WO2010087165A1 - Bead core forming apparatus and bead core forming method - Google Patents

Abstract

Provided are a bead core forming apparatus and a bead core forming method capable of applying uniform taper shaping to bead wires having engaging portions which mutually match and engage with engaging portions of other bead wires adjacent in the width direction. The bead core forming apparatus (F) comprising a shaping mechanism provided with at least two first pressing rollers (17, 18) arranged on a same straight line (P), and a second pressing roller (19) arranged between the first pressing rollers (17, 18) to be deviated in a perpendicular direction relative to the straight line (P) so as to hold a bead wire (W) fed to a bead former (12) between the first pressing rollers (17, 18) and the second pressing roller (19) while applying a pressing force in an axial direction (X), and shape the bead wire (W) in the axial direction (X).  The first pressing rollers (17, 18) and the second pressing roller (19) are respectively provided on roller surfaces thereof with grooves (17g, 18g, 19g) whose shapes correspond to an outer surface contour shape of the bead wire (W).

Description

Bead core molding apparatus and bead core molding method

The present invention relates to a bead core formed by winding one or a plurality of bead strands in an annular shape on a bead former, and in particular, each bead strand is between adjacent bead strands in the axial direction of the bead former. The present invention relates to a bead core forming apparatus and a bead core forming method for forming a bead core having engaging portions that fit and engage with each other.

2. Description of the Related Art Conventionally, as a bead core structure of a pneumatic tire, a structure in which a bead element wire having a circular cross section covered with insulation rubber is spirally wound in multiple layers is generally known (see, for example, Patent Document 1). .

In a pneumatic tire adopting such a bead core structure, the deformation of the insulation rubber and the locking force between adjacent bead strands are small (difficult to transmit force), especially at the time of air filling. The rotational movement of the bead core was large. Such rotational movement of the bead core greatly affects the durability of the bead part, such as carcass pull-out.

Therefore, in order to solve the above problem, the applicant of the present application disclosed in Japanese Patent Application No. 2007-134120 that the bead element wire W is not covered with the insulation rubber as shown in FIG. A bead core structure has been proposed in which the shape includes engaging portions 4 that fit and engage with each other between adjacent bead wires W in the width direction. As a result, the rotational rigidity of the entire bead core can be increased, and the rotational movement of the bead core B has been significantly suppressed.

By the way, in the bead core structure as shown in FIG. 1, in order to apply the bead seat to the rim R having a predetermined taper angle with respect to the tire width direction, the bottom side of the bead core B has the same taper with respect to the tire width direction. It is preferable to set the angle (angle α), but in this case, it is necessary to apply a taper brazing to the bead element itself to the taper angle of the bead sheet of the rim R. As shown in FIG. 3 of Patent Document 2, the taper brazing of the bead strand itself uses a plurality of rollers (deformation units), and the width direction (bead former) is applied to the bead strand fed to the bead former. It is possible to perform brazing that bends in the axial direction of

JP-A-8-175126 U.S. Pat. No. 4,406,317

However, prior to winding on the bead former, the bead wire W (see FIG. 1) having the special shape (engagement portion 4) as described above is sandwiched between a plurality of rollers having a flat roller surface and brazed. Then, the pressing force from the roller concentrates on the engaging portion and the engaging portion is crushed or the bead strand moves up and down on the roller surface and twists. It was difficult to apply. Such non-uniform brazing also causes the problem of turbulence of the bead strands when wound around the bead former.

Therefore, the present invention provides a bead core forming apparatus capable of uniformly tapering bead strands having engaging portions that fit and engage with each other between bead strands adjacent in the width direction. The main object is to provide a method for forming a bead core.

