JP2014061661A - Mold for vulcanization of tire and method for manufacturing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for vulcanization of a tire, in which a slip position mark that is not worn in an early stage can be formed in spite of a simple configuration, and to provide a method for manufacturing a pneumatic tire using the mold.SOLUTION: A mold for vulcanization of a tire includes a mark forming member 10 for forming a slip sign position mark on a tire molding surface. The mark forming member 10 is in a triangular cylindrical body. The mark forming member 10 is implanted on the tire molding surface. The protruding height position of the implanted mark forming member 10 is set at a position higher than a protruding height position of a groove forming projection 8b for forming a lateral groove that opens at an end in a tire width direction.

Description

  The present invention relates to a tire vulcanization mold and a method for manufacturing a pneumatic tire. More specifically, the present invention relates to a tire vulcanization mold that can form a slip position mark that does not wear out at an early stage while having a simple configuration, and the mold. The present invention relates to a method for manufacturing a pneumatic tire.

  In general, in the main groove of the tread of the tire, a protruding slip sign is provided at a predetermined interval in the circumferential direction so as to reduce the depth of the main groove. When the tread surface is worn by traveling and reaches the slip sign, it can be visually confirmed that slipping or the like is likely to occur. In order to be able to confirm the position where such a slip sign exists from the side of the tire, a triangular shape corresponding to the position of the slip sign is formed on the outer surface of the tire (particularly, near the shoulder portion above the sidewall). A slip sign position mark is formed.

  Conventionally, the slip sign position mark is formed in a convex shape with respect to the outer surface of the tire, for example, by a concave portion formed by punching the inner surface of the tire vulcanization mold with a punch or the like. However, if a slip sign position mark that protrudes from the profile surface of the tire is used in a tire with a high flatness ratio (low flat tire) that narrows the space of the sidewall, wear on the tread surface is at a relatively early stage. However, the slip sign position mark may disappear due to wear, making it difficult to confirm the position of the slip sign.

  For example, although the object of the present invention is different from that of the present invention, it has been proposed to provide a slip sign position mark as a convex portion having a height that does not protrude from the outer surface in a recess formed on the outer surface of a tire (Patent Document). 1). Since such a slip sign position mark does not protrude from the profile surface of the tire, the slip sign position mark is prevented from being worn out at an early stage. However, in order to manufacture such a mark, an operation of providing a pedestal portion corresponding to a dent formed on the outer surface of the tire on the inner surface of the tire mold and further forming a recess by driving the pedestal portion with a punch or the like. Since it becomes necessary, there is a problem that the manufacturing man-hour (time and cost) of the mold increases.

Japanese Utility Model Publication No.59-188705

  An object of the present invention is to provide a tire vulcanization mold capable of forming a slip position mark that does not wear at an early stage while having a simple configuration, and a method for manufacturing a pneumatic tire using the mold.

  In order to achieve the above object, a tire vulcanization mold according to the present invention is a tire vulcanization mold having a mark forming member for forming a slip sign position mark on a tire molding surface, wherein the mark forming member is a triangular cylindrical body. Yes, this mark forming member is implanted on the tire molding surface, and the protruding height position of the implanted mark forming member is the projection height position of the groove forming projection that forms a groove that opens at the end in the tire width direction. It is characterized in that it is set at a position that protrudes further.

  In the present invention, as described above, the mark forming member protrudes from the tire molding surface, and the protrusion height position of the mark forming member is the protrusion height of the groove forming protrusion that forms a groove that opens at the end in the tire width direction. The slip sign position mark formed on the tire has a concave shape deeper than the groove bottom line of the groove opening at the end in the tire width direction because the position is set to be protruded from the position protruding from the position. . Therefore, the slip sign position mark can be prevented from being worn out at an early stage, so that it can function for a long period as an index indicating the position of the slip sign. In addition, since the mark forming member has a simple configuration in which a triangular cylindrical body is implanted on the tire molding surface, an increase in the number of mold manufacturing steps can be avoided.

  In the tire vulcanization mold according to the present invention, the mark forming member may have a specification formed by processing a plate-like body. Alternatively, the specification may be such that the mark forming member is a pipe material previously formed in a triangular cylinder shape. By using such a mark forming member, the manufacture of the mold can be simplified.

  In the tire vulcanization mold according to the present invention, the implantation depth of the mark forming member is set to 3 mm to 4 mm, for example. As a result, it is possible to prevent the mark forming member from falling off and to avoid a reduction in mold productivity.

  In the tire vulcanization mold of the present invention, it is preferable that the mark forming member is implanted within a range of 15 mm from the tire width direction end of the tread pattern forming portion in the tire center direction. By implanting the mark forming member at such a position, it is possible to ensure high visibility of the slip sign position mark while preventing early wear of the slip sign position mark.

  The tire vulcanization mold of the present invention is preferably used for tire vulcanization with a flatness ratio of 30% to 60%. Since the low flat tire has a narrow sidewall space and the slip sign position mark easily wears out, the tire vulcanization mold of the present invention is used for vulcanizing such a low flat tire. It becomes easier to obtain an early wear prevention effect.

