JP2005212197A - Tire manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire manufacturing method related to a tire, which has characters or lines having a hue different from that of the periphery on its side wall parts, capable of efficiently manufacturing a tire of another kind easy in the changeover in size without requiring a large-sized extruder and capable of manufacturing a tire enhanced in the precision of a shape or the dimension of each of respective members, excellent from an aspect of uniformity or tire balance, clear in the contour of a character or a line and having no problem from an aspect of appearance. <P>SOLUTION: At the time of molding of a green tire, a side wall rubber and a cover rubber are bonded by winding a rubber ribbon a plurality of times and the tire is vulcanized so that the minimum value of the thickness of the cover rubber on the side surface of a protruded part before buffing after vulcanization becomes half or below with respect to the average value of the thickness of the cover rubber of the part corresponding to the side surface of the protruded part in the green tire. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a tire having characters or lines of a color different from the surroundings in a sidewall portion, and particularly relates to a tire capable of efficiently producing a high-quality tire with a clear character or line outline.

  Forming green tires by attaching each tire component to the outside of a toroidal carcass member fixed on a rigid core or molding drum in order to make the shape of the product tire and the dimensions of each member highly accurate And the manufacturing method of the tire which vulcanizes this is proposed (for example, refer patent document 1). In this manufacturing method, the rubber member of these tire constituent members is attached by winding a plurality of continuous rubber ribbons, and according to this manufacturing method, the rubber having a cross section corresponding to the member cross section of the product tire is wound only once. In contrast to the case where this is formed by winding, it is not necessary to extrude a rubber member having a large cross section, so that the extruder can be downsized, and further, the rubber ribbon extruded from the downsized extruder can be directly used. It can be wound on a toroidal carcass member to eliminate the large amount of intermediate stock required for the production of other types of tires.

  Also, when molding green tires of different sizes, it is possible to form different cross-section members by changing only the number of windings and the winding position of rubber ribbons of the same cross-sectional shape. It has the feature that can be molded continuously.

  Furthermore, in a tire made of a rubber member formed by winding a rubber ribbon a plurality of times in this manner, there is no seam over the entire width of each member, so that the quality is high in terms of uniformity and tire balance. .

  However, it has been found that when this manufacturing method is applied to a tire having characters or lines of colors different from the surroundings in the sidewall portion, there are the following problems.

  FIG. 1 is a perspective view showing, as an example, a portion of a sidewall portion of a product tire where, for example, white and a letter “I” are formed, and FIG. 2 is in the process of manufacturing a tire portion where the letter is formed. It is sectional drawing corresponding to the II-II arrow of FIG. 1 which shows the state of FIG. 1, FIG. 3 is sectional drawing and a perspective view which show the detail of this character part in a product tire. In FIG. 1, B shows a black rubber part, W shows a white rubber part, and in FIGS. 1-3, T is an arrow which shows the circumferential direction of a tire. In addition, the aa arrow view in FIG.3 (b) respond | corresponds to the cross section of Fig.3 (a).

  In order to form this white character, as shown in FIG. 2 (a), in the step of molding the green tire, the side wall portion where the white character should be exposed, the black side outside the carcass member 91 serving as the base After the wall rubber 92 is pasted, the black cover rubber 93 is pasted. When the green tire is vulcanized, as shown in FIG. 2 (b), the white character portion is projected from the other portion using a mold having a concave portion corresponding to the white character.

Next, as shown in FIG. 3A, if the protruding portion is buffed to remove the cover rubber 93, the white side wall rubber 92 appears from below to form white characters. However, when the cover rubber 93 is formed by overlapping rubber ribbons having a narrow cross-sectional rectangular shape, as shown in FIG. 3B, a step between the ribbons appears on the cross-section 93a where the overlapping portions of the ribbons are buffed. It was a problem in appearance. In order to solve this problem, even if it is attempted to wind the ribbon so that the gap between the ribbons becomes zero, it is difficult to actually make the gap zero, and gaps and overlaps are generated, and the appearance has not been improved.
International Publication No. 02/078939 Pamphlet

  The present invention has been made in view of such problems, and relates to a tire having characters or lines of a color different from the surroundings on the sidewall portion, and does not require a large extruder and can be easily switched in size. High-quality tires can be produced efficiently, and the shape and dimensions of each component are high-precision, excellent in terms of uniformity and tire balance. An object of the present invention is to provide a method for manufacturing a tire that can produce a tire free of tires.