In order to achieve the above object, a bead core forming apparatus according to the present invention is a bead core formed by winding one or a plurality of bead strands in an annular shape on a bead former, and the bead strands In a bead core forming apparatus for forming a bead core having engaging portions that engage with each other between bead strands adjacent to each other in the axial direction of the bead former, at least two first presses arranged on the same straight line A bead element wire having a roller and a second pressing roller disposed between the first pressing rollers and shifted in a direction perpendicular to the straight line, and supplying the bead wire to the bead former. A brazing mechanism that brazes the bead element wire in the axial direction by being sandwiched while applying a pressing force in the axial direction by the pressing roller and the second pressing roller; 1 of the pressing roller and the second pressing roller is characterized in that it has with their roller surface to the outer surface contour of the bead wires corresponding shape grooves respectively. In addition, the “brazing in the axial direction” of the bead wire here means that the bead former extends straight in a tensioned state while being tensioned, but in the natural shape where no tension is applied, in the axial direction of the bead former. It means a brazing that curves, and more specifically means a brazing in which the radius of curvature along the axial direction differs between one side and the other side of the bead element in the width direction.

In such a bead core forming apparatus, when the bead strand wound around the bead former is passed between the first pressing roller and the second pressing roller, the bead strand is converted into the first roller and the second roller. Thus, it is sandwiched while a pressing force is applied in the axial direction. As a result, the bead element wire is brazed in the axial direction of the bead former (that is, brazed so as to bend in a plane along the axial direction). At this time, the outer surface contour shape of the bead strand matches the shape of the groove provided on the roller surfaces of the first and second rollers, so that the pressing force is concentrated and the engaging portion of the bead strand is crushed. There is no possibility that the bead wire moves up and down on the roller surface and twists.

Therefore, according to the bead core forming apparatus of the present invention, the bead element wire can be prevented from being crushed and the bead element wire from being twisted at the time of brazing by the brazing mechanism. Brazing can be performed, and a highly accurate bead core without turbulence can be stably formed.

The bead core forming apparatus of the present invention includes an auxiliary roller that presses the bead element wire against at least one of the first pressing roller and the second pressing roller, and the auxiliary roller is disposed on the surface of the bead. It is preferable to have the groove part of the shape corresponding to the outer surface outline shape of a strand.

In order to achieve the above object, the bead core forming method of the present invention is a bead core formed by winding one or a plurality of bead strands on a bead former in an annular shape. In a bead core forming method for forming a bead core having an engaging portion that engages with each other between bead strands adjacent to each other in the axial direction of the bead former, at least two first lines arranged on the same straight line A first pressing roller having a groove corresponding to the outer contour shape of the bead element wire on the roller surface, and a vertical direction with respect to the straight line between the first pressing rollers. A second pressing roller arranged in a shifted manner and a second pressing roller having a groove portion having a shape corresponding to the outer surface contour shape of the bead element wire on the roller surface. Before the bead wire is wound around the bead former, the bead wire fed to the bead former is pressed in the axial direction by the first pressure roller and the second pressure roller. The bead element wire is brazed in the axial direction by being pinched while being added.

According to the present invention, a bead core forming apparatus capable of uniformly tapering bead strands having engaging portions that fit and engage with each other between adjacent bead strands in the width direction, and A bead core molding method can be provided.

FIG. 1 is a cross-sectional view along the tire width direction showing a bead portion of a pneumatic tire having a bead core formed by application of the present invention together with a compatible rim. FIG. 2 is a cross-sectional view in the width direction of another bead core exemplifying a bead strand targeted by the present invention. FIG. 3 is a schematic perspective view showing a bead core forming apparatus according to an embodiment of the present invention. FIG. 4 is a plan view of a brazing mechanism in the bead core forming apparatus of FIG. FIG. 5 is a cross-sectional view taken along the line II of FIG. 6A and 6B are diagrams schematically showing the natural shape of the bead wire brazed by the brazing mechanism, where FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view taken along line II- in FIG. It is sectional drawing along the II line. FIG. 7 is a cross-sectional view taken along line III-III in FIG. FIG. 8 is a cross-sectional view showing another brazing mechanism applicable to the present invention in the same cross section as FIG.

