JP2012035481A - Rubber band for bead lock and tire molding apparatus equipped with bead lock part having rubber band for bead lock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rubber band for a bead lock of a bead lock part of a tire molding apparatus from tightly sticking a tire constituting member, and to prevent a cracking of the rubber band for the bead lock from being generated caused by tightly sticking.SOLUTION: The rubber band 40 for the bead lock is mounted on the outer peripheral face of the bead lock part for pinching and holding both side parts of a carcass band arranged on a molding drum of the tire molding apparatus between the bead lock part and a bead core. A ridge processing or a fabric processing is applied to a contact face of the rubber band 40 for the bead lock with the tire component member and a silicon processing is applied thereon. In addition, a channel with a circular arc-shape cross-section is provided on a bending support point part F on which a bending stress repeatedly acts when tightly contacted.

Description

  The present invention relates to a beadlock rubber band and a beadlock rubber band having a beadlock rubber band for use in a tire molding apparatus for molding a green tire by arranging a carcass ply, a bead core, etc. around a molding drum. The present invention relates to a provided tire forming apparatus.

  A pneumatic tire is generally made of a plurality of tire constituent members such as a pair of bead cores and a carcass ply extending therebetween, and a raw tire is molded by combining them to be vulcanized. In addition, as a raw tire molding apparatus, conventionally, a molding drum on which a tire constituent member is arranged, a bead lock portion for fixing a bead core provided on the molding drum, and a central portion of the tire constituent member are expanded (inflated). A tire forming apparatus provided with a means such as a bladder.

In this conventional tire molding apparatus, a cylindrical tire constituent member (carcass band) made of a carcass ply or the like is disposed on the outer periphery of a molding drum, and the bead lock portion inside thereof is expanded to be disposed on the outer periphery of the carcass band. The pair of bead cores are fixed from the inside in the radial direction. Subsequently, the bead cores are brought closer to each other by bringing the bead lock portions closer to each other, and at the same time, the carcass band between the bead cores (the inner liner and the carcass ply overlapping in the radial direction, or the side wall rubber attached to both sides thereof) The raw tire is formed by expanding the diameter by applying an internal pressure.
In this tire molding apparatus, a beadlock rubber band is used on the outer peripheral surface of the beadlock portion in order to hold both sides of the carcass band between the bead core and the bead core.

FIG. 3 is a cross-sectional view showing a conventional beadlock portion including a beadlock rubber band, which is not described in the patent literature.
The bead lock portion 30 includes an inner segment 31 and an outer segment 32 of the tire molding apparatus, and a bead lock rubber band in a fitting groove formed when the segment 31 and the segment 32 are combined. 40 is configured to be fitted and fixed.
The bead lock unit 30 holds the carcass band 70 on the molding drum together with the bead cores 71 by sandwiching the carcass band 70 between the bead cores 71 arranged on the outer peripheral side. The bead lock portion 30 expands and displaces the segments 31, 32, and the inner peripheral surface of the carcass band 70 that faces the contact surface (the outer peripheral surface on the upper side in the drawing) of the bead lock rubber band 40 on the radially outer side. To the inner peripheral portion of the bead core 71 and restrained, and the side portions of the carcass band 70 are respectively fixed.

FIG. 4 is an enlarged cross-sectional view of the beadlock rubber band 40 shown in FIG.
The beadlock rubber band 40 has a substantially H-shaped cross section as shown in the figure, and when attached to the beadlock portion 30, an outer peripheral portion 41 made of a rubber material G1 having a relatively good releasability on the outer side in the circumferential direction. And an inner peripheral portion 42 that is made of the rubber material G2 and that is on the inner side in the circumferential direction, and an intermediate portion 43 that connects the outer peripheral portion 41 and the inner peripheral portion 42.
As shown in the drawing, the beadlock rubber band 40 is reinforced with a fiber reinforcing layer 44 made of a fiber reinforcing material over the entire surface except for the inner peripheral surface of the inner peripheral portion 42. Also, a rubber cover G3 having a relatively good releasability is disposed on the contact surface of the outer peripheral portion 41 with the tire constituent member (carcass band), and a silicon processing 45 for preventing adhesion is applied thereon. ing.

