JP7803687B2 - Method for designing a tire molding mold, tire molding mold, and method for manufacturing a tire molding mold - Google Patents

Description

The present invention relates to a method for designing a tire mold, a tire mold, and a method for manufacturing a tire mold.

Patent Document 1 describes a sipe blade for forming three-dimensional grooves (sipes) in tires, and a tire molding die having this sipe blade. The element shape of this sipe blade is a three-dimensional shape consisting of two diamond-shaped cones with a common side connected to each other and a diamond-shaped base. The element shape is a continuous three-dimensional structure along a single plane.

Patent Document 2 describes a method for manufacturing sipe blades for tire molds. Patent Document 2 exemplifies a high-performance sipe blade with a complex, three-dimensional shape in which the bent shape after bending is composed of two types of bent shapes with different developed lengths in the same direction within a single continuous shape. It also describes that the sipe blade is formed by bending.

Japanese Patent Application Laid-Open No. 2004-243644 Japanese Patent Application Laid-Open No. 2003-145545

In addition to the main grooves, tires may also have numerous narrow grooves called sipes. Sipes are formed for purposes such as reducing slippage when driving on wet roads, improving water breakage (the edges break the water film), improving the ability of the grooves to supply and drain water, and improving traction on the road surface, as well as adjusting the rigidity characteristics of the rubber. Because forming sipes in tires helps maintain the rigidity of the rubber and thereby reduce one-sided wear, there has been a noticeable trend in recent years toward thinner sipes (thinner grooves) and more complex shapes.

As exemplified by Patent Document 2, the conventional method for manufacturing the sipe portion of a tire mold, i.e., sipe blades (an example of a tire molding mold), has been to cut out a rolled material of high strength (e.g., steel) and press-form it in a mold (so-called stamp molding). In recent years, direct molding methods using so-called 3D printers have also begun to be adopted. Using a 3D printer offers greater flexibility in varying the thickness of sipe blades and accommodating complex shapes. Especially when producing a wide variety of products in small quantities, 3D printers offer the advantage of enabling shorter delivery times than stamping methods, as they do not require stamp molds.

However, manufacturing methods using 3D printers tend to result in lower strength and greater variation in strength compared to sipe blades manufactured by stamp molding using rolled material. As a result, they are sometimes less suitable for mass production than manufacturing by stamp molding.

The present invention was made in light of these circumstances, and its purpose is to provide an efficient method for designing a tire mold, a tire mold, and a method for manufacturing a tire mold, which improves the strength of the tire mold while improving the performance of the sipes.

In order to achieve the above object, the method for designing a tire mold according to the present invention comprises the steps of:
A method for designing a tire mold for molding a tire having sipes formed in the tread, comprising:
A mold that is a basic shape for forming the sipe is defined as a unit cell, and the unit cells are arranged to define the overall shape of the sipe.

The above method provides an efficient method for designing a tire mold that improves the strength of the tire mold while improving the performance of the sipes.

The above method allows for the determination of a basic shape that improves the strength of the tire mold while also improving the performance of the sipes, and for this basic shape to be defined as a unit cell, the smallest unit of mold shape for the portion of the tire mold that molds the sipes. The overall shape of the sipes can then be determined through the simple process of arranging these unit cells, enabling the design of a tire mold with a highly efficient procedure.

The tire mold design method according to the present invention further includes the steps of:
In a direction along the axial direction of the tire, the unit cell may be provided with a thick portion having a thickness that is relatively thicker than other portions of the unit cell.

The above method allows the thickened portions to create areas within the sipe grooves that form wider gaps than other areas. As a result, when the sipes in the tread deform due to deformation of the tire tread rubber while the tire is in motion, the wide gaps formed by the thickened portions can remain within the sipe gaps even after the opposing inner surfaces come into contact with each other in the narrow gaps within the sipes. This allows water absorbed from the road surface to flow through these gaps.

The tire mold design method according to the present invention further includes the steps of:
A protrusion may be formed on the unit cell, and the protrusion may serve as the thick portion.

Every time a tire is demolded from the mold, the mold for the sipe portion is repeatedly subjected to external forces from the sipes of the tire. The above method can improve durability, for example, repeated fatigue life, against the external forces applied to the mold for the sipe portion when the tire is demolded.

