JP4261937B2 - Pneumatic tire manufacturing method and apparatus - Google Patents

Description

【００４９】
【発明の効果】
叙上の如く本発明は、高圧空気に代えてプロフアイルデッキの拡径によってカーカスを膨出せしめ、トレッドリングの内周面にカーカスを押し付けて貼着しているため、ブレーカ下でのカーカスコードの蛇行を抑制できる。その結果、加硫成形の際のカーカスの動きを抑えるとともにコードテンションの均一化を図ることができ、操縦安定性、乗り心地性、およびユニフォミティー等を向上しうる。
【図面の簡単な説明】
【図１】本発明のタイヤの製造方法によって形成された空気入りタイヤの一実施例を示す断面図である。
【図２】本発明の製造方法の一実施例を概念的に示す線図である。
【図３】本体カバー形成工程を説明する線図である。
【図４】タイヤの製造装置の構造の一例を説明する断面図である。
【図５】クランプリングを拡大して示す断面図である。
【図６】プロファイルデッキの拡径及び縮径の状態を示す周方向断面図である。
【図７】プロファイルデッキの輪郭形状を示す子午断面図である。
【図８】従来技術を説明する線図である。
【符号の説明】
２Ｇ トレッドゴム
５ ビードコア
６Ａ カーカスプライ
７ ブレーカ
９ 本体カバー
１５ トレッドリング
２０ クランプリング
２１ プロフアイルデッキ
２２ 膨出貼着手段[0001]
BACKGROUND OF THE INVENTION
The present invention can suppress the meandering of the carcass cord under the breaker when the carcass and the tread ring are joined, and can achieve the uniformity of the carcass cord tension in the finished tire, thereby improving the steering stability and uniformity. about the production how of a pneumatic tire.
[0002]
[Background Art and Problems to be Solved by the Invention]
In general, in a raw tire manufacturing process for a radial tire, as shown in FIG. 8, a cylindrical body cover c including a carcass ply b locked on both sides by a bead core a is formed, and the bead core a approaching the axial direction is formed. A raw tire in which the main body cover c is expanded in a toroidal shape between a and is brought into pressure contact with an inner peripheral surface of a tread ring d waiting outside in the radial direction, and the tread ring d and the main body cover c are integrated. Is forming. At this time, the swelling of the main body cover c is conventionally performed by filling with high-pressure air.
[0003]
However, in joining the tread ring d and the main body cover c by filling the high-pressure air, there is a problem that the carcass cord meanders under the breaker d1. As a result, sufficient tension does not act on the carcass cord under the breaker d1 during vulcanization molding, resulting in uneven cord tension, impairing steering stability and ride comfort, and carcass movement during vulcanization molding. It becomes easier and has a negative impact on uniformity.
[0004]
The meandering of the carcass cord is caused by the fact that the carcass cord b1 (indicated by the alternate long and short dash line in the figure) which is about to bulge out by filling with internal pressure is constrained linearly by the tread ring d. Only the carcass cord b1 undergoes compression in the length direction and meanders. Further, the meandering is more prominent as the tread ring d has a smaller inner diameter, that is, a tire with a smaller flatness.
[0005]
Patent Document 1 describes a technique in which a main body cover is bulged by a low internal pressure of 100 kPa or less and a core diameter that can be reduced and adhered to the inner peripheral surface of a tread ring d.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-67184
The present invention is based on the fact that the carcass is expanded by expanding the profile deck, and the carcass cord under the breaker is adhered to the inner peripheral surface of the tread ring by sticking the carcass in the shape pushed up by the profile deck. meander can be suppressed, and suppresses movement of the carcass during the vulcanization molding achieving uniform code tension, are intended to provide a steering stability and a pneumatic tire capable of improving the uniformity and the like manufacturing how .
