JP4526869B2 - Pneumatic tire manufacturing method and pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire including a step of forming a tread rubber layer on the outer peripheral side of a molded article including a carcass layer spanned between bead portions and a belt layer disposed on the outer peripheral side of the carcass layer. And a carcass layer spanned between bead portions, a belt layer disposed on the outer peripheral side of the carcass layer, and a tread rubber layer disposed on the outer peripheral side of the belt layer. Regarding tires.

  Generally, a pneumatic tire is composed of a plurality of tire rubber members, and a tread rubber member is disposed on the outer peripheral side of the belt layer in the tread portion. Conventionally, a tread rubber member has been formed by cutting a rubber extruded from an extruder with a predetermined length through a die corresponding to its cross-sectional shape. However, in this method, it is necessary to prepare a base suitable for each tire size, and to perform the replacement work of the base every time the tire size is changed. Moreover, there has been a problem that the rubber member is distorted and contracted by continuously extruding and cutting the rubber, resulting in a decrease in tire uniformity.

  Therefore, a so-called ribbon winding method has been proposed in which an unvulcanized rubber ribbon (rubber strip) is spirally stacked along the tire circumferential direction and wound to form a rubber member having a predetermined cross-sectional shape. For example, Patent Document 1 below discloses a method of forming a tread portion by spirally winding a rubber strip around the outer peripheral surface of a belt. Patent Document 2 below forms a tread lower portion by winding a large rubber sheet. A method of forming a tread upper part by winding a small rubber strip around the outer peripheral surface is disclosed. However, these methods involve sequentially winding rubber ribbons having a relatively small cross-sectional shape with high accuracy, so that there is a problem that the molding time becomes long and the productivity of the tire decreases.

Patent Document 3 below discloses a method of forming a tread rubber member by winding a rubber strip around the outer peripheral surface of an extruded rubber extrudate. However, since the inner peripheral surface of the tread rubber member is obtained by extrusion molding, conventionally, it has been necessary to provide a sheet-like cushion rubber layer between the belt layer and improve adhesion. The formation of the cushion rubber layer requires a calender roll for rubber sheet molding, a cutting mechanism for cutting the molded rubber sheet into a predetermined size according to the tire size, and there is a problem that the equipment is enlarged. there were.
JP 2003-236950 A JP 2001-179848 A JP 2000-94542 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic tire manufacturing method and a pneumatic tire capable of simplifying the formation of a cushion rubber layer and improving tire productivity. Furthermore, it is to provide a pneumatic tire manufacturing method and a pneumatic tire that are excellent in tire uniformity and can reduce the number of parts.

The above object can be achieved by the present invention as described below. That is, the method for manufacturing a pneumatic tire according to the present invention includes a carcass layer spanned between bead portions, and an outer peripheral side of a molded product including an unvulcanized belt layer disposed on the outer peripheral side of the carcass layer. Further, in the method of manufacturing a pneumatic tire including a step of forming an unvulcanized tread rubber layer, a rubber ribbon is spirally wound around the outer circumferential side of the belt layer along the tire circumferential direction to wind the unvulcanized tire . A step of forming a rubber ribbon layer, and a belt-shaped rubber member formed by cutting the rubber continuously extruded using an extruder at a predetermined length on the outer peripheral side of the rubber ribbon layer along the tire circumferential direction. forming a by setting unvulcanized strip rubber layer, on the outer circumferential surface and side surfaces of the belt-shaped rubber layer, by winding superposed spirally the same or different rubber ribbon and the ribbon along the tire circumferential direction, And forming a rubber ribbon layer of unvulcanized covering over the entire width of the serial strip rubber layer.

  According to the above manufacturing method, by providing a step of forming a rubber ribbon layer by wrapping a rubber ribbon around the outer peripheral side of the belt layer, the equipment can be downsized as compared with the case where a sheet-like cushion rubber layer is provided, and the hot state When the rubber ribbon is wound, since the rubber ribbon layer is effectively bonded to the belt layer and the belt-like rubber member, the formation of the cushion rubber layer can be simplified. Also, the amount of rubber ribbon wound is reduced compared to the conventional ribbon winding method by providing a step of forming a band-shaped rubber layer by arranging a band-shaped rubber member along the tire circumferential direction on the outer peripheral side of the rubber ribbon layer. Therefore, the formation time of the tread rubber layer is shortened, and the productivity of the tire is improved.

