JPH05177742A - Split mold for regenerated tire and manufacture of regenerated tire - Google Patents

Abstract

PURPOSE:To prevent a cost of equipment from becoming immense by using a base tire economically. CONSTITUTION:A sector mold 12 which has been made cylindrical is divided circumferentially into equal five parts. When an inner diameter of the sector mold 12 is enlarged, a spacer mold 18 which has the same section as a section 12C of a sector mold piece 24 and is made wedge-shaped when locked at from a shaft direction is arranged between respective sector mold pieces 24, and a spacer ring 26 is arranged in an annular gap formed between a top force and a bottom force 16. Then, a split mold 10 for regenerated tire in this executed example becomes capable of regenerating a base tire having an outer diameter beyond a regenerating possible range of a conventional split mold for regenerated tire which can not vary an inner diameter of the sector mold 12, and necessity for preparing a plurality of split molds for regenerating tires having different inner diameters as conventionally will also be removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split mold type split mold for retreaded tires and a method for manufacturing a retreaded tire using a split mold type split tire for retreaded tire.

[0002]

2. Description of the Related Art When manufacturing a retreaded tire, it is desirable that the base tire has a uniform belt outer diameter as in the case of manufacturing a new tire.

By the way, the outer diameter of the belt varies depending on the base tires even with the same size. For example, in a truck tire of size 10.00R20, the outermost belt diameter after buff cutting is 1014 mm (center value). The range is around ± 5 mm (see the distribution chart in Fig. 4 (A)). However, the outermost belt has a certain thickness on the outer side in the radial direction, for example, 1 mm.
The remaining tread rubber buffed with the remaining rubber of No. 1 can be rehabilitated with one mold for retreaded tires, which is around 1014 mm ± 3 mm, which is less than the above range.
Stand tires outside this range (hatched portion in the distribution diagram of FIG. 4A)
Is not rehabilitated.

[0004] For a stand tire below the standard range, a sheet for increasing the thickness of the tread after buffing can be sandwiched and tread contours can be attached to enable rehabilitation, but the material cost and the number of man-hours are increased. .. On the other hand, a base tire having a diameter exceeding the reference range cannot be rehabilitated because shape distortion occurs when it is set in the mold, and waste of the base tire cannot be eliminated.

In order to solve the above-mentioned drawback, it is possible to prepare a plurality of molds for retreaded tires whose inner diameters are slightly different corresponding to the outer diameter of the tires for rehabilitation, but waste of the tires is eliminated. On the other hand, it is necessary to prepare a plurality of molds for retreaded tires, which are complicated and expensive to process, resulting in a huge equipment cost and a large installation space for the retreaded tire molds.

[0006]

In view of the above facts, the present invention provides a split mold for a retreaded tire and a method for manufacturing a retreaded tire, in which a stand tire is used without waste and the equipment cost does not become huge. Is the purpose.

[0007]

The invention according to claim 1 is
A split mold for a retreaded tire, comprising a sector mold having a tread portion forming surface that forms a tread surface of a tire to be formed and configured by a plurality of sector mold pieces divided in the tire circumferential direction, between the sector mold pieces. And a spacer mold for expanding the inner diameter of the sector mold and forming the tread surface of the tire to be molded together with the sector mold piece.

According to a second aspect of the present invention, an unvulcanized tread contour is adhered to the tread portion of the base tire, and the tread portion forming surface that forms the tread surface of the tire to be formed is provided in a plurality in the tire circumferential direction. A method for manufacturing a retreaded tire by vulcanization molding using a split mold for a retreaded tire, comprising a sector mold composed of divided sector mold pieces, wherein an inner diameter of the sector mold is enlarged between the sector mold pieces. In addition, a spacer mold for forming the tread surface of the tire to be molded together with the sector mold piece is provided, and the base tire having the tread contour attached thereto is vulcanized and molded.

[0009]

In the split mold for a retreaded tire according to the present invention, a spacer is provided between the sector mold pieces to increase the inner diameter of the sector mold and to form the tread surface of the tire to be molded together with the sector mold pieces. A mold is provided. Therefore, the inner diameter of the sector mold can be changed between the case where the spacer mold is not arranged between the sector mold pieces and the case where the spacer mold is arranged between the sector mold pieces. The inner diameter of the sector mold can be finely changed by increasing the number of divisions and increasing or decreasing the number of sector mold pieces, or by increasing or decreasing the size of the spacer mold. Therefore, it becomes possible to vulcanize and form a base tire that cannot be handled by the conventional split mold for retreaded tires whose inner diameter cannot be changed. Further, there is no need for a spacer or the like arranged between the tread contour and the base tire to absorb the difference in diameter between the sector mold and the base tire.

