Method for manufacturing a tire mold and method for manufacturing a tire

Abstract

Provided are a manufacturing method of a mold for a tire and a manufacturing method of a tire, which can efficiently manufacture a mold capable of manufacturing a tire having an excellent appearance. The present invention relates to a manufacturing method of a mold (8) for manufacturing a tire (2) having a recessed portion (6) recessed from a reference surface on a surface. The method includes the following steps: (A) forming a base cavity surface (20) for forming the reference surface when the recessed portion (6) is not present; (B) forming a metal layer (22) in a region of the base cavity surface (20) including a position corresponding to the recessed portion (6); and (C) cutting the metal layer (22) to form a protruding portion (16) having a shape corresponding to the recessed portion (6).

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a mold for a tire and a manufacturing method of a tire. BACKGROUND

[0002] Generally, characters, marks are engraved on the surface of a tire. These characters, marks are formed as recessed portions in most cases, which are recessed from a reference surface of the tire. In a mold for manufacturing the tire, a cavity surface has a protrusion for forming the recessed portion.

[0003] Since the shape of the characters, marks is complicated, a carving machine is generally used in the formation of the protrusion. The portion other than the protrusion is cut from the portion of the surface of a base material for the mold, which forms the cavity surface. The remaining portion after the cutting becomes the protrusion. However, generally, the area where the characters, marks exist is small. In this method, the area to be cut by the carving machine is large, and thus, the processing time of the mold becomes long.

[0004] In Japanese Patent Application Publication No. H01-310913, a method for efficiently manufacturing a mold having a protrusion is reported. In the manufacturing method, the mold has a main body having a notch and a display forming portion formed as a separate member from the main body. The protrusion is formed by cutting the surface of the display forming portion. By inserting the display forming portion into the notch, a cavity surface having the protrusion is formed.

[0005] Patent Document 1: Japanese Patent Application Publication No. H01-310913

[0006] In the method of inserting another member into the main body of the mold, a step difference is easily generated at the boundary of the main body and the other member on the cavity surface. The step difference can affect the appearance of the tire. A method for efficiently manufacturing a mold that can form a tire having an excellent appearance is desired. SUMMARY

[0007] An object of the present application is to provide a manufacturing method of a mold, which can efficiently manufacture a mold that can manufacture a tire having an excellent appearance.

[0008] The present application relates to a manufacturing method of a mold for manufacturing a tire having a recessed portion from a reference surface on the surface. The method includes the following steps:

[0009] (A) forming a base cavity surface for forming the reference surface when the recessed portion is not present;

[0010] (B) forming a metal layer in an area of the base cavity surface including a position corresponding to the recessed portion; and

[0011] (C) cutting the metal layer to form a protrusion having a shape corresponding to the recessed portion.

[0012] Preferably, the metal layer is formed by plating in the process of (B).

[0013] Preferably, the layer of iron or iron alloy is formed in the process of (B).

[0014] Preferably, the base cavity surface is formed by lathe processing in the process of (A).

[0015] Preferably, the protrusion is formed by engraving processing in the process of (C).

[0016] In the case where the mold has a side plate that contacts the side portion of the green tire, the cavity surface of the side plate is preferably formed by the processes of (A) to (C).

[0017] The manufacturing method of the present application for a tire includes the following processes:

[0018] The mold is manufactured by any of the above-described methods.

[0019] The green tire is pressurized and heated in the mold.

[0020] In the manufacturing method of the mold of the present application, a metal layer is formed in a region of the base cavity surface that includes a position corresponding to the recess. The protrusion is formed by cutting the metal layer. In the manufacturing method, in order to form the protrusion, it is only necessary to cut the metal layer. The region that should be cut in order to form the protrusion can be reduced. In the method, the mold can be efficiently formed. In the manufacturing method, since no other member is embedded in the main body, no step difference between them occurs. In the manufacturing method, a tire having an excellent appearance can be manufactured. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a perspective view showing the side surface of a tire manufactured using a mold manufactured by the manufacturing method of the present application.

[0022] Figure 2 is a plan view showing an example of a mold manufactured by the manufacturing method of the present application.

[0023] Figure 3 is a sectional view along the III-III line of Figure 2 .

[0024] Figure 4 is a sectional view of a portion of Figure 3 enlarged.