The tire mold design method according to the present invention further includes the steps of:
The convex portion may be formed continuously, and the thick portion may be provided along the ridge line of the convex portion.

The above method allows water sucked up from the road surface to flow through the gaps in the sipes formed along the convex portions (the gaps that remain after the opposing inner surfaces come into contact in the narrow parts of the gaps within the sipes).

The tire mold design method according to the present invention further includes the steps of:
The first cell, which is the first unit cell, and the second cell, which is the second unit cell adjacent to the first cell, may be arranged so that the ridge lines of the first cell and the second cell are continuous.

The above method allows the gaps between each part of the sipe formed by adjacent unit cells (the gaps that remain after the opposing inner surfaces come into contact in the narrow part of the gap within the sipe) to be connected, allowing water absorbed from the road surface to flow through these connected gaps.

In order to achieve the above object, the tire mold according to the present invention comprises:
A tire mold for molding a tire having sipes formed in the tread,
Molds that are the basic shapes that form the sipes are arranged as unit cells.

The tire mold according to the present invention further comprises:
The unit cell may be provided with a thick portion that is thicker than other portions of the unit cell in a direction along the axial direction of the tire.

The tire mold according to the present invention further comprises:
A protrusion may be formed in the unit cell, and the protrusion may be the thick portion.

The tire mold according to the present invention further comprises:
The convex portion may be formed continuously, and the thick portion may be provided along the ridge line of the convex portion.

The tire mold according to the present invention further comprises:
The first cell, which is the first unit cell, and the second cell, which is the second unit cell adjacent to the first cell, may be arranged so that the ridge lines of the first cell and the second cell are continuous.

These configurations improve sipe performance and provide a tire mold with improved strength that can be efficiently designed and manufactured. In addition, the functions and effects of the tire mold design method described above corresponding to each of the above configurations can be achieved.

In order to achieve the above object, the method for manufacturing a tire mold according to the present invention comprises the steps of:
A method for manufacturing a tire mold for molding a tire having sipes formed in the tread, comprising:
A mold having a basic shape for forming the sipe is arranged as a unit cell.

The above method provides an efficient method for manufacturing a tire mold that can improve the strength of the tire mold while improving the performance of the sipes. In addition, the above-mentioned functions and effects of the tire mold design method and tire mold can be achieved.

3A and 3B are diagrams showing the configuration of a sipe blade according to the present embodiment. FIG. 2 is a perspective view showing the shape of a cell of the first embodiment. FIG. 2 is a perspective view showing the shape of a cell of the first embodiment. FIG. 2 is a perspective view showing the shape of a mold part of the first embodiment. 4A and 4B are diagrams showing the shape of a space within a sipe formed by the mold portion of the first embodiment. FIG. 10 is a perspective view showing the shape of a cell of a second embodiment. FIG. 10 is a perspective view showing the shape of a mold part of a second embodiment. 10A and 10B are diagrams showing the shape of a space within a sipe formed by a mold portion of a second embodiment. FIG. 10 is a perspective view showing the shape of a cell according to a third embodiment. FIG. 10 is a perspective view showing the shape of a cell according to a third embodiment. FIG. 10 is a perspective view showing the shape of a mold part of a third embodiment. 10A and 10B are diagrams showing the shape of a space within a sipe formed by a mold portion of a third embodiment.

With reference to the drawings, a method for designing a tire mold, a tire mold, and a method for manufacturing a tire mold according to an embodiment of the present invention will be described.

The tire molding mold design method according to this embodiment relates to a method for designing a tire molding mold for molding a tire with sipes formed in the tread.

Figure 1 shows a sipe blade 100 (hereinafter referred to as blade 100) as an example of a tire molding mold according to this embodiment. Blade 100 is a mold used to form sipes (grooves) in the tread of a tire during tire vulcanization.

Blade 100 comprises a base portion A that is fixed to a tire mold for forming the tire tread, and a mold portion B that is, for example, integrally molded with base portion A, in which unit cells 1 (hereinafter referred to as cells 1) are arranged as molds that form the basic shapes for forming sipes in the tire tread. Unit cells 1 and mold portion B are plate-shaped with a curved structure across the entire plate surface. The thickness direction of mold portion B or unit cells 1 in blade 100 may be aligned with the axial direction of the tire (the direction of the central axis of the ring).