In the method for manufacturing a retreaded tire according to the second aspect of the present invention, when a base tire having a large outer diameter that does not correspond to the inner diameter of the sector mold when the spacer mold is not disposed between the sector mold pieces is vulcanized and molded. Has
A spacer mold is disposed between the sector mold pieces to increase the inner diameter of the sector mold. by this,
A base tire having a large outer diameter can be used for a sector mold having an enlarged inner diameter. Thereafter, the base tire having the tread contour attached thereto is subjected to vulcanization molding.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIGS.
A description will be given according to (B).

As shown in FIGS. 1A and 2A,
The split mold 10 for retreaded tire to which the present invention is applied,
Sector mold 12, upper mold (not shown), lower mold 16,
It is composed of a spacer mold 18 and a spacer ring 20.

The upper mold (not shown) and the lower mold 16 are formed in an annular shape, and the surfaces facing each other contact the sidewalls of the base tire 13 (shown in phantom in FIG. 2A) to be rehabilitated. I have come into contact with them.

As shown in FIG. 2A, the sector mold 12 has a substantially cylindrical shape and is arranged radially outward of the upper die 16 and the lower die 16. Further, a tread outer contour forming surface 12A which is recessed radially outward is provided at an axially intermediate portion of the inner periphery of the sector mold 12. It should be noted that the tread outer contour forming surface 12A is provided with irregularities for forming a tread pattern.

As shown in FIGS. 1 (B) and 2 (B), the inner peripheral surfaces 12B on both axial ends of the sector mold 12 are in contact with the outer peripheral surfaces 22 of the upper and lower molds 16 described above. When it is done, it will come into close contact.

As shown in FIG. 1 (A), the sector mold 12 has a cutting surface 12C along the radial direction and is divided into five equal parts in the circumferential direction. As shown in FIGS. 2A and 2A, a spacer mold 18 having the same cross section as the cut surface 12C of the sector mold piece 24 and having a wedge shape when viewed from the axial direction is arranged. ..

As shown in FIG. 1B, when the spacer mold 18 is not provided between the sector mold pieces 24, only one of the upper mold and the lower mold 16 is shown in FIG. 1B. ) The outer peripheral surface 22 of the sector mold 12
The inner peripheral surface 12B of the sector mold 12 is in close contact with the cut surface 12C of each sector mold piece 24, and the cut surface 12C of the adjacent sector mold piece 24 is in close contact with the cut surface 12C. Outer contour forming surface 12
A has a diameter D1 (at the tread center) of 1045 mm,
The tire circumferential length is about 3283 mm.

As shown in FIG. 1A, the tire circumferential length L of the tread outer contour forming surface 18A per spacer mold 18 disposed between each sector mold piece 24 is the tire circumferential length L in this embodiment. Is 3.8 mm. Therefore, when the spacer molds 18 are arranged one by one between the sector mold pieces 24, the sector molds 12
The inner diameter D2 of the tread outer contour forming surface 12A is about 6 mm (3.8 mm × 3.8 mm) larger than the inner diameter D1 of the tread outer contour forming surface 12A of the sector mold 12 when the spacer mold 18 is not arranged between the sector mold pieces 24. 5 ÷ π)
To be enlarged.

Therefore, it becomes possible to rehabilitate the base tire 13 having an outer diameter which is 6 mm out of the rehabilitable range of the conventional split mold for rehabilitated tires in which the inner diameter of the sector mold 12 cannot be changed. That is, when the inner diameter without the spacer mold 18 is the same as the inner diameter of the conventional split mold for retreaded tires, when the spacer mold 18 is placed, the outer diameter is 6 mm larger than the conventional rehabilitable range. It becomes possible to rehabilitate the base tire 13 having a diameter, and if the inner diameter when the spacer mold 18 is not provided is made 6 mm smaller than the inner diameter of the conventional split mold for rehabilitated tires, the rehabilitable range of the prior art is reduced. It is possible to rehabilitate the base tire 13 having an outer diameter smaller by 6 mm. Incidentally, the split mold 1 for retreaded tire of the present embodiment
0, since the inner diameter D1 when the spacer mold 18 is not arranged is set to be 3 mm smaller than the inner diameter of the conventional split tire mold for retreaded tires, the re-growth range in the conventional split mold for retreaded tires, It is possible to rehabilitate the base tire 13 having an outer diameter smaller by 3 mm and the base tire 13 having an outer diameter larger by 3 mm (see FIG. 4 (B)).