  According to the above manufacturing method, the weight balance and uniformity of the tread rubber layer can be improved by providing a step of forming a rubber ribbon layer by winding a rubber ribbon around at least one of the outer peripheral surface and the side surface of the belt-shaped rubber layer. Becomes better. In addition, by appropriately adjusting the winding of the rubber ribbon, a tread portion corresponding to each tire size can be formed, so that a belt-like rubber member can be shared between tires of different sizes, and the number of parts can be reduced. Can do.

Further, the pneumatic tire of the present invention is disposed on the outer circumferential side of the carcass layer spanned between the bead portions, the unvulcanized belt layer disposed on the outer circumferential side of the carcass layer, and the belt layer. a pneumatic tire comprising unvulcanized tread rubber layer, the outer periphery of the tread rubber layer, and the unvulcanized rubber ribbon layer formed by winding superposed spirally along the ribbon in the tire circumferential direction, the rubber ribbon layer An unvulcanized belt-shaped rubber layer disposed on the side, and a rubber ribbon that is the same as or different from the rubber ribbon is wound around the outer circumferential surface and the side surface of the belt-shaped rubber layer in a spiral shape along the tire circumferential direction, An unvulcanized rubber ribbon layer covering the rubber layer over the entire width.

  The pneumatic tire with the above configuration has a tread rubber layer arranged on the outer peripheral side of the belt layer and a rubber ribbon layer formed by wrapping a rubber ribbon, thereby reducing the size of the equipment compared to the case of providing a sheet-like cushion rubber layer. In addition, when the hot rubber ribbon is wound, it effectively adheres to the belt layer and the belt-like rubber member, so that the formation of the cushion rubber layer can be simplified. In addition, by providing a belt-like rubber layer on the outer peripheral side of the rubber ribbon layer, there is less area formed by wrapping the rubber ribbon than when using the conventional ribbon winding method, so the tread rubber layer formation time is short and productivity is improved. Yes.

  According to the above configuration, by providing the rubber ribbon layer formed by winding the rubber ribbon around at least one of the outer peripheral surface and the side surface of the belt-shaped rubber layer, the weight balance and uniformity of the tread rubber layer can be improved, and the uniformity can be improved. In addition, by appropriately adjusting the winding of the rubber ribbon, a tread portion corresponding to each tire size can be formed, so that a belt-like rubber member can be shared between tires of different sizes, and the number of parts can be reduced. Can do.

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

  FIG. 1 is a cross-sectional view showing an example of a tire. The bead part 1 is comprised by the bead filler 1b arrange | positioned by the cyclic | annular bead 1a which is a converging body of a bead wire, and the tire radial direction outer side of the bead 1a. The carcass layer 4 includes at least one carcass ply in which a cord such as a polyester cord is arranged in parallel at an angle of approximately 90 ° with respect to the tire equator line C, and is arranged so as to be bridged between the pair of bead portions 1. Has been. A sidewall portion 2 extending outward from the bead portion 1 in the tire radial direction is provided on the outer side in the tire width direction of the carcass layer 4, and a tread portion 3 is connected to an outer peripheral side end of the sidewall portion 2. In the tubeless tire, an inner liner layer 5 for maintaining air pressure is provided in the innermost layer.

  In the tread portion 3, a belt layer 7 that reinforces the effect of warping is disposed on the outer peripheral side of the carcass layer 4, and a tread rubber layer 8 is disposed on the outer peripheral side of the belt layer 7. The belt layer 7 is composed of at least one belt ply in which cords are arranged in parallel in the tire circumferential direction. In this embodiment, the two belt plies in which the steel cord is inclined at about 20 ° with respect to the tire equator line C. Are stacked so that their inclination directions are opposite to each other. The tire structure is the same as that of a general tire, and the present invention can be applied to any tire in which a tread rubber layer is disposed on the outer peripheral side of the belt layer.