[0008]
[Means for Solving the Problems]
In order to achieve the above object, claim 1 of the present application is an invention of a method for manufacturing a pneumatic tire, wherein a cylindrical main body cover including a carcass ply locked on both sides by a pair of bead cores can be enlarged or reduced. And around the profile deck,
The bead core of the main body cover is clamped by a pair of clamp rings that can approach the axial direction,
And with the movement of the clamp ring approaching, the profile deck is expanded in diameter so that the main body cover is pushed up in a shape along the profile deck to bulge between the bead cores,
The outer peripheral surface of the push-up-shaped main body cover by the profile deck is adhered to the inner peripheral surface in the radial direction of an annular tread ring made of a tread member including a breaker and tread rubber.
[0009]
According to a first aspect of the present invention, the profile deck includes a tapered first segment in which both side surfaces in the circumferential direction gradually approach inward in the radial direction in a cross section perpendicular to the axial direction, and vice versa. Are formed by alternately combining the second segments whose both side surfaces are asymptotically outward in the radial direction, and the first segment and the second segment have a radially outer periphery in an expanded state. The surface is formed in a perfect circle, and the diameter D1 on the tire equator of the profile deck in the expanded state is a value obtained by subtracting the thickness of the main body cover from the diameter D2 of the inner peripheral surface of the breaker in the finished state. It is characterized by conformity .
[0010]
Furthermore, in the meridional section including the tire shaft, the radial outer peripheral surface of the profile deck has a curvature radius R1 and a finished curvature radius R2 of the radial inner peripheral surface of the tread ring breaker. The difference is 200 mm or less, and the width W1 in the tire axial direction is larger in the range of 10 to 50 mm than the width W2 in the tire axial direction of the radially inner peripheral surface of the breaker .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a method for manufacturing a pneumatic tire according to the present invention will be described with reference to the drawings together with a manufacturing apparatus used therefor. FIG. 1 is a meridional sectional view of a pneumatic tire formed by the manufacturing method of the present invention, and FIG. 2 is a schematic diagram conceptually showing the manufacturing method.
[0012]
In FIG. 1, a pneumatic tire T is a tire for a passenger car in this example, and includes a carcass 6 extending from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and an inner side of the tread portion 2. The breaker 7 is formed so as to overlap the outside of the carcass 6 in the radial direction.
[0013]
The carcass 6 is formed of one or more, in this example, one carcass ply 6A in which carcass cords are arranged at an angle of 75 to 90 ° with respect to the tire circumferential direction. The carcass ply 6A is integrally provided with ply turn-back portions 6b that are folded back from the inside around the bead core 5 and locked to both ends of the ply main body portion 6a straddling the bead cores 5 and 5 between them. A bead apex rubber 8 for reinforcing the bead extending radially outward from the bead core 5 is disposed.
[0014]
The breaker 7 is composed of two or more breaker plies 7A and 7B in this example, in which breaker cords are arranged at an angle of, for example, 10 to 35 ° with respect to the tire circumferential direction. Each of the breaker plies 7A and 7B increases the breaker rigidity by crossing the cords between the plies, and reinforces substantially the entire width of the tread portion 2 with a tagging effect.
[0015]
In the meridional section including the tire shaft, the tread portion 2 curves in a convex arc shape from the tire equator C toward the tread end E. In this example, in the finished state in the vulcanization mold, A radially inner peripheral surface 7S of the breaker 7 (hereinafter sometimes referred to as a breaker inner peripheral surface 7S) is formed with a convex arcuate profile with a radius of curvature R2. The radius of curvature R2 is measured as the radius of curvature of a three-point arc passing through the center point in the tire axial direction of the breaker inner circumferential surface 7S and both outer end points when the breaker inner circumferential surface 7S is other than a single arc.
[0016]
Next, as shown conceptually in FIG.