  Since the pneumatic tire manufactured using the tire vulcanization mold of the present invention has a concave slip sign position mark deeper than the groove bottom line of the groove opened at the end in the tire width direction, the slip sign position mark is It can be prevented from wearing out early.

It is sectional drawing which shows an example of the mold for tire vulcanization | cure which consists of embodiment of this invention. It is sectional drawing which expands and shows a part of side type | mold of the tire vulcanization mold of FIG. It is a perspective view which shows an example of the mark formation member of this invention. It is a perspective view which shows the other example of the mark formation member of this invention. It is a perspective view which shows an example of the pneumatic tire of this invention. FIG. 6 is a partially enlarged cross-sectional view of the pneumatic tire of FIG. 5.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  As illustrated in FIG. 1, the mold for tire vulcanization according to the present invention forms an upper annular mold 1 that molds one sidewall of a tire, an annular lower mold 2 that molds the other sidewall, and a tread. An annular side mold 4 comprising a plurality of sectors 3 is provided.

  The upper mold 1 has sidewall molding surfaces 5 and 6 for molding the sidewalls on the lower surface side and the lower mold 2 on the upper surface side, respectively. The side mold 4 has a tread molding portion 7 that molds a tread (and a part of the sidewall) on the inner peripheral surface side. The tread molding portion 7 is provided with an appropriate number of groove forming protrusions 8a and 8b. The groove forming protrusion 8a extends in the circumferential direction, and the groove forming protrusion 8b extends in the width direction. A slip sign forming portion 9 for forming a slip sign on the tire is provided at the tip of the groove forming protrusion 8a with a gap in the circumferential direction. Further, a mark forming member for forming a slip sign position mark on at least one width direction end portion of the tread molding portion 7 (side wall molding surface 5 side in the example of FIG. 1) as illustrated in FIGS. 10 are planted.

  The mark forming member 10 is a triangular cylindrical body as illustrated in FIGS. 3 and 4, and is formed at a position corresponding to the circumferential direction of the slip sign forming portion 9 in the mold (side mold 4). Accordingly, in the manufactured pneumatic tire, the triangular slip sign position mark indicates the position of the slip sign by the apex thereof. The mark forming member 10 is set at a position where the protruding height position protrudes from the protruding height position of the groove forming protrusion 8b that forms a groove opened at the end in the tire width direction.

  5 and 6 illustrate the pneumatic tire of the present invention manufactured using the vulcanization mold of the present invention.

  As illustrated in FIGS. 5 and 6, the pneumatic tire 11 of the present invention has an appropriate number (two in the example of FIGS. 5 and 6) of circumferential grooves 13 a extending in the tire circumferential direction on the tread surface 12. A plurality of lateral grooves 13b extending from the circumferential groove 13a toward the tire width direction end and opening at the tire width direction end are provided. The circumferential groove 13a is formed by the groove forming protrusion 8a, and the lateral groove 13b is formed by the groove forming protrusion 8b. In the circumferential groove 13a, slip signs 14 are formed at appropriate locations at predetermined intervals in the circumferential direction. A slip sign position mark 15 is formed in a region outside the tire width direction corresponding to the slip sign 14. The tread pattern of the pneumatic tire 11 of the present invention is not limited to that illustrated in FIGS. 5 and 6, and at least a circumferential groove 13 a having a slip sign 14 in the groove and a lateral groove opening at the end in the tire width direction. 13b.

  The slip sign position mark 15 has a triangular shape in which a sipe recessed with respect to the profile surface of the tire 11 forms three sides, and the apex angle of the triangle indicates the slip sign 14. And since the slip sign position mark 15 is manufactured using the above-mentioned tire vulcanization mold of the present invention, the slip sign position mark 15 has a concave shape deeper than the groove bottom line of the lateral groove 13b opened at the end in the tire width direction. Yes.

  Thereby, it is possible to prevent the slip sign position mark 15 from being worn out at an early stage. Moreover, since the mark forming member 10 has a simple configuration in which a triangular cylindrical body is implanted on the tire molding surface, an increase in the number of mold manufacturing steps can be avoided. A method for implanting the mark forming member 10 will be described later.

  The mark forming member 10 is preferably made of metal. For example, stainless steel, general carbon steel, and aluminum alloy can be used. It is composed of a triangular cylindrical mark forming member 10 formed by processing a plate-like body as shown in FIG. 3, or a pipe material previously formed in a triangular cylindrical shape as shown in FIG. A mark forming member 10 may be used. By using such a mark forming member 10, the manufacturing process of the mold can be simplified. The mark forming member 10 of FIG. 3 that can be formed by bending a plate-like body can be manufactured at low cost. Since the mark forming member 10 of FIG. 4 using a pipe material is hardly deformed, the service life can be extended.

