JP2013158963A - Method of manufacturing tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire manufacturing method that reduces ruggedness and carcass ply appearing on a tire surface and waves of a belt owing to vulcanization.SOLUTION: A method of manufacturing a tire 1 includes the steps of: arranging an unvulcanized component 5 being a land 1b in a vulcanization metal mold 31, charging a raw case 3 being a tire body 1a in the vulcanization metal mold 31, and vulcanizing the land component 5 together with the raw case 3 and coupling them to each other when manufacturing the tire 1 having the land 1b on a tread of the tire 1.

Description

  The present invention relates to a method for manufacturing a tire having a plurality of land portions on a tread, and in particular, unevenness appearing on a tire surface caused by vulcanization when manufacturing the tire, and a carcass ply or belt generated inside the tire. The present invention relates to a method for manufacturing a tire that can effectively reduce the wave (swing, rolling, etc.) of the tire and improve the appearance and performance of the tire.

  In tires attached to agricultural vehicles used in wetlands, soft ground, and construction vehicles traveling on rough terrain, tires with lugs in which a plurality of lugs are formed on a tread are used to obtain traction. Conventionally, as a method of forming a lug on a tire, a vulcanization mold having a recess corresponding to the lug is used, and a raw tire is loaded into the vulcanization mold to perform vulcanization. A method is adopted in which the rubber in the mold is caused to flow into the recess and the lug protrudes from the outer surface of the tire body (see, for example, Patent Document 1).

JP-A-8-156527

  The tire as described above will be described with reference to FIG. The lug tire 41 in the figure has a high height of the lug 45 rising from the outer surface 43 of the tire, so when loading a raw tire into a vulcanization mold and vulcanizing, the vulcanization mold corresponding to the lug At the same time, a large amount of the rubber of the tire body flows into the recess (arrow f in the figure), and the groove portion 47 is strongly pressed against the vulcanization mold. For this reason, large deformation occurs in the periphery of the lug, resulting in irregularities on the tire surface and deterioration in appearance quality, and waves in the belt and carcass ply inside the tire are generated, affecting the durability of the tire. There was a risk of causing.

  In order to suppress surface irregularities and belt and carcass ply waves that occur during vulcanization, measures have been taken by increasing the tread gauge, but this leads to increased vulcanization time and material costs. There has been a demand for a new tire manufacturing method that does not impair the appearance and performance of the tire while suppressing an increase in time and cost for such manufacturing.

  Therefore, the present invention reduces the unevenness appearing on the tire surface and the carcass ply and belt wave generated inside the tire caused by vulcanization when manufacturing a tire having a land portion on the tread, and also improves the performance of the tire. It is an object of the present invention to provide a novel tire manufacturing method that can be improved.

  The present invention has been made in order to solve the above-described problems, and the tire manufacturing method according to the present invention provides an unvulcanized land portion which becomes a land portion when manufacturing a tire having a land portion on a tread of the tire. A step of arranging the constituent members in the vulcanizing mold, a step of loading a raw case serving as a tire body into the vulcanizing die, and a step of vulcanizing the land constituent members together with the raw case and coupling them together It is characterized by having.

  In such a tire manufacturing method, an unvulcanized land component constituting a land portion is placed in a vulcanization mold, and after the raw case is loaded in the vulcanization mold, the land component member is generated. Since it was vulcanized with the case and bonded together, the rubber of the raw case was prevented from flowing into the recess of the vulcanization mold corresponding to the land part of the tire during vulcanization, It is possible to reduce unevenness on the tire surface and waves of the belt and carcass ply. In addition, by using the unvulcanized land portion constituent member, high adhesiveness can be obtained with the raw case serving as the tire body, and durability can be improved.

  In the tire manufacturing method of the present invention, it is preferable to dispose the unvulcanized land portion constituent member in the vulcanization mold by injection. According to this, compared with the case where the unvulcanized land component is disposed manually, the land component can be disposed more uniformly and accurately, and the time can be shortened. Furthermore, after placing the unvulcanized land component by injection, immediately vulcanize, so that it can be transferred from the injection to the vulcanization process in a high temperature state, the vulcanization time can be shortened, It leads to improvement of production efficiency.

  In the tire manufacturing method of the present invention, it is preferable that the radial height of the land portion after manufacturing from the tire body is 25% to 35% of the tire cross-section height SH. A land portion having a desired height without deteriorating the durability of the tire body by the tire manufacturing method of the present invention in which an unvulcanized land portion component and a raw case are respectively placed in a vulcanization mold and vulcanized. Can be formed. The “tire cross-section height SH” here is an industrial standard that is effective in the region where it is used. (Organization) STANDARD MANUAL, in the United States, the tire is assembled to the rim specified in TRA (THE TIRE AND RIM ASSOCIATION INC.) YEAR BOOK etc. This means 1/2 of the difference between the outer shape of the tire and the rim diameter.