(1) The present invention relates to a first color sidewall rubber in which at least one sidewall is exposed as a character or a line, and respective second color sidewalls located on both radial sides of the first color sidewall rubber. When manufacturing a tire made of rubber and a second color cover rubber that covers the first color sidewall rubber part other than characters or lines, a recess was provided at a position corresponding to the characters or lines in the vulcanization process. In the tire manufacturing method using a mold, forming a convex portion corresponding to the concave portion on the tire, and after vulcanization, buffing the convex portion of the tire to expose the first color letters or lines,
When molding the green tire, the second color sidewall rubber and the first color sidewall rubber are respectively connected to the side surface of the carcass member formed in a toroidal shape, and the second color rubber ribbon and the first color rubber ribbon are continuous. A plurality of wraps around, and then the cover rubber is affixed with a plurality of wraps around a rubber ribbon around the sidewall rubber,
Add the tire so that the maximum thickness of the cover rubber on the side surface of the convex part after vulcanization and before buffing is less than half the average value of the cover rubber thickness of the part corresponding to the side surface of the convex part in the green tire. A tire manufacturing method characterized by vulcanizing.
Here, the “second color” means the color that is the base color of the tire, usually black, and the “first color” is contrasted with the “second color” to decorate characters or lines. It means the color used, and white is widely used as the “first color”.

(2) The present invention relates to a first color sidewall rubber in which at least one sidewall is exposed as a character or a line, and respective second color sidewalls located on both radial sides of the first color sidewall rubber. When manufacturing a tire made of rubber and a second color cover rubber that covers the first color sidewall rubber part other than characters or lines, a recess was provided at a position corresponding to the characters or lines in the vulcanization process. In the tire manufacturing method using a mold, forming a convex portion corresponding to the concave portion on the tire, and after vulcanization, buffing the convex portion of the tire to expose the first color letters or lines,
When molding the green tire, the second color sidewall rubber and the first color sidewall rubber are respectively connected to the side surface of the carcass member formed in a toroidal shape, and the second color rubber ribbon and the first color rubber ribbon are continuous. A plurality of wraps around, and then the cover rubber is affixed with a plurality of wraps around a rubber ribbon around the sidewall rubber,
In the tire manufacturing method, the rubber rubber is wound at a pitch that is half the total of the rubber ribbon width and the rubber ribbon thickness when the cover rubber is applied.

(3) The present invention relates to a first color sidewall rubber in which at least one sidewall is exposed as a character or a line, and respective second color sidewalls located on both radial sides of the first color sidewall rubber. When manufacturing a tire made of rubber and a second color cover rubber that covers the first color sidewall rubber part other than characters or lines, a recess was provided at a position corresponding to the characters or lines in the vulcanization process. In the tire manufacturing method using a mold, forming a convex portion corresponding to the concave portion on the tire, and after vulcanization, buffing the convex portion of the tire to expose the first color letters or lines,
When molding the green tire, the second color sidewall rubber and the first color sidewall rubber are respectively connected to the side surface of the carcass member formed in a toroidal shape, and the second color rubber ribbon and the first color rubber ribbon are continuous. A plurality of wraps around, and then the cover rubber is affixed with a plurality of wraps around a rubber ribbon around the sidewall rubber,
In the tire manufacturing method, a rubber ribbon having a thickness at both end portions in the width direction smaller than a thickness at a center portion in the width direction is used when the cover rubber is attached.

