JP5185703B2 - Rubber member for tire, method for producing the same, and method for producing the tire - Google Patents

Description

  The present invention relates to a rubber member for a tire that is useful for improving tire uniformity and preventing molding defects during vulcanization, a method for manufacturing the same, and a method for manufacturing a tire.

  The pneumatic tire is composed of various rubber members such as tread rubber, sidewall rubber, clinch rubber, cushion rubber, and inner liner rubber. Conventionally, these rubber members have been extruded with a predetermined cross-sectional shape from, for example, a rubber extruder. However, such a method has a drawback that it is necessary to prepare a die of an extruder for each cross-sectional shape and also requires a lot of time for the replacement work.

  In order to eliminate the conventional drawbacks, for example, as shown in FIG. 9, it was formed by spirally winding an unvulcanized rubber strip S in the form of a ribbon around a cylindrical body c. It has been proposed to use a so-called strip laminate (in this example, a strip laminate used as a tread rubber is shown) b as a rubber member for a tire (see Patent Documents 1 and 2 below).

  Such a strip laminated body b can easily obtain a desired cross-sectional shape by changing the winding pitch of the rubber strip S or the like. Therefore, unlike the prior art, it is not necessary to prepare various types of caps and to exchange them sequentially. Further, such a method has an advantage that, for example, the strip laminated body b is directly formed on the outer side of the tire constituent member, thereby eliminating intermediate stock of rubber parts and further improving the production efficiency of the tire.

JP 2000-202921 A JP 2006-168329 A

  By the way, when the rubber member of the pneumatic tire is molded using the rubber strip S, as shown in FIG. 10, the winding start side of the unvulcanized rubber strip S is wound on the substantially cylindrical body to be wound c. The end e1 is fixed, and then the rubber strip S is spirally wound in the axial direction A, for example. At this time, the end e1 of the rubber strip S is usually covered with the rubber strip S that has been circulated.

  However, since the end e1 of the conventional rubber strip S is cut at a right angle to the side edge of the rubber strip S, a large step extending in the axial direction is formed at the position of the end e1. There is a disadvantage that. Such a level difference tends to worsen the mass imbalance and thus worsen the tire uniformity. Further, as shown in FIG. 11A, which is a cross-sectional view taken along the line AA of FIG. 10, there is a drawback that an air reservoir i is likely to occur inside the step. These steps and air pockets i cause vulcanization defects that appear on the rubber surface as scratches or bulges after vulcanization molding. Similarly, as shown in FIG. 10B, there is a disadvantage that a step extending in the tire axial direction is also formed at the end e2 on the winding end side of the rubber strip S.

The present invention has been made devised in view of the above problems, an end portion of the winding start side of the rubber strip in a plan view, the other side edge of the rubber strip from one side edge of which forms the tip In principle, it is possible to prevent the occurrence of a large level difference extending in the tire axial direction by providing an inclined edge extending at an angle α of not less than 10 degrees and not more than 80 degrees with respect to the one side edge. As a result, it aims at providing the rubber member for tires which can prevent the molding defect of a tire and the deterioration of uniformity, its manufacturing method, and the manufacturing method of a tire.

The invention according to claim 1 of the present invention is a rubber member for a tire formed by spirally winding an unvulcanized rubber strip, and an end portion on the winding start side of the rubber strip is In plan view, an inclined edge extending from one side edge side forming the tip toward the other side edge of the rubber strip and extending obliquely at an angle α of 10 degrees or more and 80 degrees or less with respect to the one side edge. Yes, and the winding start side end portion of the rubber strip, with the other side edge is positioned in the width direction of the outer edge of the rubber member, and in a direction toward the one side edge from the other side edge A rubber strip is spirally wound so as to cover at least a part of the inclined end edge .

  The invention according to claim 2 is the rubber member for tire according to claim 1, wherein the inclined edge has the angle α of 25 to 75 degrees.