(1) A main body cover forming step S1 (shown in FIG. 3) for forming a cylindrical main body cover 9 including a carcass ply 6A locked on both sides by a pair of bead cores 5;
(2) A clamping step S2 in which the main body cover 9 is disposed around the profile deck 21 capable of expanding and contracting, and then the bead core 5 is clamped by the clamp ring 20;
(3) When the profile deck 21 is enlarged in diameter as the clamp ring 20 moves closer, the main body cover 9 is pushed up in a shape along the profile deck 21 to bulge between the bead cores 5 and 5. And a bulging / sticking step S3 for sticking and integrating the outer peripheral surface of the body cover 9 in the shape of a push-up by the profile deck 21 on the radially inner peripheral surface of the annular tread ring 15 formed in advance. :
It is comprised including.
[0017]
Here, in the present example, the main body cover forming step S1 is carried out by using a former 10 having a well-known structure as shown in FIG. The former 10 has a cylindrical molding drum 11 capable of expanding the diameter, and forms the main body cover 9 in the following order of steps. That is,
(A) Step S1a of winding a main body cover constituent member including the carcass ply 6A around the outer peripheral surface of the forming drum 11 to form a straight cylindrical wound body 12;
(B) Step S1b of inserting the bead core 5 from both axial ends of the wound body 12 and setting the bead core 5 on the radially outer side of the wound body 12,
(C) Step S1c for folding both end portions 12a of the wound body 12 around the bead core 5 and thereby locking both ends of the carcass ply 6A.
[0018]
The main body cover constituting member is generally composed of the carcass ply 6A and an inner liner rubber disposed on the inner side in the radial direction thereof. However, a side wall rubber, a clinch rubber, or the like may be further included as required.
[0019]
The tread ring 15 is also formed by substantially the same method as before, that is, by sequentially winding a tread member including the breaker 7 and the tread rubber 2G on a belt drum having a known structure. In this example, the tread ring 15 is formed in a substantially trapezoidal cross section in which the inner peripheral surface forms a straight line in the meridional section. The diameter Dt of the inner peripheral surface of the tread ring 15 is a vulcanized stretch ratio (1 to 5%) than the diameter D2 (shown in FIG. 1) on the tire equator C of the inner peripheral surface 7S of the breaker in the finished state. Only set to small.
[0020]
And in this embodiment, the body cover 9 formed by said body cover forming step S1, after removal from the former 10 by diameter of the forming drum 11, and transferred to the manufacturing apparatus 1, by using the manufacturing apparatus 1 The clamping step S2 and the bulging / sticking step S3 are performed.
[0021]
As shown in FIG. 4, the manufacturing apparatus 1 includes a pair of clamp rings 20 that clamp the bead cores 5 and 5 of the transferred body cover 9 so as to be close to each other in the axial direction, and the body cover 9 with the bead cores 5 and 5. A bulging and sticking means 22 having a profile deck 21 bulging in between is provided.
[0022]
In this example, as shown in FIG. 5, the clamp ring 20 includes a seat portion 23 </ b> A seated on the bottom surface of the bead core 5 via a carcass ply 6 </ b> A and the like, and an axially inner end of the seat portion 23 </ b> A. A locking portion 23B that locks and positions the inner side surface in the axial direction of the bead core 5 by standing up at a small height, and an inclined portion 23C for guiding the bead core that extends downwardly from the axial outer end of the seating portion 23A in a cone shape. And formed.
[0023]
In this example, one clamp ring 20A (on the right side in FIG. 4) is fixed to, for example, the front end portion of the drum shaft 26 so as to be integrally rotatable with the drum shaft 26 using the first mounting bracket 24. The The clamp ring 20B on the other side (the left side in FIG. 4) uses the second mounting bracket 25, and can be rotated integrally with the drum shaft 26 via a sleeve tube 27 externally attached to the drum shaft 26. The direction is held so as to be slidable.
[0024]
The first mounting bracket 24 has a disk-shaped side wall portion 24A that rises radially outward from an adhering portion fixed to the drum shaft 26, and the clamp ring 20A is attached to the radially outer edge portion thereof. Bolts are connected.