  When the tire is changed from the state of the green tire shown in FIG. 2A to the state after vulcanization shown in FIG. 2 is set to the minimum height necessary for buffing, and the minimum value of the cover rubber thickness g on the side surface of the convex portion in FIG. ), The average value G of the cover rubber thickness of the portion corresponding to the convex side surface in the green tire was not so small, and was at least more than half of G.

  In the invention of (1), g is set to be equal to or less than half of G, which means that the height of the convex portion is made higher than the necessary height for the buff. When a tire is vulcanized using a mold having a deep concave portion corresponding to such a high convex portion, the rubber of the cover rubber portion vigorously flows toward the concave portion of the mold, and this flow causes a step portion between the ribbons. Can be smoothed.

  According to (2), when the cover rubber is affixed, the rubber ribbon is wound at a pitch that is half the sum of the width of the rubber ribbon and the thickness of the rubber ribbon. The thickness after ribbon winding can be made uniform.

  According to (3), when the cover rubber is affixed, since the rubber ribbon having a thickness at both ends in the width direction smaller than the thickness at the center in the width direction is used, similarly, the cover rubber after winding the ribbon in the green tire is used. The thickness can be made uniform.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 4 is a meridian cross-sectional view showing the tire formed according to the first embodiment in a cross section of a half portion provided with characters or lines of a color different from the surroundings, among the half portions separated by the equator plane. . In the tire 1, the sidewalls 2 arranged on one side in the axial direction of the carcass 8 are, for example, a first color sidewall rubber 3 expressed as a character 3 a and a radial side of the first color sidewall rubber 3. Each of the second color side wall rubbers 4A and 4B positioned and a cover rubber 5 of the second color covering the first color side wall rubber 3 other than the character 3a, and the first color side wall rubber 3 and the second color rubber 2 Each of the color sidewall rubbers 4A and 4B and the cover rubber 5 includes a continuous first color rubber ribbon 3r, a second color rubber ribbon 4r and a second color rubber ribbon 5r which are wound around a plurality of turns. Here, the first color is, for example, white, and the second color is, for example, black.

  In the figure, the boundary surfaces of the first color sidewall rubber 3 on both sides in contact with the second color sidewall rubbers 4A and 4B are inclined substantially in parallel, but these boundary surfaces are opposite to each other. The first color sidewall rubber 3 may be inclined, and the radial extension width on the outer side in the axial direction and the radial extension width on the inner side in the axial direction may be larger, The second color sidewall rubbers 4 </ b> A and 4 </ b> B may be continuous on the inner side in the axial direction of the first color sidewall rubber 3.

  A side wall (not shown) disposed on the other side in the axial direction of the carcass 8 is composed of a continuous second color rubber ribbon 4r that is wound around the entire region in a plurality of rounds. Denotes a belt, and 9 denotes a bead core, and the tread 6 is also composed of a continuous rubber ribbon wound around a plurality of turns.

  FIG. 5 is a perspective view showing a detailed portion of a part of the character 3a shown in correspondence with FIG. 3 (b) used previously, and there is a jagged step in the peripheral portion of the character 3a of the cover rubber 5. The contour extending in the direction orthogonal to the tire circumferential direction T of the character 3a can be clearly expressed without appearing.

  A method for manufacturing the tire 1 will be described. FIG. 6 is a green tire meridian cross-sectional view for explaining a process of molding a green tire by attaching a side wall having characters or lines, and first, as shown in FIG. The carcass member 18 is formed in a toroidal shape on the outside of the molding drum or the rigid core. FIG. 6A shows that the belt member 17 and the tread rubber 16 are already on the radially outer side of the carcass member 18 thus formed. The pasted state is shown.

  After the state shown in FIG. 6 (a), as shown in FIG. 6 (b), the second color side wall rubber 14A on the outer side in the radial direction is connected to the second side wall rubber 14A that is continuous in the radial direction. The color rubber ribbon 14r is wound around a plurality of turns, and then the first color sidewall rubber 13 is attached by winding a plurality of continuous first color rubber ribbons 13r around, followed by the second color inside the radial direction. The sidewall rubber 14B is pasted by winding a plurality of continuous second color rubber ribbons 14r. Thereafter, as shown in FIG. 6C, the cover rubber 15 is attached to the outside of the side wall rubbers 13, 14A, 14B by winding a plurality of rubber ribbons 15r having a rectangular cross section around the green rubber 10 Is molded.