According to a third aspect of the present invention, the rubber strip is wound substantially in parallel with the circumferential direction of the rubber member from an end portion on the winding start side, and the rubber strip is on the other side edge side. From one side edge side to the one side edge side and at a distance approximately equal to the width of the rubber strip, and after being locally bent obliquely, it is wound again in parallel with the circumferential direction, and at least a part of the inclined edge is The rubber member for tire according to claim 1 or 2, wherein the rubber member is covered with the rubber strip that has circulated.

  According to a fourth aspect of the present invention, the end portion of the rubber strip provided with the inclined end edge is provided with a tapered portion whose thickness gradually decreases toward the inclined end edge. The rubber member for tires according to any one of 1 to 3.

  Further, the invention according to claim 5 is the rubber member for tire according to claim 4, wherein the taper portion has a taper angle β larger than 0 degree and not larger than 45 degrees.

  The invention according to claim 6 is a method of manufacturing a rubber member for a tire by spirally winding an unvulcanized rubber strip, and the end portion on the winding start side of the rubber strip has a plan view. And having an inclined end edge extending from one side edge side forming the tip toward the other side edge of the rubber strip and extending obliquely at an angle α of not less than 10 degrees and not more than 80 degrees with respect to the one side edge. A step of fixing the end to a substantially cylindrical body to be wound, and covering the rubber strip in a direction from the other side edge to the one side edge and covering at least a part of the inclined edge. A method of manufacturing a rubber member for a tire.

The invention according to claim 7 is a tire manufacturing method including a step of forming a green tire using the tire rubber member manufactured by the manufacturing method according to claim 6 and a step of vulcanizing the green tire. Is the method.

In the first aspect of the present invention, the end portion on the winding start side of the rubber strip extends from one side edge side forming the front end to the other side edge of the rubber strip in plan view and the one side. And an inclined edge extending obliquely at an angle α of not less than 10 degrees and not more than 80 degrees with respect to the side edge. When a rubber strip is wound on such an inclined edge, the step is inclined with respect to the tire axial direction. Such a step improves the uniformity of the tire compared to the conventional case because the mass is dispersed in the tire circumferential direction.

  Further, in the method of manufacturing a rubber member according to claim 6, the step of fixing the winding start side end of the rubber strip having the inclined end edge to a substantially cylindrical body to be wound, and the rubber strip, Wrapping in a direction from the other side edge side toward the one side edge side so as to cover at least a part of the inclined end edge. Here, since the inclined end edge extends to the other side edge, when the rubber strip is wound on the inclined end edge, the air between the two rubber strips can easily travel to the outside of the rubber member along the inclined end edge. To be discharged. Therefore, it is possible to manufacture a rubber member with less air accumulation inside.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a cross-sectional view of an embodiment of a pneumatic tire manufactured using the rubber member of the present embodiment. The pneumatic tire 1 includes a toroidal carcass 6 that extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and a belt layer 7 that is disposed on the radially outer side of the carcass 6.

  The carcass 6 is formed of at least one carcass ply 6A in which carcass cords are arranged at an angle of, for example, 70 to 90 ° with respect to the tire equator C. The carcass ply 6A includes, for example, folded portions that are folded back from the inner side to the outer side in the tire axial direction around the bead core 5 on both sides of the body portion 6a from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. 6b. The belt layer 7 is formed by two belt plies 7A and 7B in the present embodiment in which belt cords made of, for example, steel are arranged at an angle of, for example, 10 to 35 ° with respect to the tire equator C.

  Further, the pneumatic tire 1 is disposed on the inner side of the tread rubber G1 disposed on the outer side of the belt layer 7, the sidewall rubber G2 disposed on the outer side in the tire axial direction of the carcass 6 in the sidewall portion 3, and the carcass 6. An inner liner rubber G3 made of a non-air-permeable rubber, a clinch rubber G4 that is arranged on the outer side in the tire axial direction of the carcass 6 in the bead portion 4 and has excellent wear resistance that can come into contact with a rim (not shown), both ends of the belt layer 7 and The main rubber member includes a cushion rubber G5 having a substantially triangular cross section disposed on the inner side in the radial direction and a hard bead apex G6 extending from the bead core 5 to the outer side in the tire radial direction.