  The thickness t of the mark forming member 10 is preferably set to 0.1 mm to 3.0 mm. More preferably, the thickness is about 0.5 mm to 1.0 mm. If the thickness t of the mark forming member 10 is smaller than 0.1 mm, each side of the slip sign position mark 15 formed on the tire 11 becomes too thin, and it becomes difficult to ensure sufficient visibility. If the thickness t of the mark forming member 10 is larger than 3.0 mm, the slip sign position mark 15 formed on the tire 11 becomes large and the appearance of the tire 11 is impaired. In particular, when processing a plate-like body, the thicker the mark forming member 10, the more difficult it is to process into a predetermined shape, resulting in a decrease in productivity.

  The shape of the mark forming member 10 is an isosceles triangle whose apex angle points to the position of the slip sign 14. The size of the isosceles triangle is such that the width w of the base is 4 mm to 12 mm and the height h is 1.4 times the width w of the base (that is, 5.6 mm to 16.8 mm). JATMA regulations on tires excluding tires).

  The implantation depth of the mark forming member 10 is preferably 3 mm to 4 mm. As shown in FIG. 2, when the mark forming member 10 is implanted with an inclination with respect to the tire molding surface (profile surface in the tire) of the mold (side mold 4), the depth of the shallowest portion Is the depth of implantation. If the implantation depth is less than 3 mm, the mark forming member 10 may fall off during the manufacture of the mold or the vulcanization of the tire. When the implantation depth is larger than 4 mm, the implantation groove for planting the mark forming member 10 is deepened, which causes a decrease in productivity.

  The protruding height of the mark forming member 10 is, for example, 0.5 mm to 5.0 mm. As shown in FIG. 2, when the mark forming member 10 is implanted with an inclination with respect to the tire molding surface (profile surface in the tire) of the mold, the projection height of the lowest portion is defined as the projection height. To do. If the protruding height is smaller than 0.5 mm, the slip sign position mark 15 formed on the tire 11 is too shallow, and it becomes difficult to maintain high visibility. If the protruding height is larger than 5.0 mm, a large load tends to be generated on the mark forming member 10 and its periphery when the vulcanized tire 11 is extracted.

  The planting of the mark forming member 10 can be performed as follows, for example. First, a triangular implantation groove corresponding to the mark forming member 10 is provided on the tire molding surface using a punch or the like. At this time, the width of the implantation groove is made about 5% and 20% larger than the thickness t of the mark forming member 10 so that the mark forming member 10 can be easily inserted into the implantation groove. Then, by inserting the mark forming member 10 into the implantation groove and performing punching so as to fill the gap between the implantation groove and the mark forming member 10, the mark forming member 10 can be caulked and planted. . Therefore, unlike the prior art, there is no need to provide a pedestal corresponding to the recess formed on the outer surface of the tire on the inner surface of the tire mold, so that the mark forming member 10 can be easily provided.

  The mark forming member 10 is implanted in a range of 15 mm from the tire width direction end of the tread pattern forming surface for forming the tread in the tire center direction. The end in the tire width direction of the tread pattern molding surface is a position corresponding to the pattern end 12a of the manufactured tire 11. If the mark forming member 10 is arranged on the inner side in the tire center direction than this range, the slip sign position mark 15 is difficult to visually recognize from the tire side in the manufactured tire.

  The mold for tire vulcanization according to the present invention can be used for vulcanizing tires of any size, but is suitable for tire vulcanization having a flatness ratio of 30% to 60%. That is, in such a low flat tire, the space of the sidewall portion is narrow and the slip sign position mark 15 is easily worn out. Therefore, by adopting the tire vulcanization mold of the present invention, it is possible to effectively prevent early wear of the slip sign position mark 15 formed on the tire 11.

DESCRIPTION OF SYMBOLS 1 Upper mold | type 2 Lower mold | type 3 Sector 4 Side mold | type 5,6 Side wall molding surface 7 Tread molding part 8 Groove formation protrusion 9 Slip sign formation part 10 Mark formation member 11 Pneumatic tire 12 Tread surface 12a Pattern end 13a Circumferential groove 13b Horizontal groove (groove that opens at the end in the tire width direction)
14 Slip sign 15 Slip sign position mark

Claims (7)

In the tire vulcanization mold having a mark forming member for forming a slip sign position mark on the tire molding surface,
The mark forming member is a triangular cylindrical body, the mark forming member is implanted on the tire molding surface, and the protruding height position of the implanted mark forming member is provided with a groove opening at the end in the tire width direction. A tire vulcanization mold, characterized in that the mold is set at a position protruding from a protrusion height position of a groove forming protrusion to be formed.   The mold for tire vulcanization according to claim 1, wherein the mark forming member is formed by processing a plate-like body.   The tire vulcanization mold according to claim 1, wherein the mark forming member is a pipe material formed in a triangular tube shape in advance.   The tire vulcanization mold according to claim 1, wherein an implantation depth of the mark forming member is 3 mm to 4 mm.   The tire vulcanization mold according to any one of claims 1 to 4, wherein the mark forming member is planted in a range of 15 mm from a tire width direction end of a tread pattern molding surface to a tire center direction.   The mold for tire vulcanization according to any one of claims 1 to 5, wherein the mold is for tire vulcanization having a flatness ratio of 30% to 60%.   A pneumatic tire manufactured using the tire vulcanization mold according to claim 1.

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