JP2002052620A - Method for manufacturing pneumatic radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a pneumatic radial tire further improved in uniformity. SOLUTION: A first cylindrical molded object S1, wherein both ends of an unvulcanized carcass layer 5 are folded back to the periphery of an annular bead core 7, is molded on a first molding drum 1. The deflection quantity of the annular bead core 7 with respect to the round centering around the center axis of the first molded object S1 is measured over one round. The position becoming the center axis of the bead core 7 is judged on the basis of the deflection quantity. When a second molded object S2 is transferred toward the outer periphery of the first molded object S1, the center axis of the bead core 7 is allowed to coincide with the holding center axis O'' of a transfer device 12. The first molded object S1 is inflated into a troidal shape by a shape-up drum to be bonded to the inner periphery of the second molded object S2 under pressure to mold a green tire G.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a pneumatic radial tire, and more particularly, to a method for manufacturing a pneumatic radial tire with improved uniformity of the tire.

[0002]

2. Description of the Related Art Generally, in the production of a pneumatic radial tire, in a green tire molding process, both ends of an unvulcanized carcass layer are turned around a ring-shaped bead core by a first molding drum. While the body is formed, the unvulcanized belt layer is wound around the second forming drum to form a cylindrical second formed body.

Next, after the first compact is transferred to the shape-up drum, the second compact is transferred to the outer peripheral side of the first compact by the transfer device. The transfer device holds and transfers the outer peripheral surface of the second formed body over one round, and aligns the holding central axis of the transfer device with the center axis of the shape-up drum.

Then, the first molded body is inflated in a toroidal shape, and is pressed against the inner peripheral side of the second molded body to form a green tire. When manufacturing a pneumatic radial tire in this manner, it is extremely difficult to make the tire uniform and round, and a reduction in uniformity is inevitable.

In order to improve the uniformity, there has been proposed a technique of dispersing splice portions of each tire component such as a carcass layer and a belt layer in the tire circumferential direction, and has exerted a certain effect. However, since the decrease in uniformity increases tire vibration and contributes to vehicle noise, further improvement has been strongly demanded.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a pneumatic radial tire which enables a further improvement in uniformity.

[0007]

To achieve the above object, a method of manufacturing a pneumatic radial tire according to the present invention comprises the following steps.
While forming both ends of the unvulcanized carcass layer around the annular bead core on the forming drum to form the first cylindrical body, the unvulcanized belt layer is wound around the second forming drum. Forming a second shaped body in a shape, transferring the first shaped body to a shape-up drum, holding the outer circumferential surface of the second shaped body by a transfer device over one round, and forming the second shaped body. Pneumatic transfer of the first molded body to the outer peripheral side of the first molded body, inflation of the first molded body in a toroidal shape by the shape-up drum, and pressure bonding to the inner peripheral side of the second molded body to form a green tire. In the method for manufacturing a radial tire, after the first molded body is molded, a run-out amount of the annular bead core with respect to a perfect circle centered on a central axis of the first molded body is measured over one round, and the run-out amount is measured. Based on the bead A) determining the position of the center axis of the bead, and when transferring the second compact to the outer peripheral side of the first compact by the transfer device, the center axis of the bead core and the holding center axis of the transfer device; It is characterized in that they match each other.

[0008] In this manner, the amount of deflection of the bead core is obtained, the position serving as the center axis of the bead core is determined based on the amount of deflection, and when the second compact is transferred to the outer peripheral side of the first compact,
When the center axis of the bead core and the holding center axis of the transfer device are made to coincide with each other, the first molded body and the second molded body are inflated in a toroidal shape and pressed against the second molded body. Can be pressed against the bead core so as to approach a concentric perfect circle. for that reason,
The roundness of the tire constituent material with respect to the tire shaft is increased, and uniformity can be improved.