  Further, in the pneumatic tire 1, at least one of the rubber members G1 to G6 is a ribbon-like unvulcanized rubber strip S as shown in FIG. 2 and FIG. As shown, it is formed using a rubber member R made of a strip laminate formed by spirally winding on a substantially cylindrical body to be wound U. 4A illustrates a rubber member R1 for the tread rubber G1, and FIG. 4B illustrates a rubber member R2 for the sidewall rubber G2.

  As shown in FIG. 2, an end e1 on the winding start side of the rubber strip S extends from one side edge E1 forming a sharp tip T to the other side edge E2 of the rubber strip S in a plan view. An inclined end edge 10 is provided which extends obliquely at an angle α of 10 degrees or more and 80 degrees or less with respect to the one side edge E1.

As shown in FIG. 5, when the rubber strip S that has been circulated on the inclined end edge 10 is wound, the level difference between the rubber strip S and the tire axial direction is along the inclined end edge 10. And tilt up. Such a step, since inhomogeneities mass Ru is dispersed in the tire circumferential direction, a small mass imbalance. Therefore, the rubber member R manufactured using such a rubber strip S improves tire uniformity. Although not shown, the same effect can be obtained when the end e2 of the rubber strip S on the winding end side is provided on the rubber member R.

  As an example of a method for manufacturing the rubber member R, first, the end e1 on the winding start side of the rubber strip S is fixed to the substantially cylindrical body U using its own adhesiveness. . Then, the rubber strip S is wound so as to be covered with the rubber strip S1 in which at least a part of the inclined end edge 10 circulates in the direction X from the other side edge E2 toward the one side edge E1. At this time, since the rubber strip S wound on the inclined end edge 10 contacts the inclined end edge 10 from the tip T side, the air between the inner and outer rubber strips S, S is inclined to the inclined end edge. 10 is easily discharged to the outside of the rubber member R. Therefore, it is particularly preferable in that the rubber member R with less air accumulation can be manufactured.

  In the embodiment of FIG. 5, the rubber strip S is wound substantially parallel to the circumferential direction of the wound body U from the end e1 on the winding start side, and the inclined edge 10 is substantially formed. After covering, after being bent locally and obliquely at a distance substantially equal to the width W of the rubber strip S in the direction (arrow X) from the other side edge E2 side to the one side edge E1 side, the circumference again Wrapped parallel to the direction. Thereafter, the rubber strip is similarly wound so that the one side edge E1 is in contact with the other side edge E2. In the present specification, the winding mode as described above is included in a mode in which the rubber strip S is wound in a “spiral shape”.

  Here, when the angle α of the inclined edge 10 is less than 10 degrees, the rigidity of the tip T of the rubber strip S is remarkably lowered, so that the shape is not stable and the handling becomes difficult. On the other hand, when the angle α exceeds 80 degrees, the effect of dispersing the mass of the step in the tire circumferential direction is reduced, and the above-described effect of exhausting internal air tends to be reduced. From such a viewpoint, the angle α is more preferably 25 degrees or more, further preferably 30 degrees or more, and preferably 75 degrees or less, more preferably 60 degrees or less. The inclined edge 10 can be easily obtained by cutting the rubber strip S obliquely.

  Further, as shown in FIG. 3, the thickness t and the width W of the rubber strip S are not particularly limited. However, if these are too small, the number of windings of the rubber strip S for producing the rubber member R increases and the production is performed. There is a tendency to deteriorate. Therefore, in order to improve the productivity of the rubber member R and consequently the productivity of the pneumatic tire 1, the thickness t of the rubber strip S is preferably 0.2 mm or more, more preferably 0.3 mm or more. Similarly, the width W of the rubber strip S is preferably 3 mm or more, more preferably 5 mm or more.

  On the other hand, when the thickness t or the width W of the rubber strip S becomes excessively large, the workability of winding around the wound body U tends to deteriorate, and it becomes difficult to accurately form a desired cross-sectional shape. . From such a viewpoint, the thickness t of the rubber strip S is preferably 5 mm or less, more preferably 4 mm or less. Similarly, the width W of the rubber strip S is preferably 50 mm or less, more preferably 40 mm or less.