FIG. 2 is a cross-sectional view showing an example of a tread portion of a pneumatic tire not included in the present invention. In FIG. 2, the tread rubber layer 8 includes a rubber ribbon layer 13 formed on the outer periphery of the belt layer 7 and a belt-shaped rubber layer 9 disposed on the outer periphery of the rubber ribbon layer 13. The rubber ribbon layer 13 is formed by spirally winding the rubber ribbon 6 along the tire circumferential direction, and the belt-like rubber layer 9 is made of a belt-like rubber member integrally formed by extrusion molding. The rubber ribbon 6 in the drawing is conceptually described, and actually has a finer cross-sectional shape.

  Hereinafter, the manufacturing method of the pneumatic tire which has the said tread part is demonstrated. First, a rubber member to be the inner liner layer 5 and a carcass ply to be the carcass layer 4 are sequentially attached and laminated on the outer peripheral surface of the cylindrical forming drum. Subsequently, the rubber members constituting the sidewall portion 2 and the like are arranged, the annular bead 1a is extrapolated in the vicinity of the end portion of the carcass ply, and the width direction end portion of the carcass ply is wound back through the bead 1a. Next, the central portion is inflated and deformed along the tire shape, and then a belt ply is disposed on the tread portion 3 to form a belt layer 7. A rubber ribbon layer 13 and a belt-shaped rubber layer 9 are formed on the outer peripheral side of the molded product. Are sequentially disposed to form the tread rubber layer 8.

  The rubber ribbon layer 13 can be formed using, for example, the apparatus shown in FIG. The forming drum 10 is configured to be rotatable in the R direction around a shaft 10a. The rubber ribbon supply device 11 includes a rubber extruder and a base provided at a discharge port of the rubber extruder, and has a function of supplying a rubber ribbon 6 having a predetermined cross-sectional shape. The rubber ribbon supply device 11 is configured to be movable in the drum axis direction by a moving mechanism (not shown). The control device 12 has a function of controlling the rotation of the molding drum 10 and the movement of the rubber ribbon supply device 11.

  According to the above apparatus, the rubber ribbon layer 13 can be formed as follows. First, the winding start end of the rubber ribbon 6 supplied from the rubber ribbon supply device 11 is fixed to the outer peripheral surface of the belt layer 7 formed in an annular shape on the outer peripheral side of the forming drum 10. Subsequently, the rubber ribbon supply device 11 is moved in the drum axis direction while rotating the molding drum 10 in the R direction. Thereby, the rubber ribbon 6 can be wound in a spiral manner in the tire circumferential direction. At that time, the rotational speed of the forming drum 10 and the moving speed of the rubber ribbon supply device 11 in the drum axial direction are appropriately adjusted by the control device 12 to form the rubber ribbon layer 13 having a predetermined size and cross-sectional shape. In such a case, since the rubber ribbon 6 that is in a hot state immediately after molding is wound, the rubber ribbon layer 13 is effectively bonded to the belt layer 7.

  The rubber ribbon 6 is made of an unvulcanized rubber composition having a relatively small width dimension and thickness dimension, and each dimension can be variously changed according to the tire size and the like. The cross-sectional shape of the rubber ribbon 6 is not particularly limited, and a preferable shape such as a rectangular shape, a trapezoidal shape, or a crescent shape can be adopted according to the cross-sectional shape of the rubber ribbon layer 13. The rubber ribbon 6 may be wound continuously, but may be discontinuous. Further, the cross-sectional shape or size of the rubber ribbon 6 may be changed during winding. Here, the rubber composition is prepared by kneading a rubber material and its compounding material by a conventional method. The rubber material is not particularly limited, and general-purpose rubbers such as natural rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), and isoprene rubber (IR) can be used.

  The belt-like rubber layer 9 is formed by sticking a belt-like rubber member having a width wider than that of the rubber ribbon 6 on the outer circumferential surface of the rubber ribbon layer 13 in a ring shape along the tire circumferential direction. The belt-like rubber member is formed by continuously extruding rubber using an extruder and cutting it at a predetermined length. As described above, when the rubber ribbon layer 13 is in a hot state, the adhesiveness with the belt-like rubber member is effectively improved. The cross-sectional shape of the belt-like rubber layer 9 is not particularly limited.

