roller 11a and a narrow stitching roller 11b, and the second pressing means 12 includes a narrow stitching roller 12a and a wide stitching roller 12b. The two sets of pressing means 11 and 12 are configured so that they can move laterally from the center of the 2nd cover toward the side edges while rotating synchronously, as shown in FIG. It is supported by one clamp 21.

Then, as shown in FIGS. 2 and 3, a narrow stitching roller 12a is located at a position facing the wide stitching roller 11a, and a wide stitching roller 12a is located at a position facing the narrow stitching roller 11b. A stitching roller 12b is arranged.

As a result, a portion that overlaps with each other is formed on a part of the pressing surface of the two wide stitching rollers 11a and 12b, so that the pressing surface of the wide stitching roller ensures pressing at the center of the 2nd cover. can do.

Then, except for the central portion of the 2nd cover, each stitching roller moves laterally from the central portion of the 2nd cover that rotates together with the 1st cover toward the side edge portion to press the 2nd cover, so that the entire range is covered. It can be pressed for sufficient stitching.

As a result, there are no parts that cannot be pressed during stitching, the generation of air residue is sufficiently suppressed, and in the product tire after vulcanization, bares may occur or the gauge distribution may become uneven. It can be sufficiently suppressed.

FIG. 4 is a diagram showing a state of arrangement of each stitching roller in two sets of pressing means provided in the stitching device according to the present embodiment. In FIG. 4, S1 is the pressing surface of the wide stitching roller 11a, S2 is the pressing surface of the wide stitching roller 12b, S3 is the pressing surface of the narrow stitching roller 12a, and S4 is the narrow stitching. It is a pressing surface of the roller 11b. Further, c is a gap formed between the wide stitching rollers 11a and 12b and the narrow stitching rollers 11b and 12a.

At this time, as shown in FIG. 4, the total width of the pressing means 11 and 12 in which the wide stitching rollers 11a and 12b and the narrow stitching rollers 11b and 12a are arranged with the gap c separated is T. Assuming that the distance from the side surface of the wide stitching roller 11a to the end of the pressing surface S1 is W1 and the distance from the side surface of the wide stitching roller 12b to the end of the pressing surface S2 is W2, these are W1 + W2> T. It is preferable that the relationship of

As a result, the overlapping portion can be reliably secured. The difference between (W1 + W2) and T in the above formula is the amount of overlap between the pressing surfaces of the stitching rollers.

In the present embodiment, the amount of overlapping of the concrete pressing surfaces is preferably 5 to 20 mm, and more preferably 8 to 15 mm. If the amount of overlap between the pressing surfaces is too small, it may not be possible to sufficiently eliminate the insufficient stitching at the center, while if it is too large, the width of one roller will be narrowed and a sufficient stitching effect will be obtained. It may not be obtained.

Then, in the present embodiment, it is preferable that the corners of each stitching roller are chamfered. Since the corners are chamfered, it is possible to suppress the occurrence of biting in the shoulder portion. As a specific chamfering process, either R processing as shown in FIGS. 2 and 3 or C surface processing as shown in FIG. 4 may be adopted, but R processing is more preferable.

Even with the stitching rollers whose corners are chamfered in this way, in the present embodiment, as described above, a portion overlapping the pressing surfaces of the wide stitching rollers is formed. Therefore, it is possible to sufficiently press the center portion of the 2nd cover, and it is possible to prevent the occurrence of insufficient stitching.

As described above, in the present embodiment, in each of the two sets of pressing means, two stitching rollers having different widths are arranged to form an overlapping portion on the pressing surfaces of the wide stitching rollers. Therefore, there is no possibility that a portion that is not pressed is generated in the central portion. Further, since a wide stitching roller is used, it is possible to sufficiently suppress the occurrence of insufficient stitching at the side edge portion regardless of the rigidity of the belt structure. Further, since the chamfering process is performed, biting does not occur at the side edge portion. As a result, it is possible to sufficiently suppress the generation of bears, non-uniform gauge distribution, generation of bron, etc. in the tire after vulcanization.

