JP6977415B2 - Raw tire molding equipment - Google Patents

Description

The present invention relates to an apparatus for molding raw tires.

Conventionally, a raw tire forming apparatus has been proposed in which a case protruding portion outside the bead core in the axial direction is folded back by a rubber bladder among cylindrical tire cases (see, for example, Patent Document 1 below).

In the raw tire forming apparatus, the bead lock means has an enlarged diameter, and the bead core is held by pressing the tire case against the inner peripheral surface of the bead core. However, at this time, since the inner end portion of the protruding portion of the case is lifted by the beadlock means, the protruding portion of the case tends to have a bent portion. Further, if the protruding portion of the case is folded back in such a state, partial wrinkles may occur in the tire case, which may lead to deterioration of the uniformity of the formed tire.

Japanese Unexamined Patent Publication No. 2012-152953

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a raw tire forming apparatus capable of suppressing the occurrence of wrinkles in a tire case.

In the present invention, an annular bead core is extrapolated on the outer peripheral surface of a cylindrical tire case including a carcass so as to be separated from each other, and the outer portion of the bead core outside the case in the axial direction of the tire case is located outside the bead core. A device for forming a raw tire by folding back around the bead holding portion capable of holding the extrapolated bead core, and the case around the bead core held by the bead holding portion by expanding. The bead holding portion includes a folded bladder that folds the outer portion, and the bead holding portion is via the tire case and the folded bladder by expanding the diameter of a plurality of segments arranged along the circumferential direction of the bead core toward the bead core. It has an annular segment group that holds the bead core, and a plurality of plates that are connected to each segment by an inner end portion in the axial direction and extend outward in the axial direction. In the bead lock state holding the bead core, the outer portion of the case is supported via the folded bladder.

In the raw tire forming apparatus of the present invention, it is desirable that the outer surface of the plate is inclined with respect to the axis direction in the beadlock state.

In the raw tire forming apparatus of the present invention, it is desirable that the angle of the outer surface of the plate with respect to the axis direction changes with the expansion or contraction of the annular segment group.

In the raw tire forming apparatus of the present invention, it is desirable that the outer surface of the plate is parallel to the axis direction in the state where the annular segment group is most reduced in diameter.

In the raw tire forming apparatus of the present invention, it is desirable that the plate is tiltably connected to the segment.

The bead holding portion of the raw tire forming apparatus of the present invention is an annular segment that holds the bead core via a tire case and a folded bladder by expanding the diameter of a plurality of segments arranged along the circumferential direction of the bead core toward the bead core. It has a group and a plurality of plates in which an inner end portion in the axial direction is connected to each segment and extends outward in the axial direction. The plate supports the outer side of the case via a folded bladder in a beadlocked state in which the annular segment group holds the bead core. Such a plate can suppress partial bending of the outer side of the case, and thus can suppress the occurrence of wrinkles in the tire case.

It is a top view which conceptually shows one Embodiment of the raw tire forming apparatus of this invention. It is sectional drawing which shows the part of the former enlarged. (A) and (b) are enlarged sectional views of a segment and a plate. (A) is an enlarged cross-sectional view of a segment and a plate of the raw tire forming apparatus of another embodiment of the present invention, and (b) is an enlarged plan view of the plate of (a). FIG. 3 is an enlarged cross-sectional view of a segment and a plate of a raw tire forming apparatus according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view conceptually showing an embodiment of the raw tire forming apparatus 1 of the present invention. As shown in FIG. 1, the raw tire forming apparatus 1 of the present embodiment extrapolates two annular bead cores B apart from each other on the outer peripheral surface of a cylindrical tire case A including a carcass. Further, the raw tire forming apparatus 1 folds back the outer case outer portion A1 outside the axial core direction of the tire case A with respect to each bead core B around the bead core B. As a result, the primary tire C including the tire case A and the bead core B is formed.

The raw tire forming apparatus 1 of the present embodiment has, for example, a former. The former 2 holds the tire case A and inflates the case body A2, which is a region between the bead cores B and B, in a toroid shape. As a result, the primary raw tire C and the tread T that has been made to stand by on the outer side in the radial direction thereof are united, and the raw tire is formed.

In the present embodiment, for example, a tire case A is separately formed on a band drum (not shown), the tire case A is moved onto the former 2, and then the bead core B and other tire components are formed on the former 2. Is shown. However, in another aspect, the raw tire forming apparatus 1 may have a mode in which the bead core B is extrapolated to the tire case A on the band drum and these are moved onto the former 2. Further, the raw tire molding apparatus 1 may be, for example, in a mode in which a sheet-shaped member is wound in a cylindrical shape on a former 2 to form a tire case A, and a bead core B is externally inserted therein (so-called single stage molding method).

The former 2 includes, for example, a central shaft portion 4 and a pair of drums 5 and 5 that are supported by the central shaft portion 4 so as to be close to each other in the axial center direction thereof. In the present specification, the direction toward the tire equatorial line Co, which is the central position in the axis direction between the drums 5 and 5, is defined as the inside of the axis direction, and the opposite direction is defined as the outside of the axis direction.

