JP4052386B2 - Tire mold and method of manufacturing pneumatic tire using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire mold and a method of manufacturing a pneumatic tire using the same, and more specifically, a sectional type tire mold that suppresses deformation of a sipe molding blade that extends to a sector division position and the same. The present invention relates to a method for manufacturing a pneumatic tire using a rubber.
[0002]
[Prior art]
Generally, a sectional type tire mold includes a sector in which a side mold is divided into a plurality of parts between upper and lower molds. In a sectional type tire mold used to manufacture tires with sipes on land such as blocks and ribs, a sipe molding blade is projected on the molding surface of the sector. Often, a sipe forming blade of a book extends to a sector division position and further extends to adjacent sectors.
[0003]
Thus, when a tire is manufactured with a tire mold having a sipe molding blade extending to the sector division position, the sipe molding blade may be deformed when the mold is released after vulcanization because it is very thin, It must be corrected each time.
[0004]
Therefore, conventionally, as a countermeasure, for example, a technique has been proposed in which the height of the sipe forming blade at the sector division position is lowered to make it difficult to deform (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 3004776 [0006]
[Problems to be solved by the invention]
However, if the height of the sipe forming blade is lowered as described above, the sipe depth formed in the land portion of the tread surface becomes shallower than other sipe, so that the sipe characteristics that should be originally cannot be maintained. There was a problem. There is also a problem that the appearance of the tread pattern changes remarkably when the tread surface is worn early (the shallow sipe is lost due to wear).
[0007]
An object of the present invention is to provide a tire mold capable of maintaining good sipe characteristics and suppressing deformation of a sipe forming blade without causing an appearance change of a tread pattern due to wear, and a pneumatic tire using the same It is in providing the manufacturing method of.
[0008]
[Means for Solving the Problems]
The tire mold of the present invention that achieves the above object is a sectional type tire mold in which a sipe molding blade that extends to a sector division position is directly provided on a molding surface of a plurality of divided sectors, and one of the sipe molding blades A reinforcing portion made of a metal plate is provided only on the side surface of the sipe forming blade adjacent to the sector dividing position, and the reinforcing portion extends in the width direction of the sipe forming blade from the sector dividing position, while the height of the sipe forming blade extends from the molding surface of the sector. It extends in the vertical direction and has a thickness equal to or less than the thickness of the sipe forming blade .
[0009]
The pneumatic tire manufacturing method of the present invention is characterized by manufacturing a pneumatic tire using the tire mold.
[0010]
According to the above-described present invention, the sipe forming blade can be effectively reinforced by the reinforcing portion provided on the side surface of the sipe forming blade adjacent to the sector division position, so that the height of the sipe forming blade is not lowered. The deformation of the sipe molding blade at the time of mold release can be suppressed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0012]
FIG. 1 shows an example of a tire mold according to the present invention. This sectional type tire mold has annular upper and lower molds 1 and 2 and an annular side mold 3 disposed therebetween, and the side mold 3 is composed of sectors 4 divided into a plurality.
[0013]
The upper mold 1 has a molding surface 1a for molding one side portion of the tire on the lower surface. The lower mold 2 includes a molding surface 2a for molding the other side portion of the tire on the upper surface. Upper and lower bead rings B <b> 1 and B <b> 2 for forming a bead portion of a tire are provided on the inner peripheral side of the upper mold 1 and the lower mold 2. Each sector 4 has a molding surface 4a for molding the tread portion of the tire on the inner peripheral surface.
[0014]
On the molding surface 4 a of the sector 4, a plurality of groove forming blades 5 for forming circumferential grooves on the tread surface are projected along the circumferential direction of the side mold 3, and on the molding surface 4 a between the groove forming blades 5 , A plurality of sipe forming blades 6 are provided so as to protrude directly . The sipe forming blade 6 extends obliquely between the groove forming blades 5 at the same height, and a part of the sipe forming blade 6X extends to the sector division position X as shown in FIG. One sipe is formed in cooperation with the four sipe forming blades 6X.
[0015]
A reinforcing portion 7 made of a metal plate P is fixedly provided adjacent to the sector division position X only on one side surface of each sipe forming blade 6X. The reinforcing portion 7 is provided so as to extend from the sector division position X in the width direction of the sipe forming blade 6X and to extend from the forming surface 4a in the height direction of the sipe forming blade 6X .
[0016]
In this way, by providing the reinforcing portion 7 made of the metal plate P adjacent to the sector division position X on the side surface of the sipe forming blade 6X to reinforce the sipe forming blade 6X, the height of the sipe forming blade is not lowered. The deformation of the sipe molding blade 6X at the time of mold release can be suppressed. Therefore, it is possible to suppress deformation of the sipe forming blade 6X without impairing the sipe characteristics that should be originally provided and without causing a change in the appearance of the tread pattern due to wear.
[0017]
In the present invention, the height h of the reinforcing portion 7 is preferably set to a position that is 1/4 to 1/2 times the height H of the sipe molding blade 6X from the molding surface 4a. If the height h of the reinforcing portion 7 is lower than 1/4 times the height H of the sipe forming blade 6X, it is difficult to obtain effective reinforcement. Conversely, if the height h exceeds 1/2 times, the sipe characteristics are deteriorated. Invite.
[0018]
The length m of the reinforcing portion 7 along the direction in which the sipe forming blade 6X extends is set to be ¼ to ½ times the length M of the sipe forming blade 6X from the sector division position X. It is good to do. If the length m of the reinforcing portion 7 is shorter than 1/4 times the length M of the sipe forming blade 6X, it is difficult to obtain a good reinforcing effect. Conversely, if the length m exceeds 1/2 times, it is not preferable in terms of sipe characteristics. . The length m of the reinforcing portion 7 and the length M of the sipe forming blade 6X are the lengths measured on the center lines O and O ′ passing through the center in the thickness direction as shown in the figure.
[0019]
The thickness t of the reinforcing portion 7, shall be the following thickness T of the sipe molding blade 6X in terms of the sipe characteristics. As the lower limit value, various values can be taken depending on the material of the reinforcing portion 7, but the same material as the sipe forming blade, that is, the sipe forming blade is generally formed of stainless steel. It is preferable from the viewpoint of the reinforcing effect that the thickness T is 6 times or more of 6X.
[0020]
As shown in FIG. 3, the reinforcing portion 7 described above has a thickness which is integrally formed into a plate shape with the same material as the sipe forming blade 6X only on one side surface of the sipe forming blade 6X, as shown in FIG. You may make it comprise from the meat part 10. FIG.
[0021]
The principal part of the pneumatic tire manufactured using the tire metal mold | die mentioned above in FIG. 4 is shown. A plurality of circumferential grooves 22 extending along the tire circumferential direction C are provided on the tread surface 21, and a plurality of sipes 23 are formed in land portions 24 formed between the circumferential grooves 22. The sipe 23 communicates with the circumferential groove 22, and the sipe 23X straddling the sector division position X has a configuration in which a wide portion 23Xa is formed at an intermediate portion of the sipe 23X corresponding to the position.
[0022]
In a pneumatic tire having such a sipe 23X, the tire mold is attached to a tire vulcanizer, and a green tire is set in the tire mold in the same manner as before and then vulcanized by heating under pressure. Can be obtained.
[0023]
In the above-described embodiment, the present invention has been described with respect to an example of a tire mold having a sipe forming blade 6 extending linearly. However, the shape of the sipe forming blade extends in a zigzag shape or a curved shape. In addition, the sipe forming blade 6 may be a sectional type tire mold having a sipe forming blade extending to the sector division position X, not limited to the one extending between the groove forming blades 5 as described above. It can be applied to any one.
[0024]
The reinforcing part 7 described above, but only Ru is disposed adjacent to the sector splitting position X on one side of the sipe molding blade 6X, length m of the reinforcing portion 7 is of length M of the sipe molding blade 6X 1 If the ratio is less than 2 times, a similar auxiliary reinforcing portion may be provided on one side surface of the sipe forming blade 6X spaced from the reinforcing portion 7. In this case, the total length of the auxiliary reinforcing portion and the length m of the reinforcing portion 7 does not exceed 1/2 times the length M of the sipe forming blade 6X.
[0025]
【The invention's effect】
As described above, the present invention provides a sectional type tire mold having a sipe forming blade extending to a sector dividing position on a molding surface of a plurality of divided sectors, and adjacent to the sector dividing position on the side surface of the sipe forming blade. Since the plate-shaped reinforcing portion is provided, the deformation of the sipe forming blade can be suppressed without damaging the appearance of the tread pattern due to wear while maintaining good sipe characteristics.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an essential part showing an example of a tire mold of the present invention.
2A and 2B are enlarged views of essential parts of the sector, in which FIG. 2A is an enlarged view seen from the inner peripheral side of the annular side mold, and FIG. 2B is an enlarged view seen from the arrow direction of FIG.
FIG. 3 is an enlarged cross-sectional view of a main part showing another example of a sector used in the tire mold of the present invention in a cross section crossing a sipe forming blade including a reinforcing part.
4 is an enlarged plan view of an essential part showing an example of a pneumatic tire manufactured using the tire mold of FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper mold | type 2 Lower mold | type 3 Side mold | type 4 Sector 4a Molding surface 6,6X Sipe molding blade 7 Reinforcement part 10 Thick part H Height of sipe molding blade M Length of sipe molding blade P Metal plate T Thickness of sipe molding blade X Sector division position h Reinforcement height m Reinforcement length t Reinforcement thickness

