JP4467332B2 - Raw tire molding method and pneumatic tire - Google Patents

Description

The present invention has the inner liner, a pneumatic tire manufactured by forming type method and a method of green tire comprising a two or more carcass plies disposed on its outer side, and an inner liner, top The present invention proposes a technique for preventing air confinement between an inner layer carcass ply and between adjacent carcass plies and preventing an unexpected decrease in the thickness of the inner liner.

  For example, when the inner liner and each of the two or more carcass plies are sequentially laminated directly or indirectly on the tire molding drum with or without the squeegee rubber, the inner liner is formed. If the joints of the rubber material in the circumferential direction and the joints of the cord material for forming the innermost carcass ply overlap in the radial direction of the green tire, the green tire is vulcanized and molded. In the product tire, there is a problem that an air confinement residue is generated between both joints or a thickness is reduced in the inner liner joint, and this air confinement residue is disposed adjacent to each other. The problem also occurs when the cord material joints are arranged radially overlapping between the carcass plies installed There was.

  In order to solve such a problem, it is effective to assist the escape of containment air during vulcanization molding of a raw tire by forming a small hole in the overlapping portion of the joint by piercing.

  By the way, in recent years, for example, for the purpose of improving the uniformity of product tires, improving the static and dynamic balance, the joints in the circumferential direction of the rubber material for the inner liner and the cord material for the carcass ply are artificially made. From this point of view, if the circumferential dimension of each material is reduced to increase the number of joints, the joints will overlap in the radial direction. In order to prevent the overlap, the joints of the inner and outer adjacent layers are connected to each other in the circumferential direction, for example, within the range of the pitch length on the basis of one material pitch length. In addition, when positive displacement is performed with a displacement amount corresponding to the number of stacked layers, uniformity and the like can be further improved.

  However, even in this case, the relative distance in the circumferential direction of each joint portion of the inner and outer adjacent layers is coupled with the narrowing of the pitch length of the material, that is, the unit length in the circumferential direction. Since the size is inevitably small, there is a high risk that unintended overlap in the radial direction occurs between the joint portions of adjacent layers due to accumulation of manufacturing errors, joining errors, and the like.

  And once such overlap has occurred, it is very difficult to pinpoint the exact location, so even if you try to deal with it with piercing processing, This was practically impossible unless piercing was applied to all the joints.

Therefore, the present invention is a tire molding method capable of effectively preventing the material joints of the inner and outer adjacent layers from overlapping in the radial direction while reducing the circumferential length of the material, that is, the material pitch length, and A pneumatic tire manufactured by the method is provided.

The method for molding a raw tire according to the present invention includes a rubber material for forming an inner liner and a carcass ply for molding an inner liner layer and a tire having two or more carcass plies disposed on the outer layer side thereof. The inner circumferential liner adjacent to the inner circumference side of the cord material forming the innermost layer of the carcass ply is made the same in the circumferential length of the cord material forming the innermost carcass ply. A similar joint of the rubber material to be formed is positioned by being displaced in the circumferential direction over a distance that is half the circumferential length of the rubber material, and disposed on the outer peripheral side of the innermost carcass ply. Each cord material forming one or more carcass plies in the circumferential direction corresponds to the inner liner rubber material joints alternately from the inner layer side. The circumferential position, is in is positioned on each of the corresponding circumferential position as the junction of the cord material for the innermost layer of the carcass ply.

  Here, preferably, the number of joint portions in the circumferential direction of the rubber material for the inner liner and all the materials of the respective carcass ply cords is four or more.

  Moreover, it is preferable that the joining of the rubber material for the inner liner is performed by connecting the inclined surfaces that form the overlapping surface contact between the inclined surfaces.

  By the way, it is preferable that the circumferential length of each material before joining is a length obtained by adding the joining margin length between the materials to a length that is an integral multiple of 1 inch.

  The pneumatic tire according to the present invention is manufactured according to any one of the methods described above.

In the method according to the present invention, the rubber material that forms the inner liner and the circumferential length of each cord material that forms the carcass ply are both equal, and the joint portion of the innermost carcass ply cord material is With respect to the joint portion of the rubber material, the rubber material is displaced in the circumferential direction over a distance that is half the circumferential length of the rubber material, so that both the joint portions in the circumferential direction of the raw tire By maximizing the relative separation distance, the overlap in the radial direction between the rubber material joint and the cord material joint in the raw tire can be reduced to the presence or absence of manufacturing errors and joining errors of the rubber material and cord material. Regardless, it can be sufficiently prevented.