FIG. 2 shows a cross-sectional view showing a part of the former 2 in an enlarged manner. As shown in FIG. 2, the central shaft portion 4 includes a central shaft 6 and a support cylinder 7 arranged concentrically on the outer side in the radial direction thereof. The central shaft 6 is a screw shaft having a right-hand thread portion and a left-hand thread portion formed on both sides of the tire equator Co. A nut metal fitting 8 is screwed into each screw portion.

The support cylinder 7 is formed with an elongated guide hole 7A extending in the axial direction. A moving body 9 that can move in the axial direction is arranged in the guide hole 7A. By engaging with the nut fitting 8, the moving body 9 can move in the axial direction integrally with the nut fitting 8 as the central shaft 6 rotates in the forward and reverse directions.

Each drum 5 includes a cylindrical drum body 5A, a bead holding portion 10 supported by the drum body 5A, and a folded bladder 11 arranged on the outer peripheral surface side of the drum body 5A. The drum body 5A is extrapolated to the support cylinder 7 so as to be slidable, for example. The drum body 5A can move integrally with the moving body 9, for example, by connecting with the moving body 9. The bead holding portion 10 can hold the bead core B extrapolated to the tire case A. By expanding the folded bladder 11, the outer portion A1 of the case can be folded around the bead core B held by the bead holding portion 10.

The bead holding portion 10 is interlocked with, for example, the cylinder chamber 13 formed in the drum body 5A, the piston portion 14 capable of moving in the cylinder chamber 13 in the axial direction, and the movement of the piston portion 14 in the axial direction. It has an annular segment group 15 that can be expanded and contracted.

The cylinder chamber 13 forms, for example, an annular shape concentric with the drum body 5A. Further, in the present embodiment, a cone-shaped bearing surface 14s that inclines inward in the radial direction toward the inward in the axial direction is formed at the inner end portion of the piston portion 14 in the axial direction.

The annular segment group 15 is arranged in the guide hole 16 formed in the drum body 5A. The guide hole 16 extends outward in the radial direction from the inner end portion in the axial direction of the cylinder chamber 13 and opens on the outer peripheral surface of the drum main body 5A.

The annular segment group 15 includes a plurality of segments 15A arranged along the circumferential direction of the bead core B. Each segment 15A is movably guided in and out of the radial direction by the guide hole 16. A bearing surface 15s inclined at the same gradient as the bearing surface 14s of the piston portion 14 is formed at the inner end portion in the radial direction of each segment 15A. As a result, each segment 15A can move in the radial direction in conjunction with the movement of the piston portion 14 in the axial direction, and the diameter of the annular segment group 15 can be expanded or contracted. In another aspect, a roller may be provided instead of the bearing surface 15s, and the piston portion 14 and each segment 15A may be connected by a link.

The annular segment group 15 can hold the bead core B via the tire case A and the folded bladder 11 by expanding the diameter of the plurality of segments 15A toward the bead core B. For example, a recess for fixing the bead core B may be provided on the outer surface of each segment 15A.

FIGS. 3 (a) and 3 (b) show enlarged cross-sectional views of the segment 15A. FIG. 3A is a state in which the annular segment group 15 has the smallest diameter, and FIG. 3B is a beadlock state in which the annular segment group 15 holds the bead core B. As shown in FIGS. 3A and 3B, in the bead holding portion 10 of the present embodiment, a plurality of plates 20 having an inner end portion in the axial direction connected to each segment 15A and extending outward in the axial direction. have. The plate 20 supports the case outer portion A1 via the folded bladder 11 in the beadlock state in which the annular segment group 15 holds the bead core B. Such a plate 20 can suppress partial bending of the case outer portion A1 and, by extension, suppress the occurrence of wrinkles in the tire case A.

It is desirable that the outer surface of the plate 20 is formed of, for example, a flat surface. In another aspect, the outer surface of the plate 20 may be configured with a curved surface along the outer surface of the tire case A.

The plate 20 of the present embodiment is tiltably connected to, for example, the segment 15A. Specifically, the plate 20 is connected to the segment 15A via, for example, a pivot point 21 such as a hinge. It is desirable that the pivot point 21 is provided, for example, at the outer end portion of the outer surface of the segment 15A in the axial center direction. As a result, the angle of the outer surface of the plate 20 with respect to the axis direction changes with the expansion or contraction of the annular segment group 15. Such a plate 20 can exert the above-mentioned effects without hindering the expansion of the diameter of the segment 15A and the expansion of the folded bladder 11.

The outer surface of the plate 20 of the present embodiment is parallel to the axial core direction, for example, in the most reduced diameter state in which the annular segment group 15 has the smallest diameter. Further, in the maximum reduced diameter state, the outer surface of the segment 15A and the outer surface of the plate 20 are substantially the same in radial distance from the axis.