Therefore, the tire size is 10.00R2.
When rehabilitating a base tire 13 of 0 (as an example, the outer diameter of the new tread is 1052 mm, the outermost belt diameter is 1014 mm), conventionally, the base tire 13 with the outermost belt diameter of 1014 mm plus or minus 3 mm (as an example) is used. If the split mold 10 for retreaded tire according to the present embodiment is used, the tire cannot be rehabilitated unless it is 1014 mm plus or minus 6 mm in the widest range of the outermost belt diameter.
It is possible to rehabilitate.

The total length of the tread outer contour forming surface 18A of the spacer mold 18 in the tire circumferential direction is the tread outer contour forming surface 12 of the sector mold 12.
2% or less of the tire circumferential direction length of A is preferable, and 1% or less is further preferable. Further, the tire circumferential direction length of the tread outer contour forming surface 18A per one spacer mold 18 is preferably 1% or less of the inner circumferential length of the tread outer contour forming surface 12A of the sector mold 12, and more preferably 0.6%. % Or less is preferable. If the total length of the tread outer contour forming surface 18A of the spacer mold 18 in the tire circumferential direction exceeds 2% of the tire circumferential direction length of the tread outer contour forming surface 12A of the sector mold 12, the tire outer contour shape after molding is formed. It is not preferable because it affects the In this embodiment, the total length of the tread outer contour forming surface 18A of the spacer mold 18 in the tire circumferential direction is 0.58% (3.8 mm × 5) of the inner peripheral length of the tread outer contour forming surface 12A of the sector mold 12. ÷ 3283mm × 100%)
It is said that.

Further, as shown in FIG. 1 (A), when the spacer mold 18 is arranged between the sector mold pieces 24 to expand the diameter of the sector mold 12, as shown in FIG. As shown in FIG. 2 (A), the upper mold 16 and the lower mold 16
The spacer ring 26 is provided in the annular gap formed between
Is preferably provided. In addition, sector mold 1
Since the diameter of 2 is expanded by 6 mm, the spacer ring 26
The radial thickness of is set to 3 mm. Stand tire 13
Since it is vulcanized, the spacer ring 26 is not always necessary, and a spacer may be provided in a part of the annular gap to stabilize the mold during vulcanization. It need not be provided.

As shown in FIG. 3, the dividing line 27 formed by the cut surface 12C of the sector mold piece 24 is located on the tread surface of the tread land portion 28 of the tread outer contour forming surface 12A. The lateral groove 30 (the groove in the direction intersecting with the tire circumferential direction (the direction of arrow A in FIG. 3A)) is not located. This is because the lateral groove is divided and is not continuous, which is not preferable in appearance.

Next, the operation of this embodiment will be described. For example, when rehabilitating the base tire 13 having the outermost belt diameter of 1008 mm to 1014 mm, the spacer mold 18 is not arranged between the sector mold pieces 24. by this,
The outermost belt diameter of the sector mold 12 is 1008 mm ~
The inner diameter corresponds to the base tire 13 of 1014 mm. Then, an unvulcanized tread contour 25 (imaginary line in FIG. 2 (B)) is attached to the tread portion of the base tire 13, and a predetermined pressure and heat are applied and vulcanization molding is performed.

Further, for example, the outermost belt diameter is 1014 mm
When rehabilitating the base tire 13 having a size of 1020 mm, one spacer mold 18 is provided between each sector mold piece 24 and a spacer ring 20 is provided between the upper mold 16 and the lower mold 16 and the sector mold 12. Arrange. As a result, the sector mold 12 has an inner diameter corresponding to the base tire 13 having an outermost belt diameter of 1014 mm to 1020 mm. Then, an unvulcanized tread contour 25 (imaginary line in FIG. 2 (B)) is attached to the tread portion of the base tire 13, and a predetermined pressure and heat are applied and vulcanization molding is performed.

