JP2008188856A - Manufacturing method of pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a pneumatic tire which suppresses a variation in a curled state of both end parts of carcass ply winding a bead core. <P>SOLUTION: Bending crease is attached to one end part 23A and the other end part 23B by moving a rotary press blade along the end part longitudinal direction while pressing the winding inner surface sides of the one end part 23A and the other end part 23B of the carcass ply 13 before molding to wind a pair of bead cores into the groove with the rotary press blade. In that case, the moving direction J of the rotary press blade at the one end part 23A and the moving direction K of the rotary press blade at the other end part 23B are reversed to each other. In the result, the moving direction of the rotary press blade at the one end part 23A and the other end part 23B can be the twisted-cord direction relative to the cord C arranged in the carcass ply 13 before molding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic tire manufacturing method in which a carcass ply both ends that are wound around a bead core are brazed in advance, and then both ends of the carcass ply are wound around a bead core to manufacture a tire.

  In the manufacture of a pneumatic tire, both ends of the carcass ply are folded around a bead core. In order to perform this folding, conventionally, both ends of the carcass ply are brazed in advance.

  When this brazing is performed, the carcass ply before molding is usually placed on a support base on which a groove for brazing is formed, and the inner surfaces of the windings of the carcass plies wound around the pair of bead cores are pushed in. By moving the pushing blade along the longitudinal direction of the end portion while pushing into the groove with the blade, bent ends of the carcass ply are attached (see, for example, Patent Documents 1 and 2).

However, there is a problem that the brazed state at both ends of the carcass ply is not uniform.
JP 2002-59492 A JP 2001-315220 A

  In view of the above facts, an object of the present invention is to provide a method for manufacturing a pneumatic tire in which variations in the brazed state at both ends of the carcass ply wound around the bead core are suppressed.

  The inventor paid attention to the fact that the brazed state differs greatly between one end and the other end of the carcass ply, and examined the cause. And it discovered that it originated in the twist direction of a cord.

  Conventionally, the moving direction of the pressing blade when brazing is the same in the left and right (the same direction at both ends of the carcass ply). For this reason, with respect to the twisting direction of the cord, the moving direction of the pressing blade is the same as the twisting direction at one end portion of the carcass ply and opposite to the twisting direction at the other end portion of the carcass ply.

  Therefore, the present inventor considered that the moving direction of the pushing blade with respect to the twisting direction of the cord is the same at both ends of the carcass ply, conducted an experiment, and further completed the present invention.

  According to the first aspect of the present invention, the one end of the carcass ply before molding and the inner surface of the other end of the carcass ply wound around the pair of bead cores are pushed into the groove with the pushing blade while the pushing blade is moved along the longitudinal direction of the end A pneumatic tire manufacturing method in which bent ends are bent at the one end and the other end by moving the push blades in opposite directions at the one end and the other end. The moving direction of the pressing blade at the one end portion and the other end portion is a cord twist direction with respect to the cord arranged in the carcass ply.

  Cords having the same twist direction are arranged on the carcass ply. In the first aspect of the invention, the one end and the other end of the carcass ply before molding wound around the bead core are pushed in the opposite directions so that the pushing blade moves in the opposite direction. The moving direction of the blade is the twist direction of the cord with respect to the cord. Thereby, stable brazing can be formed at both ends of the carcass ply, and variations in the brazing state at both ends of the carcass ply can be easily suppressed.

  According to the present invention, it is possible to easily manufacture a pneumatic tire in which variations in the brazed state at both ends of the carcass ply are suppressed.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described. In the present embodiment, description will be given of brazing both ends of a carcass ply used for a pneumatic tire.

  FIG. 1 is a partial perspective view showing a brazing device 10 used in an embodiment of the present invention, and 11 in FIG. 1 denotes a support base. For example, as shown by phantom lines in FIG. 1, the support 11 is composed of a plurality of carcass cords C that are aligned and arranged in parallel with each other, for example, a carcass ply 13 before being molded under mutual connection with unvulcanized coating rubber or the like. It functions to support (hereinafter referred to as pre-molding carcass ply 13).