  Furthermore, in the tire manufacturing method of the present invention, the land portion is preferably a lug, and the tire is preferably an agricultural lug tire. An agricultural lug-equipped tire has a land portion (lug) that largely protrudes from the tire body, so that the carcass ply and the belt are easily deformed during vulcanization, and the present invention is more effectively applied.

  According to the present invention, it is possible to reduce irregularities appearing on the tire surface and carcass ply and belt waves generated inside the tire caused by vulcanization when manufacturing the tire, and improve the performance of the tire. Thus, a novel tire manufacturing method can be provided.

It is the perspective view which showed the tire with a lug manufactured according to this invention, and the figure which expanded and showed one of these lugs. It is the figure which showed the cross section cut | disconnected by the surface containing the rotating shaft of a tire about the tire with a lug manufactured according to this invention, (a) is sectional drawing which shows the principal part of a tire, (b) is a lug of It is sectional drawing which shows the principal part. It is a perspective view which shows the principal part of the vulcanization die of the tire used by this invention. It is the schematic which shows the mode at the time of vulcanization | cure of the tire with a conventional lug.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an agricultural lug tire which is an example of a tire manufactured according to the present invention. This lug-equipped tire 1 includes a tire main body 1a which is a main portion of the tire, and at least one (here, a plurality of) lugs formed on the outer peripheral surface of the tire main body 1a at intervals along the circumferential direction of the tire. A raw case 3 made of 1b, which is a separately formed tire main body 1a, and a lug constituent member (land constituent member) 5 which becomes a lug 1b are joined together by vulcanization. In addition, the tire manufactured by this invention is not limited to a tire with a lug, What kind of tire may be sufficient if it is a tire which has a land part fundamentally.

  The lug-equipped tire 1 has a conventional tire structure, and specifically, extends in a toroidal shape from the tread portion 7 through the sidewall portion 9 to the bead portion 11 as shown in FIG. In addition, a carcass ply 15 in which ends thereof are wound around a pair of bead cores 13 disposed in the bead portions 11 on both sides, and a belt 17 disposed on the tread portion 7 outside the carcass ply 15 in the tire radial direction, It is what has. An outermost rubber layer 19 is disposed on the outermost side of the tire body 1a. The carcass ply 15 and the belt 17 are formed by embedding a cord such as steel or organic fiber in a predetermined direction on a rubber sheet, and depending on the type of tire, one or a plurality of laminated sheets A sheet is used.

  The raw case 3 that is used in the present embodiment and becomes the tire body 1a after vulcanization will be described. The raw case 3 can be formed by various methods. For example, the carcass ply 15 is wound around a molding drum, the bead cores 13 are attached to both sides of the wound carcass ply 15, and then the belt 17 and the outermost layer rubber are used. 19 can be wound around the top of the carcass ply 15 in order.

  The unvulcanized lug constituent member 5 is formed separately from the raw case 3 that becomes the tire body, as shown in FIG. As a method of forming the lug component 5, for example, it can be formed by an extrusion process using an extruder (not shown). The bottom surface 5a joined to the outermost layer rubber 19 by vulcanization has a shape along the outer peripheral surface so as to fit the outer peripheral surface of the tire body 1a. In this embodiment, as shown in FIG. 1, the lug component 5 has a shape that protrudes radially outward from the curved bottom surface 5a. For example, the shape of the bottom surface may be a rectangular shape. The shape of the land part can be determined. Here, “unvulcanized” includes a semi-vulcanized state that does not reach the degree of vulcanization required for the final product, and is a lug component in a semi-vulcanized state that has been moderately advanced. When is used, it is possible to shorten the time for vulcanization together with the raw case. The degree of vulcanization of the unvulcanized lug component (land component) can be selected according to the type and size of the various members of the tire.

  Here, an apparatus used for vulcanization will be described. The apparatus includes a vulcanizer (not shown) including the upper and lower vulcanization molds 31 shown in FIG. 3 and a bladder (not shown) located at the inner center of the vulcanization mold 31. The vulcanization mold 31 includes an upper mold 31a and a lower mold 31b, and an internal space 33 formed when the upper mold 31a and the lower mold 31b are closed has a shape corresponding to the tire 1 with a lug. In addition to the upper and lower molds, the vulcanization mold to be used can be configured to include a segment. The vulcanizer can select vulcanization conditions (vulcanization time and vulcanization temperature) according to the type and size of the tire.

Hereafter, the manufacturing process of the tire with a lug in this embodiment is demonstrated.
First, the above-described unvulcanized lug component 5 is manually placed in a tire vulcanization mold 31 shown in FIG. In the internal space 33 of the vulcanizing mold 31, a recess 33a is formed at a portion corresponding to the lug 1b, and the unvulcanized lug component 5 having appropriate flexibility has no gap in the recess 33a. Inserted.