[0025]
The second mounting bracket 25 includes a slidable slide cylinder 29 that is externally inserted into the sleeve tube 27, and a mounting bracket body 30 that is fixed to the inner end side in the axial direction of the slide cylinder 29. The mounting bracket body 30 includes a cylindrical body 30A that forms a piston chamber H between the sleeve tube 27 and the sleeve body 27 by making the diameter larger than that of the slide cylinder 29, and the axial direction of the body 30A. A first side wall portion 30B that is bolted to the slide cylinder 29 is integrally formed at the outer end, and a second side wall portion 30C that is bolted to the clamp ring 20B is integrally formed at the inner end in the axial direction. The
[0026]
A case part 32 is rotatably attached to the outer end side in the axial direction of the slide cylinder 29 via a bearing piece 31 such as a ball bearing. For example, a ball screw mechanism is used for the case part 32. The slide moving means 33 is linked.
[0027]
Therefore, the clamp rings 20A and 20B can move relatively close to each other by the parallel movement of the case portion 32 by the slide moving means 33, and the mounting brackets 24 and 25 and the clamp rings 20A and 20A 20B can rotate integrally with the drum shaft 26.
[0028]
Next , the profile deck 21 has a tapered shape in which both side surfaces sa in the circumferential direction gradually approach inward in the radial direction, as shown in FIG. 6, in a cross section (circumferential cross section) perpendicular to the axial direction. The large first segment 21A and, conversely, the small second segment 21B having both side surfaces sb asymptotically outward in the radial direction are alternately combined.
[0029]
The segments 21A and 21B can be moved radially outward by the expansion / contraction diameter means 34 described later, and in the diameter expansion state Y1 in which the adjacent side surfaces sa and sb substantially come into contact with each other, the radial outer peripheral surface 21S (hereinafter referred to as the deck outer peripheral surface 21S). Is formed in a perfect circle. Further, when the diameter is reduced, the profile deck 21 can be reduced in diameter by making the moving distance inward in the radial direction of the second segment 21B larger than the moving distance of the first segment 21A. .
[0030]
The profile deck 21 is preferably composed of 8 to 16 segments in order to smoothly perform the operation of the expansion / contraction diameter and to ensure a sufficient difference in the radius of the expansion / contraction diameter. The diameter D1 of the profile deck 21 on the tire equator in the expanded diameter state Y1 substantially matches the value obtained by subtracting the thickness of the main body cover 9 from the diameter D2 of the inner peripheral surface 7S of the breaker in the finished state. .
[0031]
And particularly important for the present invention, as shown in FIG. 7, in the meridional section including the tire shaft, the deck outer peripheral surface 21S has a convex arc-shaped profile according to the breaker inner peripheral surface 7S in the finished state. Is to have.
[0032]
Specifically, in the meridional section, the deck outer peripheral surface 21S is formed of a single arc in this example, and has a radius of curvature R1 (shown in FIG. 6 as “D1” of D1 = 2 · R1) , In the finished state, the difference (R1−R2) with the radius of curvature R2 of the inner peripheral surface 7S of the breaker is 200 mm or less, and the shape is close to the inner peripheral surface 7S of the breaker. Preferably, the difference (R1−R2) is set to 150 mm or less, further 100 mm or less, and approximated by the breaker inner peripheral surface 7S. When the deck outer peripheral surface 21S is other than a single arc, the radius of curvature of a three-point arc passing through the center point and both outer end points of the deck outer peripheral surface 21S is R1. Further, the deck outer peripheral surface 21S has a width W1 in the tire axial direction larger than a width W2 (shown in FIG. 1) of the inner peripheral surface 7S of the breaker in the tire axial direction in the finished state.
[0033]
Next, the expansion / contraction diameter means 34 includes guide means 34A for guiding the segments 21A and 21B inward and outward in the radial direction and movement means 34B for moving the segments 21A and 21B along the guide means 34A.