  The size of the belt-like rubber member is not particularly limited, but the width size is preferably 50% or more of the width size of the belt layer 7, and the thickness dimension (maximum thickness portion dimension) is 3 mm or more. Those are preferred. When the width dimension is less than 50% of the width dimension of the belt layer 7 or when the thickness dimension is less than 3 mm, the winding amount of the rubber ribbon 6 increases, so that the effect of shortening the tire molding time is poor. Further, the belt-like rubber member preferably has a smaller width dimension than the rubber ribbon layer 13. Thereby, the rubber ribbon 6 can be wound around the outer periphery of the width direction edge part of the belt layer 7, and edge separation can be suppressed.

  The tread rubber layer 8 of the present embodiment has a cap / base structure including a tread base constituted by the rubber ribbon layer 13 and a tread cap constituted by the belt-like rubber layer 9. Accordingly, the effects of the cap / base structure can be obtained by appropriately adjusting the composition of the rubber composition constituting the rubber ribbon 6 and the belt-like rubber member. For example, by forming the rubber ribbon layer 13 from a relatively hard rubber and forming the belt-like rubber layer 9 from a relatively low hardness rubber, it is possible to ensure wear resistance and grip. Alternatively, the rolling resistance can be reduced by configuring the rubber ribbon layer 13 with rubber whose loss tangent tan δ is controlled within a predetermined range. The rubber composition constituting the rubber ribbon 6 and the belt-shaped rubber member is not particularly limited, but the rubber ribbon 6 is preferably made of a rubber composition having excellent adhesiveness.

FIG. 4 is a cross-sectional view showing a tread portion according to the present invention . In FIG. 4, the tread rubber layer 8 is formed on the rubber ribbon layer 13 formed on the outer periphery of the belt layer 7, the belt-shaped rubber layer 9 disposed on the outer periphery of the rubber ribbon layer 13, and the outer peripheral surface and side surfaces of the belt-shaped rubber layer 9. The rubber ribbon layer 14 thus formed. The rubber ribbon layer 14 is formed by winding a rubber ribbon 16 in a spiral shape along the tire circumferential direction. Note that the rubber ribbon 16 in the figure is conceptually described, and actually, it is finer and the cross-sectional shape is complicated. The rubber ribbon layer 14 is formed by the apparatus and method exemplified above. The rubber ribbon 16 may be made of the same rubber composition as that of the rubber ribbon 6, but may be different.

  When the rubber ribbon layer 14 is formed on the side surface of the belt-like rubber layer 9, it is preferable that the end of the belt-like rubber layer 9 is inclined and has a skirt as shown in FIG. Thereby, it becomes easy to continue the rubber ribbon 16 on the side surface of the belt-like rubber layer 9.

[Another embodiment]
(1) In the above-described embodiment, an example in which the rubber ribbon layer 13 is formed on the outer peripheral surface of the belt layer 7 has been shown. However, in the present invention, a well-known belt reinforcing layer is disposed on the outer peripheral surface of the belt layer 7. The rubber ribbon layer 13 may be formed on the outer peripheral side.

(2 ) In the example of FIG. 4, the rubber ribbon layer 13 has a smaller width dimension than the belt layer 7, but is not limited to this, and a belt-like rubber is formed on the outer peripheral side of the rubber ribbon layer 13 having a larger width dimension than the belt layer 7. The layer 9 and the rubber ribbon layer 14 may be disposed.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. For the evaluation of the following items, test tires of tire size P265 / 70R16 were used.

(1) Molding time When the test tire was manufactured, the time required for forming the tread rubber layer was measured, and the result of Comparative Example 1 was set as 100, and the index was evaluated. The larger the index, the shorter the formation time and the better the productivity.

(2) Uniformity Based on the test method prescribed | regulated to JISD4233, RFV (radial force variation) was measured and the uniformity of the tire was evaluated. Specifically, the tire was pressed against the rotating drum so that a predetermined load was applied, and the amount of variation in the reaction force in the radial direction that occurred when the tire was rotated while keeping the distance between both axes constant was measured. The index is evaluated with the result of Comparative Example 1 being 100, and the larger the index, the better the uniformity.

Comparative Examples 1 and 2
A test tire in which a tread rubber layer is formed by a band-shaped rubber member integrally formed by extrusion molding is referred to as Comparative Example 1, and a test tire in which a tread rubber layer is formed by spirally wrapping a rubber ribbon along the tire circumferential direction is formed. It was set as Comparative Example 2.