As described above, in the split mold 10 for retreaded tire to which the present invention is applied, the inner diameter of the sector mold 12 is determined by whether the spacer mold 18 is provided or not.
Since it can be adjusted according to the diameter of No. 3, it is possible to rehabilitate the base tire 13 that could not be rehabilitated due to the outermost belt diameter in the conventional split mold for rehabilitating tires. Never waste. further,
Since it is possible to deal with the base tires 13 having different diameters only by providing the simple spacer mold 18 and the spacer ring 20 without providing a plurality of expensive split tire split tire molds, the cost of equipment for retread tires is increased. Can be suppressed. Moreover, since it is not necessary to provide a plurality of split molds 10 for retreaded tires, a large installation space is not required.

In the present embodiment, there is only one type of spacer mold 18 and spacer ring 20, but the present invention is not limited to this, and a plurality of thicker spacer molds 18 and spacer rings 20 are prepared. By doing so, the stand tire 13 having a larger or smaller outermost belt diameter can be rehabilitated.

Further, in the present embodiment, the spacer molds 18 are provided one by one or not provided between the sector mold pieces 24, but the present invention is not limited to this. It may be arranged at any one arbitrary place of the sector mold 12, and when the outer diameter difference of the base tire 13 is small, it is preferable to arrange it at only one place in terms of workability. Also, the inner diameter of the sector mold 12 may be finely adjusted by appropriately increasing or decreasing the number of spacer molds 18. In this case, the spacer rings 20 having different radial thicknesses are attached to the spacer mold 18.
It is preferable to provide a plurality according to the number of

Further, in this embodiment, the sector mold 12 is used.
Was divided into five in the circumferential direction, but the present invention is not limited to this number of divisions.

[0030]

EFFECTS OF THE INVENTION Since the split mold for retreaded tire of the present invention has the above-mentioned structure, the stand tire can be used without waste and the facility cost does not become enormous. According to the method for producing a retreaded tire of the present invention, It has an excellent effect that the tire can be vulcanized and molded without wasting it.

[Brief description of drawings]

FIG. 1 (A) is a sectional view taken along line 1 (A) -1 (A) of FIG. 2 (A) when a spacer mold and a spacer ring of a split mold for a retreaded tire according to an embodiment of the present invention are arranged. FIG. 2 (B) is a view (B) -1 of FIG. 2 (A) when the spacer mold and the spacer ring of the split mold for a retreaded tire according to an embodiment of the present invention are not provided.
(B) A line cross section.

FIG. 2 (A) is a sectional view taken along line 2 (A) -2 (A) of FIG. 1 (A) when a spacer mold and a spacer ring of a split mold for a retreaded tire according to an embodiment of the present invention are arranged. FIG. 1 (B) is a view (B) -2 of FIG. 1 (A) when the spacer mold and the spacer ring of the split mold for a retreaded tire according to an embodiment of the present invention are not provided.
(B) A line cross section.

FIG. 3 is a plan view of a tread outer contour forming surface of a split mold for retreaded tire according to an embodiment of the present invention.

FIG. 4A is a distribution diagram showing the relationship between the number of base tires and the diameter of the outermost belt of the base tire, showing the range in which the base tire can be refurbished with the conventional split mold for retread tires. (B) is a distribution diagram showing the relationship between the number of base tires and the diameter of the outermost belt of the base tire, showing the reproducible range of the base tire that can be refurbished with the split mold for the retread tire of the present embodiment.

[Explanation of symbols]

 10 Split mold for retreaded tire 12 Sector mold 12A Tread outer contour forming surface (tread portion forming surface) 13 tires 18 Spacer mold 18A Tread portion forming surface 24 Sector mold piece 25 Tread contour 28 Tread land portion (tread surface portion)

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Claims (2)

[Claims] 1. A split mold for a retreaded tire, comprising a sector mold having a tread portion forming surface that forms a tread surface of a tire to be molded and configured by sector mold pieces divided into a plurality in the tire circumferential direction, A split mold for a retreaded tire, which is provided between the sector mold pieces, and is provided with a spacer mold for enlarging an inner diameter of the sector mold and forming a tread surface portion of the tire to be molded together with the sector mold pieces. 2. A sector mold piece having an unvulcanized tread contour adhered to a tread portion of a base tire and having a tread portion forming surface forming a tread surface of a tire to be molded and divided into a plurality in the tire circumferential direction. A method for producing a retreaded tire by vulcanization molding using a split mold for a retreaded tire having a sector mold configured by: a tire to be formed while enlarging the inner diameter of the sector mold between the sector mold pieces. A method for manufacturing a retreaded tire, characterized by arranging a spacer mold for forming the tread surface portion together with the sector mold piece and vulcanizing and molding the base tire to which the tread contour is adhered.