[0025] Figure 5 (a), (b), and (c) of Figure 4 are sectional views showing the processes of manufacturing a side plate of

[0026] Figure 6 (a) and (b) are examples of manufacturing. Figure 4 A plan view of the process for the side panel.

[0027] Label Explanation

[0028] 2: Tire; 4: Text; 6: Recess; 8: Mold; 10: Fan-shaped body; 12: Side plate; 14: Bead ring; 16: Protrusion; 18: Main body; 20: Basic cavity surface; 22: Metal layer; 24: Cavity surface of the fan-shaped body; 26: Cavity surface of the side plate; 28: Cavity surface of the bead ring. Detailed Implementation

[0029] Hereinafter, with appropriate reference to the accompanying drawings, the present invention will be described in detail based on preferred embodiments.

[0030] exist Figure 1 The image shows a portion of the sidewall of tire 2. Figure 1 In the diagram, arrow X indicates the radial direction of tire 2, and arrow A indicates the circumferential direction of tire 2. As shown in the figure, the character 4 is engraved on the side of tire 2. These characters 4 are formed as recesses 6 that are lower than the reference surface 5 of tire 2.

[0031] Figure 2 It shows the manufacturing process. Figure 1 The diagram shows a plan view of the mold 8 for tire 2. Figure 2 In the diagram, arrow X indicates the radial direction, arrow A indicates the circumferential direction, and the direction perpendicular to the paper surface is the axial direction. Mold 8 has a fan-shaped body 10, a side plate 12, and a bead ring 14.

[0032] Figure 3 It shows along Figure 2 The cross-section of line III-III. In Figure 3 In the diagram, arrow X indicates the radial direction, arrow Y indicates the axial direction, and the direction perpendicular to the paper is the circumferential direction. In this state, mold 8 is closed. In this state, the sector 10, side plate 12, and bead ring 14 are combined to form a cavity for housing the green tire R. The green tire R is also shown in this figure.

[0033] like Figure 2 As shown, the planar shape of each sector 10 is essentially arc-shaped. Multiple sectors 10 are arranged in a ring around the side plate 12. The sector 10 is located outside the radial direction of the side plate 12. Each sector 10 has a cavity surface 24 that contacts the tread portion of the green tire R.

[0034] like Figure 2 As shown, the side plate 12 has a ring-shaped planar shape. Figure 3As shown, there is an upper and lower pair of side plates 12. Each side plate 12 has a cavity surface 26 of the side plate that contacts a major portion of the tire side portion of the green tire R.

[0035] As shown, the planar shape of the bead ring 14 is ring-like. As shown, Figure 2 Figure 3 As shown, there is an upper and lower pair of bead rings 14. Each bead ring 14 has a cavity surface 28 of the bead ring that contacts a major portion of the bead of the green tire R.

[0036] Figure 4 A portion of Figure 3 is shown enlarged. In this figure, the lower side side plate 12 and the tire side portion of the green tire R are mainly shown. On the outer surface of this tire side portion, the characters 4 are engraved. That is, there is a recess 6 on the outer surface of this tire side portion. As shown, Figure 4 on the cavity surface 26 of the side plate, a protrusion 16 is provided at a position corresponding to the position of this recess 6. By this protrusion 16, the recess 6 is formed on the tire side portion of the green tire R.

[0037] Hereinafter, the manufacturing method of the lower side side plate 12 will be described using Figure 5 and 6 . This manufacturing method includes the following processes:

[0038] (1) a process of preparing a base material;

[0039] (2) a process of forming a base cavity surface 20;

[0040] (3) a process of forming a metal layer 22 on the base cavity surface 20;

[0041] (4) a process of forming a protrusion 16 by cutting the metal layer 22.

[0042] In the process of (1) above, a base material of the side plate 12 is prepared. This base material is ring-like. On this base material, the cavity surface 26 of the side plate is not formed. Typically, the material of the base material is steel.

[0043] In the process of (2) above, the surface of the base material that forms the cavity surface 26 of the side plate is cut. By this, the base cavity surface 20 is formed. The base cavity surface 20 is the surface that corresponds to the reference surface 5 of the tire 2 when there is no recess 6 on the surface of the tire 2. In Figure 5 (a) above, the base material after the base cavity surface 20 is formed (here, referred to as the main body 18) is shown. This figure shows a cross section after the main body 18 is cut with a surface perpendicular to the circumferential direction. Although not shown, the base cavity surface 20 is ring-like extending in the circumferential direction. As shown in this figure, in this cross section, the base cavity surface 20 is a slightly curved smooth surface.