  Here, on the surface of the support base 11, three groove portions 14 to 16 having a substantially V-shaped cross section and extending in parallel to each other at intervals in the axial direction of the carcass cord C are formed. The interval between the groove portions 14 to 16 here is such that, for example, a bead core is formed in a side portion of the pre-molding carcass ply 13 so as to bend in a direction around the bead core disposed in the tire bead portion. It is preferable to set the dimension corresponding to the distance between the corners in the cross-sectional contour shape.

  Further, here, the rotary pressing blades 17 to 19 having a disk shape as a whole and having the same diameter are separated from each other in the same horizontal plane at positions corresponding to the respective groove portions 14 to 16. The respective blade portions are arranged so as to be rotatable around a central axis located at the periphery, and the blade edge portions located in the peripheral portions of the respective rotary pressing blades 17 to 19 are made independent of each other or integrally. It can be pushed into 14 to 16 with a required force.

  Further, the relative distances of the central axes of the rotary pushing blades 17 to 19 are set to be different from each other in the direction in which the entry areas of the respective blade tips into the grooves 14 to 16 are orthogonal to the grooves 14 to 16. Is selected in relation to the rotary pressing blade diameter so as to be spaced apart from each other in the extending direction of the grooves 14 to 16 until they overlap with each other. Prevent the blades from working simultaneously.

  When forming the three bent portions at predetermined positions on the side portion of the pre-molding carcass ply 13 with the brazing device 10 configured as described above, first, as shown in FIG. As a posture in which C intersects each of the grooves 14 to 16 at a predetermined angle, the pre-molding carcass ply 13 is positioned and arranged on the support base 1, and then around the central axis of each of the rotary pushing blades 17 to 19 The rotary drive and the rotary push blades 17 to 19 and, as a result, the blade tips are pushed into the respective groove portions 14 to 16 with a required force in an appropriate order, and the rotary push blades 17 to 17 Based on the horizontal relative displacement between 19 and the support base 11, the respective rotary pushing blades 17 to 19 are displaced along the grooves in the respective groove portions 14 to 16.

  Therefore, the rotary pressing blades 17 to 19 that rotate at the same speed are sequentially passed over each carcass cord C with a time corresponding to the relative distance of the central axis, and the respective rotary pressing blades are The carcass cord is subjected to bending processing as illustrated in FIG. 2 in cooperation with each of the grooves 14 to 16 at respective positions spaced apart in the axial direction of the carcass cord.

  In the above description, the device portion that performs brazing on one end portion 23A (see FIG. 3) of the pre-molding carcass ply 13 wound around the bead core has been described, but the brazing device 10 includes one end portion of the pre-molding carcass ply 13. The other end portion 23B (see FIG. 3) parallel to 23A is also provided with a device portion for simultaneously brazing. And as shown in FIG. 3, the moving direction J of the rotary pushing blades 17-19 in the apparatus part which brazes one end part 23A, and the rotational pushing blade in the apparatus part which brazes the other end part 23B The moving direction K is opposite to each other.

  In the present embodiment, the brazing device 10 is used to braze both end portions 23 (one end portion 23A and the other end portion 23B) of the carcass ply 13 before molding.

  In the present embodiment, first, the pre-molding carcass ply 13 is placed at a predetermined position on the support base 11. In that case, it mounts so that the upper surface side 23U (refer FIG. 2) of the both ends 23 may become the winding inner surface side to a bead core. Here, in the pre-molding carcass ply 13, a cord C in which all the twisting directions are rightward is arranged. Accordingly, the twisting direction of the cord C at the one end 23A and the twisting direction of the cord C at the other end 23B are opposite to each other when viewed from the sides 24 and 26 orthogonal to the one end 23A and the other end 23B. It has become. In other words, when viewed from the side of the one end 23A in FIG. 3 as seen in the direction of arrow 4A, as shown in FIG. 4A, the twisting direction R of the cord C is clockwise and from the side of the other end 23B. Even when viewed in the direction of the arrow 4B, the twist direction R of the cord C is clockwise as shown in FIG.