  Here, the order in which the side wall rubbers 13, 14 </ b> A, and 14 </ b> B are affixed can be appropriately determined according to the way in which the rubber ribbons are laminated.

  Thereafter, when the green tire 10 is formed on the molding drum, the green tire 10 is removed from the molding drum and transferred to the vulcanizer, and when the green tire 10 is formed on the rigid core, The tire 10 is transferred to the vulcanizer without removing the tire 10 from the rigid core, and the green tire 10 is vulcanized by the vulcanizer.

  When vulcanizing the green tire 10, in accordance with the above-described conventional technique, a convex portion corresponding to the concave portion is formed on the tire using a mold having a concave portion corresponding to a character or a line. Buff the convex part to make the first color letter or line appear.

FIG. 7 is a diagram showing changes before and after vulcanization of the cover rubber, FIG. 7 (a) is a meridian cross-sectional view showing the cover rubber 15 before vulcanization, and FIG. 7 (b) is before buffing after vulcanization. The cover rubber 15 in the green tire before vulcanization is wound a plurality of times while partially overlapping the rubber ribbon 15r, the maximum thickness is Gx, and the minimum thickness is Gn. in, no sheet-like cross-sectional shape having a step portion, the average thickness of G _0. Before vulcanized buff, maximum thickness g ₁ of the convex portion side surface of the first color side wall rubber 3, to vulcanize to satisfy the relationship of formula (1) is a feature of the present invention.

_{g 1 ≦ (G 0/2} ) (1)

Here, as the height H of the projection is high, since the cover rubber 15 is stretched, the thickness g ₁ is decreased, the convex height H, by high enough to satisfy the (1) When the tire is vulcanized using a mold having deep recesses corresponding to the high protrusions, the cover rubber 15 flows vigorously toward the mold recesses, and this flow causes the ribbons of the cover rubber 5 to overlap each other. It is possible to smooth the stepped portion formed by. However, when the height H of the convex portion is lowered to a state where (1) is not satisfied, it becomes difficult to prevent the appearance problem due to the step.

  Here, in order to attach the sidewall rubbers 13, 14A, 14B or the cover rubber 15, a known method of winding a rubber ribbon can be used, but FIG. 8 shows an example, and a molding drum (not shown) is shown. For example, in the case of the second color sidewall rubber 14A on the side surface of the carcass member 18 formed on the upper side, after the front end of the second color rubber ribbon 14r is pressed, the radial position of the second color rubber ribbon 14r is controlled. The second color sidewall rubber 14A is adhered by rotating the molding drum 61 a plurality of times in the direction R while moving the affixing roller 61 that presses against the side surface of the carcass member 18. At this time, the second color rubber ribbon 14r is pushed out from the extruder 62 in synchronism with the winding amount of the second color rubber ribbon 14r, but by providing the festoon 63, the second color rubber ribbon 14r is wound. The imbalance between the applied amount and the extrusion amount can be adjusted.

  According to this rubber ribbon winding method, the extruder 62 can be reduced in size, and rubber members having various cross-sectional shapes can be formed with one type of rubber ribbon 14r. The trajectory program for displacing the sticking roller 61 can be performed simply by selecting and starting up the program stored in advance corresponding to the size, thereby enabling instantaneous size switching. It is possible to efficiently produce a small variety of varieties.

  Next, a second embodiment will be described. The tire 1 formed according to this embodiment also has the structure shown in FIG. In the production of the tire 1, when a green tire is molded by attaching a side wall having letters or lines, as shown in FIGS. 6 (a) and 6 (b), the outer side in the radial direction is used. The second color sidewall rubber 14A is attached by winding a plurality of continuous second color rubber ribbons 14r, and then the first color sidewall rubber 13 is wound by a plurality of continuous first color rubber ribbons 13r. Subsequently, the second color sidewall rubber 14B on the radially inner side is pasted by winding a plurality of continuous second color rubber ribbons 14r around the circumference. After that, as shown in FIG. 9A, the rubber ribbon 25r of the second color is wound a plurality of times and the cover rubber 25 is attached.