Claims (6)

In a sectional type tire mold in which a sipe forming blade extending directly to a sector dividing position is provided directly on a molding surface of a plurality of divided sectors, a metal adjacent to the sector dividing position is provided only on one side surface of the sipe forming blade. A reinforcing portion made of a plate is provided , and the reinforcing portion extends in the width direction of the sipe forming blade from the sector division position, and extends in the height direction of the sipe forming blade from the sector forming surface, and has a thickness that is the sipe forming blade. Tire mold that is less than the thickness . 2. The tire mold according to claim 1, wherein the reinforcing portion is formed integrally with the same material as that of the sipe forming blade on one side surface of the sipe forming blade instead of the metal plate.   The tire mold according to claim 1 or 2, wherein the reinforcing portion extends from the molding surface to a position that is 1/4 to 1/2 times the height of the sipe molding blade.   4. The tire mold according to claim 1, wherein the reinforcing portion extends from the sector division position to a position that is ¼ to ½ times the length of the sipe forming blade. The tire mold according to claim 1, 2, 3, or 4, wherein the sipe forming blade and the reinforcing portion are made of stainless steel, and the thickness of the reinforcing portion is 1/2 or more times the thickness of the sipe forming blade. . The manufacturing method of the pneumatic tire which manufactures a pneumatic tire using the tire metal mold | die of any one of Claim 1 thru | or 6.

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