Method for Producing Pneumatic Tires, Tire Mold, and Pneumatic Tires

• US 20200130310A1
• Filed: 04/18/2018
• Published: 04/30/2020
• Est. Priority Date: 04/20/2017
• Status: Active Application

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Hatano, Atsuya
• Application Number:
  US16/606,181
• Publication Number:
  US 20200130310A1
• Time in Patent Office: Days
• CPC Class Codes: B29C 33/42 characterised by the shape of the moulding surface, e.g. ribs or grooves
• CPC Class Codes: B29C 33/428 For altering indicia, e.g. data, numbers for injection moulding B29C45/374
• CPC Class Codes: B29D 2030/0612 Means for forming recesses or protrusions in the tyres, e.g. grooves or ribs, to create the tread or sidewalls patterns
• CPC Class Codes: B29D 2030/0618 Annular elements, e.g. rings, for moulding the tyre shoulder areas
• CPC Class Codes: B29D 2030/726 Decorating or marking the sidewalls before tyre vulcanization protecting, decorating, marking tyre sidewalls B60C13/00
• CPC Class Codes: B29D 30/0606 Vulcanising moulds not integral with vulcanising presses for solid tyres B29D30/02
• CPC Class Codes: B29D 30/72 Side-walls
• CPC Class Codes: B60C 13/001 Decorating, marking or the like

Abstract

In manufacturing a pneumatic tire, a replaceable member having a smooth flat surface is attached to a mold body of a tire mold configured to vulcanize an unvulcanized tire into a predetermined shape by contact with the unvulcanized tire. A mold inner surface that forms the shape of a tire side surface portion includes a curved surface of the mold body and the flat surface surrounded by the curved surface. A vulcanized tire is produced by vulcanizing the unvulcanized tire by bringing the unvulcanized tire into contact with the mold inner surface. A two-dimensional code is engraved in a planar surface region of the vulcanized tire, which corresponds to the flat surface. In the two-dimensional code, a dot pattern is formed by two types of gray scale elements that are formed identifiable from each other by surface unevenness.

Claims

1. A method for manufacturing a pneumatic tire, the method comprising:

attaching a replaceable member including a smooth flat surface to a mold body of a tire mold configured to vulcanize an unvulcanized tire into a predetermined shape by contact with the unvulcanized tire, and forming a mold inner surface including a curved surface of the mold body and the flat surface surrounded by the curved surface, the mold inner surface being configured to form shapes of sidewall portions and bead portions of a vulcanized tire;

vulcanizing the unvulcanized tire by bringing the unvulcanized tire into contact with the mold inner surface and manufacturing a vulcanized tire; and

manufacturing a pneumatic tire by engraving a two-dimensional code in a planar surface region of at least one of the sidewall portions or the bead portions of the vulcanized tire, the planar surface region corresponding to the flat surface, the two-dimensional code including a dot pattern formed by two types of gray scale elements formed identifiable from each other by surface unevenness.

2. The method for manufacturing a pneumatic tire according to claim 1, wherein the flat surface of the mold inner surface is a surface located inward from a base portion of the curved surface surrounding the flat surface in a direction away from the unvulcanized tire.

3. The method for manufacturing a pneumatic tire according to claim 1, wherein in a case where a portion of a side rubber member prior to engraving of the two-dimensional code in which the two-dimensional code of the vulcanized tire is to be engraved has a minimum thickness of 5.8 mm or less, the flat surface is a surface located inward in a direction away from the unvulcanized tire.

4. The method for manufacturing a pneumatic tire according to claim 1, wherein the flat surface of the mold inner surface is a surface located outward from a base portion of the curved surface surrounding the flat surface in a direction toward the unvulcanized tire.

5. The method for manufacturing a pneumatic tire according to claim 1, wherein in a case where a portion of a side rubber member prior to engraving the two-dimensional code in which the two-dimensional code of the vulcanized tire is to be engraved has a minimum thickness of greater than 5.8 mm, the flat surface is a surface located outward in a direction toward the unvulcanized tire.

6. The method for manufacturing a pneumatic tire according to claim 4, wherein in the vulcanized tire, a shortest distance from the planar surface region of the vulcanized tire to a portion of a carcass cord in the vulcanized tire, which is closest to the planar surface region is 65% or greater of a shortest distance from the base portion to a portion of the carcass cord which is closest to the base portion.

7. The method for manufacturing a pneumatic tire according to claim 1, wherein the flat surface is provided so that the planar surface region of the vulcanized tire is inclined with respect to a plane defined by a base portion of the curved surface region surrounding the planar surface region.

8. The method for manufacturing a pneumatic tire according to claim 7, wherein one portion of the flat surface is located outward from the base portion in a direction toward the unvulcanized tire, and another portion of the flat surface is an inclined surface inclined with respect to the base portion and located inward in a direction away from the unvulcanized tire.

9. The method for manufacturing a pneumatic tire according to claim 1, wherein an outermost surface of the flat surface is provided with a plated layer.

10. The method for manufacturing a pneumatic tire according to claim 1, comprising:

attaching a plurality of the members to a plurality of locations of the mold body and forming the mold inner surface; and

at the time of engraving the two-dimensional code, engraving the two-dimensional code in the planar surface region of the sidewall portion or the bead portion, the planar surface region corresponding to the flat surface in each of the plurality of locations.

11. The method for manufacturing a pneumatic tire according to claim 1, wherein the two-dimensional code is engraved by making a plurality of dot holes extending in a direction orthogonal to a plane of the planar surface region.

12. A tire mold configured to vulcanize an unvulcanized tire into a predetermined shape by contact with the unvulcanized tire, the tire mold comprising:

a mold body including a contact portion with the unvulcanized tire including a curved surface; and

a replaceable member including a contact portion with the unvulcanized tire including a flat surface, the flat surface being disposed surrounded by the curved surface, the flat surface being located inward from a base portion of the curved surface surrounding the flat surface in a direction away from the unvulcanized tire or being located outward from the base portion in a direction toward the unvulcanized tire.

13. A pneumatic tire, comprising:

a tread portion contactable with a road surface;

sidewall portions provided sandwiching the tread portion on opposite sides in a tire lateral direction; and

bead portions connected to the sidewall portions and located inward of the sidewall portions in a tire radial direction;

wherein

a surface of at least one of tire side surface portions of the sidewall portions or the bead portions includes;

a curved surface region formed in a curved shape and protruding in the tire radial direction and outward in the tire lateral direction; and

a planar surface region disposed surrounded by the curved surface region, the planar surface region being provided with a two-dimensional code in which a dot pattern is formed by two types of gray scale elements formed identifiable from each other by surface unevenness.

14. The pneumatic tire according to claim 13, wherein the planar surface region is inclined with respect to a reference plane orthogonal to a rotation axis of the pneumatic tire.

15. The pneumatic tire according to claim 13, wherein an arithmetic mean roughness Ra of the planar surface region is less than an arithmetic mean roughness Ra in a region including a base portion of the curved surface region surrounding the planar surface region.

16. The pneumatic tire according to claim 13, wherein the surface unevenness is formed by a plurality of dot holes formed in the planar surface region, and

the dot holes extend in a direction orthogonal to a plane of the planar surface region.