JP5662760B2 - Manufacturing method of tire ply material - Google Patents

Description

  According to the present invention, a plurality of tape pieces obtained by cutting a narrow-band corded rubber tape with a predetermined length are sequentially overlapped and joined between the side end portions on both outer sides in the width direction, thereby obtaining one tire. The present invention relates to a method for manufacturing a tire ply material for forming a ply material for a tire.

  For example, in Patent Document 1 below, a plurality of tape pieces obtained by cutting a narrow-band corded rubber tape with a predetermined length are used, and side end portions on both outer sides in the width direction are sequentially overlapped and joined. A manufacturing method for forming a tire ply material has been proposed.

  In this method, by adjusting the cutting length of the tape pieces and the number of tape pieces to be joined, the tire ply for one tire is made from one type of corded rubber tape with various ply widths according to the tire size. And a ply length. Therefore, compared to the conventional method in which the ply material is cut out from the raw material of the rubber sheet containing a wide cord with a length of 500 to 600 m and a width of about 1.5 m in the past, the occurrence of intermediate stock is small. In addition, it is possible to achieve a significant reduction in factory space and equipment costs, especially in the manufacture of tires, which are particularly prone to high-mix low-volume production.

  However, as shown in FIG. 6, since the side ends a1 and a1 of the tape piece a are sequentially overlapped and joined to each other, the joining portion J has a large thickness and the tire cord c overlaps vertically. This increases the code density. Therefore, in a tire using such a ply material for a carcass, when the air is filled, a so-called joint dent is formed on the side wall surface so that the joint portion J is recessed as compared with other portions. There arises a problem of reducing Mitty and the like. In particular, in the above method, since the number of joints J is large, the influence on the appearance quality and uniformity is great.

JP 2009-148910 A

  Therefore, the present invention provides a method for manufacturing a tire ply material that can efficiently form a ply material that suppresses an increase in thickness and a variation in cord density at a joint portion while ensuring a bonding strength between tape pieces. The purpose is that.

In order to solve the above-mentioned problems, the invention of claim 1 of the present application provides a long narrow strip-like rubber tape with cords in which cord cords arranged in parallel are covered with unvulcanized rubber. The tire ply material is formed by cutting the length to form a tape piece and forming the tire ply material by sequentially superimposing and joining the side ends on both outer sides in the width direction of the cut tape piece. A manufacturing method comprising:
The cord array includes an outermost tire cord disposed on both outer sides in the width direction, and an adjacent tire cord adjacent to the outermost tire cord,
The corded rubber tape has a substantially parallelogram shape in which the side end surfaces on both sides in the width direction are inclined with respect to the upper surface and the lower surface in a cross section perpendicular to the cord length direction,
Moreover, a concave groove extending along the side end surface on the upper surface and on one side end portion, and a ridge formed between the concave groove and the side end surface and protruding from the height position of the groove bottom of the concave groove. A concave groove extending along the side end surface on the lower surface and on the other side end portion, and a groove of the concave groove formed between the concave groove and the side end surface. It consists of a ridge that rises from the height position of the bottom, and is provided with a lower concavo-convex part that can mesh with the upper concavo-convex part,
The concave groove has a triangular cross-section, and the top of the groove bottom is located between the outermost tire cord and the adjacent tire cord;
And the above-mentioned ridge forms a cross-sectional triangle shape sandwiched between the groove wall surface of the above-mentioned concave groove and the side end surface, and the top is located above or below the outermost tire cord ,
The corded rubber tape is characterized in that the difference (TH) between the thickness T and the groove depth H of the concave groove is larger than the diameter D of the tire cord .

  According to a second aspect of the present invention, the adjacent tire cord and the tire cord disposed on the inside thereof are arranged in parallel at a substantially constant inter-cord pitch Li, and the outermost tire cord and the adjacent tire cord are The inter-code pitch Lo is larger than the inter-code pitch Li.

  In the invention of claim 3, the groove depth H of the concave groove is larger than the coating thickness t from the tire cord to the upper surface or the lower surface.