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

As shown in FIG. 1, a tire including a bead core B formed by a bead core forming apparatus F to be described later to which the present invention is applied is a pneumatic radial tire mainly made of rubber, and fitted to a rim R of a wheel. A pair of bead portions 1 to be joined, a tread portion (not shown) contacting the road surface, a pair of sidewall portions (not shown) extending outward from each bead portion 1 in the radial direction of the tire and continuing to the tread portion, and a toroidal carcass 3 is provided.

The bead core B is formed by annularly winding a plurality of bead strands W arranged in parallel in the tire width direction. The bottom side of the bead core B is inclined at a predetermined angle α with respect to the tire width direction (axial direction). Each bead strand W has an engaging portion 4 that fits and engages with each other between the bead strands W adjacent in the tire width direction. The cross-sectional shape of the bead wire W is not limited to the example of FIG. 1, and as illustrated in FIG. 2, a cross-sectional parallelogram (FIG. 2A) and a shape having a step on the side surface in the width direction (FIG. 2). (B), (c), (e) and (f)), and a shape having a convex or concave curved surface on the side surface in the width direction (FIG. 2D). Moreover, although the cross-sectional shape as a whole of the bead core B (the contour shape of the bead core B in the tire width direction) is a parallelogram in this embodiment, it may be a polygon other than a rectangle or a rectangle.

Hereinafter, the forming apparatus F for the bead core B will be described. As shown in FIG. 3, a plurality of bead wires W respectively supplied from a plurality (five in this embodiment) of supply spools 10 are wound in a state of being aligned in parallel (in the direction of arrow X in the figure). The bead core forming device F that forms the bead core B has a bead core forming concave groove 11 on the outer periphery thereof, and a bead former 12 that is driven and rotated by a motor (not shown), and the bead former 12 and a feeding spool. 10 and a brazing mechanism 13 that applies a predetermined brazing to each bead wire W prior to winding around the bead former 12. Before and after the brazing mechanism 13, guide pins 14 and 15 are provided for guiding the bead strand W sent to the brazing mechanism 13 in a direction parallel to the tangential direction of the bead former 12. The five bead wires W respectively fed from the feeding spool 10 are wound around the concave groove 11 of the bead former 12 after being subjected to predetermined brazing by the brazing mechanism 13.

As shown in detail in FIG. 4, the brazing mechanism 13 includes two first pressing rollers 17 that are arranged on the same straight line P, that is, at intervals along the longitudinal direction of the bead strand W to be brazed. , 18 and a second pressing roller 19 disposed between the first pressing rollers 17 and 18 with a distance d shifted in the direction perpendicular to the straight line P. That is, the first pressing rollers 17 and 18 and the second pressing roller are arranged in a triangular shape on the same plane. The second pressing roller 19 applies a pressing force to the bead strand W from the side opposite to the side where the first pressing roller 17 or 18 and the bead strand W are in contact with each other, and performs brazing. Each pressing roller 17, 18, 19 is rotatably supported by a shaft portion standing on the base of each brazing mechanism 13. Here, the distance d is set to a distance at which a predetermined pressing force is applied to the bead strand W when the bead strand W is passed between the first press rollers 17 and 18 and the second press roller 19. That is, if the distance d is decreased, the pressing force is increased. Conversely, if the distance d is increased, the pressing force is decreased.