Further, another method of manufacturing a pneumatic radial tire according to the present invention is characterized in that the both ends of an unvulcanized carcass layer are folded around an annular bead core on a first forming drum to form a cylindrical first molded body. On the other hand, an unvulcanized belt layer is wound around a second forming drum to form a cylindrical second formed body,
The first molded body is transferred to a shape-up drum, and the outer peripheral surface of the second molded body is moved by a transfer device by one.
The green tire is held over the circumference, transferred to the outer peripheral side of the first molded body, inflated in a toroidal shape by the shape-up drum, and pressed against the inner peripheral side of the second molded body to form a green tire. In the method for manufacturing a pneumatic radial tire to be molded, after the first molded body is molded, the amount of deflection of the annular bead core with respect to a perfect circle centered on the central axis of the first molded body is measured over one round. On the other hand, during the transfer of the transfer device, the run-out amount of the inner peripheral surface of the second formed body with respect to a perfect circle centered on the holding central axis of the transfer device is measured over one round, and the second formed body is measured. After being transferred to the outer peripheral side of the first molded body, the phases of the first molded body and the second molded body are matched so that the deflection tendency of the deflection amount of the bead core and that of the second molded body match. To be Than it is.

[0010] In this way, the amount of deflection of the bead core and the second molded body is obtained, and after the second molded body is transferred to the outer peripheral side of the first molded body, the first molded body and the second molded body are moved so that the deflection tendency coincides. By adjusting the phases of the two molded bodies, even when the bead core and the second molded body are at eccentric positions, when the first molded body is inflated in a toroidal shape and pressed against the second molded body, The first molded body and the second molded body can be pressure-bonded to the bead core so as to be close to a concentric perfect circle, and the uniformity can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 to 4 show an example of a method of manufacturing a pneumatic radial tire according to the present invention.
Denotes a second forming drum, and 3 denotes a shape-up drum.
First, in the first forming drum 1, an unvulcanized inner liner layer 4 is wound around the drum 1, and an unvulcanized carcass layer 5 is wound around the outer periphery thereof (FIG. 1A). Next, the left and right auxiliary drums 1A are reduced in diameter, and the annular bead core 7 having the bead filler 6 is attached to the left and right ends 5a of the carcass layer 5.
[FIG. 1 (b)].

Next, a bladder (not shown) provided in the auxiliary drum 1A is inflated so that both end portions 5a of the left and right carcass layers are turned around the bead core 7, and the auxiliary drum 1
After retreating A left and right, an unvulcanized side tread rubber 8 is wound around the left and right outer peripheral sides of the carcass layer 5 to form a cylindrical first molded body S1 (FIG. 1C).

After the first compact S1 has been formed, the distance to the inner peripheral surface of the bead core 7 (both ends 5a of the carcass layer) is measured by a non-contact type sensor X such as a laser sensor disposed on the inner peripheral side of the bead core 7. I do. At this time, the first forming drum 1 is rotated once, and the measurement is performed over one rotation. The distance information is input to the computer C, where the first compact S
The deflection amount of the bead core 7 with respect to a perfect circle centered on one central axis M (coincident with the rotation central axis O of the first forming drum 1) is determined over one round. FIG. 2 shows an example of a waveform (first-order waveform) corresponding to the shake amount. From this waveform, the position serving as the central axis of the bead core 7 is determined.

On the other hand, in the second molding drum 2, an unvulcanized belt layer 9 is wound around the drum 2, and an unvulcanized cap tread rubber 10 is wound around the outer peripheral side thereof to form a cylindrical second molded body S 2. It is molded (FIG. 3A). O ′ is the rotation center axis of the second forming drum 2, N is the center axis of the second forming body S 2, and on the second forming drum 2, the central axis N of the second forming body S 2 and the second forming drum 2 The rotation center axis O 'coincides.

Next, after the first compact S1 is transferred to the shape-up drum 3, the second compact S2 is transferred to the outer periphery of the first compact S1 (FIG. 4A). As shown in FIG. 3B, the outer peripheral surface of the second formed body S <b> 2 is held by the cylindrical holding portion 12 a of the transfer device 12 during the transfer, as shown in FIG. O ″ in the figure is the holding unit 12a
Is the holding central axis. When the second compact S2 is transferred,
The center axis O ″ of the holding part 12a is made to coincide with the center axis of the bead core 7. The holding unit 12a holds the first molded body S1 until it is pressed against the second molded body S2.

Then, the first compact S1 is inflated in a toroidal shape by the shape-up drum 3 and pressed against the inner peripheral side of the second compact S2 to form a green tire G (FIG. 4B). ].