In a tire mold used to mold a tire tread, blade 100 is fixed with mold portion B positioned on the radially inner side of the tire and base portion A positioned on the radially outer side of the tire. The plate surface of blade 100 is fixed to the tire mold along the circumferential direction of the tire. For ease of explanation, the direction toward base portion A as viewed from mold portion B, i.e., the direction corresponding to the radially outer side of the tire, will be referred to as "up" and the direction corresponding to the radially outer side of the tire as "down," and the direction along the radial direction of the tire will be described as the "up-down" direction. The direction along the circumferential direction of the tire will also be described as the "lateral" direction.

Mold section B is designed using a design method in which the mold (shape) that will form the basic shape of the sipe is defined as cell 1, and the cells 1 are arranged to determine the overall shape of the sipe. Mold section B can be manufactured by arranging cells 1 to match the desired sipe size (depth and width). Mold section B and blade 100 equipped with it can be output (constructed), for example, using a 3D printer. That is, first, the mold for cell 1 is determined, and then the overall shape of mold section B is designed by arranging it. Mold section B can then be manufactured by outputting it using a 3D printer to match the designed overall shape.

In this embodiment, the cell 1 may be formed in a rectangular shape when viewed from the front of the plate surface. Figure 1 illustrates an example in which the cell 1 is square. Alternatively, the cell 1 may be formed in a shape that can be formed into a single plate by arranging cells 1 of the same shape adjacent to each other. One example of another shape that the cell 1 can take is a hexagon.

The shape of the cell 1 mold can take various forms depending on the required specifications of each tire. Specific examples of the shapes of the cell 1 and mold portion B according to this embodiment are described below.

(First embodiment)
2 and 3 show a cell 2 having a wave-shaped configuration as an example of the cell 1 according to this embodiment. Fig. 3 is a view of the cell 2 shown in Fig. 2 as seen from the rear side.

Cell 2 has thickened portions 22, 24, and 26 that are relatively thicker than the other portions of cell 2. Thickened portions 22, 24, and 26 are formed as convex portions with vertices (ridges). Cell 2 also has bent portions 21 formed in the vertical direction as convex portions shaped like a bent plate surface. Bent portions 21 extend from the top to the bottom of cell 2. In other words, bent portions 21 are continuous from the top to the bottom of cell 2.

The thick portion 22 is formed to extend along the ridge line of the bent portion 21. The ridge line of the thick portion 22 and the ridge line of the bent portion 21 are aligned. The thick portion 22 extends from the upper end to the lower end of the cell 2. The thick portion 22 extends from the upper end to the lower end of the cell 2. In other words, the thick portion 22 is continuous from the upper end to the lower end of the cell 2 along the ridge line of the bent portion 21.

The thickened portions 24 extend vertically from the top to the bottom at the horizontal ends of the cell 2. In this embodiment, thickened portions 24, 24 are formed at both horizontal ends of the cell 2.

The thick portions 26 are formed to extend from one end to the other in the horizontal direction. In this embodiment, the thick portions 26, 26 are located at the upper and lower ends of the cell 2.

Between the thick portions 22 and 24, a thin portion 23 extends vertically in thickness relative to the thick portions 22 and 24. Between the thick portions 26 and 26, a thin portion 25 extends horizontally in thickness relative to the thick portions 26 and 26.

Figure 4 shows a mold section B formed by arranging six cells 2 (two adjacent in the vertical direction and three adjacent in the horizontal direction) adjacent to each other, with the horizontal direction being the longitudinal direction, as an example. When the cells 2 of this embodiment are arranged adjacent to each other, the ridge lines of the thick portions 22 formed along the bends 21 of each of the vertically adjacent cells 2, 2 extend continuously from the upper end to the lower end of the mold section B. Note that the number of arranged cells 2 is not limited to six, and may be five or fewer or seven or more.

In addition, in mold section B, which is formed by arranging cells 2, the valleys of the thin-walled portions 23 of adjacent cells 2, 2 in the vertical direction are formed so as to extend continuously from the upper end to the lower end of mold section B.