  Next, the raw case 3 is loaded into the vulcanization mold 31. At this time, since the bladder is contracted, the loading of the raw case 3 is not hindered. Thereafter, the vulcanization mold 31 is closed and vulcanization is performed under predetermined vulcanization conditions. During vulcanization, the bladder swells from the inside of the raw case 3, expands the raw case 3, and presses the outer peripheral surface of the raw case 3 against the bottom surface 5a of the lug component 5, so that they can be coupled to each other.

  When the raw tire is loaded into a vulcanization mold and vulcanized without separating the lug constituent members as in the prior art, the rubber of the tire body is placed in the recess of the vulcanization mold corresponding to the lug. However, in accordance with the present invention, the lug component 5 and the raw case 3 are loaded into the vulcanization mold 31 and vulcanized in accordance with the present invention. Since the bonding of both proceeds gradually during vulcanization, the raw case 3 can be expanded uniformly, suppressing the waves of the carcass ply 15 and the belt 17 and preventing the unevenness of the tire surface from occurring. it can. Further, since the rubber of the raw case 3 is prevented from flowing into the recess 33a corresponding to the lug, the gauge of the tire body can be easily controlled.

  As another embodiment of the present invention, a method for manufacturing a tire with lugs in which unvulcanized lug components are automatically arranged from the outside of a mold by injection (injection) will be described.

  Although not shown in the drawings, the apparatus used in this embodiment is formed on the wall surface of the recess corresponding to the lug of the mold, and injects unvulcanized rubber into the recess of the mold to form the lug component (land portion It includes upper and lower molds having injection holes for disposing constituent members.

  In the tire manufacturing process of the present embodiment, first, a raw case having the same configuration as that of the above-described embodiment is loaded into a mold, and the mold is closed. Next, pressure is applied from the inside by the bladder to press the outer surface of the raw case against the mold, and in the space corresponding to the lug of the tire after manufacture, surrounded by the outer surface of the raw case and the recess of the mold, Injecting unvulcanized rubber by injection from the injection hole formed in the mold, placing the unvulcanized lug component, and then vulcanizing to bond the raw case and the lug component to each other It is.

  According to the manufacturing method of the present embodiment, by placing the lug constituent member in the vulcanization mold by injection, the step of forming the lug constituent member of a predetermined shape in advance as in the method of the previous embodiment can be omitted. It becomes possible to manufacture a tire more efficiently. In addition, the vulcanization time is shortened by starting the vulcanization before the temperature of the unvulcanized lug components injected into the mold drops and joining the raw case and the lug components together. can do.

  By using the tire manufacturing method according to the present invention described above, a tire having a land portion having a desired shape can be manufactured without reducing the durability of the tire. Further, the land portion and the tire body can be made of different materials. For example, in a manufactured tire, a high traction performance is obtained when the radial height h of the lug from the outer surface of the tire body shown in FIG. 2 (a) is 25% to 35% of the tire cross-section height SH. be able to. Further, the traction performance can be enhanced by selecting a material so that the rubber hardness of the lug (land portion) after manufacture is higher than the rubber hardness of the outermost layer rubber of the tire body. Furthermore, if foam rubber is used for the outermost layer rubber of the lug or the tire body, it is possible to reduce adhesion of mud and the like to the tire when traveling in a place with a lot of moisture such as mud.

  The tire manufacturing method of the present invention can be applied to any tire having a land portion, but is particularly effective in a tire having a particularly high land portion height, such as an agricultural lug tire. It is.

  According to the present invention, it is possible to effectively reduce irregularities appearing on the tire surface and carcass ply and belt waves generated inside the tire caused by vulcanization when manufacturing a tire having a tread portion, and the performance of the tire. It is possible to stably supply new tires with improved performance.

1 tire (lug tire)
1a Tire body
1b Rug (Land)
3 Raw case 5 Lug component (land component)
7 Tread part 9 Side wall part
11 Bead section
13 Beadcore
15 Carcass ply
17 belt
19 Outermost layer rubber
31 Vulcanizing mold
33 Internal space

Claims (4)

In manufacturing a tire having a land portion on the tread of the tire,
Arranging unvulcanized land part components to be land parts in a vulcanization mold;
Loading a raw case to be a tire body into the vulcanization mold;
A method of manufacturing a tire, comprising the step of vulcanizing the land component members together with the raw case to bond them together. The unvulcanized land part component is placed in a vulcanization mold by injection,
The tire manufacturing method according to claim 1.   The method for manufacturing a tire according to claim 1 or 2, wherein a radial height from the tire body of the land portion after manufacture is 25% to 35% of a tire cross-section height SH.   The tire manufacturing method according to any one of claims 1 to 3, wherein the land portion is a lug, and the tire is an agricultural lug tire.

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