2. Stitching method Next, a stitching method according to the present embodiment using the above-mentioned stitching device will be described.

FIG. 5 is a diagram illustrating a stitching method according to the present embodiment. In FIG. 5, CL is the center line, the broken line is Brk (breaker), the Sh portion is the shoulder portion of the low cover, and P is the 1st cover.

In the present embodiment, each stitching roller of each pressing means moves synchronously in the direction of the white arrow to perform stitching.

Specifically, first, the molded 1st cover P is set on the rotation axis (not shown) of the low cover molding apparatus, and then expanded to perform shaping. After that, a 2nd cover formed by laminating a breaker Brk and a tread TR is separately arranged on the outer side of the 1st cover P, and two sets of pressing means 11 and 12 are separately placed on the outer peripheral surface of the 2nd cover to cover the 1st cover. Arrange along the circumferential direction of.

Next, the rotation of the 1st cover P is started. Along with this, the stitching rollers of each pressing means start rotating and move synchronously in the lateral direction from the center line CL toward the respective side edges.

Then, when the pressing means reaches the side edge portion, specifically, the shoulder portion Sh, the moving direction of the pressing means is changed from the horizontal direction along the shoulder portion Sh, and the breaker Brk is used by the stitching roller. And the tread TR is pressed against the 1st cover P to stitch.

3. 3. Effects of the present embodiment The effects of adopting the present embodiment will be summarized and described as follows, including the effects already described.

(1) At the start of stitching, there is no part that is not pressed in the central part, and the entire stitch can be sufficiently stitched, so that bears are not generated and the gauge distribution is not uneven.

(2) In the case of racing tires, etc., it is predicted that a large load will be applied momentarily, so it is necessary to prevent peeling at the breaker edge, and at the edge of the breaker pressed on the ply, a joint A less band is placed, and a rubber sheet to prevent peeling is sandwiched between breakers. For this reason, the number of members increases, the structure becomes highly rigid, it is difficult to sufficiently crimp each member to each other, and bronze is likely to occur.

However, in the present embodiment, since it can be sufficiently pressed by a wide stitching roller, each member can be sufficiently crimped to each other, and even a tire having a high rigidity structure such as a race tire can be sufficiently pressed. It can be stitched and the generation of bron can be suppressed.

(3) By chamfering all the stitching rollers, the low cover is not damaged when stitching at the shoulder portion, and the occurrence of bears on the tire can be sufficiently reduced.

(4) When the clamp rotates, the tread edge may flutter due to centrifugal force. However, in the present embodiment, since the pressing is performed by using a plurality of sets of pressing means, as shown in FIG. 6, the tread is suppressed while suppressing the repulsion from the 1st cover P set in the low cover molding apparatus 2. The edge can be pressed, and stitching can be performed with less fluttering.

As a result, the waviness of the tread edge and the variation in the gauge of the tread shoulder portion can be reduced, so that the appearance quality of the tire can be improved.

Hereinafter, the present invention will be described in more detail based on Examples.

1. 1. Experimental Method A low cover for a racing tire was produced by a two-stage molding method.

At this time, the stitching device was configured by using the roller-shaped stitching rollers shown in Table 1 for both of the two sets of pressing means.

2. Evaluation We observed the occurrence of bears (center and shoulders), waviness at the tread edge, and tread float (bron) in each of the prepared low covers, and evaluated the situation in the following three stages.
Good: No occurrence Yes: A defect has occurred, but it does not cause a problem on the product. No: A defect that causes a problem on the product has occurred.

The evaluation results are shown in Table 1.

From the results shown in Table 1, it was found that there was no evaluation of "impossible" in Experimental Examples 1 to 3 satisfying the requirement of claim 1. Among these, it was found that in Experimental Example 1 in which the left and right rollers were sufficiently overlapped and the corners of the rollers were rounded, the evaluation results of the bear generation rate, the tread edge waviness, and the bron generation amount were all good.