According to the present inventors, as a result of earnestly studying the uniformity, the following has been found. That is, conventionally, in the green tire molding process, the second molded body S
2 is transferred to the outer peripheral side of the first molded body,
And the center axis of the shape-up drum 3 (the center axis M of the first compact S1). However, when the first compact S1 is inflated by the shape-up drum 3, the portion of the bead core 7 is gripped and the first compact S1 inflates in a toroidal shape starting therefrom. Aligning the axis O ″ with the central axis of the bead core 7 is extremely important for improving uniformity.

The bead core 7 is driven into the position shown in FIG. 1B by a bead setting device. To facilitate this, a certain gap is secured between the bead core 7 and the auxiliary drum 1A. 7 is loosely fitted on the outer peripheral side of the auxiliary drum 1A. Also,
Since the inner liner layer 4 and the carcass layer 5 wound around the first forming drum 1 in a cylindrical shape have splices, when the carcass layer both ends 5a are turned around the bead core 7 by a bladder, the carcass layer both ends 5a Starts to be folded back from the part distant from the splice. As a result, as shown in FIG. 5, the position y serving as the central axis of the bead core 7 is shifted from the central axis M of the first compact S1, and the bead core 7 is eccentric. The same eccentricity occurs on the left and right. Since the first molded body S1 is inflated in a toroidal shape with the center axis aligned as described above and pressed against the second molded body S2, the roundness with respect to the tire axis is greatly reduced, and the uniformity is deteriorated. It is.

Therefore, in the present invention, as described above, the amount of runout of the bead core 7 is measured over one round, and the position y serving as the central axis of the bead core 7 is determined based on the amount of runout.
This is made to coincide with the holding center axis O ″ of the holding portion 12a (FIG. 6A). When the first molded body S1 is inflated in a toroidal shape in this manner, the left portion a having a smaller distance from the second molded body S2 is pressure-bonded to the second molded body S2 first, and then the right portion b is formed. Crimped, but on the right side b
In the process of inflation and subsequent pressure bonding following the left portion a, the left portion a is already pressed against the second molded body S2, and the carcass layer of that portion is not extended, and the state is maintained. The end 5a of the carcass layer folded around the bead core 7 is inflated and crimped while being pulled back. Therefore, at the time of press bonding, as shown in FIG. 6B, the first compact S1 and the second compact S2 come close to a perfect circle concentric with the bead core 7. Therefore, in the green tire G, the roundness of the tire constituent material with respect to the tire axis can be increased, so that the uniformity can be improved.

FIG. 7 shows another example of the pneumatic manufacturing method of the present invention. After being formed by the second forming drum 2 as described above, the second formed body S2 is transferred to the shape-up drum 3 by the transfer device 12, where the transfer device 1
It is difficult to completely hold the second molded body S2 in the perfect circular shape by the second holding portion 12a, and there is a case where the second molded body S2 has an elliptical shape and is held with some eccentricity.

Therefore, during the transfer of the transfer device 12, similarly to the above-described bead core 7, a non-contact type sensor X 'such as a laser sensor disposed on the inner circumferential side of the belt layer 9 is used to transfer the inner periphery of the second compact S2. The distance to the surface (belt layer 9) is measured. At this time, the holder 12a is rotated once, and measurement is performed over one rotation. The distance information is input to the computer C, where the amount of deflection of the second compact S2 with respect to a perfect circle centered on the holding central axis O ″ of the holding unit 12a is determined over one round. FIG. 8A shows a waveform (1) corresponding to the shake amount.
An example is shown below.

After transferring the second compact S2 to the outer peripheral side of the first compact S1 on the shape-up drum 3,
The first molded body S1 and the second molded body S2 facing each other such that the deflection tendency of the deflection amount of the bead core 7 and the second molded body S2 coincide.
The phases of 2 are matched.

For example, in the bead core 7, FIG.
Assuming that a waveform (primary waveform) corresponding to the amount of shake as described above has been obtained, the waveform shown on the same screen by matching the shake tendency of both shake amounts is as shown in FIG. 8C. .

Therefore, in order to match the phases of the first compact S1 and the second compact S2 facing each other, either one of the first compact S1 and the second compact S2 is set to 270 ° or 90 ° in the opposite direction. Will be rotated. FIG. 9 shows the bead core 7
The figure which combined the 2nd molded object S2 is shown. By adjusting the phases of the two as described above, the eccentricity of the bead core 7 and the eccentricity of the second molded body S2 can be canceled each other, so that the uniformity can be improved.

