JP2012011690A - Tire vulcanizing mold and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire vulcanizing mold which can sufficiently suppress the uneven wear of a vulcanized tire while preventing the separation, breakage or the like on vulcanizing release of blades for a sipe arranged adjacently at the division position of a sectional mold, and to provide a pneumatic tire.SOLUTION: Regarding the tire molding face 2 of a sector 1, in blades 5a, 5b for sipes projectingly provided in a circumferential direction at a prescribed pitch, about the blade 5b for a sipe arranged adjacently to the division position PL of the sector 1, a turning point P is provided between either edge A on the side far from the division position PL of the sector 1 and the other edge B on the side near from the division point PL, the part in a space from the turning point P to either edge A is made to lie as an original shape, the part in a space from the turning point P to the other edge B is changed to a direction farther from the division position PL than the original shape, and the length L1 from the turning point P to the other edge B is controlled to ≤1/2 of the whole length of the blade 5a for a sipe with an original shape.

Description

  The present invention relates to a tire vulcanization that can sufficiently suppress uneven wear of a vulcanized tire while preventing sipe blades arranged adjacent to a divisional position of a sectional mold from being detached or damaged during vulcanization. The present invention relates to a sulfur mold and a pneumatic tire.

  In recent years, grooves of various shapes are provided in the tread and sipes are provided in the block surface for the purpose of improving various performances of the tire. On a tire molding surface of a tire vulcanization mold for manufacturing such a tire, a sipe blade made of a metal such as stainless steel for molding a sipe is projected along with an aluminum groove forming projection for forming a groove. For example, as shown in FIG. 6, groove forming projections 3 and sipe blades 4, 5 project from the tire molding surface 2 of the sector 1 of the sectional type vulcanization mold. Since the sipe blades 4 and 5 are projected in a direction perpendicular to the tread surface of the tire (that is, a direction perpendicular to the tire molding surface 2), the sipe blades 4 and 5 are projected from the circumferential center of the tire molding surface 2 of the sector 1. The sipe blade 4 is oriented in a direction substantially parallel to the expansion / contraction movement direction of the sector 1, but the direction of the sipe blade 5 provided in the vicinity of the division position PL of the sector 1 (both ends in the circumferential direction of the sector 1) is The direction of expansion / contraction movement of sector 1 is not parallel and has a certain degree of angle. Therefore, an external force (bending moment) is likely to act on the sipe blade 5 projecting in the vicinity of the division position PL of the sector 1 when releasing the vulcanized tire by moving the sector 1 in diameter. Become. Therefore, in the vicinity of the division position PL of the sector 1, the closer to the division position PL, the more easily the sipe blade 5 is detached and damaged from the tire molding surface 2 by an unnecessary external force, and the tire at the root of the sipe blade 5 There was a problem that the molding surface 2 was easily damaged.

  In order to solve such a problem, a tire vulcanization mold has been proposed in which a sipe blade protruding at a position adjacent to a sector division position is rearranged so as to be separated from the sector division position. (For example, refer to Patent Documents 1 and 2). In these proposals, since the target sipe blades are rearranged as a whole, the change in the block rigidity of the vulcanized tire between the areas where the sipe blades are rearranged and the areas where the sipe blades are not rearranged. Becomes larger. Therefore, there has been a problem that uneven wear of the tire cannot be sufficiently suppressed.

JP 2002-292640 A JP 2007-44946 A

  An object of the present invention is to sufficiently suppress uneven wear of a vulcanized tire while preventing separation or breakage of a sipe blade disposed adjacent to a divisional position of a sectional mold during vulcanization release. The object is to provide a tire vulcanization mold and a pneumatic tire.

  In order to achieve the above object, a tire vulcanization mold of the present invention is a sectional type tire vulcanization mold provided with sipe blades protruding at a predetermined constant pitch in a circumferential direction on a tire molding surface of a sector. The sipe blade disposed adjacent to the division position of the sector is provided with a turning point in the middle of the sipe blade in the length direction. The part between one end on the far side and the turning point remains in the original shape, and the part between the other end on the side closer to the dividing position and the turning point is divided from the original shape. The length from the turning point to the other end is made to be ½ or less of the total length of the original sipe blade.

  The pneumatic tire of the present invention is characterized by being vulcanized using the tire vulcanization mold described above.

  According to the present invention, for the sipe blade arranged adjacent to the division position of the sector, a turning point is provided in the middle of the sipe blade in the length direction, and among the both ends in the length direction of the sipe blade, The portion between one end on the side far from the division position and the turning point remains the original shape, and the portion between the other end near the division position and the turning point is the original shape. Further, since it is changed in a direction away from the division position, an unnecessary external force acting on the sipe blade when releasing the vulcanized tire can be reduced. As a result, it is possible to prevent sipe blades arranged adjacent to the sector division positions from being detached or damaged. In addition, the length from the turning point to the other end is less than half of the total length of the original sipe blade, and only the shape (arrangement) of a part of the sipe blade is changed. The change in the block rigidity of the vulcanized tire can be reduced as compared with the case where the sipe blades are all arranged and changed. Therefore, uneven wear of the tire can be sufficiently suppressed.