In the beadlock state, the outer surface of the plate 20 is inclined toward the inside in the axis direction and away from the axis. The angle θ1 with respect to the axis direction of the plate 20 is preferably, for example, 5 to 10 °.

The length L1 of the plate 20 in the axial direction is preferably, for example, preferably 100 to 300 mm, more preferably 200 to 300 mm. Such a plate 20 can support the outer side portion A1 of the case in a wide range, and effectively suppresses the occurrence of wrinkles in the tire case A.

From the same viewpoint, it is desirable that the circumferential length L2 (not shown) of the plate 20 is, for example, 0.5 to 1.0 times the circumferential length of the segment 15A.

4 and 5 show enlarged cross-sectional views of the segment 15A and the plate 20 of the raw tire forming apparatus 1 of another embodiment of the present invention. In FIGS. 4 and 5, the same reference numerals are given to the elements common to the above-described embodiments, and the description thereof is omitted here.

The plate 20 of the embodiment shown in FIG. 4A is fixed to the segment 15A. As shown in FIG. 4 (b), in this embodiment, the plate 20 is formed in a comb-teeth shape in a plan view. The outer surface of the drum body 5A is provided with a recess 24 having a shape corresponding to the comb-shaped plate 20. In the most contracted state, the plate 20 is housed in the recess 24. In FIG. 4B, the gap between the plate 20 and the drum body 5A is colored for easy understanding.

In this embodiment, since the angle of the plate 20 with respect to the axis direction can be arbitrarily set, the angle of the case outer portion A1 in the beadlock state can be freely set, whereby the occurrence of wrinkles in the tire case is further suppressed. Further, in this embodiment, since the plate 20 is fixed to the segment 15A, the frequency of maintenance of the device can be reduced.

In the plate 20 of the embodiment shown in FIG. 5, the end portion on the outer side in the axial direction is connected to the drum body 5A via the pivot point 22, and the end portion on the inner side in the axial direction is integrated with the segment 15A inward and outward in the radial direction. It is connected so that it can be moved. In this embodiment, the end portion of the plate 20 is placed on the stepped portion 23 provided on the outer surface of the segment 15A. Since such a plate 20 inclines around the pivot point 22 when the segment 15A expands in diameter, a force is applied to the case outer portion A1 supported by the plate 20 toward the outside in the axial direction, and thus the plate 20 is subjected to a force toward the outside in the axial direction. The occurrence of wrinkles can be further suppressed.

Although the raw tire forming apparatus according to the embodiment of the present invention has been described in detail above, the present invention is not limited to the above-mentioned specific embodiment, and can be changed to various embodiments.

As an embodiment, a raw tire forming apparatus having the plate shown in FIG. 3 or FIG. 4 (a) or (b) was prepared. As a comparative example, a conventional raw tire forming apparatus having no plate was prepared. These devices were tested as follows.

<Number of raw tires with wrinkles>
Twenty raw tires of size 275 / 35RF21 were molded by each device, and the number of raw tires with wrinkles in the tire case was measured. The smaller the value, the more the occurrence of wrinkles in the tire case is suppressed.
The test results are shown in Table 1.

As a result of the test, it was confirmed that the raw tire forming apparatus of the example effectively suppressed the occurrence of wrinkles in the tire case.

10 Bead holding part 11 Folded bladder 15 Circular segment group 15A segment 20 Plate A Tire case B Bead core A1 Case outer part

Claims (5)

An annular bead core is externally inserted onto the outer peripheral surface of a cylindrical tire case including a carcass so as to be separated from each other, and the outer side of the case outside the tire case in the axial direction is folded around the bead core. It is a device for molding raw tires.
A bead holding portion capable of holding the extrapolated bead core, and
Including a folded bladder that folds the outer portion of the case around the bead core held by the bead holding portion by inflating.
The bead holding portion is
The bead core plurality of segments radially movable out of parallel BiKatsu the tire casing along the circumferential direction of the bead core, by whose diameter increases towards said bead core, through the tire casing and the folded bladder And a group of circular segments that hold
Each of the segments that can move inward and outward in the radial direction has a plurality of plates having an inner end portion in the axial direction connected to the segment and extending outward in the axial direction.
The plate supports the outer portion of the case via the folded bladder in a beadlock state in which the annular segment group holds the bead core.
Raw tire molding equipment. The outer surface of the plate is inclined with respect to the axis direction in the beadlock state.
The raw tire molding apparatus according to claim 1. The angle of the outer surface of the plate with respect to the axis direction changes with the expansion or contraction of the annular segment group.
The raw tire forming apparatus according to claim 1 or 2. The outer surface of the plate is parallel to the axis direction in the state where the annular segment group is most reduced in diameter.
The raw tire molding apparatus according to any one of claims 1 to 3. The plate is tiltably connected to the segment,
The raw tire molding apparatus according to any one of claims 1 to 4.

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