JP3390532B2 - Bladder in radial tire molding equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bladder in a radial tire forming apparatus.

[0002]

2. Description of the Related Art Generally, when forming a radial tire, first, ring-shaped bead wires are attached to the bead portions at both ends of a cylindrical carcass, and the bead portions of the carcass can be moved toward and away from each other. Supported by a pair of movable bodies. A bladder made of an elastic material such as rubber is attached between the two moving bodies, and the carcass is arranged on the outer peripheral side of the bladder. Then, compressed air is supplied to the inner side of the bladder to bring the bladder into close contact with the inner peripheral surface of the carcass. By moving the parts toward each other, the carcass is deformed into a toroidal shape. Next, a breaker layer, a tread rubber layer, a sidewall rubber layer, and the like are sequentially attached to the outer surface of the toroidal carcass to complete the molding of the tire before vulcanization.

[0003]

However, in the prior art,
It has been difficult to form a bladder made of an elastic material so that the entire bladder has a uniform expansion rate, or to form the entire bladder to have a uniform thickness. Therefore, when compressed air is supplied to the inner side of the bladder to expand and expand the bladder, the bladder may have a distorted shape instead of the predetermined toroidal shape set in advance. As a result, the carcass that is bulged and deformed via the bladder cannot be molded into a required toroidal shape, and there is a problem that a tire before vulcanization having a good shape cannot be obtained.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a radial tire forming apparatus capable of surely expanding and expanding a predetermined toroidal shape. Providing a bladder.

[0005]

In order to achieve the above object, in the invention of claim 1, the pressure medium is supplied to the inside of the bladder with the cylindrical carcass being arranged on the outer peripheral side of the bladder. In the radial tire molding apparatus that deforms the carcass in a toroidal shape by expanding the diameter of the intermediate portion in the axial direction of the carcass and moving the bead portions at both ends of the carcass toward each other, the bladder is pair have a tensile strength, aggregate and its aggregate consisting yarn a plurality of inextensible covering the sandwich
Of constituted by a rubber layer, the aggregate second yarn group disposed along a direction intersecting the first yarn group disposed along the circumferential direction of the bladder and its first yarn group And the arrangement structure of each yarn constituting the aggregate so that the aggregate has a predetermined toroidal shape when the bladder is expanded and expanded. Set the first thread
The yarn group and the second yarn group are mutually connected at the intersections of the respective yarns.
It is one that is connected to the sea.

According to the invention of claim 2, in claim 1,
The yarns forming the first yarn group are arranged in parallel to each other along the circumferential direction of the bladder, and the yarns forming the second yarn group are bladder in a side view of the tire when the diameter of the bulge is increased. When expanding and expanding the diameter , make sure that the
The two yarn groups are arranged such that the adjacent yarns of the two yarn groups have a narrow gap between both ends and a wide intermediate gap.

[0007]

[0008]

Therefore, according to the first aspect of the present invention, when the pressure medium is supplied to the inside of the bladder and the bladder is expanded and expanded, the aggregate in the bladder has a predetermined toroidal shape. Become. Since each yarn constituting the aggregate has a high tensile strength, it does not grow as the bladder expands and expands, and the aggregate is reliably held in a predetermined shape. As a result, the bladder is surely bulged and expanded into a shape along the shape of the aggregate, that is, a predetermined toroidal shape set in advance. Further, according to the invention of claim 1, the aggregate is constituted.
Since the arrangement structure of each yarn is not disturbed,
The set predetermined toroidal shape is reliably retained.

According to the second aspect of the present invention, since the axial middle portion of the bladder is bulged and expanded, in the second yarn group of the aggregate, the interval between both ends of the adjacent yarns is narrowed, If the distance between the intermediate portions is widened, the bladder can be expanded and expanded to a predetermined toroidal shape without difficulty.

[0010]

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 3 and 4, the pair of moving bodies 10 include pipe-shaped operating shafts 10a, and each operating shaft 10a is connected to a moving mechanism (not shown). Then, with the operation of the moving mechanism, both moving bodies 10 are moved toward and away from each other. The bladder 1 has a substantially cylindrical shape, and the peripheral edges of both ends of the bladder 1 are attached to the peripheral edge of each moving body 10. A supply hole 10b is formed in the operating shaft 10a of one moving body 10, and compressed air as a pressure medium is supplied to the inside of the operating shaft 10a and the supplying hole 10 by a supply device (not shown).
It is supplied to the inside of the bladder 1 via b. As shown in FIG. 3, a cylindrical carcass 11 is arranged between both moving bodies 10 on the outer peripheral side of the bladder 1, and a ring-shaped bead wire 12 is provided at bead portions 11 a at both ends of the carcass 11.
Is set.