Therefore, according to this, in the product tire, it is possible to the inner liner and with sufficiently eliminate the risk of containment of air into between the innermost carcass ply, the inner liner, to sufficiently prevent thinning at the junction .

  Here, the rubber material for the inner liner is formed by alternately connecting the circumferentially connecting portions of the respective cord materials forming one or more carcass plies arranged on the outer peripheral side of the innermost carcass ply. Between each carcass ply adjacent to the inside and outside by being positioned at each of the circumferential position corresponding to the joint portion and the circumferential position corresponding to the joint portion of the cord material for the innermost layer carcass ply, The relative position of the cord material joints can also be separated most in the circumferential direction, and such relative spacing is still sufficiently large due to the production error and joining error of the cord material of each carcass ply. Therefore, it is possible to sufficiently prevent air from remaining between the carcass plies in the product tire.

Here, when the joint material in the circumferential direction of the rubber material for the inner liner and the cord material for each carcass ply is set to four or more in the circumferential direction, the above-described effects are sufficiently secured, Based on increasing the number of joints, it is possible to improve the uniformity of the product tire, improve the static and dynamic balance, and the like.

By the way, when connecting the rubber material for the inner liner to the inclined surface connecting the inclined surfaces to each other, it is possible to sufficiently prevent the occurrence of protrusions caused by the bonding of the rubber material. It can get rid of it up for containment of air into between the innermost carcass ply to more advantageously, together, under the securing large inclined contact surface, to ensure sufficient bonding strength of the rubber material it can.

By making the circumferential lengths of the inner liner rubber material and the carcass ply cord material equal to each other, the predetermined positioning of the joint portions of the respective cord materials with respect to the joint portions of the inner liner rubber material, etc. Can be performed easily and reliably.

Embodiments of the method according to the present invention will be described below based on the drawings.
FIG. 1 shows an embodiment of the method of the present invention, in which the inner drum and two carcass plies are laminated on the molding drum to form a cylindrical carcass band as a whole. It is a principal part cross-sectional perspective view which follows a direction.

In the figure, 1 shows a molding drum having a cylindrical shape capable of expanding and contracting the diameter in a diameter-enlarging posture, 2 is an inner liner adhered on the peripheral surface of the molding drum 1, and 3 Reference numerals 4 denote carcass plies on the inner layer side and the outer layer side, which are sequentially attached to the outer peripheral side of the inner liner 1 with or without a squeegee rubber.
Here, the carcass ply may be a plurality of layers of three or more layers.

By the way, as shown in this figure, the rubber material 2a forming the inner liner 2, the cord materials 3a and 4a for forming the respective carcass plies 3 and 4, more precisely, linearly or zigzag extending in parallel. The lengths in the circumferential direction of the molding drum 1 in each of the cord / rubber composites obtained by applying rubber coating to a plurality of cords to be arranged are both equal length l.
Therefore, these materials 2a, 3a, 4a have a uniform length l even before being attached to the molding drum 1.

Note that the length l of the rubber material 2a that form formed on both sides portions of the circumferentially inclined surface in the figure, in which the sticking previous flat posture, the midpoint distance between each of the inclined surfaces 2b, in other words For example, the length of the neutral shaft under the curved posture on the drum is taken.

  Here, the equal length l is an integer multiple of 1 inch plus the joint allowance length between the materials. There is an advantage that only one type of material 2a, 3a, 4a having a length l can be dealt with.

  Here, first, the rubber material 2a having such a length l in the circumferential direction is adhered to the circumferential surface of the drum 1 in an extending posture in the central axis direction of the molding drum 1 and adjacent to each other. The rubber materials 2a are joined to each other without any unevenness in and out of the radial direction by connecting the inclined surfaces that are in contact with each other on the overlapping surfaces of the inclined surfaces, and the rubber material 2a is joined over the entire circumference of the molding drum 1. Thus, the inner liner 2 that is continuous in a cylindrical shape is formed.