  In the present invention, as described above, the ply material is formed by sequentially overlapping and joining the side end portions of a plurality of tape pieces cut from the narrow-band corded rubber tape. Therefore, as in the case of Patent Document 1, by adjusting the cutting length of the tape pieces and the number of bonded pieces, for example, the ply material for one tire can be made with various ply widths and ply lengths according to the tire size. It can be formed, and has the advantage that production of intermediate inventory can be suppressed and the production equipment can be downsized.

  The tape piece is provided with upper and lower concavo-convex portions that can mesh with each other at one side end of the upper surface and the other side end of the lower surface. This uneven | corrugated | grooved part consists of the ditch | groove extended along a side end surface, and the protruding item | line formed between this ditch | groove and a side end surface. Accordingly, when the side end portions of adjacent tape pieces are overlapped, the convex strip of one tape piece falls into the concave groove of the other tape piece, so the thickness of the joint portion is set to the groove depth of the concave groove. It can be reduced by a considerable amount.

  Further, since the concave grooves and the convex stripes have a triangular cross section, they can be guided to each other at the time of meshing to suppress positional deviation, and can be joined with high accuracy. In addition, the top of the triangular groove is located between the outermost tire cord and the adjacent tire cord, and the top of the ridge is located above or below the outermost tire cord. Therefore, the outermost tire cord in one tape piece can be positioned between the outermost tire cord in the other tape piece and the adjacent tire cord at the joint. That is, it is possible to ensure a high joint strength by the meshing while minimizing the code density variation by minimizing the overlap width. Therefore, coupled with the reduction in the joint thickness, joint dents and the like can be suppressed, and deterioration in appearance quality and uniformity can be suppressed.

  In particular, when the inter-cord pitch Lo between the outermost tire cord and the adjacent tire cord is made larger than the inter-cord pitch Li of the tire cord disposed on the inner side, the variation in cord density is further increased. This can be further suppressed, and the above effect can be further enhanced.

It is a conceptual diagram explaining the manufacturing method of the ply material for tires of this invention. It is sectional drawing orthogonal to the cord length direction of the rubber tape containing a cord. It is sectional drawing explaining the joining state of the tape piece. It is a pattern figure explaining the flow of water which is a front view explaining the shape of the shaping | molding port of a die plate. It is sectional drawing which shows the dimension of each part of the corded rubber tape of Table 1. It is sectional drawing which expands and shows the junction part of the conventional tape piece.

Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIGS. 1 and 3, the tire ply material manufacturing method according to the present invention has a narrow strip shape in which a cord array 2 of tire cords 1 aligned in parallel is covered with unvulcanized rubber G. Using a long corded rubber tape 3, the corded rubber tape 3 is cut at a predetermined length to form a tape piece 4, and side ends E 1 on both outer sides in the width direction of the cut tape pieces 4, One ply material 5 is formed by sequentially superposing and joining E2s.

  Therefore, in the manufacturing method of this embodiment, by adjusting the cutting length of the tape piece 4 and the number of joined pieces of the tape piece 4, for example, the ply material 5 for one tire is formed from one type of corded rubber tape 3. It is possible to form with various ply widths and ply lengths according to the tire size. In this example, the case where the ply material 5 is used as a carcass ply is shown, but it can also be applied to a belt ply or a bead reinforcing ply.

  Next, as shown in FIG. 2, the corded rubber tape 3 has a substantially parallelogram shape in which the side end surfaces Es on both sides in the width direction are inclined with respect to the upper surface SU and the lower surface SL in a cross section perpendicular to the cord length direction. Make. The corded rubber tape 3 is formed on the upper surface SU and one side end E1 between the groove 6 extending along the side end surface Es and between the groove 6 and the side end surface Es. An upper concavo-convex portion 8 </ b> U composed of the ridges 7 protruding from the height position of the groove bottom is provided. The corded rubber tape 3 is formed on the lower surface SL and the other side end E2 between the concave groove 9 extending along the side end surface Es and between the concave groove 9 and the side end surface Es. A lower concavo-convex portion 8 </ b> L is provided which is composed of a ridge 10 protruding from the height position of the groove bottom and can mesh with the upper concavo-convex portion 8 </ b> U.