In FIG. 3 again, the beadlock rubber band 40 abuts against the carcass band 70 and presses it against the bead core 71 in accordance with the diameter increase of the beadlock portion 30 when molding the raw tire, and the carcass according to the reduced diameter. The operation of leaving the band 70 is repeated.
In this case, the contact surface of the beadlock rubber band 40 with the carcass band 70 is silicon-processed, so that it does not adhere to the carcass band 70 at the time of pressing at first, but is in contact with and away from the carcass band 70. As the operation repeats, the silicon wears out relatively early. When the silicon wears, when the outer peripheral surface of the beadlock rubber band 40 is pressed against the carcass band 70, the unvulcanized rubbers are brought into close contact with each other, and the beadlock portion 30 is moved inward in the radial direction. Even if it does not peel.

FIG. 5A is a cross-sectional view showing a state in which the beadlock rubber band 40 in close contact with the carcass band is bent as the beadlock portion 30 is reduced in diameter. That is, when the beadlock rubber band 40 is in close contact with the carcass band 70, the beadlock rubber band 40 is pulled by the beadlock portion 30 that has a reduced diameter while in close contact with the outer peripheral portion 41 and the above-described portion. It is bent so as to open at the center F of the intermediate portion 43 (referred to as a bending fulcrum portion), and the rear surface of the outer peripheral portion 41 is pulled away from the upper surface of the segment 31.
FIG. 5B is a cross-sectional view showing a state where the beadlock rubber band 40 is pressed against the carcass band. When the diameter of the bead lock portion 30 is increased, as shown in FIG. 5B, the surface of the outer peripheral portion 41 of the bead lock rubber band 40 is pressed against the bead core 71 through the carcass band 70 and compressed, and a step is formed on the surface. Arise.

When the beadlock rubber band 40 repeats the above operation as the beadlock portion 30 is expanded or contracted by an expansion / contraction mechanism (not shown), the bending fulcrum portion F is repeatedly fatigued due to concentrated stress acting, and finally cracks occur. appear.
In order to solve this problem, the adhesion prevention between the beadlock rubber band 40 and the carcass band 70 which is a tire constituent member may be made stronger. As a conventionally known adhesion prevention means, for example, A resin material in which a fiber cord layer is disposed so as to be exposed on the surface of the rubber sheet surface in contact with the tire bead surface (see Patent Document 1) or a beadlock rubber band having excellent releasability, for example It is made of polyurethane resin, or a short fiber is mixed in rubber to prevent adhesion (see Patent Document 2), or liquid silicon is applied to the surface or roughened (Patent Document) 3).

  However, either a material that has been subjected to special processing as described in Patent Documents 1 and 2, or a material that has been coated with a material for preventing adhesion as described in Patent Document 3, There is also a possibility that adhesion may occur relatively early due to wear during repeated use. Therefore, even if the conventional means is applied to a beadlock rubber band, it is not possible to prevent the bending fulcrum F from cracking.

Description and drawings of Japanese Utility Model Application No. 3-47533 (Japanese Utility Model Application Publication No. 5-423) JP 2004-9457 A JP 2001-293793 A

  The present invention has been made in view of the above problems of the conventional beadlock rubber band, and the object thereof is to prevent the beadlock rubber band and the tire constituent member from being in close contact with each other, and to beadlock rubber band. This is to prevent cracks from occurring at the bending fulcrum.

The present invention relates to a beadlock rubber that is mounted on the outer peripheral surface of a beadlock portion in order to hold both side portions of a tire constituent member disposed on a molding drum of a tire molding device between the bead core by a beadlock portion. A beadlock rubber band, characterized in that a ridge process is performed on a contact surface of the beadlock rubber band with a tire constituent member, and a silicon process is performed thereon.
The present invention is also a tire molding device including a bead lock portion having the rubber band for the bead lock.

  According to the present invention, the beadlock rubber band and the tire component are prevented from closely contacting with each other, and the beadlock rubber band is subjected to a strain relaxation process, thereby greatly improving the durability of the beadlock rubber band. Can be improved.

It is principal part sectional drawing which shows schematic structure of the tire shaping | molding apparatus of this embodiment, and cut | disconnects in the surface containing the horizontal axis line, and shows one side. FIG. 2A is an enlarged cross-sectional view schematically showing a main part of a beadlock rubber band, FIG. 2B is a ridge processing surface thereof, and FIG. 2C is a perspective view showing a cloth processing surface thereof. It is sectional drawing which shows the bead lock part provided with the conventional rubber band for bead locks. It is sectional drawing which shows the conventional rubber band for bead locks. FIG. 5A is a cross-sectional view showing a state in which the beadlock rubber band in close contact with the carcass band is bent as the beadlock portion is reduced in diameter, and FIG. 5B shows a state in which the beadlock rubber band is pressed against the carcass band. It is sectional drawing.

