JP2013163313A - Tire member manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire member manufacturing method which allows air to escape sufficiently by preventing a through hole formed once by a pricking device from being closed again and can manufacture a tire having stable performance.SOLUTION: A tire member manufacturing method includes a pricking step in which a through hole is formed in a sheet-shaped tire member by using a pricking device, and a cooling step in which the pricked tire member is cooled by using a cooling apparatus set immediately behind the pricking device. In the tire member manufacturing method, the cooling apparatus is a roller the inside of which is filled with a circulated cooling medium. In the tire member manufacturing method, the penetration ratio of the tire member is controlled to be a prescribed value by controlling the temperature of the cooling medium. In the tire member manufacturing method, a transportation step for transporting the tire member by a belt conveyer is provided at the downstream side of the cooling step, and the belt conveyer is formed of a material whose thermal conductivity is higher than that of the tire member.

Description

  The present invention relates to a method for manufacturing a tire member that can suppress air residue during vulcanization.

  In the tire manufacturing process, various tire members (components) such as an inner liner, a carcass ply, and a belt ply are attached to each other. Air may enter and generate air residue.

  If this air residue is present even after vulcanization, the quality of the product tire such as uniformity will be impaired, so that air that has entered between each tire member is released to the outside during vulcanization. Specifically, in the manufacture of these sheet-like tire members (also referred to as “preps”), a prepicking device as shown in FIG. A through hole is provided (for example, Patent Document 1). As a result, the air that has entered between the tire members at the time of pasting escapes to the outside along the through hole, so that the remaining air after vulcanization is suppressed.

JP 2008-162028 A

  However, the current priking device is particularly affected by the environmental temperature, and the rubber fluidity is high when the rubber surface temperature of the tire member is high (30 degrees or more). There is a problem in that the air that has been blocked and that has entered between the tire members cannot be sufficiently released.

  Therefore, in view of the above problems, the present invention provides a tire member capable of manufacturing a tire with stable performance by suppressing the through-hole once provided by the priking device from being blocked again and sufficiently releasing air. It is an object to provide a manufacturing method.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by the invention described below, and has completed the present invention.

The invention described in claim 1
A precicking step of providing a through hole in a sheet-like tire member using a pricing device;
And a cooling step of cooling the tire member that has been prepked using a cooling device that is provided immediately after the priming device.

The invention described in claim 2
The tire member manufacturing method according to claim 1, wherein the cooling device is a roller filled with a circulating cooling medium.

The invention according to claim 3
The tire member manufacturing method according to claim 2, wherein the penetration rate of the tire member represented by the following formula is controlled to a predetermined value by controlling the temperature of the cooling medium.
Penetration rate = {(number of through-holes after cooling) / (number of priming)} × 100

The invention according to claim 4
A downstream side of the cooling step includes a transport step for transporting the tire member by a belt conveyor,
4. The tire member manufacturing method according to claim 1, wherein the belt conveyor is made of a material having a higher thermal conductivity than the tire member. 5.

  According to the present invention, there is provided a tire member manufacturing method capable of manufacturing a tire with stable performance by preventing air from being sufficiently blocked by reclosing a through-hole once provided by a priking device. can do.

It is a schematic perspective view of the principal part of the manufacturing apparatus of the tire member used for one embodiment of this invention. It is a figure which shows an example of a pricking apparatus.

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

  FIG. 1 is a schematic perspective view of a main part of a tire member manufacturing apparatus used in the present embodiment. As shown in FIG. 1, a sheet-like tire member G molded to a predetermined size is conveyed in the direction indicated by an arrow, and after a through hole for air escape is opened in the prepicking device 1 (pre-packing step). Then, it is cooled in the cooling device 3 provided immediately after the priming device 1 (cooling step).

  The prepicking device 1 is the same device as the conventional prepicking device, and has a large number of pliking needles. By passing through from above, a large number of air escape through holes (diameter: about 1 mm) are formed in the tire member G.

  However, the thickness (gauge) of the prepked prep is different for each prep. For this reason, a difference arises in the cooling state of the prep after prepicking, and there is a possibility that the through hole formed by prepicking will be closed again.

  That is, when the gauge is a thin prep, the prepucked prep is cooled in a short time, so that the through hole is held. On the other hand, in the case of a prep with a thick gauge, it takes time to cool the prep and the fluidity of the rubber cannot be quickly reduced, so that the once formed through hole is closed again.

  Further, the holding of the through hole depends on the environmental temperature. When the difference between the temperature of the prep after prepicking and the environmental temperature is large, the through hole is held at a high ratio. Specifically, through-holes are retained at a higher rate in winter when the temperature is lower than in summer when the temperature is high.

The penetration rate can be used as an index for determining the degree to which the through-hole provided by the prepicking device is closed again. This penetration rate is defined by the ratio (%) between the number of precricks performed on a prep with a length of 300 mm and the number of through holes remaining after cooling. It is.
Penetration rate = {(number of through-holes after cooling) / (number of priming)} × 100

  This penetration rate is preferably 45 to 90%. If the penetration rate is less than 45%, since many of the through holes once opened by the priming device are blocked, there is a possibility that a sufficient air escape effect cannot be obtained. On the other hand, if it exceeds 90%, there is a risk of causing a poor appearance of the product tire.

  Therefore, in the present embodiment, the cooling device 3 is provided immediately after the prepicking device 1 and is formed once by rapidly cooling the prepked prep to reduce the fluidity of the rubber. This prevents the through hole from being closed again.