[0034]
The guide means 34A comprises a plurality of guide shafts 36 extending radially outward from the drum shaft 26, and the guide shafts 36 are fitted with guide holes provided in the segments 21A and 21B. The segments 21A and 21B can be guided inward and outward in the radial direction.
[0035]
The moving means 34B is a cylindrical reciprocating member 39 disposed in the piston chamber H and capable of sliding in the axial direction on the sleeve tube 27, the reciprocating member 39 and the first segment 21A. 1st link body 40 which connects between, and the 2nd link body 41 which connects between reciprocating member 39 and the 2nd segment 21A. Here, the link length of the second link body 41 is larger than the link length of the first link body 40, thereby reducing the amount of diameter reduction of the second segment 21B from the expanded diameter state Y1. It can be set smaller than the diameter reduction amount of the first segment 21A.
[0036]
In this example, the reciprocating member 39 can slide in and out in the axial direction by a linear actuator 42 which is an air cylinder fixed to the frame F. The linear actuator 42 is connected to the reciprocating member 39 through a rod member 43 including a joint shaft 43A that extends through the first side wall portion 30B in the axial direction.
[0037]
In this example, the case where the moving means 34B is arranged only on one side (left side in FIG. 3) of the profile deck 21 is illustrated, but it can be arranged on both sides of the profile deck 21 as required.
[0038]
However, as shown in FIG. 2, the cylindrical main body cover 9 transferred to the manufacturing apparatus 1 is held with its bead core 5 seated on the clamp ring 20 (clamping step S2).
[0039]
Thereafter, the bulging / sticking step S3 is performed. In this step, the slide moving means 33 is actuated to slide the bead core 5 in a direction approaching each other to a predetermined position J where a predetermined inter-bead distance is obtained, and the profile deck 21 is expanded by the operation of the linear actuator 42. Let the diameter. Accordingly, the main body cover 9 can be pushed up and swelled in a shape along the profile deck 21, and the main cover 9 of the raised shape by the profile deck 21 can be formed on the inner peripheral surface of the tread ring 15 that has been standby in advance. Can be attached by pressing the outer peripheral surface.
[0040]
At this time,
-Enlargement of the profile deck 21 allows sufficient tension to be applied to the carcass cord; and-Since the deck outer peripheral surface 21S has a convex arc-shaped profile that approximates the finished inner peripheral surface 7S of the breaker, The tread ring 15 can be attached to the main body cover 9 while being deformed into a profile close to the finished state;
Thus, the meandering of the carcass cord under the breaker can be reliably suppressed. In addition, since the tension close to the finished state can be applied to the carcass cord under the breaker during sticking, the carcass cord tension during vulcanization molding can be made more uniform, and the movement of the carcass during vulcanization molding can be further improved. Can be suppressed. Accordingly, the tire performance such as steering stability and ride comfort in the finished tire, and uniformity can be improved.
[0041]
Further, in the past, both ends of the tread ring 15 are rolled down radially inward using a stitcher and attached to the main body cover 9, so that wrinkles or the like occur at the unwinding portion and the code arrangement is disturbed at the end of the breaker. is doing. However, in the present invention, since the main body cover 9 is firmly held in the raised shape by the profile deck 21, the amount of unwinding at both ends of the tread ring can be greatly reduced, and the wrinkles and the cord arrangement are disturbed. Can be suppressed, and uniformity and the like can be further improved.
[0042]
As described above, the particularly preferred embodiment of the present invention has been described in detail. For example, the main body cover 9 is directly formed around the profile deck 21 without changing the main body cover 9 from the former 10 according to a single stage molding method. The present invention is not limited to the illustrated embodiment, and can be implemented in various forms.
[0043]
【Example】
Based on the manufacturing method of the present invention, a tire for a passenger car having a tire size of 225 / 60R16 is prototyped according to the specifications shown in Table 1, and the handling stability, riding comfort, road noise characteristics, and uniformity (RFV) of each sample tire are measured. ) And the like were measured and compared with a conventional example in which the main body cover was bulged with high-pressure air. The tire is formed under the same conditions except for the method of swelling the main body cover.