In addition, in mold section B formed by arranging cells 2, the thick portions 24, 24 formed at the ends of laterally adjacent cells 2, 2 face each other, forming an integral, vertically extending bent portion 29 that extends from the upper end to the lower end of mold section B. The ridge line of bent portion 29 coincides with the ridge line of the opposing thick portions 24, 24.

In addition, in mold section B, which is formed by arranging cells 2, the thick-walled portions 26 of each laterally adjacent cell 2 are formed so as to extend continuously from one end to the other end in the horizontal direction. Similarly, in mold section B, the thin-walled portions 25 of each laterally adjacent cell 2 are also formed so as to extend continuously from one end to the other end in the horizontal direction.

In this way, in mold part B of this embodiment, if a certain cell 2 is designated as a first cell and another cell 2 adjacent to the first cell 2 is designated as a second cell, the ridges of the first cell and the second cell are continuous.

Each time the tire is demolded from the mold, mold section B is repeatedly subjected to external forces from the tire's sipes. However, in mold section B according to this embodiment, the bent sections 21 and 29 are made thicker, improving durability (e.g., repeated fatigue life) in terms of strength against the external forces applied to mold section B when the tire is demolded.

Figure 5 shows the shape of the space Ba that will remain within a sipe formed using mold portion B shown in Figure 4 when the sipe deforms as the tire tread rubber deforms and the inner surfaces of the sipe (portions of opposing inner surfaces that are close together) come into contact with each other during tire operation. In other words, Figure 5 shows the shape of the space Ba that will always be maintained within the sipe when a tire with sipes formed using mold portion B shown in Figure 4 is in operation.

In Figure 5, each cell space 2a is part of the space within the sipe formed by the cells 2. Space 22a is a space formed by the bent portion 21 of each cell 2, which extends continuously from the upper end to the lower end of mold portion B. Similarly, space 26a is a space formed by the thick portion 26 of each cell 2, which extends continuously from one end to the other in the left-right direction of mold portion B. Similarly, space 29a is a space formed by the thick portion 24 (bent portion 29 of mold portion B, see Figure 4). Spaces 22a and 29a are continuous in the vertical direction, extending from the upper end to the lower end of the sipe. Space 26a is continuous in the horizontal direction, extending from one end to the other in the horizontal direction of the sipe.

As shown in Figure 5, sipes formed using cells 2 can have portions (spaces 22a, 26a, 29a) within the sipe grooves that are wider than other portions. As a result, when the sipes deform due to deformation of the tire tread rubber during tire travel, even after the opposing inner surfaces come into contact at the narrow portions of the sipe gaps (gap portions formed corresponding to thin-walled portions 23 and 25 of mold section B shown in Figure 4), wide gaps (spaces 22a, 26a, 29a) formed by the thick portions remain within the sipe gaps. This allows water drawn from the road surface to flow through these gaps (spaces 22a, 26a, 29a). Furthermore, the gaps (spaces 22a, 26a, 29a) between the sipe portions formed by adjacent cells 2 in mold section B are formed as continuous spaces, allowing water drawn from the road surface to flow through these continuous spaces, thereby enabling appropriate water supply and drainage between the sipes and the tread pattern. In other words, mold portion B in this embodiment can improve the strength and also the supply and drainage performance of the sipes.

Second Embodiment
6 shows a cell 3 having a wave-bent shape different from that of the first embodiment as an example of the cell 1 according to this embodiment. In the following description, descriptions of parts that are the same as those of the first embodiment will be omitted as appropriate.

Cell 3 has thickened portions 32, 34, 36, and 38 that are thicker than the other portions of cell 3. Thickened portions 32, 34, 36, and 38 are formed as convex portions with vertices (ridges). Cell 3 also has bent portions 31, 35, and 75, which are convex portions formed by bending the plate surface.

Bent portion 31 extends continuously from the top to the bottom in the vertical direction. Bent portions 35 and 37 extend continuously from one end to the other in the horizontal direction. Bent portion 35 is bent in the opposite direction to bent portion 37. In other words, when bent portion 37 is a convex portion when viewed from the front, bent portion 35 is a concave portion, and bent portion 35 is a convex portion when viewed from the rear.

The thickened portions 32, 36, and 38 are formed so as to be continuous with the ridgelines of the bent portions 31, 35, and 37, respectively, and extend over the same range as the ridgelines. The ridgelines of the thickened portions 32, 36, and 38 are aligned with the ridgelines of the bent portions 31, 35, and 37.