According to the present invention, in the above-described embodiment, the cap tread rubber 10 is wound around the outer peripheral side of the belt layer 9 to form the second molded body S2.
2 is formed only from the belt layer 9, and the first formed body S 1 is inflated by the shape-up drum 3 to form the second formed body S 2.
After pressing, a cap tread rubber 10
May be wound to form a green tire. At least the both ends of the unvulcanized carcass layer may be folded back around an annular bead core on the first forming drum to form a cylindrical tire. 1 While molding the molded body,
A second unmolded belt layer formed into a cylindrical shape on a second forming drum
Any method can be suitably used as long as it is a method for forming a molded body.

[0027]

[Example] Tire size was set to 265 / 70R16 112
Method of the present invention in which S is common and the center axis of the transfer device is made to coincide with the center axis of the bead core (Example 1)
And a method (Example 2) of the present invention in which the runout tendency of the runout amount of the bead core and the runout amount of the second molded body are matched with each other.
Using a conventional method (conventional example) in which the center axis of the molded body was made to coincide with the holding center axis of the transfer device, 30 test tires were manufactured.

Each of these test tires was rim size 16 × 8
When mounted on a JJ rim, the air pressure was set to 200 kPa, and a uniformity evaluation test was performed under the following measurement conditions, the results shown in Table 1 were obtained.

Uniformity: Each test tire was mounted on a drum tester, and the radial force variation (RFV) was measured in accordance with JASO C607-87. Table 1 shows the average value and standard deviation of RFV. The smaller these values are, the better the uniformity is.

[0030]

[Table 1]

As apparent from Table 1, Examples 1 and 2
The pneumatic radial tire manufactured by the method 2 is:
The average value and the standard deviation of RFV were smaller than those manufactured by the method of the conventional example, and the uniformity was good.

[0032]

As described above, according to the method of manufacturing a pneumatic radial tire of the present invention, the center axis of the bead core and the holding center axis of the transfer device are made to coincide with each other, and the deflection amount of the bead core and the second molded body is changed. When the first molded body and the second molded body are in phase with each other so as to match, when the first molded body is inflated in a toroidal shape and pressed against the second molded body, the first molded body and the second molded body are in contact with each other. The second molded body can be pressure-bonded to the bead core so as to be close to a concentric perfect circle, and the uniformity can be improved.

[Brief description of the drawings]

FIG. 1 shows an example of a step of forming a first molded body in a method of manufacturing a pneumatic radial tire of the present invention,
(A) is an explanatory view showing a state in which an inner liner and a carcass layer are wound around a first forming drum, (b) is an explanatory view showing a state in which a bead core is further set, and (c) is a first forming drum on the first forming drum. It is explanatory drawing which shows the state which molded the molded object.

FIG. 2 is a waveform diagram showing a deflection amount of a bead core in a first molded body.

FIG. 3 shows an example of a step of molding and transferring a second molded body in the method of manufacturing a pneumatic radial tire according to the present invention, and (a) is an explanatory view showing a state in which the second molded body has been molded;
(B) is an explanatory view showing a state in which the second molded body is transferred.

FIG. 4 shows an example of a step of inflating a first molded body and press-bonding it to a second molded body in the method of manufacturing a pneumatic radial tire according to the present invention, wherein (a) shows the first molded body and the second molded body; FIG. 4 is an explanatory view showing a state in which the body is set on a shape-up drum, and FIG. 4B is an explanatory view showing a state in which a first molded body is pressed against a second molded body.

FIG. 5 is an explanatory diagram showing a positional relationship between a bead core and a first molded body in the first molded body.

FIG. 6 shows a step of inflating a first molded body and press-bonding the same to a second molded body in the method of manufacturing a pneumatic radial tire according to the present invention. Explanatory drawing showing a state in which the holding central axes of the transfer device are made to coincide with each other, and (b) shows a positional relationship between a bead core, a first molded body, and a second molded body when the green tire is molded by inflation. FIG.

FIG. 7 is an explanatory view showing an example of a step of measuring a distance of an inner surface of a second molded body in a pneumatic radial tire manufacturing method according to another embodiment of the present invention.