Further, the brazing mechanism 13 reliably presses the bead wire W passing between the first and second pressing rollers 17, 18, 19 against the first and second pressing rollers 17, 18, 19. The auxiliary roller that freely rotates together with the pressing rollers 17, 18, 19 and stably passes the bead wire W to be brazed between the first pressing rollers 17, 18 and the second pressing roller 19. 20, 21, 22. More specifically, the auxiliary roller 20 is disposed so as to be opposed to the first pressing roller 17 in the direction perpendicular to the straight line P, and the bead element wire W is arranged between the pressing roller 17 and the auxiliary roller 20. I try to pinch it. Similarly, the auxiliary roller 21 is disposed so as to face the other first pressing roller 18 in a direction perpendicular to the straight line P, and the bead element wire W is arranged between the other first pressing roller 18 and the auxiliary roller 21. I try to pinch it. The auxiliary roller 22 is disposed so as to be opposed to the second pressing roller 19 in a direction perpendicular to the straight line P, and the bead wire W is sandwiched between the second pressing roller 19 and the auxiliary roller 22. The auxiliary rollers 20, 21, and 22 are also rotatably supported by shaft portions that are erected on the base of each brazing mechanism 13, similarly to the pressure rollers 17, 18, and 19. In this way, the bead strand W to be brazed is placed between the first pressing roller 17 and the auxiliary roller 20, between the first pressing roller 18 and the auxiliary roller 21, and between the second pressing roller 19 and the auxiliary roller. By adopting a configuration of being sandwiched between the two, the bead strand W can be stably passed and uniform brazing can be performed.

As shown in FIG. 5, in the cross section along the axial direction X, the first pressing rollers 17, 18, the second pressing roller 19, and the auxiliary rollers 20, 21, 22 Then, on the roller surface 19s of the pressing roller 19 and the roller surface of the auxiliary roller 22, a groove portion having a shape corresponding to the outer surface contour shape including the engaging portion 4 of the bead element wire W (here, the groove portion 19g of the pressing roller 19). And a groove portion 22g of the auxiliary roller 22 is illustrated).

Next, a method for forming a bead core using the forming apparatus F will be described.

First, as shown in FIG. 4, each bead wire W fed from each feed spool 10 is meshed with the first pressing rollers 17 and 18 and the second pressing roller 19, that is, the first By applying a pressing force in the axial direction X with the pressing rollers 17 and 18 and the second pressing roller 19 and pulling it out while applying tension, each bead wire W is brazed in the plane along the axial direction X. I do.

After that, as shown in FIG. 3, a plurality of (here, five) bead strands W that have passed through the brazing mechanisms 13 while rotating the bead former 12 by a motor are arranged in parallel in the axial direction X. It winds in the concave groove 11 of the former 12. As a result, each bead wire W that has been brazed and wound around the bead former 12 in an annular shape is wound in a state inclined by α degrees on the bead former 12. 6 (a) and 6 (b), the bead element wire W brazed to bend in the axial direction X of the bead former 12 has one side S1 and the other side of the bead element wire W in the width direction. the magnitude of the curvature radius _{r s1, r s2} in the axial direction X on the side _{S2 (r s1> r s2)} , the side s1 radius of curvature is larger when wrapped around the annular radially outwardly of the bead core B (FIG. 6 (B) An attempt is made to rotate in the direction of arrow F1 in the figure, and conversely, the side S2 having a small radius of curvature is to be rotated inward in the radial direction of the bead core B (the direction of arrow F2 in FIG. Because.

In this way, as shown in FIG. 7, a first bead strand L1 is formed in which the bottom of each bead strand W is inclined at an angle α with respect to the axial direction X (tire width direction). . Then, the second row, the third row, the second row, and the nth row are sequentially formed by winding the second row of bead strands on the first row of bead strands L1. The When the predetermined number of turns is finally reached, the molding of the bead core B is completed.

According to the forming device F and the forming method of this embodiment, when the bead wire W is brazed in the axial direction X, the outer surface contour shape including the engaging portion 4 of the bead wire W and the first and second presses. Since the shape of the grooves 17g, 18g, and 19g provided on the roller surfaces 17s, 18s, and 19s of the rollers 17, 18, and 19 fits, the pressing force is concentrated and the engaging portion 4 of the bead wire W is crushed. In addition, there is no risk of the bead strand W moving up and down on the roller surface and twisting, and the bead strand W can be evenly brazed and thus has a high precision bead core B with no winding disturbance. Can be formed stably.