  In the present embodiment, the one end portion 23A and the other end portion 23B of the pre-molding carcass ply 13 placed on the support base 11 are pressed with three rotary pressing blades to perform brazing. At this time, as described above, the moving direction J of the rotary pressing blade at the one end 23A and the moving direction K of the rotary pressing blade at the other end 23B are opposite to each other. 3 and 4, at one end 23A, the rotary pushing blades 17 to 19 move along the moving direction J so as to be in the twisting direction R (clockwise direction) of the cord C with respect to the cord C. In the other end portion 23B, the rotary pushing blade moves along the moving direction K so as to be in the twisting direction R (clockwise direction) of the cord C with respect to the cord C.

  As a result, the moving direction J of the rotary pressing blade at the one end 23A of the carcass ply 13 before molding is the same as the twisting direction R of the cord C, and the moving direction K of the rotary pressing blade at the other end 23B is the cord C. The direction is the same as the twist direction R. Therefore, stable brazing can be performed under the same conditions between the one end portion 23A and the other end portion 23B, and variations in the brazed state of the both end portions 23 can be suppressed. That is, as shown in FIG. 5, at one end 23 </ b> A of the pre-molding carcass ply 13, the first brazing portion 30 is formed by the rotary pushing blade 17, and the second brazing portion 32 is formed by the rotary pushing blade 18, A third brazing portion 34 is formed by the rotary pushing blade 19, and any of the three brazing portions is formed in a stable and uniform shape over the entire end portion 23A. The other end portion 23B, like the one end portion 23A, is formed in a stable and uniform shape over all three brazing portions.

In the present embodiment, it has been described that the carcass ply both end portions 23 are brazed at the same time. However, a device configuration in which the brazing portion is not provided on the other end portion 23B is provided, and the carcass ply one end portion 23A is provided. After the brazing, the pre-molding carcass ply may be rotated by 180 ° around the mounting surface of the support base 11 and placed again, and the other end portion 23B of the carcass ply may be brazed. Thereby, the number of the rotary pressing blades to be arranged and the mechanism for driving them can be halved.
Further, the brazing may be performed multiple times with a rotary pressing blade.

<Test example>
In order to confirm the effect of the present invention, the present inventor is an example of the above-described embodiment (hereinafter referred to as an example method), and the right end portion (one end portion 23A) and the left end portion (other end portion 23B) of the carcass ply 13 before molding. As shown in FIG. 6, the right end portion (one end portion) of the pre-molding carcass ply 83 (having the same structure as the pre-molding carcass ply 13) is formed by a conventional manufacturing method (hereinafter referred to as a conventional method). 83A) and the left end portion (the other end portion 83B) were brazed.

Various conditions in the example method are shown below.
・ Width of carcass ply before molding: 900mm
-Brazing width of the carcass ply before molding: 3 locations at intervals of 8 mm (Note that the preferable range of the brazing width of the carcass ply before molding is 4 to 12 mm)
-Brazing pressure: 0.3 Mpa (same left and right pressure)

  In the conventional method, as shown in FIG. 6, the moving direction of the rotary pushing blade is set to the same direction K at both end portions 83 of the pre-molding carcass ply 83 wound around the bead core. For this reason, when viewed from the side of the one end 83A in FIG. 6 as seen in the direction of the arrow 7A, as shown in FIG. 7A, the direction of twisting R (clockwise direction) of the cord C is opposite to that of the cord C. As shown in FIG. 7B, when the rotary pushing blade moves along the movement direction K and is viewed from the other end 83B side in FIG. The rotary pushing blade moves along the moving direction K so as to be in the twisting direction R (clockwise direction) of C. In the conventional method, the other conditions are the same as in the method of the embodiment.