  Furthermore, it is desirable that the end e1 on the winding start side of the rubber strip S of the present embodiment is provided with a tapered portion 12 whose thickness gradually decreases toward the inclined end edge 10, as shown in FIG. Since such a taper portion 12 changes smoothly in thickness, as shown in FIG. 6A which is a BB cross-sectional view of FIG. It can be easily arranged with close contact. Therefore, since the change in the thickness of the rubber member b becomes very smooth at the end e1, the mass unbalance is further reduced, the tire uniformity is improved, and a large air pocket as in the prior art is formed. Can be prevented more reliably. Also, as shown in FIG. 6B, the change in the thickness of the rubber member b can be made very smooth by providing the tapered portion 12 also at the end e2 on the winding end side.

  Here, as shown in FIG. 7, the taper angle β of the tapered portion 12 is preferably 80 degrees or less, more preferably 60 degrees or less, still more preferably 45 degrees or less, and most preferably 30 degrees or less. However, considering the workability, about 45 degrees is desirable. As shown in FIG. 7, the taper angle β is an angle between the inclined surface 12a of the tapered portion 12 and the flat surface 12b facing the tapered surface 12a, and is inclined as shown by the line AA in FIG. It is assumed that the measurement is performed on a cross section orthogonal to the edge 10. In addition, the tapered portion 12 is preferably formed so as to be continuous to the inclined end edge 10 as in the present embodiment, and the end portion 10 has a sharp thickness of zero.

  Note that the wound body U around which the rubber strip S is wound is not particularly limited as long as it has a substantially cylindrical shape. As such a wound body U, for example, a forming drum can be mentioned, but it may be a carcass 6 or a belt layer 7 forming a part of a raw tire. That is, the rubber member R may be formed by winding the rubber strip S directly around the outside of the carcass 6 or the belt layer 7.

  A pneumatic tire excellent in uniformity can be easily manufactured by forming a green cover using the rubber members R1 and R2 as described above and vulcanizing the raw cover. Moreover, in the pneumatic tire 1 manufactured in this way, as described above, a step or an air pocket hardly occurs at the end portion of the rubber strip S, so that it is possible to prevent poor vulcanization and deterioration of uniformity.

  FIGS. 8A and 8B show another embodiment of the method for manufacturing the rubber member R (wrapping form of the rubber strip S). In the embodiment shown in FIG. 8A, the winding method shown in FIG. 5 is used as a basis, but a mode in which only a part of the inclined end edge 10 is covered with the rubber strip S that is turned around is shown. The rubber member R of the present invention includes such an embodiment. However, if the width CW of the inclined edge 10 covered by the rubber strip S that has circulated is excessively reduced, the end of the rubber member R of the inclined edge 10 is reduced. A notch-shaped recess 15 is formed at the edge, which may cause scratches and air accumulation. From such a viewpoint, the coating amount (CW / W) obtained by dividing the covering width CW of the inclined edge 10 by the width W of the rubber strip S is preferably 20% or more, more preferably 30% or more.

  Further, in the embodiment of FIG. 8 (b), after the rubber strip S is wound more than one turn in the circumferential direction so as to completely cover the inclined edge 10 of the end e1 of the rubber strip S, the rubber strip is then wound. S may be smoothly wound in a spiral. In addition, although not shown, it goes without saying that the rubber strips S adjacent in the axial direction may overlap in addition to the aspect in which the side edges are in contact with each other.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments described above, and can be implemented by being modified into various modes.

100 pneumatic tires for passenger cars of size 215 / 45ZR17 were produced using clinch rubber formed by winding rubber strips shown in Table 1 in the form shown in FIG. The other portions were the same, and the rubber strip was a ribbon having a width of 10 mm and a thickness of 1.0 mm, and both ends were processed as shown in Table 1. In addition, the finished state and uniformity of the clinch rubber after vulcanization molding of each tire was tested.
The test method is as follows.