  After that, on the outer peripheral surface of the inner liner 2, the cord materials 3 a adjacent to each other are joined together by overlapping each other under an extending posture in the drum axis direction, and joining caused thereby The portion 5 is positioned with respect to the joining portion 6 of the rubber material 2a by being displaced in the circumferential direction over a distance l / 2 that is half the circumferential length l of the rubber material 2a. The endless inner layer side carcass ply 3 is sufficiently separated from the inner liner 2 by separating them and performing these operations over the entire circumference of the drum 1 to sufficiently prevent the joining portion 5 from overlapping with the joining portion 6 in the radial direction. Are laminated.

  Further, on the outer peripheral surface of the inner layer side carcass ply 3, the cord materials 4 a that also extend in the drum axial direction are joined to each other by overlap joining, and the joining portion 7 formed by this is joined. By positioning the rubber material 2a at the circumferential position corresponding to the joint portion 6, the joint portion 7 is most separated from the joint portion 5 generated in the inner layer side carcass ply 3, which is directly connected to the molding drum 1. Specifically, the outer layer side carcass ply 4 having a cylindrical shape as a whole is laminated on the inner layer side carcass ply 3 by repeating over the entire circumference of the inner layer side carcass ply 3.

  When the inner liner 2 and the inner and outer carcass plies 3 and 4 are formed in this way, as described above, the joint 5 is located at the position farthest from the joint 6, and the joint 7 is Since they are located at the positions farthest from the joint 5, some manufacturing errors occur in the respective materials 2 a, 3 a, 4 a, and there are some in the joining of these respective materials 2 a, 3 a, 4 a. Even if a minute error occurs, it is possible to sufficiently prevent the overlapping of the respective joint portions of the inner and outer adjacent layers in the radial direction, which is the same as that of the respective materials 2a, 3a, 4a themselves. This is the same regardless of the length in the circumferential direction.

  Therefore, when the carcass band 8 is configured in this manner, air can be sufficiently prevented from being contained between the joint portions of the inner and outer adjacent layers in the product tire, and the joint portion 6 of the inner liner 2 can be prevented. Can be effectively prevented.

  By the way, the carcass band 8 shown in the figure is often transferred to another molding drum under the reduced diameter deformation of the molding drum 1, where other tire constituent members are attached, shaped, inflated, and the like. It is applied and molded into the required raw tire.

  The case where the inner and outer two carcass plies 3 and 4 are formed has been described above. However, when three or more carcass plies are provided, the respective carcass disposed further outside the outer layer side carcass ply 4 is described. For the ply, the cord material joints are alternately arranged from the inner layer side toward the outer layer side, the circumferential position corresponding to the joint portions 5 of the inner layer side carcass ply cord material 3a, and the rubber material for the inner liner. It is located in a circumferential position corresponding to the joint portion 2a of 2a, thereby sufficiently preventing the joint portion from overlapping inside and outside in the radial direction.

It is a principal part section perspective view showing an embodiment of a method concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding drum 2 Inner liner 2a Rubber material 2b Inclined surface 3 Inner layer side carcass ply 3a, 4a Code material 4 Outer layer side carcass ply 5, 6, 7 Joint 8 Carcass band l Length

Claims (4)

Inner liner and, per the raw tire having a two or more carcass plies disposed on the outer side to adult-type,
The rubber material forming the inner liner and the cord material forming the carcass ply are both equal in circumferential length, and the cord material forming the innermost carcass ply is connected in the circumferential direction. The innermost layer of the rubber material, which forms an inner liner adjacent to the inner circumference of the rubber material, is displaced in the circumferential direction over a distance that is half the circumferential length of the rubber material. Each of the cord materials forming one or more carcass plies disposed on the outer peripheral side of the carcass ply is joined in the circumferential direction alternately from the inner layer side to the inner liner rubber material joint. A method for molding a green tire that is positioned at each of a corresponding circumferential position and a circumferential position corresponding to a joint portion of the innermost carcass ply cord material.   The method for molding a raw tire according to claim 1, wherein the number of joint portions in the circumferential direction of the rubber material for the inner liner and the cord material for each carcass ply is four or more.   The method for molding a raw tire according to claim 1 or 2, wherein the joining of the rubber material for the inner liner is performed by connecting the inclined surfaces that are in contact with each other on the overlapping surfaces of the inclined surfaces. A pneumatic tire comprising manufactured by any of the molding process according to claim 1-3.

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