  In this embodiment, when the cover rubber 25 is affixed, the rubber ribbon is wound at a pitch P that is half the total of the rubber ribbon width W and the rubber ribbon thickness t. FIG. 9B shows the rubber ribbon 25r. FIG. 9C is a meridian cross-sectional view showing the cover rubber 25 formed by winding the rubber ribbon 25r. As shown in these figures, the cross-section of the ribbon 25r is a conventional cross-sectional view. Even if it is rectangular like this, the thickness after ribbon winding can be made uniform.

  Next, a third embodiment will be described. The tire 1 formed according to this embodiment also has the structure shown in FIG. 4, and in the manufacture of the tire 1, when forming a green tire by attaching a side wall having letters or lines, the above-described figure 6 (a) and FIG. 6 (b), the second color sidewall rubber 14A on the outer side in the radial direction is affixed by winding a plurality of continuous second color rubber ribbons 14r, and then the first color. The side wall rubber 13 is pasted by winding a plurality of continuous first color rubber ribbons 13r, followed by a second color side wall rubber 14B radially inward and a plurality of continuous second color rubber ribbons 14r. And paste. Then, as shown in FIG. 10A, the rubber rubber 35r of the second color is wound a plurality of times and the cover rubber 35 is attached.

  In the present embodiment, when the cover rubber 35 is pasted, the cross-sectional shape of the rubber ribbon 35r is characterized in that a rubber ribbon whose thickness at both ends in the width direction is thinner than the thickness at the center in the width direction is used. ) Is a cross-sectional view showing a cross section of the rubber ribbon 35r, and FIG. 10C is an enlarged meridian cross-sectional view showing the cover rubber 35 formed by wrapping the rubber ribbon 35r. As shown in these figures, the rubber ribbon The cross-sectional shape of 35r is formed into a tapered shape that is sharp at both ends in the width direction, whereby the thickness of the cover rubber can be made uniform.

  Here, as shown in FIGS. 10D to 10F, there are rubber ribbons 35ra, 35rb, 35rc, and the like as rubber ribbons having other cross-sectional shapes in which both ends in the width direction are tapered.

  As another example of the rubber ribbon in which the thickness at both ends in the width direction is thinner than the thickness at the center in the width direction, the rubber ribbon 36ra or 36rb having a cross section shown in FIG. 11 (a) or FIG. 11 (b) can be used. Also in this case, as shown in FIG. 11C, the cover rubber 36 having a uniform thickness can be formed.

  The shape of the rubber ribbon and the method for laminating the rubber ribbon disclosed in the present invention can also be applied to a tire having no character or line of a color different from the surroundings.

It is a perspective view which shows the character part expressed on the product tire surface. It is sectional drawing which shows the state in the middle of manufacture of a character part. It is sectional drawing and the perspective view which show the detail of the character part in a prior art. It is sectional drawing which shows the quarter part of the tire of embodiment which concerns on this invention in a meridian plane. It is a perspective view which shows the detailed part of a part of character. In 1st embodiment, it is a green tire meridian sectional drawing for demonstrating the process of sticking a sidewall rubber | gum and shape | molding a green tire. In 1st embodiment, it is sectional drawing which shows the change of the cover rubber before and behind vulcanization. It is a perspective view which shows the method of winding a rubber ribbon and forming sidewall rubber. In 2nd embodiment, it is sectional drawing of a green tire, cover rubber, and a rubber ribbon explaining the process of shape | molding cover rubber. In 3rd embodiment, it is sectional drawing of the green tire, cover rubber, and rubber ribbon explaining the process of shape | molding cover rubber. It is sectional drawing of the rubber ribbon of another aspect used in 3rd embodiment, and cover rubber | gum.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire 2 Side wall 3 First color side wall rubber 3a Character 3r First color rubber ribbon 4A, 4B Second color side wall rubber 4r Second color rubber ribbon 5 Cover rubber 5r Rubber ribbon 6 Tread 7 Belt 8 Carcass 9 Bead core 10 Rubber sponge roller 13 first color side wall rubber 13r first color rubber ribbon 14A, 14B second color side wall rubber 14r second color rubber ribbon 15 cover rubber 15r rubber ribbon 16 tread rubber 17 belt member 18 carcass member 25 cover rubber 25r rubber ribbon 35 cover rubber 35r, 35ra, 35rb, 35rc, rubber ribbon 36 cover rubber 36ra, 36rb rubber ribbon 61 sticking roller 62 extruder 63 festoon