In this state, compressed air is supplied from the supply device to the inside of the bladder 1, and the moving mechanism moves the two moving bodies 10 in the direction in which they approach each other. Then, from the state in which the bladder 1 is in close contact with the inner peripheral surface of the cylindrical carcass 11, as shown in FIG. Both bead parts 11a of 11 are moved in the direction approaching each other. As a result, the carcass 11 is bulged and deformed in a toroidal shape.

A ring-shaped pressing tube 13 is provided on the outer periphery of each moving body 10, and the carcass 1
At the time of expanding and expanding the diameter of No. 1, compressed air is also supplied into each pressing tube 13 so that the tube 13 is expanded. Then, Fig. 4
As shown in FIG.
Both end portions of 1 are pressed, and both end portions of the bead wire 12
Can be folded to wrap. As a result, the carcass 11
The bead wires 12 are integrally attached to the bead portions 11a at both ends of the.

After that, a breaker layer, a tread rubber layer, a sidewall layer (all not shown) and the like are sequentially attached to the outer surface of the carcass 11 formed in a toroidal shape as described above. Then, a mold (not shown) having an inner surface shape corresponding to the outer shape of the radial tire before vulcanization is brought into pressure contact with the outer surfaces of these layers, whereby the molding of the radial tire before vulcanization is completed.

A breaker layer, a tread rubber layer and the like are held in advance on the inner surface of the die, and the die is moved to both moving bodies 10.
The outer peripheral side of the carcass 11 set between them is made to stand by. Then, as the carcass 11 swells and expands in a toroidal shape as described above, the breaker layer, the tread rubber layer, and the like in the mold may be attached to the outer surface of the carcass 11.

As shown in FIGS. 1 and 2, the bladder 1 is
Is composed of an aggregate 3 composed of a plurality of yarns 2 having a high tensile strength and not extending, and a rubber 4 as an elastic material covering the aggregate 3. This rubber 4 is go
Layer. 1 is a partially cutaway perspective view showing a state where the bladder 1 is expanded and expanded, and FIG. 2 is a schematic perspective view showing the aggregate 3 in the bladder 1 in a developed state. Yarn 2
Are formed of aramid fibers such as Kevlar. The aggregate 3 includes a first yarn group 5 arranged along the circumferential direction of the bladder 1 and a second yarn group 6 arranged along a direction intersecting with the first yarn group 5. Are formed in a lattice shape.

The yarns 2 constituting the first yarn group 5 are arranged parallel to each other along the circumferential direction of the bladder 1. Each of the yarns 2 is longer as the yarn 2 is located at an intermediate portion in the axial direction of the bladder 1 and is shorter as the yarns 2 are located at both ends. That is, the length of each yarn 2 corresponds to the circumferential length of each portion in the axial direction of the bladder 1 when the axially intermediate portion of the bladder 1 is expanded and expanded as shown in FIG. It is set to length. Further, each yarn 2 constituting the second yarn group 6 is radiated about the axis of the bladder 1 when the axially intermediate portion of the bladder 1 is expanded and expanded as shown in FIG. Direction, so that the tire axial direction
In the side view of the tire viewed from above, the distance between both ends of the adjacent yarns 2 is narrow and the distance between the intermediate portions is wide.

That is, in this embodiment, the aggregate 3 has a predetermined toroidal shape in a state where the axially intermediate portion of the bladder 1 is expanded and expanded as shown in FIG. The length and array structure of each yarn 2 that constitutes the aggregate 3 are set. The first yarn group 5 and the second yarn group 6 are connected to each other at the intersections of the yarns 2 by thermocompression bonding or an adhesive.

[0019] The aggregate 3 can be easily manufactured as follows. That is, a molding die (not shown) having an outer shape of a predetermined toroidal shape is prepared, and a groove is formed on the outer surface of the molding die at a position corresponding to the arrangement position of each yarn 2 constituting the aggregate 3. To form. Then, by arranging the yarns 2 in the groove and connecting the yarns 2 to each other at their intersections by thermocompression bonding or an adhesive, it is easy to form the aggregate 3 having a predetermined toroidal shape. Can be manufactured. Further, a rubber layer is arranged in advance on the outer surface of the mold, the thread 2 is arranged on the outer surface of the rubber layer to form the aggregate 3, and then the aggregate 3 is covered with another rubber layer. , If the aggregate 3 is sandwiched between a pair of rubber layers,
The aggregate 3 can be easily covered with the rubber 4.