The thickened portions 34 extend vertically from the top to the bottom at the horizontal ends of the cell 2. In this embodiment, thickened portions 34, 34 are formed at both horizontal ends of the cell 2.

In cell 3, portions other than thick-walled portions 32, 34, 36, and 38 are relatively thin-walled portions, similar to cell 2 in the first embodiment. A detailed description of each thin-walled portion of cell 3 is omitted.

Figure 7 shows a mold section B formed by arranging six cells 3 adjacent to each other, as an example. When the cells 3 of this embodiment are arranged adjacently, the ridge lines of the thick-walled portions 33 formed along the bends 31 of each of the vertically adjacent cells 3, 3 extend continuously from the upper end to the lower end of the mold section B. Furthermore, when the cells 3 of this embodiment are arranged adjacently, the ridge lines of the bends 35, 37 formed along the bends 35, 37 of each of the horizontally adjacent cells 3, 3 extend continuously from one end to the other end of the mold section B in the horizontal direction.

In addition, in mold section B formed by arranging cells 3, the thick portions 34, 34 formed at the ends of each of laterally adjacent cells 3, 3 face each other to form a single, vertically bent portion 39 extending from the upper end to the lower end of mold section B. The ridge line of bent portion 39 coincides with the ridge line of the opposing thick portions 34, 34.

Furthermore, in mold section B, which is formed by arranging cells 3, the thick-walled portions 36 and 38 of each horizontally adjacent cell 3 are formed so as to extend continuously from one horizontal end to the other.

Figure 8 shows the shape of the space Ba for the sipe formed using mold part B shown in Figure 7.

In Figure 8, each cell space 3a is a portion of the space within the sipe formed by the cells 3. Space 32a is a space formed by thick-walled portion 32. Similarly, spaces 36a and 38a are spaces formed by thick-walled portions 36 and 38. Similarly, space 39a is a space formed by thick-walled portion 34 (bent portion 39 of mold portion B, see Figure 7). Spaces 32a and 39a are continuous in the vertical direction, extending from the upper end to the lower end of the sipe. Spaces 36a and 38a are continuous in the horizontal direction, extending from one end to the other end of the sipe in the horizontal direction. As described in the first embodiment, mold portion B in this embodiment can also improve the strength and the air supply/discharge and drainage performance of the sipe.

(Third embodiment)
9 and 10 show a dimple-shaped cell 4 having a different shape from that of the above embodiment as an example of a cell 1 according to this embodiment. FIG. 10 is a view of the cell 4 shown in FIG. 9 from the rear side. As shown in FIGS. 9 and 10, the cell 4 is formed in a hexagonal shape when viewed from the front. In addition, the center portion of the cell 4 when viewed from the front is formed as a smooth convex portion 4A (see FIG. 9 ) that protrudes to one side, and the opposite surface is formed as a concave portion 4B whose center portion when viewed from the front (rear) is smoothly recessed. In the following description, descriptions of parts similar to those of the first embodiment will be omitted as appropriate.

Cell 4 has six thick sections 42 that are relatively thicker than the rest of the cell 4. The thick sections 42 are formed as convex sections with vertices (ridges). The thick sections 42 protrude from the same side of the cell 4 plate surface as the protruding section 4A. Cell 4 also has six bent sections 41 formed as convex sections formed by bending the plate surface.

In Figure 9, an imaginary line R is shown along the ridge of the bent portion 41. The ridge of the bent portion 41 is on the same side of the plate surface of the cell 4 as the protruding portion 4A. The ridge of each bent portion 41 is the edge of the plate surface of the cell 4, extending from the center of each side of the hexagonal shape of the cell 4 to just before the protruding portion 4A.

Each thick portion 42 is formed so as to be continuous with the ridge line of each bent portion 41 and extend over the same area as the respective ridge lines. The ridge lines of the thick portions 42 and the ridge lines of the bent portions 41 are aligned.

In cell 4, the portions other than the thick-walled portion 42 are relatively thin-walled, similar to cell 2 in the first embodiment. A detailed description of each thin-walled portion of cell 4 is omitted.