  The cord array 2 includes an outermost tire cord 1a arranged on both outer sides in the width direction, an adjacent tire cord 1b adjacent to the outermost tire cord 1a, and an inner side of the adjacent tire cord 1b. And the tire cord 1c disposed therein. In the present example, the adjacent tire cord 1b and the tire cord 1c disposed on the inner side thereof are arranged in parallel at a substantially constant inter-cord pitch Li, and the outermost tire cord 1a and the adjacent tire cord. The inter-code pitch Lo between 1b is set larger than the inter-code pitch Li.

  The concave grooves 6 and 9 have a triangular cross section, and the top portion P1 forming the groove bottom is located between the outermost tire cord 1a and the adjacent tire cord 1b. The ridges 7 and 10 have a triangular cross section sandwiched between the groove wall surface 12 of the grooves 6 and 9 and the side end surface Es, and the top portion P2 is above or below the outermost tire cord 1a. positioned.

Therefore, as shown in FIG. 3, when the side end portions E1 and E2 of the adjacent tape pieces 4 and 4 are overlapped with each other, the ridges 7 of the lower tape piece 4 are recessed in the upper tape piece 4. 9, and the protrusion 10 of the upper tape piece 4 falls into the concave groove 6 of the lower tape piece 4. Can be reduced. Since the concave grooves 6 and 9 and the ridges 7 and 10 have a triangular cross section, it is possible to suppress the positional deviation and increase the joining accuracy when meshing. In addition, since each apex P1, P2 of the triangle is arranged at the above position,
In the joint portion J, the outermost tire cord 1a in one tape piece 4 can be positioned between the outermost tire cord 1a in the other tape piece 4 and the adjacent tire cord 1b. That is, it is possible to ensure a high joint strength by the meshing while minimizing the cord density variation by minimizing the overlap width W. Therefore, coupled with the reduction in the joint thickness, joint dents can be suppressed, and deterioration in appearance quality and uniformity can be suppressed.

  In particular, when the inter-cord pitch Lo> the inter-cord pitch Li 1, the above effect can be further improved by further suppressing variations in the chord density.

  Here, the groove depth H of the concave grooves 6 and 9 is preferably larger than the coating thickness t from the tire cord 1 to the upper surface SU or the lower surface SL, whereby the thickness of the joint portion J is increased. It can be further reduced. Further, when the joining portion J is pressed and the tape pieces 4, 4 are pressure-bonded, the outermost tire cord 1 a in one tape piece 4 is adjacent to the outermost tire cord 1 a in the other tape piece 4. 1b, and can be advantageous by suppressing variations in cord density.

  The corded rubber tape 3 preferably has a difference (TH) between the thickness T and the groove depth H of the concave groove larger than the diameter D of the tire cord 1. The reason is as follows.

  As shown in FIGS. 1 and 4, the cord-containing rubber tape 3 is formed on the molding port 20 of the extrusion head 22 provided with a die plate 21 having a molding port 20 at the front end. The rubber G can be continuously formed by passing it in the cord length direction. The extrusion head 22 is attached to the front end of a rubber extruder body 23 such as a screw type.