Claims (3)

At least one side wall of the first color side wall rubber that appears as letters or lines, the second color side wall rubber that is located on both sides in the radial direction of the first color side wall rubber, and other than letters or lines When manufacturing a tire made of a cover rubber of the second color covering the first color sidewall rubber part of this, in the vulcanization process, using a mold provided with a recess at a position corresponding to the character or line, In the tire manufacturing method of forming a convex portion corresponding to the concave portion on the tire, vulcanizing, and buffing the convex portion of the tire to expose the first color letters or lines,
When molding the green tire, the second color sidewall rubber and the first color sidewall rubber are respectively connected to the side surface of the carcass member formed in a toroidal shape, and the second color rubber ribbon and the first color rubber ribbon are continuous. A plurality of wraps around, and then the cover rubber is affixed with a plurality of wraps around a rubber ribbon around the sidewall rubber,
Add the tire so that the maximum thickness of the cover rubber on the side surface of the convex part after vulcanization and before buffing is less than half the average value of the cover rubber thickness of the part corresponding to the side surface of the convex part in the green tire. A method of manufacturing a tire characterized by vulcanizing. At least one side wall of the first color side wall rubber that appears as letters or lines, the second color side wall rubber that is located on both sides in the radial direction of the first color side wall rubber, and other than letters or lines When manufacturing a tire made of a cover rubber of the second color covering the first color sidewall rubber part of this, in the vulcanization process, using a mold provided with a recess at a position corresponding to the character or line, In the tire manufacturing method of forming a convex portion corresponding to the concave portion on the tire, vulcanizing, and buffing the convex portion of the tire to expose the first color letters or lines,
When molding the green tire, the second color sidewall rubber and the first color sidewall rubber are respectively connected to the side surface of the carcass member formed in a toroidal shape, and the second color rubber ribbon and the first color rubber ribbon are continuous. A plurality of wraps around, and then the cover rubber is affixed with a plurality of wraps around a rubber ribbon around the sidewall rubber,
A method for manufacturing a tire, characterized in that when a cover rubber is pasted, the rubber ribbon is wound at a pitch that is half the sum of the width of the rubber ribbon and the thickness of the rubber ribbon. At least one side wall of the first color side wall rubber that appears as letters or lines, the second color side wall rubber that is located on both sides in the radial direction of the first color side wall rubber, and other than letters or lines When manufacturing a tire made of a cover rubber of the second color covering the first color sidewall rubber part of this, in the vulcanization process, using a mold provided with a recess at a position corresponding to the character or line, In the tire manufacturing method of forming a convex portion corresponding to the concave portion on the tire, vulcanizing, and buffing the convex portion of the tire to expose the first color letters or lines,
When molding the green tire, the second color sidewall rubber and the first color sidewall rubber are respectively connected to the side surface of the carcass member formed in a toroidal shape, and the second color rubber ribbon and the first color rubber ribbon are continuous. A plurality of wraps around, and then the cover rubber is affixed with a plurality of wraps around a rubber ribbon around the sidewall rubber,
A method for manufacturing a tire, wherein a rubber ribbon having a thickness at both end portions in the width direction smaller than a thickness at a center portion in the width direction is used when the cover rubber is pasted.

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