In this embodiment, since the auxiliary rollers 20, 21, and 22 that press-contact the bead strand W to the first and second pressing rollers 17, 18, and 19 are further provided, the bead strand W at the time of brazing is provided. Can be further suppressed, and a bead core B with higher accuracy can be stably formed.

The above description shows only a part of the embodiment of the present invention, and these configurations can be combined with each other or various changes can be made without departing from the gist of the present invention. For example, according to the present invention, the bead element wire W as shown in FIG. 2 can be manufactured in addition to the bead element wire W shown in FIG. 1, and in that case, a part thereof is illustrated in FIG. As described above, it is possible to use a pressing roller having a groove portion having a shape that matches the outer surface contour shape of the bead wire W. The present invention can also be suitably applied to a bead element wire having a more complicated cross-sectional shape than the bead element wire W of FIGS. 2B and 2C, the bead core may be formed in a rectangular shape as a whole by aligning and laminating both ends of each bead element wire W, and both ends of each bead element wire W. It is good also as a parallelogram shape as a whole by laminating | stacking and laminating | stacking. Further, in the present invention, although not shown, at least one of the first pressing rollers 17 and 18 and the second pressing roller 19 is set in a direction perpendicular to the straight line P connecting the first pressing rollers 17 and 18. It is preferable to provide a driving means for the pressing roller that relatively moves the pressing rollers 17, 18, and 19 to increase or decrease the distance d (see FIG. 4). According to this, since the pressing force by the pressing roller can be freely changed via the driving means, a taper angle according to the desired can be easily given to each bead element wire W.

According to the present invention, when a bead core is formed using bead strands having engaging portions that fit and engage with each other between adjacent bead strands in the tire width direction, the bead core is high without causing turbulence. It became possible to mold with accuracy.

DESCRIPTION OF SYMBOLS 1 Bead part 3 Carcass 4 Engaging part 10 Feed spool 11 Groove 12 Bead former 13 Brazing mechanism 14, 15 Guide pins 17, 18 First press roller 19 Second press roller 20, 21, 22 Auxiliary roller B Bead core F Bead core forming apparatus L1 Bead strand W W Bead strand

Claims (3)

A bead core formed by annularly winding one or a plurality of bead strands on a bead former, wherein the bead strands are mutually connected between bead strands adjacent in the axial direction of the bead former. In a bead core forming apparatus for forming a bead core having engaging portions that engage with each other,
At least two first pressing rollers arranged on the same straight line, and a second pressing roller arranged between these first pressing rollers and shifted in a direction perpendicular to the straight line, The bead wire to be fed to the bead former is brazed in the axial direction to the bead wire by sandwiching the bead wire while applying a pressing force in the axial direction with the first pressing roller and the second pressing roller. With a brazing mechanism,
The bead core forming apparatus, wherein the first pressing roller and the second pressing roller respectively have groove portions having shapes corresponding to the outer surface contour shape of the bead wire on their roller surfaces. An auxiliary roller that presses the bead element wire against at least one of the first pressing roller and the second pressing roller, and the auxiliary roller has a shape corresponding to an outer surface contour shape of the bead element wire on the roller surface; The bead core molding device according to claim 1, having a groove portion. A bead core formed by annularly winding one or a plurality of bead strands on a bead former, wherein the bead strands are mutually connected between bead strands adjacent in the axial direction of the bead former. In a bead core molding method for molding a bead core having engaging portions that engage with each other,
A first pressure roller having at least two first pressure rollers arranged on the same straight line and having a groove portion having a shape corresponding to the outer surface contour shape of the bead element wire on the roller surface; A second pressing roller disposed between the pressing rollers in a direction perpendicular to the straight line, the second pressing roller having a groove portion having a shape corresponding to the outer surface contour shape of the bead wire on the roller surface. And make up the brazing mechanism,
Prior to winding the bead strand around the bead former, the bead strand to be fed to the bead former is sandwiched between the first pressing roller and the second pressing roller while applying a pressing force in the axial direction. Thus, the bead core forming method is characterized in that the bead core wire is brazed in the axial direction.

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