Figure 11 shows mold part B, which is formed by arranging six cells 4 adjacent to each other in a triangular houndstooth pattern, as an example. When the cells 4 of this embodiment are arranged adjacent to each other, the ridge lines of each thick portion 42 are formed so that they are continuous with the ridge lines of the thick portions 42 of adjacent cells 4.

Figure 12 shows the shape of the space Ba for the sipe formed using mold part B shown in Figure 11.

In Figure 12, each cell space 4a is part of the space within the sipe formed by the cells 4. Space 42a is a space formed by the thick-walled portion 42. Each space 42a is connected in a network-like manner to form space Ba that extends to the upper and lower ends and both lateral ends of the sipe. As with the first embodiment, mold portion B in this embodiment can improve the strength and the air supply and drainage performance of the sipe.

In this way, a method for designing a tire molding mold, a tire molding mold, and a method for manufacturing a tire molding mold can be provided.

Please note that the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments. Modifications may be made as appropriate within the scope of the present invention.

The present invention can be applied to a method for designing a tire molding mold, a tire molding mold, and a method for manufacturing a tire molding mold.

1: Cell (unit cell)
100: Blade (sipe blade, tire molding mold)
2: Cell 21: Bent portion 22: Thick portion 22a: Space 23: Thin portion 24: Thick portion 25: Thin portion 26: Thick portion 26a: Space 29: Bent portion 29a: Space 2a: Cell space 3: Cell 31: Bent portion 32: Thick portion 32a: Space 33: Thick portion 34: Thick portion 35: Bent portion 36: Thick portion 36a: Space 37: Bent portion 38: Thick portion 39: Bent portion 39a: Space 3a: Cell space 4: Cell 41: Bent portion 42: Thick portion 42a: Space 4A: Convex portion 4B: Concave portion 4a: Cell space A: Base B: Mold portion Ba: Space R: Imaginary line

Claims (6)

A method for designing a tire mold for molding a tire having sipes formed in the tread, comprising:
A mold that is a basic shape for forming the sipe is defined as a unit cell, and only the unit cells of the same shape are arranged adjacent to each other to define the overall shape of the sipe ;
a thick portion having a thickness greater than that of other portions of the unit cell in a direction along the axial direction of the tire;
forming a protrusion on the unit cell, the protrusion being the thick portion;
The convex portion is continuously formed, and the thick portion is provided along the ridge line of the convex portion;
A method for designing a tire molding mold, comprising: arranging a first cell, which is a first of the unit cells, and a second cell, which is a second of the unit cells adjacent to the first cell, so that the ridge lines of the first cell and the second cell are continuous . 2. The method for designing a tire mold according to claim 1 , wherein the unit cell is a square or a regular hexagon when viewed from the front. A tire mold for molding a tire having sipes formed in the tread,
Molds having a basic shape for forming the sipe are arranged adjacent to each other as unit cells,
Adjacent unit cells all have the same shape,
a thick portion having a thickness that is relatively thicker than other portions of the unit cell in a direction along the axial direction of the tire;
a protrusion is formed in the unit cell, the protrusion being the thick portion,
the protrusion is formed continuously, and the thick portion is provided along the ridge line of the protrusion,
A tire molding mold in which a first cell, which is a first unit cell, and a second cell, which is a second unit cell adjacent to the first cell, are arranged so that the ridge lines of the first cell and the second cell are continuous . 4. The tire mold according to claim 3 , wherein the unit cells are square or regular hexagonal in front view. A method for manufacturing a tire mold for molding a tire having sipes formed in the tread, comprising:
A mold having a basic shape for forming the sipe is used as a unit cell, and only the unit cells having the same shape are arranged adjacent to each other,
a thick portion having a thickness greater than that of other portions of the unit cell in a direction along the axial direction of the tire;
forming a protrusion on the unit cell, the protrusion being the thick portion;
The convex portion is continuously formed, and the thick portion is provided along the ridge line of the convex portion;
A method for manufacturing a tire mold, comprising: arranging a first cell, which is a first of the unit cells, and a second cell, which is a second of the unit cells adjacent to the first cell, so that the ridge lines of the first cell and the second cell are continuous . The method for manufacturing a tire mold according to claim 5 , wherein the unit cell has a square or regular hexagonal shape when viewed from the front.