[0044] ​In this embodiment, the base cavity surface 20 is formed by lathe processing. Although not shown, in the lathe processing, a cutting edge comes into contact with the surface of the cavity surface 26 of the base material that forms the side plate. In this state, the ring-shaped base material is rotated with the center thereof as an axis. Thus, the smooth base cavity surface 20 is formed. Thus, the main body 18 is formed.

[0045] In the process of (3) described above, the metal layer 22 is formed in the region of the base cavity surface 20 that includes the position corresponding to the recess 6 of the tire 2. Figure 5 (b) of FIG. 8 is a cross-sectional view showing the metal layer 22 together with the main body 18. Figure 6 (a) of FIG. 8 is a plan view showing the metal layer 22 together with the main body 18. (b) of FIG. 8 is a view as seen from above of (a) of FIG. 8. In this embodiment, the metal layer 22 is formed on the base cavity surface 20 in the region corresponding to the region that surrounds the plurality of characters 4 as a whole. In this embodiment, the planar shape of the metal layer 22 is rectangular. Figure 5 (a) of FIG. 8 is a plan view showing the metal layer 22 together with the main body 18. (b) of FIG. 8 is a view as seen from above of (a) of FIG. 8. In this embodiment, the metal layer 22 is formed on the base cavity surface 20 in the region corresponding to the region that surrounds the plurality of characters 4 as a whole. In this embodiment, the planar shape of the metal layer 22 is rectangular.

[0046] In this embodiment, the metal layer 22 is formed by plating. Specifically, the metal layer 22 is formed by electroplating. The material of the metal layer 22 is iron or iron alloy. In this embodiment, the material of the metal layer 22 is iron alloy in which the content rate of iron is 99% by mass. The method of forming the metal layer 22 can also be other than plating. For example, the metal layer 22 can also be formed by sputtering. The metal layer 22 can also be formed by other methods.

[0047] In the process of (4) described above, the protrusion 16 is formed by cutting the metal layer 22. The metal layer 22 is cut away leaving the protrusion 16 in the shape corresponding to the recess 6 of the tire 2. Thus, the protrusion 16 is formed on the base cavity surface 20. Figure 5 (c) of FIG. 10 is a cross-sectional view showing the protrusion 16 together with the main body 18. Figure 6 (b) of FIG. 10 is a plan view showing the protrusion 16 together with the main body 18. In this embodiment, the protrusion 16 is formed by engraving processing. By forming the protrusion 16 on the base cavity surface 20, the cavity surface 26 of the side plate is obtained.

[0048] In the case where the upper side plate 12 has the protrusion 16, the side plate 12 is formed by the processes of (1) to (4) described above. In the case where the upper side plate 12 does not have the protrusion 16, the side plate 12 is formed by the processes of (1) and (2) described above.

[0049] In the above embodiment, the side plate 12 is formed by the processes of (1) to (4) described above. Other constituent members of the mold 8 can also be formed by these processes.

[0050] In the manufacture of the tire 2, the side plate 12 is formed by the above-described process. Next, the segment 10 and the bead ring 14 are prepared, thereby obtaining the mold 8. The green tire R is put into the mold 8. The green tire R is heated while being pressed in the closed mold 8. By the pressing and the heating, the rubber composition of the green tire R flows in the cavity. The rubber is cross-linked by the heating. Thus, the tire 2 is obtained.

[0051] Hereinafter, the effects of the present application will be described.

[0052] In the manufacturing method of the mold 8 of the present application, the metal layer 22 is formed in the region of the base cavity surface 20 that includes the position corresponding to the recess 6. The projection 16 is formed by cutting the metal layer 22. In the manufacturing method, in order to form the projection 16, it is only necessary to cut the metal layer 22. The region that should be cut in order to form the projection 16 can be reduced. In the method, the mold 8 can be efficiently formed. In the manufacturing method, since no other member is embedded in the main body, no step difference between them is generated. In the manufacturing method, the tire 2 having an excellent appearance can be manufactured.