Examples 1-3
A test tire having a tread portion having the structure shown in FIG. 4 was produced. That is, a rubber ribbon layer is formed by overlapping and winding a rubber ribbon along the tire circumferential direction, and a belt-like rubber member obtained by extrusion molding is disposed on the outer periphery of the rubber ribbon layer to form a belt-like rubber layer. A tread rubber layer was formed by wrapping a rubber ribbon around the outer peripheral surface and side surfaces of the rubber layer. The thickness of the rubber ribbon layer formed on the outer periphery of the belt layer was fixed at 1.5 mm. Further, the above-mentioned items were evaluated by changing the width dimension of the belt-shaped rubber member to have a substantially trapezoidal shape with a constant thickness dimension of 2.0 mm. In Table 1, the width of the belt-like rubber member is shown as a ratio to the width of the belt layer.

表１に示すように、比較例１は、押出成形で得られた帯状ゴム部材をベルト層に貼り付けるだけでよいため、成形時間が最も短い。しかし、ゴムを連続的に押し出してカットすることにより歪みや収縮が発生し易いため、タイヤのユニフォミティが比較的低い。比較例２は、ゴムリボン層の均一性に優れておりユニフォミティが良好であるが、ゴムリボンを幾重にも巻き付ける必要があるため、成形時間が比較的長くなる。一方、実施例１〜３においては、成形時間およびユニフォミティがそれぞれ好適な範囲にあり、タイヤの生産性およびユニフォミティに優れていることがわかる。

As shown in Table 1, Comparative Example 1 has the shortest molding time because only the belt-like rubber member obtained by extrusion molding needs to be attached to the belt layer. However, since the rubber is apt to be distorted and contracted by continuously extruding and cutting the rubber, the tire uniformity is relatively low. In Comparative Example 2, the uniformity of the rubber ribbon layer is excellent and the uniformity is good, but since the rubber ribbon needs to be wound several times, the molding time becomes relatively long. On the other hand, in Examples 1 to 3, it can be seen that the molding time and uniformity are in a suitable range, and that the tire productivity and uniformity are excellent.

Sectional view showing an example of a tire Sectional drawing which shows an example of the tread part of the pneumatic tire which is not included in this invention The figure which shows an example of a structure of a rubber ribbon winding apparatus Sectional drawing which shows the tread part of the pneumatic tire which concerns on this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 3 Tread part 4 Carcass layer 6 Rubber ribbon 7 Belt layer 8 Tread rubber layer 9 Band-shaped rubber layer 13 Rubber ribbon layer 14 Rubber ribbon layer 16 Rubber ribbon C Tire equator line

Claims (2)

Forming a non-vulcanized tread rubber layer on the outer peripheral side of a molded article comprising a carcass layer spanned between bead portions and an unvulcanized belt layer disposed on the outer peripheral side of the carcass layer; In the manufacturing method of the pneumatic tire provided,
A step of forming a non-vulcanized rubber ribbon layer by winding a rubber ribbon spirally along the tire circumferential direction on the outer peripheral side of the belt layer;
On the outer peripheral side of the rubber ribbon layer, a belt-shaped rubber member formed by cutting the rubber continuously extruded using an extruder with a predetermined length is disposed along the tire circumferential direction to form an unvulcanized belt shape Forming a rubber layer;
An unvulcanized rubber ribbon layer covering the entire width of the belt-like rubber layer is formed on the outer circumferential surface and side surfaces of the belt-like rubber layer by winding a rubber ribbon that is the same as or different from the rubber ribbon in a spiral manner along the tire circumferential direction. And a process for producing a pneumatic tire. A carcass layer spanned between bead portions, an unvulcanized belt layer disposed on the outer peripheral side of the carcass layer, and an unvulcanized tread rubber layer disposed on the outer peripheral side of the belt layer In pneumatic tires,
The tread rubber layer, and the unvulcanized rubber ribbon layer formed by winding superposed spirally along the tire circumferential direction rubber ribbon, and unvulcanized strip rubber layer disposed on the outer peripheral side of the rubber ribbon layer, wherein An unvulcanized rubber ribbon layer covering the entire width of the belt-like rubber layer is provided on the outer circumferential surface and side surfaces of the belt-like rubber layer. A pneumatic tire characterized by that.

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