<Finished state of clinch rubber after vulcanization>
The surface of the clinched rubber after vulcanization is observed with the naked eye, and the end of the rubber strip winding end side is the main cause of the scratches on the surface and the swelling caused mainly by the air remaining inside the rubber member, respectively. Examined. As a result, the number of scratches and bulges recorded was recorded. The smaller the value, the better.

<Uniformity>
For each test tire, radial force variation (RFV), which is a fluctuation component of force in the tire radial direction during rotation, was measured in accordance with the uniformity test conditions of JASO C607: 2000. About RFV, it is an overall at the time of a low speed rotation (6.8 km / H). The smaller the value, the better the uniformity.
The test results are shown in Table 1.

  From the test results, it was confirmed that the tires of the examples had a significant effect that there were fewer vulcanization defects and better uniformity than the comparative examples.

It is sectional drawing of the pneumatic tire manufactured by this invention. It is a top view of a rubber strip. It is a perspective view of a rubber strip. (A), (b) is sectional drawing of the rubber member which consists of a strip laminated body made using the rubber strip. It is a top view which shows the process of manufacturing a rubber member. (A) is BB sectional drawing of FIG. 5, (b) is sectional drawing of the winding end side of the rubber strip S. FIG. It is AA sectional drawing of FIG. (A), (b) is a top view which shows other embodiment of the manufacturing method of a rubber member. It is sectional drawing of the conventional strip laminated body. It is an enlarged plan view of the end portion on the winding start side. (A) is AA sectional drawing of FIG. 10, (b) is sectional drawing of the edge part by the side of the winding end of a rubber strip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Side wall part 4 Bead part 10 Inclined edge 12 Tapered part S Rubber strip e1, e2 End part E1 of rubber strip One side edge E2 of rubber strip The other side edge R of rubber strip Member U Wrap body T Rubber strip tip

Claims (7)

A rubber member for a tire formed by spirally winding an unvulcanized rubber strip,
Winding start side end portion of the rubber strip in plan view, and more than 10 degrees with respect to the other towards the side edges Katsu Nobi said one side edge of the rubber strip from one side edge of which forms the tip 80 have a tilt edge extending obliquely in degrees from alpha,
The end on the winding start side of the rubber strip has the other side edge located at the outer edge in the width direction of the rubber member, and
A rubber member for a tire, wherein a rubber strip is spirally wound in a direction from the other side edge side toward one side edge side and covering at least a part of the inclined end edge .
  The rubber member for a tire according to claim 1, wherein the angle α is 25 to 75 degrees.   The rubber strip is wound substantially in parallel with the circumferential direction of the rubber member from an end of the winding start side,
The rubber strip is bent obliquely locally in a direction from the other side edge side toward the one side edge side and at a distance substantially equal to the width of the rubber strip, and then wound again in parallel with the circumferential direction,
The tire rubber member according to claim 1 or 2, wherein at least a part of the inclined end edge is covered with the rubber strip that has circulated.
  The end portion of the rubber strip provided with the inclined end edge is provided with a tapered portion whose thickness gradually decreases toward the inclined end edge. Rubber member for tires.   The rubber member for a tire according to claim 4, wherein the taper portion has a taper angle β larger than 0 degree and not larger than 45 degrees. A method of manufacturing a rubber member for a tire by winding an unvulcanized rubber strip in a spiral shape,
The end portion on the winding start side of the rubber strip extends from one side edge side forming the tip to the other side edge of the rubber strip in a plan view, and is at least 10 degrees and 80 degrees with respect to the one side edge. Having an inclined edge extending obliquely at an angle α of less than or equal to the degree, and fixing the end to a substantially cylindrical body to be wound;
And a step of winding the rubber strip in a direction from the other side edge side to the one side edge side so as to cover at least a part of the inclined end edge. . A method for manufacturing a tire, comprising: a step of forming a green tire using the rubber member for a tire manufactured by the manufacturing method according to claim 6; and a step of vulcanizing the green tire.

Images