  The shortest distance from the sipe blade arranged adjacent to the division position of the sector to the division position is, for example, 1.5 mm to 3.0 mm. According to this specification, it is possible to ensure a good balance between prevention of detachment and breakage of the sipe blade disposed adjacent to the sector division position and suppression of uneven wear of the tire.

  For example, the length from the turning point to the other end is set to 1/3 or less of the total length of the original sipe blade. According to this specification, since the change in the block rigidity of the vulcanized tire becomes smaller, it becomes more advantageous for suppressing uneven wear of the tire.

  The sipe blade arranged adjacent to the division position of the sector has 1 to 10 bending points in a portion between the turning point and the other end, and the bending angle thereof is 30 ° or more and 175 °. The following specifications can also be made.

It is a top view which illustrates partially expanding the tire molding surface of the mold for tire vulcanization of the present invention. It is a top view which illustrates the circumference | surroundings of the blade for sipe arrange | positioned adjacent to the division | segmentation position of a sector. It is a top view which illustrates the block of the tire vulcanized using the mold of Drawing 1. It is a top view which shows the modification of the blade for sipe of FIG. It is a top view which shows the modification of the blade for sipe of FIG. It is a side view which illustrates a sector.

  Hereinafter, the mold for tire vulcanization of the present invention is explained based on the embodiment shown in the figure.

  The tire vulcanization mold of the present invention (hereinafter referred to as a mold) is of a sectional type as illustrated in FIG. 6 and includes a plurality of arc-shaped sectors 1 that are assembled to form an annular shape. Each sector 1 moves in the radial direction of the ring so as to expand and contract the ring.

  As illustrated in FIGS. 1 and 2, the sipe blades 5a and 5b protruding from the tire molding surface 2 are arranged at a predetermined constant pitch in the circumferential direction of the sector 1 (left and right in FIGS. 1 and 2). ing. The sipe blades 5a and 5b are made of metal such as stainless steel, general carbon steel, and iron. Although the size of the sipe blades 5a and 5b varies depending on the tire size, the total length L is, for example, 3 mm to 100 mm, and the thickness C is, for example, about 0.4 mm to 2.0 mm.

  In this embodiment, a circumferential groove forming protrusion 3 a and a width direction groove forming protrusion 3 b are projected from the tire forming surface 2. The sector 1 and the groove forming projections 3a and 3b are an integral body cast from a metal such as aluminum. Both ends of each sipe blade 5a, 5b are embedded in the circumferential groove forming projection 3a. The circumferential groove forming protrusion 3a and the width direction groove forming protrusion 3b protrude upward from the tire forming surface 2 relative to the sipe blades 5a and 5b.

  In the present invention, the shape (arrangement) of the sipe blade 5b disposed adjacent to the division position PL of the sector 1 is partially changed. The sipe blade 5b arranged adjacent to the division position PL is the portion closest to the division position PL and the division position when the sipe blades 5a and 5b are arranged at a predetermined constant pitch in the circumferential direction of the sector 1. This refers to the sipe blade 5b in which the interval cannot be secured with the PL, that is, the interval is zero or less.

  The shape of the sipe blade 5a arranged on the side away from the division position PL at a predetermined constant pitch in the circumferential direction of the sector 1 is called an original shape.

  A turning point P is provided in the longitudinal direction of the sipe blade 5b disposed adjacent to the division position PL. The turning point P is a point where the direction of the blade changes from that point. Of the longitudinal ends A and B of the sipe blade 5b, the portion between the one end A far from the dividing position PL and the turning point P remains in the original shape. A portion between the other end B near the division position PL and the turning point P is changed in a direction away from the division position PL rather than the original shape. The length L1 from the turning point P to the other end B is ½ or less of the total length L of the original sipe blade 5a. In FIGS. 1 and 2, a case where the sipe blade 5b has an original shape is indicated by a two-dot chain line.

The tire 6 vulcanized using the sector 1 becomes a tread as illustrated in FIG.
The tread is formed with a circumferential groove 8a formed by the circumferential groove forming protrusion 3a and a width direction groove 8b formed by the width direction groove forming protrusion 3b, and the circumferential groove 8a and the width direction groove 8b. As a result, the block 7 is formed. In the block 7, sipes 9a and 9b are formed by sipes blades 5a and 5b.