Hereinafter, an embodiment of the present invention will be described.
First, a tire forming apparatus to which a beadlock rubber band according to the present embodiment is applied will be described.
In the same manner as the conventional tire molding apparatus described above, this tire molding apparatus forms a raw tire by combining tire constituent members, for example, a molding that directly forms a raw tire on a molding drum to produce a pneumatic radial tire or the like. Device.

FIG. 1 is a main part sectional view showing a schematic configuration of the tire forming apparatus of the present embodiment, and shows one side (upper side in the figure) by cutting along a plane including the horizontal axis.
As shown in the figure, the tire molding apparatus 1 includes a substantially cylindrical molding drum 10 that can rotate around an axis, and a driving device (not shown) for the molding drum 10 that rotates the molding drum 10 at a predetermined speed around the axis. And.

  The forming drum 10 is configured to be bilaterally symmetric with respect to the center surface CL, and a cylindrical carcass band 70 including at least a carcass ply is disposed on the forming drum 10. In addition, a pair of annular bead cores (here, bead cores in which the bead filler 72 is provided radially outward) 71 are disposed on both sides on the outer peripheral side of the carcass band 70.

  The molding drum 10 includes an inflatable and deformable bag-like bladder 11 disposed at the center thereof, an annular core body 12 capable of expanding and contracting disposed on the inner central surface CL, and sandwiching them. A pair of folding means 20 and bead lock portions 30 respectively disposed on both sides in the axial direction are provided at predetermined positions inside the carcass band 70, respectively.

  The folding means 20 is disposed on the outer side in the axial direction adjacent to the bead lock portion 30 and moves inward in the axial direction (in the direction of the arrow X) together with the bead lock portion 30 to move the side portion of the carcass band 70 on the outer surface thereof. Each bends around the bead core 71. Further, the folding means 20 expands from, for example, a plurality of folding fingers that radially expand in synchronism from the contracted state and deform the side portion of the carcass band 70 in the folding direction, or the outer peripheral surface position of the forming drum 10. Thus, the side portion of the carcass band 70 is similarly formed of a folded bladder. Here, the folding means 20 is composed of two folding bladders 21 and 22 that can be inflated, respectively, and they are contracted and expanded in a ring shape from a cylindrical state where they overlap each other in the radial direction. The side part is lifted up and folded back over the entire circumferential direction.

  The bead lock portion 30 is similar to the conventional bead lock described above, and is composed of a plurality of arc-shaped segments 31 and 32 having a substantially annular shape as a whole, and these are synchronized in a radial direction (in the figure, by a drive mechanism not shown). In the Y direction, the diameter is increased and the diameter is decreased, and the bead core 71 is fixed and supported from the inside in the radial direction. In addition, both bead lock portions 30 move symmetrically across the center plane CL in the axial direction (X direction or the opposite direction) of the forming drum 10 and approach or separate from each other, and a pair of bead cores 71 are fixed. Then, they are moved toward the center plane CL so as to approach or separate from each other.

Next, the beadlock rubber band 40 according to the embodiment of the present invention will be described.
FIG. 2A is an enlarged cross-sectional view schematically showing an essential part of the beadlock rubber band 40, showing a substantially H-shaped cross-sectional shape of one beadlock rubber band 40 as seen from the circumferential direction. The same parts as those in the prior art are denoted by the same reference numerals. 2B is a perspective view showing the ridge processing surface, and FIG. 2C is a perspective view showing the cloth processing surface.

The rubber band 40 for beadlocks according to the present embodiment has a ridge process (pointed end portion) for the purpose of preventing adhesion when the outer peripheral portion 41 is in contact with the carcass band 70 when pressed against the carcass band 70. The process which forms the protrusion which has) or cloth processing (cloth pasting process) is performed, and the process which apply | coats silicon to the protrusion processing surface or cloth processing surface similarly to the past is performed.
That is, a contact surface of the beadlock rubber band 40 with the carcass band 70, for example, a cover rubber G3 having relatively good releasability as shown in FIG. A ridge L is formed, which realizes a state in which the contact with the carcass band 70 is close to a line contact as compared with the case where the rough surface processing is simply performed as in the prior art, and the adhesion force Can be greatly reduced.
Therefore, even if the silicon layer applied to the surface is worn away and the raw rubbers are in close contact with each other, the adhesive force is greatly reduced. Therefore, the beadlock rubber band 40 can be easily peeled from the carcass band 70. it can. Therefore, the outer peripheral portion 41 of the beadlock rubber band 40 is not bent around the bending fulcrum portion F when the beadlock portion 30 is reduced in diameter as in the prior art.