FIG. 8 shows an example of a step of matching the runout tendency of a bead core and a second compact in a method of manufacturing a pneumatic radial tire according to another embodiment of the present invention, and (a) shows the runout of the second compact. FIG. 7B is a waveform chart showing the amount of deflection, FIG. 7B is a waveform chart showing the amount of deflection of the bead core, and FIG.

FIG. 9 is a cross-sectional view illustrating a method of manufacturing a pneumatic radial tire according to another embodiment of the present invention. It is explanatory drawing which shows the positional relationship of a bead core, a 1st molded object, and a 2nd molded object at the time of matching phase.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st forming drum 2 2nd forming drum 3 shape up drum 4 inner liner layer 5 carcass layer 5a end part 7 bead core 8 side tread rubber 9 belt layer 10 cap tread rubber 12 transfer device 12a holding part C computer G green tire M 1 Central axis of molded body N Central axis of second molded body O '' Holding central axis S1 First molded body S2 Second molded body X, X 'Non-contact sensor y Position of central axis of bead core

Continued on the front page (72) Inventor Seiichi Takei 2-1 Oiwake, Hiratsuka-shi, Kanagawa F-term in Yokohama Rubber Co., Ltd. Hiratsuka Works 4F212 AH20 VA02 VA15 VC02 VC22 VD03 VD07 VD09 VD10 VD12 VD22 VK03 VK33 VK53 VL14

Claims (4)

[Claims] 1. An unvulcanized carcass layer is formed on a first forming drum by turning both ends of the carcass layer around an annular bead core to form a cylindrical first formed body, and is formed on a second forming drum by an unvulcanized carcass layer. Is wound around the belt layer to form a cylindrical second molded body, the first molded body is transferred to a shape-up drum, and the outer peripheral surface of the second molded body is moved to 1 by a transfer device. Held over the circumference and transferred to the outer peripheral side of the first molded body,
In the method for manufacturing a pneumatic radial tire, the first molded body is inflated in a toroidal shape by the shape-up drum and pressed on the inner peripheral side of the second molded body to form a green tire. After molding the molded body, the deflection amount of the annular bead core with respect to a perfect circle centered on the central axis of the first molded body is measured over one round, and a position serving as the central axis of the bead core is determined based on the deflection amount. A pneumatic radial tire that makes the center axis of the bead core coincide with the holding center axis of the transfer device when the transfer device transfers the second formed body to the outer peripheral side of the first formed body. Manufacturing method. 2. An unvulcanized carcass layer is formed on a first forming drum by folding back both ends of the carcass layer around an annular bead core to form a cylindrical first formed body, and is formed on a second forming drum by an unvulcanized carcass layer. Is wound around the belt layer to form a cylindrical second molded body, the first molded body is transferred to a shape-up drum, and the outer peripheral surface of the second molded body is moved to 1 by a transfer device. Held over the circumference and transferred to the outer peripheral side of the first molded body,
In the method for manufacturing a pneumatic radial tire, the first molded body is inflated in a toroidal shape by the shape-up drum and pressed on the inner peripheral side of the second molded body to form a green tire. After forming the molded body, the amount of deflection of the annular bead core with respect to a perfect circle centered on the central axis of the first molded body is measured over one round, while the holding center of the transfer apparatus is being transferred during the transfer of the transfer apparatus. The deflection amount of the inner peripheral surface of the second molded body with respect to a perfect circle centered on an axis is measured over one round, and after transferring the second molded body to the outer peripheral side of the first molded body, the bead core and the A method for manufacturing a pneumatic radial tire in which the phases of the first molded body and the second molded body are adjusted so that the deflection tendency of the amount of deflection of the second molded body coincides. 3. An unvulcanized inner liner layer is wound on the first forming drum, the unvulcanized carcass layer is wound on the outer peripheral side thereof, and annular bead cores are provided on both left and right ends of the carcass layer. After setting, the both ends are turned around the bead core, and an unvulcanized side tread rubber is wound around the left and right sides on the outer peripheral side of the carcass layer to form the first molded body. The manufacturing method of the pneumatic radial tire of the description. 4. The second molded body is formed by wrapping the unvulcanized belt layer on the second forming drum and wrapping an unvulcanized cap tread rubber on an outer peripheral side thereof. 3. The method for manufacturing a pneumatic radial tire according to any one of 3.