  The molding port 20 of the die plate 21 has an opening shape substantially the same as the cross-sectional shape of the corded rubber tape 3, and molds the upper wall surface 20U and the lower surface SL for molding the upper surface SU of the corded rubber tape 3. Protrusions 24 having a triangular cross section for forming the concave grooves 6 and 9 are respectively provided on the lower wall surface 20L. When the cord array 2 once passed through the molding port 20 is aligned and set up in the molding port 20, if (TH) ≦ D, the tire cord 1 includes the protrusion 24, It becomes impossible to pass between the upper wall surface 20U or the lower wall surface 20L, and the work efficiency of the setup is significantly reduced. Therefore, in order to improve the work efficiency of the setup, it is preferable that (TH)> D.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  In order to confirm the effect of the present invention, a ply material is prototyped using the corded rubber tape according to the present invention having a substantially parallelogram-shaped cross section and having upper and lower uneven portions on the upper and lower surfaces based on the following specifications. did. Using this ply material for the carcass ply, a radial tire for a passenger car having a tire size of 215 / 45ZR17 was prepared, and the appearance and uniformity of the sample tire were tested. The results are shown in Table 1. The dimensions of each part of the corded rubber tape are shown in FIG. For comparison, a conventional tire was made using a corded rubber tape without upper and lower uneven portions, and compared with the tire of the example.

Tire cord: Polyester (1670dtex / 2),
Cutting angle of tape piece: 90 ° (vs. cord length direction)
Number of bonded tape pieces: 35

<Appearance>
Ten tires were prepared, and the occurrence of joint dent on the surface of the tire sidewall portion was visually inspected under the conditions of rim (17 × 7JJ) and internal pressure (200 kPa). The average value is indicated by an index with the conventional example being 100. Smaller numbers are better.

<Uniformity>
Using a force variation (FV) testing machine, RFV (OA) is measured based on the JASO C607 standard, and the average value is shown as an index with the conventional example as 100. Smaller numbers are better.

  As shown in the table, it can be confirmed that the tires of the examples are improved in both appearance and uniformity.

DESCRIPTION OF SYMBOLS 1 Tire cord 1a Outermost tire cord 1b Neighboring tire cord 2 Cord arrangement body 3 Corded rubber tape 4 Tape piece 5 Tire ply material 6, 9 Concave groove 7, 10 Convex 8U, 8L Top and bottom uneven parts E1, E2 Side end portion Es Side end surface G Rubber P1, P2 Top portion SU Upper surface SL Lower surface

Claims (3)

A long cord-like rubber tape with a cord strip of tire cords arranged in parallel and covered with unvulcanized rubber is cut to a predetermined length to form a tape piece, and this cut A method for producing a tire ply material for forming a tire ply material by sequentially overlapping and joining side end portions on both outer sides in the width direction of the tape piece,
The cord array includes an outermost tire cord disposed on both outer sides in the width direction, and an adjacent tire cord adjacent to the outermost tire cord,
The corded rubber tape has a substantially parallelogram shape in which the side end surfaces on both sides in the width direction are inclined with respect to the upper surface and the lower surface in a cross section perpendicular to the cord length direction,
Moreover, a concave groove extending along the side end surface on the upper surface and on one side end portion, and a ridge formed between the concave groove and the side end surface and protruding from the height position of the groove bottom of the concave groove. A concave groove extending along the side end surface on the lower surface and on the other side end portion, and a groove of the concave groove formed between the concave groove and the side end surface. It consists of a ridge that rises from the height position of the bottom, and is provided with a lower concavo-convex part that can mesh with the upper concavo-convex part,
The concave groove has a triangular cross-section, and the top of the groove bottom is located between the outermost tire cord and the adjacent tire cord;
And the above-mentioned ridge forms a cross-sectional triangle shape sandwiched between the groove wall surface of the above-mentioned concave groove and the side end surface, and the top is located above or below the outermost tire cord ,
In the tire ply material, the corded rubber tape has a difference (TH) between a thickness T and a groove depth H of the concave groove larger than a diameter D of the tire cord . Production method.   The adjacent tire cord and the tire cord arranged on the inside thereof are arranged in parallel with a substantially constant inter-cord pitch Li, and an inter-cord pitch Lo between the outermost tire cord and the adjacent tire cord is The tire ply material manufacturing method according to claim 1, wherein the pitch is larger than the inter-cord pitch Li. The method for producing a tire ply material according to claim 1 or 2, wherein a groove depth H of the concave groove is larger than a coating thickness t from the tire cord to the upper surface or the lower surface.

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