Further, as shown in FIG. 2C, cloth processing C (processing for attaching a cloth) may be performed on the contact surface of the beadlock rubber band 40. In addition, as a cloth to be used, a cloth made of stretchable nylon fiber or fluorine fiber is preferable. By adopting this structure, even if the silicon layer applied thereon is worn away and pressed against the carcass band 70 with the cloth exposed, it is compared with the adhesion force due to the contact between the raw rubbers as in the conventional case. The contact force can be greatly reduced, and the entire contact surface of the beadlock rubber band 40 is subjected to cloth processing as compared with the case where the fiber cord described in Patent Document 1 is exposed. By this, the said contact | adhesion power can be reduced further. Therefore, also in this case, the outer peripheral portion 41 of the beadlock rubber band 40 is reduced in diameter while being in close contact with the carcass band 70, and the outer peripheral portion 41 is greatly suppressed from being bent around the bending fulcrum portion F.
Separately from this, in this embodiment, distortion concentrates on the bending fulcrum F inside the outer peripheral portion 41 of the beadlock rubber band 40, that is, the base portion between the outer peripheral portion 41 and the intermediate portion 43. The groove | channel M in which the cross-section like illustration shows circular arc shape is formed.

  This groove M alleviates the concentration of the bending stress acting on the bending fulcrum portion F, tentatively, silicon provided on the outer peripheral portion 41 of the beadlock rubber band 40, and the ridge and cloth are worn away. Even if the outer peripheral portion 41 of the beadlock rubber band 40 is repeatedly deformed by pressing and close contact with the carcass band 70, the occurrence of cracks in the bent fulcrum portion F can be significantly suppressed.

By using the beadlock rubber band 40 of the present embodiment, cracking of the beadlock rubber band 40 due to close contact with the carcass band 70 as in the past is greatly suppressed, and molding of the raw tire molding is performed. Efficiency can be improved.
The rubber band 40 for bead lock of the present embodiment is subjected to cloth processing or ridge (projection) processing on the contact surface with the carcass band, and further subjected to strain relaxation processing on the bending fulcrum portion F, The durability can be greatly improved (about 30% in the experiment) in comparison with the conventional one.

In the above embodiment, the beadlock rubber band has been described as having an H-shaped cross section and a structure using rubber materials G1 to G3, respectively. Any structure can be applied as long as it has a structure in which the contact surface with the carcass band and the contact surface contact with the carcass band are repeatedly opened and closed around an arbitrary bending fulcrum.
Therefore, the beadlock rubber band is not limited to the one having the H-shaped cross section. The constituent material may also be a substitute for rubber.

  DESCRIPTION OF SYMBOLS 1 ... Tire shaping | molding apparatus, 10 ... Molding drum, 11 ... Bladder, 12 ... Core body, 20 ... Folding means, 21,22 ... Folding bladder, 30 ... Bead lock Part, 31, 33 ... segment, 40 ... rubber band for bead lock, 70 ... carcass band, 71 ... bead core.

Claims (6)

A beadlock rubber band that is attached to the outer peripheral surface of a beadlock portion for holding both side portions of a tire constituent member arranged on a molding drum of a tire molding device between the bead core by a beadlock portion. ,
A beadlock rubber band, wherein a ridge process is performed on a contact surface of the beadlock rubber band with a tire constituent member, and a silicon process is performed thereon. A beadlock rubber band that is attached to the outer peripheral surface of a beadlock portion for holding both side portions of a tire constituent member arranged on a molding drum of a tire molding device between the bead core by a beadlock portion. ,
A beadlock rubber band, wherein a cloth processing is performed on a contact surface of the beadlock rubber band with a tire constituent member, and silicon processing is performed thereon. The beadlock rubber band according to claim 1 or 2,
A beadlock comprising a strain relief portion at a bending fulcrum portion of a beadlock rubber band that is bent when the abutment surface is in close contact with a tire component and the beadlock portion is reduced in diameter. rubber band. In the beadlock rubber band according to claim 3,
The beadlock rubber band, wherein the strain relaxation portion is a groove having an arcuate cross section of the bent fulcrum portion. The beadlock rubber band according to claim 3 or 4,
The bend fulcrum part is formed in a substantially H-shaped cross section comprising an outer peripheral part that is an outer peripheral side of the bead lock, an inner peripheral part that is the inner peripheral side, and an intermediate part that connects the outer peripheral part and the inner peripheral part. Is a portion where the inner peripheral side surface of the outer peripheral portion intersects the intermediate portion.   A tire molding apparatus comprising a beadlock portion having a beadlock rubber band according to any one of claims 1 to 5.

Images