JP2015136835A - Tire vulcanization mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire vulcanization mold that can improve the segment durability by uniformizing the contact pressure between a side mold and a segment during the vulcanization.SOLUTION: There is provided a tire vulcanization mold in which a tire T vulcanization molding is carried out in a mold-closed state Y in which a first abutting portion 5 of the radially outer end of a side mold 2 and a second abutting portion 6 of the radially inner end of a segment 3 are abutted each other. The first and second abutting portions 5 and 6 comprise first and second abutting faces 20 and 22 constituted of conical surfaces of the same inclination to one another inclined radially inwardly toward the tire axial direction inner side.

Description

  The present invention relates to a tire vulcanization mold with improved segment durability.

  As shown in FIGS. 5A and 5B, a tire vulcanization mold a includes a pair of side molds b for forming sidewalls arranged on both sides in the tire axial direction, and a plurality of annularly arranged molds. A tread mold c for forming a tread composed of a segment c1. The mold closed state in which the first butting surfaces sb at the radially outer ends of the side molds b and the second butting surfaces sc at both sides in the tire axial direction and the radially inner ends of the segments c1 are butted against each other. The tire is vulcanized and molded at Y (see Patent Document 1).

  In the prior art, as shown in FIG. 6, the first and second butting surfaces sb and sc are formed from cylindrical surfaces having the same diameter.

  On the other hand, in the tire vulcanization mold a, since the side mold b is subjected to design processing such as marking, a hard steel material such as SS400 is used so that the design is not worn by mold cleaning such as shot blasting. Formed with. On the other hand, the segment c1 is manufactured from a soft aluminum alloy in consideration of workability in the mold manufacturing process such as casting and cutting.

  However, the tire vulcanization mold a is heated to a high temperature of, for example, 170 to 180 ° C. during vulcanization. Therefore, due to the difference in thermal expansion coefficient between the steel material and the aluminum alloy, even if the radii rb and rc of the first and second butted surfaces sb and sc are the same at room temperature, during vulcanization, as shown in FIG. As shown exaggeratedly, the radius rc1 of the second abutting surface sc is larger than the radius rb1 of the first abutting surface sb.

  As a result, as exaggeratedly shown in FIG. 7B, in the mold closed state Y during vulcanization, the contact pressure between the first and second butted surfaces sb and sc becomes non-uniform, and the contact pressure is reduced. There is a problem that the durability of the segment c1 is lowered, for example, the segment c1 is deformed starting from the high portion Q.

JP2013-144414A

  Therefore, the invention is based on the fact that the first and second butting surfaces are conical surfaces that are inclined inward in the radial direction toward the inner side in the tire axial direction, so that the contact pressure between the butting surfaces can be made uniform. An object of the present invention is to provide a tire vulcanization mold that can improve the durability of a segment.

The present invention comprises a pair of side molds for forming sidewalls arranged on both sides in the tire axial direction, and a tread mold for forming treads composed of a plurality of segments arranged in an annular shape,
The tire is added in a closed state in which the first butted portion at the radially outer end of each side mold and the second butted portion at both sides in the tire axial direction and radially inner end of each segment are butted together. A tire vulcanizing mold for performing vulcanization molding,
The first and second abutting portions include first and second abutting surfaces each having a conical surface inclined inward in the radial direction toward the inside in the tire axial direction.

  In the tire vulcanization mold according to the present invention, in the meridional section passing through the tire axis, the first and second abutting surfaces preferably have an angle θ with respect to the tire axial direction line of 20 to 60 °. .

In the tire vulcanization mold according to the present invention, the first abutting portion includes the first abutting surface and a first cylindrical surface continuous to an outer edge in the tire axial direction, and the second abutting surface. The butting portion includes the second butting surface and a second cylindrical surface continuous to the outer edge in the tire axial direction,
The radius R2 of the second cylindrical surface is preferably larger than the radius R1 of the first cylindrical surface.

  In the present invention, as described above, the first and second butting surfaces are formed by conical surfaces having the same inclination, which are inclined inward in the radial direction toward the inside in the tire axial direction.

  Therefore, although a radius difference is generated between the segment and the side mold due to heat during vulcanization, the first and second abutting surfaces form a conical surface. The butting surfaces are butted. Therefore, the contact pressure can be made uniform and the durability of the segment can be improved.

(A), (B) is sectional drawing which shows the operating state of the metal mold | die for tire vulcanization | cure of this invention. It is a perspective view which shows the part. It is a perspective view which shows a part of a side mold and a segment. (A)-(C) are the fragmentary sectional views which show the effect | action of this invention. (A), (B) is sectional drawing which shows the conventional metal mold | die for tire vulcanization. It is sectional drawing which shows the conventional butt | matching surface. (A), (B) is sectional drawing which shows the problem by the conventional butt | matching surface.

Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIG. 1, a tire vulcanization mold 1 according to this embodiment includes a pair of side molds 2 for forming sidewalls arranged on both sides in the tire axial direction, and a plurality of segments 3 arranged in an annular shape. And a tread mold 4 for forming a tread.

  Then, the mold closed state in which the first butted portions 5 at the radially outer ends of the side molds 2 and the second butted portions 6 at both sides in the tire axial direction and the radially inner ends of the segments 3 are butted against each other. At Y, the tire T is vulcanized.

  The side mold 2 includes a sidewall molding surface 2S that molds the sidewall of the tire T, and the tread mold 4 includes a tread molding surface 4S that molds the tread of the tire T. The side mold 2 and the tread mold 4 can adopt the same structure as that of the prior art except for the first and second butting portions 5 and 6.

  In the figure, reference numeral 10U denotes an upper plate that can be moved up and down to which the upper side mold 2 is mounted. For example, it is supported so as to be movable up and down via known lifting means (not shown) such as a cylinder.