In the present embodiment, when the bladder 1 is expanded and expanded, the length of each yarn 2 that constitutes the aggregate 3 is adjusted so that the aggregate 3 has a predetermined toroidal shape. And the array structure is set. Therefore, as shown in FIGS. 1 and 4, when compressed air is supplied to the inside of the bladder 1 and the bladder 1 is expanded and expanded in diameter, the aggregate 3 in the bladder 1 is set to a preset predetermined value. It becomes a toroidal shape. Since each yarn 2 that constitutes the aggregate 3 has high tensile strength, it does not extend with the expanded diameter of the bladder 1 and the aggregate 3 surely has a predetermined toroidal shape. Retained. As a result, even if the thickness and the expansion rate of the rubber 4 of the bladder 1 are partially uneven, the bladder 1 is forced to have a shape along the shape of the aggregate 3, that is, a predetermined toroidal shape set in advance. Accurately and reliably expands and expands the diameter. Therefore, the carcass 11 that is bulged and deformed via the bladder 1 can be surely molded into a required toroidal shape, and a tire before vulcanization having a good shape can be obtained.

Further, in this embodiment, the first member constituting the aggregate 3 is
The yarn group 5 and the second yarn group 6 are connected to each other at the intersections of the yarns 2, respectively. Therefore, the arrangement structure of the yarns 2 constituting the aggregate 3 is not disturbed, and the aggregate 3
Is securely retained in a predetermined toroidal shape set in advance.

The present invention is not limited to the above-mentioned embodiment, and the constitution of each part may be modified and embodied as follows. (1) The yarn 2 is formed of an organic fiber or metal material other than Kevlar.

(2) The number of the yarns 2 constituting the first yarn group 5 and the second yarn group 6 should be appropriately changed according to the size and type of the tire to be molded.

[0024]

As described in detail above, the present invention has the following excellent effects. According to the invention of claim 1, when the pressure medium is supplied to the inside of the bladder, the bladder can be surely expanded and expanded in a predetermined toroidal shape set in advance. Therefore, the carcass that is bulged and deformed via the bladder can be surely molded into a required toroidal shape, and a tire before vulcanization having a good shape can be obtained. Further, according to the invention of claim 1, the bone
The arrangement structure of each thread that composes the material is not disturbed,
Reliably holds the material in a preset toroidal shape
it can.

According to the second aspect of the present invention, the bladder can be bulged and expanded in a predetermined toroidal shape without difficulty .

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a bladder in a radial tire forming apparatus embodying the present invention.

FIG. 2 is a schematic plan view showing an expanded aggregate.

FIG. 3 is a cross-sectional view showing a state in which a carcass is set in a molding device.

FIG. 4 is a cross-sectional view showing a state where the carcass is expanded and expanded in diameter by a molding device.

[Explanation of symbols]

1 ... Bladder, 2 ... Thread, 3 ... Aggregate, 4 ... Elastic material and rubber
Rubber as a layer , 5 ... First yarn group, 6 ... Second yarn group, 1
0 ... moving body, 11 ... carcass.

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Claims (2)

(57) [Claims] 1. With a cylindrical carcass arranged on the outer peripheral side of the bladder, a pressure medium is supplied to the inside of the bladder to bulge and expand the axially intermediate portion of the carcass, and the bead portions at both ends of the carcass. by moving the towards each other, in the molding device of the radial tire to deform the carcass toroidally, the bladder, have a height tensile strength, aggregate consisting of yarn a plurality of inextensible and its The aggregate is composed of a pair of rubber layers that cover the aggregate in a sandwich shape, and the aggregate has a first yarn group arranged along the circumferential direction of the bladder and a direction crossing the first yarn group. A lattice-shaped member including the arranged second yarn group, and the aggregate is configured such that the aggregate has a predetermined toroidal shape when the bladder is expanded and expanded. Length and arrangement of each thread Set the structure, contact respectively the first yarn group and the second yarn group to the intersection of each yarn
To form radial tires that are joined together
Bladder 2. The yarns constituting the first yarn group are arranged in parallel to each other along the circumferential direction of the bladder, and the yarns constituting the second yarn group are bulged and expanded. as extend in radial direction around the axis of <br/> bladder in tire side view, Rise
2. The bladder for a radial tire forming apparatus according to claim 1, wherein the interval between both ends of the adjacent yarns of the second yarn group is narrow and the interval between the intermediate portions is wide when the diameter is expanded .