  In any of the example method and the conventional method, in this test example, the right end portion (one end portion) of the carcass ply before molding, the brazing inlet position (brazing start position), the brazing intermediate position, and The brazing height h (see FIG. 5B) at the brazing outlet position (brazing end position) was measured. And the dispersion | variation R of the brazing height in the right end part of the carcass ply before shaping | molding was computed.

  Similarly, the left end portion (other end portion) of the pre-molding carcass ply is also reinforced at the brazing inlet position (brazing start position), the brazing intermediate position, and the brazing outlet position (brazing end position). The applied height h was measured. And the dispersion | variation R of the brazing height in the left end part of the carcass ply before shaping | molding was computed.

Table 1 shows the measurement results and the calculation results.

  As can be seen from Table 1, the variation in brazing height R according to the conventional method was 4.0 mm at the right end of the carcass ply before molding and 1.0 mm at the left end. And the tendency for brazing height h of the brazing start position in a right end part to become low compared with the other part was seen.

  On the other hand, the brazing height variation R according to the example method was 1.0 mm at the right end of the carcass ply before molding and 0.5 mm at the left end. Therefore, the brazing state at the brazing inlet position, the brazing intermediate position, and the brazing outlet position is stable at the right end portion and the left end portion, and the variation in the brazing state at the right end portion of the carcass ply before molding is greatly increased. I was able to suppress it.

  The embodiments of the present invention have been described with reference to the embodiments. However, the above embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. Needless to say, the scope of rights of the present invention is not limited to the above embodiment.

It is a fragmentary perspective view of the brazing apparatus used in one embodiment of the present invention. It is sectional drawing explaining pressing the carcass ply before shaping | molding in a groove | channel with a rotary pressing blade with the brazing apparatus used by one Embodiment of this invention. In one Embodiment of this invention, it is a top view explaining the moving direction of the rotary pushing blade at the time of brazing to the both ends of the carcass ply before shaping | molding. 4 (A) and 4 (B) respectively illustrate the relationship between the twisting direction of the cord and the moving direction of the rotary pusher blade at one end and the other end of the pre-molding carcass ply according to an embodiment of the present invention. It is explanatory drawing to do. 5 (A) and 5 (B) are a perspective view showing a state in which the both ends of the pre-molding carcass ply are brazed in one embodiment of the present invention, and an end of the pre-molded carcass ply that has been brazed, respectively. It is typical sectional drawing explaining a shape. It is explanatory drawing explaining the relationship between the twist direction of the code | cord | chord of the carcass ply before shaping | molding, and the moving direction of a rotary pressing blade by the prior art example method of a test example. FIGS. 7A and 7B illustrate the relationship between the twisting direction of the cord and the moving direction of the rotary pusher blade at one end and the other end of the carcass ply before molding in the conventional method of the test example, respectively. It is explanatory drawing to do.

Explanation of symbols

13 Carcass ply before molding (carcass ply before molding)
17 Rotary push blade (push blade)
18 Rotary push blade (push blade)
19 Rotary push blade (push blade)
23A One end 23U Upper surface side (winding inner surface side)
23B Other end portion 83 Carcass ply 83A Before molding One end portion 83B The other end portion C Code J Moving direction K Moving direction R Twisting direction

Claims (1)

The one end and the one end of the carcass ply before molding to be wound around the pair of bead cores are moved along the longitudinal direction of the end while pushing the winding inner surface side of the other end into the groove with the pressing blade, and the one end and It is a method for manufacturing a pneumatic tire to bend a bend at the other end,
Cord twisting with respect to the cords arranged in the carcass ply, with the one end and the other end being moved in opposite directions, and the one and the other end being moved in the carcass ply. A method for manufacturing a pneumatic tire, characterized in that the direction is set.

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