[0044]
(1) Steering stability and ride comfort;
A sample tire is mounted on all wheels of a vehicle (2500 cc) based on a rim (16 × 6.5) and internal pressure (200 kPa) and travels on a dry asphalt test course. The comfort is displayed as an index with the conventional example being 100 based on the sensory evaluation of the driver. A larger index is better.
[0045]
(2) Road noise characteristics;
Using the vehicle, the vehicle was driven on a smooth road surface at a speed of 50 km / h, the overall noise level dB (A) was measured at the driver's seat, and displayed as an index with the conventional example being 100. A larger index is better.
[0046]
(3) Uniformity (RFV);
Using a uniformity testing machine, RFV was measured for each of 100 tires, and the average value was evaluated.
[0047]
(4) Tire finish state;
The tires before vulcanization were disassembled, and the presence or absence of meandering of the carcass cord under the breaker and the presence or absence of breaker cord arrangement disorder at the end of the breaker were observed.
[0048]
[Table 1]

[0049]
【The invention's effect】
As described above, in the present invention, the carcass is expanded by expanding the profile deck instead of the high-pressure air, and the carcass is pressed and stuck to the inner peripheral surface of the tread ring. Can be suppressed. As a result, the movement of the carcass during vulcanization molding can be suppressed and the cord tension can be made uniform, so that the handling stability, ride comfort, uniformity, and the like can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a pneumatic tire formed by the tire manufacturing method of the present invention.
FIG. 2 is a diagram conceptually showing an embodiment of the production method of the present invention.
FIG. 3 is a diagram for explaining a main body cover forming step.
FIG. 4 is a cross-sectional view illustrating an example of the structure of a tire manufacturing apparatus.
FIG. 5 is an enlarged cross-sectional view of a clamp ring.
FIG. 6 is a circumferential sectional view showing a state of diameter expansion and contraction of the profile deck.
FIG. 7 is a meridional sectional view showing a profile shape of a profile deck.
FIG. 8 is a diagram for explaining the prior art.
[Explanation of symbols]
2G tread rubber 5 bead core 6A carcass ply 7 breaker 9 body cover 15 tread ring 20 clamp ring 21 profile deck 22 bulging and sticking means

Claims (1)

While arranging a cylindrical body cover including a carcass ply locked on both sides by a pair of bead cores around a profile deck capable of expanding and contracting,
The bead core of the main body cover is clamped by a pair of clamp rings that can approach the axial direction,
And with the movement of the clamp ring approaching, the profile deck is expanded in diameter so that the main body cover is pushed up in a shape along the profile deck to bulge between the bead cores,
While sticking the outer peripheral surface of the push-up body cover by the profile deck to the radially inner peripheral surface of an annular tread ring made of a tread member including a breaker and tread rubber,
The profile deck has a tapered first segment in which both sides in the circumferential direction asymptotically approach inward in the radial direction in a cross section perpendicular to the axial direction, and conversely, both side surfaces in the radially outward direction. Are formed by alternately combining the second segments asymptotically toward the surface, and the first segment and the second segment are formed in a circular shape on the radially outer peripheral surface in the expanded diameter state. In addition, the diameter D1 on the tire equator of the profile deck in the expanded state conforms to a value obtained by subtracting the thickness of the main body cover from the diameter D2 of the inner peripheral surface of the breaker in the finished state,
In the meridional section including the tire axis, the radial outer peripheral surface of the profile deck has a difference between the curvature radius R1 and the finished curvature radius R2 of the radial inner peripheral surface of the breaker of the tread ring is 200 mm or less, and A method for manufacturing a pneumatic tire, characterized in that the width W1 in the tire axial direction is larger than the width W2 in the tire axial direction on the radially inner peripheral surface of the breaker in a range of 10 to 50 mm .

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