  As described above, the turning point P is provided in the middle of the sipe blade 5b in the length direction, and a part thereof is deformed to increase the shortest distance H between the sipe blade 5b and the division position PL. The thickness from the blade 5b to the dividing position PL is increased. Therefore, when the tire 6 vulcanized in the sector 1 is released, resistance to unnecessary external force acting on the sipe blade 5b is increased. Therefore, it is possible to prevent the sipe blade 5b from being detached or damaged, the damage to the tire molding surface 2 at the root of the sipe blade 5b, and the like.

  Further, the length from the turning point P to the other end B is set to ½ or less of the total length L of the original sipe blade 5a. That is, since only a part of the shape (arrangement) of the sipe blade 5b is changed, the block rigidity of the vulcanized tire 6 can be improved as compared with the case where the sipe blades 5b are all changed. Change can be reduced. Therefore, uneven wear of the tire 6 can be sufficiently suppressed.

  If the length from the turning point P to the other end B is 1/3 or less of the total length L of the sipe blade 5a having the original shape, the change in the block rigidity of the vulcanized tire 6 becomes smaller. It is more advantageous to suppress uneven wear.

  The shortest distance H from the sipe blade 5b arranged adjacent to the division position PL of the sector 1 to the division position PL is preferably, for example, 1.5 mm or more and 3.0 mm or less. By setting the shortest distance H within this range, it is possible to ensure a good balance between prevention of detachment and breakage of the sipe blade 5b and suppression of uneven wear of the vulcanized tire 6.

  A plurality of turning points P may be provided. In this case, the length L1 from the turning point P farthest from the other end B to the other end B is less than or equal to 1/2 of the total length L, or 1/3. Below. For example, when two turning points P are provided, the other end B side of the sipe blade 5b is deformed in two steps in a direction away from the division position PL.

  The sipe blades 5a and 5b are not limited to a simple linear shape, but may have a zigzag specification having a plurality of bending points P1 as illustrated in FIG. Also in this specification, the portion between the turning point P and the one end A of the sipe blade 5b is left in the original shape, and the portion between the turning point P and the other end B is divided into positions PL than the original shape. Change the direction away from. The length L1 (the length L1 along the shape of the sipe blade 5b) from the turning point P to the other end B is the total length L (the total length along the shape of the sipe blade 5a) of the original shape sipe blade 5a. L) or less, or 1/3 or less of L). Also in this specification, it is preferable that the shortest distance H from the sipe blade 5b to the division position PL is 1.5 mm or more and 3.0 mm or less.

  In the case of this specification, for example, 1 to 10 bending points P1 are provided in a portion between the turning point P and the other end B, and the bending angle a is set to 30 ° to 175 °. All the bending angles a can be the same, or different bending angles a can be mixed.

  In the sipe blade 5b illustrated in FIG. 4, the space between the respective bending points P1 is linear, but may be curved. In the case of a curve between the bending points P1, the bending angle a is defined by approximating a straight line. In addition, a point that is substantially bent (a point equivalent to the bending point) even if no clear corner is continuously formed in the curve is regarded as the bending point P1, and the bending angle a is defined.

  In the embodiment described above, both ends A and B of the sipe blade 5b are embedded in the circumferential groove forming protrusion 3a. However, as illustrated in FIG. 5, both ends A and B of the sipe blade 5b are groove forming protrusions. The present invention can also be applied to the case where it is not embedded in 3a. The present invention can also be applied to the case where any one end of the sipe blade 5b is not embedded in the groove forming projection 3a.

DESCRIPTION OF SYMBOLS 1 Sector 2 Tire shaping | molding surface 3 Groove shaping | molding protrusion 3a Circumferential groove shaping protrusion 3b Width direction groove shaping protrusion 4, 5, 5a, 5b Sipe blade 6 Vulcanized tire 7 Block 8a Circumferential groove 8b Width direction groove 9a, 9b Sipe

Claims (5)

In the tire vulcanization mold of the sectional type provided with sipe blades protruding at a predetermined constant pitch in the circumferential direction on the tire molding surface of the sector,
For the sipe blade arranged adjacent to the division position of the sector, a turning point is provided in the middle of the sipe blade in the length direction, and the far end of the sipe blade in the length direction is far from the division position. The portion between the one end on the side and the turning point remains the original shape, and the portion between the other end on the side closer to the dividing position and the turning point is the dividing position than the original shape. The tire vulcanization mold is characterized in that the length from the turning point to the other end is set to ½ or less of the total length of the original sipe blade.   2. The tire vulcanization mold according to claim 1, wherein a shortest distance from a sipe blade disposed adjacent to the division position to the division position is 1.5 mm or more and 3.0 mm or less.   3. The tire vulcanization mold according to claim 1, wherein a length from the turning point to the other end is equal to or less than ３ of a total length of the original sipe blade.   The tire addition according to any one of claims 1 to 3, wherein the portion between the turning point and the other end has 1 to 10 bending points, and the bending angle is not less than 30 ° and not more than 175 °. Mold for sulfur. A pneumatic tire vulcanized using the tire vulcanization mold according to claim 1.

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