Then, in Experimental Example 2 in which the outer peripheral surface of the stitching roller was not rounded, some bares were generated in the Sh portion, but there was no quality problem. Further, in Experimental Example 3 in which the total width of the stitching roller A was as small as 20 mm, some bronze was generated, but there was no quality problem.

On the other hand, in Experimental Example 4 in which the width of the gap c between the left and right rollers is as large as 10 mm, and in Experimental Example 5 in which the widths of the stitching roller A and the stitching roller B are the same and the plane width is both 0 mm, the pressing surfaces of the stitching rollers are opposed to each other. It was found that the bear occurrence rate in the central part was high because no overlap was obtained.

Further, in Experimental Example 6 in which the stitching roller of the pressing means was one stitching roller A and the plane width was 0 mm, the bear occurrence rate in the central portion was high and the tread edge waviness occurred. Further, in Experimental Example 7 in which the stitching roller of the pressing means was one stitching roller A and the outer peripheral surface of the stitching roller was not rounded, the bear generation rate of the Sh portion was high, and the tread edge waviness and the amount of bronization were generated. A good evaluation was not obtained in the evaluation.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

1 Stitching device 2 Low cover forming device 11, 31 First pressing means 11a, 12b Wide stitching rollers 11b, 12a Narrow stitching rollers 11c, 11d, 12c, 12d Rotating shafts 12, 32 Second pressing means 21 Clamps 31a, 31b, 32a, 32b Stitching rollers 31c, 31d, 32c, 32d Rotating shaft Brk breaker c Gap CL Center line N Unpressable part P 1st cover Sh Shoulder part S1, S2 Pressing surface S3 of wide stitching roller , S4 Narrow stitching roller pressing surface T Total width TR Tread W1, W2 Distance from the side of the stitching roller to the end of the pressing surface

Claims (8)

The 1st cover and the 2nd cover are crimped by pressing the outer surface of the 2nd cover, which is attached to the outer peripheral surface of the 1st cover expanded in the shape of a tire and rotates together with the 1st cover, by using a pressing means. It is a stitching device that makes you
Each of the two stitching rollers is inserted and held at one end of the rotation shaft, and a set of pressing means arranged so as to face each other is provided along the circumferential direction of the 1st cover. Provided,
The stitching rollers of the pressing means of each set press the 2nd cover against the 1st cover by moving laterally from the central portion to the side edge portion of the 2nd cover in synchronization with each other. Configured to
The two stitching rollers of the set of pressing means are stitching rollers having the same diameter but different widths.
A stitching device characterized in that, in two sets of adjacent pressing means, the stitching rollers are arranged so that a part of the pressing surfaces of the wide stitching rollers overlap each other. The stitching device according to claim 1, wherein two sets of the pressing means are provided along the circumferential direction of the 1st cover. The stitching apparatus according to claim 1 or 2, wherein each of the stitching rollers is a stitching roller having chamfered corners. The stitching apparatus according to claim 3, wherein the chamfering process is an R process. In the two sets of adjacent pressing means, the total width of the pressing means is T, and the distances from the side surface of each wide stitching roller to the end of the pressing surface on the narrow stitching roller side are W1 and W2. The stitching device according to any one of claims 1 to 4, wherein the stitching device satisfies the following formula.
W1 + W2> T The method according to any one of claims 1 to 5, wherein the amount of overlapping of the pressing surfaces of the wide stitching rollers in the two adjacent sets of the pressing means is 5 to 20 mm. Stitching device. The outer surface of the 2nd cover which is attached to the outer peripheral surface of the 1st cover expanded in the shape of a tire and rotates together with the 1st cover by using the stitching device according to any one of claims 1 to 6. Is a stitching method in which the 1st cover and the 2nd cover are crimped by pressing with a pressing means.
The stitching device is arranged on the outer peripheral surface of the 2nd cover along the circumferential direction of the 1st cover.
The 2nd cover is pressed against the 1st cover by moving the stitching rollers of the pressing means of each set laterally from the central portion to the side edge portion of the 2nd cover in synchronization with each other. A stitching method characterized by that. The stitching method according to claim 7, wherein the low cover of a racing tire is stitched.

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