[0053] In the embodiment, the metal layer 22 is formed by the plating method. By the method, the metal layer 22 is efficiently formed at the desired position of the base cavity surface 20. In the method, the mold 8 can be efficiently formed. Next, by the plating method, the metal layer 22 is firmly fixed to the base cavity surface 20. In the method, the projection 16 formed by cutting the metal layer 22 is firmly fixed to the base cavity surface 20. In the mold 8, the projection 16 is prevented from being detached from the base cavity surface 20. The durability of the mold 8 is excellent.

[0054] In the embodiment, the material of the metal layer 22 is iron alloy. The iron alloy has excellent strength. In the mold 8, the strength of the projection 16 is high. The durability of the mold 8 is excellent. Further, the iron alloy has moderate hardness. The iron alloy is easy to process. In the method, the projection 16 can be efficiently formed. In the method, the mold 8 can be efficiently formed. From this viewpoint, the material of the metal layer 22 can also be iron.

[0055] In the embodiment, the base cavity surface 20 is formed by the lathe processing. In the lathe processing, the cutting edge is brought into abutment with the surface of the ring-shaped base material while the base material is rotated. In the lathe processing, a large region can be cut at high speed. In the method, the base cavity surface 20 can be formed in a short time. In the method, the mold 8 can be efficiently formed.

[0056] In this embodiment, the convex portion 16 is formed by engraving the metal layer 22. In the engraving, the complex-shaped convex portion 16 can be formed with high precision. In this manufacturing method, the tire 2 having an excellent appearance can be manufactured. Embodiment

[0057] Hereinafter, the effects of the present application will be clarified by an embodiment, but the present application should not be interpreted limitatively based on the description of the embodiment. Embodiment

[0058] In the above-described methods (1) to (4), a cavity surface of a side plate shown in Figure 2 and 3 is formed. The cavity surface of the side plate has a convex portion for forming a letter on a tire. In the process (1) above, a base material composed of steel is prepared. In the process (2) above, a basic cavity surface is formed by lathe processing. In the process (3) above, a layer of a ferrous alloy is formed on the basic cavity surface by an electroplating method. The content of iron of the ferrous alloy is 99 mass%. The surface area of the layer of the ferrous alloy is 15% of the surface area of the basic cavity surface. In the process (4) above, the layer of the ferrous alloy is cut by engraving processing to form the convex portion for forming the letter on the tire. Thereby, the cavity surface is formed.

[0059] [Comparative Example]

[0060] A base material for a side plate identical to that of the embodiment is prepared. A surface of the base material as a cavity surface is cut by engraving processing to form a convex portion for forming a letter on a tire. Thereby, the cavity surface is formed.

[0061] [Time for forming cavity surface]

[0062] In the embodiment and the comparative example, the processing time from the preparation of the base material to the formation of the cavity surface was measured, respectively. As a result, the processing time of the embodiment was 70% of the processing time of the comparative example.

[0063] As described above, according to the present application, a mold from which a tire having an excellent appearance can be manufactured can be efficiently manufactured. Therefore, the superiority of the present application is obvious.

[0064] Industrial applicability

[0065] The above-described method can also be applied to the manufacture of a mold for each tire.

Claims

1. A manufacturing method of a mold for a tire, the mold being used to manufacture a tire having a recessed portion recessed from a reference surface on a surface, wherein the manufacturing method comprises processes of: (A) forming a base cavity surface for forming the reference surface when the recessed portion is not present; (B) forming a metal layer only at a region on the base cavity surface corresponding to the recessed portion, the metal layer having an area smaller than an area of the base cavity surface; and (C) cutting the metal layer to form a protruding portion having a shape corresponding to the recessed portion.

2. The manufacturing method according to claim 1, wherein in the process of (B), the metal layer is formed by a plating method.

3. The manufacturing method according to claim 2, wherein in the process of (B), a layer of iron or an iron alloy is formed.

4. The manufacturing method according to any one of claims 1 to 3, wherein in the process of (A), the base cavity surface is formed by lathe processing.

5. The manufacturing method according to any one of claims 1 to 3, wherein in the process of (C), the protruding portion is formed by engraving processing.

6. The manufacturing method according to any one of claims 1 to 3, wherein the mold has a side plate that contacts a side portion of a green tire, and wherein a cavity surface of the side plate is formed by the processes of (A) to (C).

7. A manufacturing method of a tire, the manufacturing method comprising processes of: manufacturing a mold by the manufacturing method of a mold for a tire according to any one of claims 1 to 6; and pressurizing and heating a green tire in the mold. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Images