  Reference numeral 10L denotes a lower plate that supports the lower side mold 2, and is attached to the lower platen plate 11L fixed to, for example, a press stand (not shown). Reference numeral 13 denotes a tread sector in which each one segment 3 is exchangeably attached. The tread sector 13 moves inward in the radial direction together with the segment 3 as the annular actuator 14 descends, and the first and second abutting portions 5 and 6 are abutted against each other to close the mold. It becomes.

  FIG. 3 is a perspective view showing a part of the side mold 2 and a part of the segment 3, and the side mold 2 and the segment 3 are clearly shown so that the first and second butted portions 5 and 6 are clearly shown. Is shown with a different viewpoint position. As shown in the figure, the first abutting portion 5 includes a first abutting surface 20 formed of a conical surface inclined inward in the radial direction toward the inner side in the tire axial direction. In this example, a case where the first butting portion 5 includes the first butting surface 20 and a first cylindrical surface 21 connected to the tire axial direction outer edge 20a is shown. The first abutting surface 20 is connected to the sidewall molding surface 2S at the tire axial direction inner edge 20b.

  The second butting portion 6 includes a second butting surface 22 formed of a conical surface having the same inclination as the first butting surface 20. In this example, a case where the second butting portion 6 includes the second butting surface 22 and a second cylindrical surface 23 connected to the outer edge 22a in the tire axial direction is shown. The second butting surface 22 is connected to the tread molding surface 4S at the tire axial direction inner edge 22b.

  The radius R2 of the second cylindrical surface 23 is larger than the radius R1 of the first cylindrical surface 21. Therefore, in the mold closed state Y at room temperature, the first and second butted surfaces 20, 22 are in close contact with each other as shown in FIG. A slight gap G is formed between the first and second cylindrical surfaces 21 and 23.

  As shown in FIG. 4B, when the tire vulcanizing mold 1 is heated, the segment 3 and the side mold 2 are thermally expanded. However, due to the difference in thermal expansion coefficient, the segment 3 and the side mold 2 are A radius difference ΔR occurs between the two.

  However, the first and second butting surfaces 20, 22 form a conical surface. Therefore, as shown in FIG. 4C, the first and second butting surfaces 20 and 22 can be butted at the same radius position. That is, the contact pressure can be disproportionated and the durability of the segment 3 can be improved. The abutting at the same radius position is achieved by moving the side mold 2 inward in the tire axial direction. At this time, a step D is formed between the tread molding surface 4S and the sidewall molding surface 2S.

  Here, as shown in FIG. 4A, in the meridional section passing through the tire axis, the first and second butting surfaces 20, 22 have an angle θ of 20 to 60 ° with respect to the tire axial line. It is preferable. When the angle θ is less than 20 °, the step D becomes large and the appearance is liable to be adversely affected. On the other hand, when the angle θ exceeds 60 °, the strength of the segment 3 such that the tip angle α of the corner portion J between the tread molding surface 4S and the second abutting surface 22 becomes too acute, resulting in missing engine. It tends to cause a decline.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  A tire vulcanization mold having the structure shown in FIG. 1 was prototyped based on the specifications shown in Table 1 and tested for durability in the segments. The mold is a mold for a tire for a passenger car having a tire size of 195 / 65R15, and the tread mold is divided into nine segments. The segment is formed of AC4 (aluminum alloy for casting), and the side mold is formed of SS400 (steel material). Each mold is different only in the abutting surface, and the other specifications are substantially the same.

  Durability was determined by measuring the shape of the butt surface of the segment every 1000 vulcanized tires in each mold and comparing with the CAD 3D model. And about 9 segments, the location where the deformation | transformation (displacement amount) of the butt | matching surface was the largest was measured, and it evaluated by the average value of the deformation | transformation. Smaller numbers result in less deformation and better segment durability.

  As shown in Table 1, it can be confirmed that the mold of the example has little deformation of the segment and can improve the durability of the segment. In Example 1, since the angle θ is as small as 10 °, the step D between the tread molding surface and the sidewall molding surface becomes large, resulting in poor appearance. In Example 5, since the angle θ is too large as 70 °, the corner portion J between the tread molding surface and the second butted surface is insufficient in strength, and the edge chipping occurs at the time of 2,000 vulcanization. .

DESCRIPTION OF SYMBOLS 1 Tire vulcanizing mold 2 Side mold 3 Segment 4 Tread mold 5 First butting portion 6 Second butting portion 20 First butting surface 21 First cylindrical surface 22 Second butting surface 23 Second cylinder Surface T Tire Y Mold closed state

Claims (3)

A pair of side molds for forming sidewalls arranged on both sides in the tire axial direction, and a tread mold for forming treads composed of a plurality of segments arranged annularly,
The tire is added in a closed state in which the first butted portion at the radially outer end of each side mold and the second butted portion at both sides in the tire axial direction and radially inner end of each segment are butted together. A tire vulcanizing mold for performing vulcanization molding,
The first and second abutting portions include first and second abutting surfaces that are conical surfaces that are inclined inward in the radial direction toward the inner side in the tire axial direction. Mold for sulfur.   2. The tire vulcanization mold according to claim 1, wherein in the meridional section passing through the tire axis, the first and second butting surfaces have an angle θ of 20 to 60 ° with respect to the tire axial direction line. . The first abutting portion includes the first abutting surface and a first cylindrical surface continuous to an outer edge in the tire axial direction, and the second abutting portion includes the second abutting surface, A second cylindrical surface continuous to the outer edge of the tire axial direction;
The tire vulcanization mold according to claim 1 or 2, wherein a radius R2 of the second cylindrical surface is larger than a radius R1 of the first cylindrical surface.

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