  Then, by setting the cooling device to a predetermined cooling temperature, it is possible to manufacture a tire member having a desired penetration rate without being influenced by the environmental temperature.

  In the above description, “immediately after the priming device” is not limited to the priming device 1 and the cooling device 3 being placed in contact with each other, and specifically, within the 70 centimeters from the priming device 1. It is sufficient if it is within 30 cm.

  As such a cooling device, a roller 3 composed of upper and lower two rolls 3a provided with a circulating cooling medium therein is preferably used. By passing the tire member G between the upper and lower rollers 3a, the tire member G is cooled from both the front and back surfaces, so that effective cooling can be performed.

  And since the cooling medium is circulated inside each roll, unlike the case where the cooling medium is brought into direct contact with the tire member G, there is no fear of causing a change in the rubber physical properties of the tire member G. The cooling medium is not particularly limited, and a liquid such as water or a gas such as nitrogen gas can be used, but water is preferable from the viewpoint of easy temperature control and low cost. Then, by controlling the temperature of the cooling medium, the fluidity of the rubber in the tire member G after being prepked is sufficiently lowered, and the tire member G penetrates as intended without being influenced by the environmental temperature. Can give rate.

  The tire member G cooled by the cooling device 3 is transported to a downstream cutting step by a belt conveyor (not shown), and then cut to a predetermined length. The belt conveyor is made of a material having high thermal conductivity, specifically Specifically, when formed from a material having a higher thermal conductivity than the rubber material, the cooling heat from the cooling device 3 can be conducted to the belt conveyor, and the cooling effect on the tire member G can be maintained for a long time. More preferred.

  Next, the present invention will be described more specifically based on examples. Below, the change of the penetration rate by the presence or absence of a cooling process was measured about two types of sheet-like tire members from which gauge thickness differs.

  Under a summer environmental temperature (30 ° C.) and a winter environmental temperature (10 ° C.), two kinds of gauge-like (0.8 mm and 1.1 mm) sheet-like tire members (each having a width of around 1445 mm) are produced. Each sheet-like tire member was pre-kicked at a temperature of 90 ° C. so that the penetration rate per 300 mm length was 60 to 85%.

  A part of each sheet-like tire member was cooled by a roller disposed at a position of 100 mm from the prepicking device. In this roller, water was circulated as a cooling medium inside, and the surface temperature was set to 10 ° C. in the summer and 25 ° C. in the winter so as to be between the precicking temperature and the environmental temperature.

  The penetration rate in each case was measured using a sheet-like tire member that was not cooled as a comparative example and a sheet-like tire member that was cooled as an example.

  Specifically, first, 300 mm is sampled from each sheet-shaped tire member after cooling, each sampled sheet-shaped tire member is placed in a dark place, and light from a fluorescent lamp or the like is applied from below or above to penetrate the light. Was visually confirmed to determine the number A of the through holes.

  Next, the number of prepicking holes left on each sampled sheet-like tire member was visually counted, and the number combined with A was defined as the number B of precickings.

After that, the above formula for obtaining the penetration rate, that is,
Penetration rate (%) = (A / B) × 100
Thus, the penetration rate in each case was obtained.

  The measurement results are shown in Table 1.

  From Table 1, when the cooling step is not provided, when the gauge thickness is large, the penetration rate is lower than that of the example (Comparative Examples 1 and 3), and when the gauge thickness is small, the penetration rate is higher than that of the example ( It can be seen that Comparative Examples 2 and 4) are established.

  It can also be seen that the penetration rate is low in the summertime at high environmental temperatures (Comparative Examples 1 and 2), while the penetration rate is high in the wintertime at low environmental temperatures (Comparative Examples 3 and 4). In particular, when the gauge is thick at a high ambient temperature (Comparative Example 1), the penetration rate is as low as 35%, and a sufficient air escape effect cannot be obtained, leaving much air remaining in the product tire. It was. Further, when the gauge was thin at a low ambient temperature (Comparative Example 4), the penetration rate was as high as 92%, and although there was almost no air remaining in the product tire, an appearance defect occurred.

  In contrast, in the case of the example provided with the cooling step, it can be seen that the penetration rate can be controlled to 70% regardless of the difference in environmental temperature (summer and winter) and the gauge thickness.

  As described above, the reason why the target penetration rate was obtained regardless of the environmental temperature and the gauge thickness was that the prepicking was performed at a predetermined priming temperature and the cooling temperature was appropriately controlled to cool.

  In addition, when the gauge is thin, the penetration rate in the comparative example is higher than the penetration rate in the example because the surface temperature of the cooling roller is set to be between the precicking temperature and the environmental temperature. It is done.

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

1 Pricking device 3 Cooling device 3a Roller G Sheet-like tire member

Claims (4)

A precicking step of providing a through hole in a sheet-like tire member using a pricing device;
And a cooling step of cooling the tire member that has been prepked using a cooling device that is provided immediately after the priming device.   The tire member manufacturing method according to claim 1, wherein the cooling device is a roller filled with a circulating cooling medium. The method for manufacturing a tire member according to claim 2, wherein the penetration rate of the tire member represented by the following formula is controlled to a predetermined value by controlling the temperature of the cooling medium.
Penetration rate = {(number of through-holes after cooling) / (number of priming)} × 100 A downstream side of the cooling step includes a transport step for transporting the tire member by a belt conveyor,
The method for manufacturing a tire member according to any one of claims 1 to 3, wherein the belt conveyor is formed of a material having higher thermal conductivity than the tire member.

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