Tire mold, production method for tire, and tire

A tire mold to produce a tire including a tread having a tread surface that comes into contact with a road surface, at least two circumferential grooves having a groove width of not less than 9 mm being formed on the tread so as to extend in a circumferential direction, thereby forming at least three land portions in the tread, the tread surface including the at least two circumferential grooves and at least three land surfaces that are outer surfaces of the at least three land portions, the tire mold comprising:

• a tread-forming surface to shape the tread surface, wherein
• the tread-forming surface includes at least two projections to respectively form the at least two circumferential grooves, and at least three land surface-forming portions to respectively form the at least three land surfaces,
• among the at least three land surface-forming portions, a first land surface-forming portion located on an outer side in an axial direction is a shoulder land surface-forming portion, a second land surface-forming portion located inward of the shoulder land surface-forming portion is a middle land surface-forming portion, and a projection between the shoulder land surface-forming portion and the middle land surface-forming portion is a shoulder projection,
• a surface that is tangent to the at least three land surface-forming portions is defined as a reference surface of the tread-forming surface, and a tangent point shared by the shoulder land surface-forming portion and the reference surface of the tread-forming surface on a shoulder projection side is defined as a first reference position on the reference surface,
• a first contour of a first portion from an end of the first contour on the shoulder projection side of said shoulder land surface-forming portion to the first reference position is represented by a first single, continuous circular arc that is convex outward in a radial direction,
• a second contour of a second portion from an end of the second contour to a second reference position on the reference surface is represented by a second single, continuous circular are that is convex outward in the radial direction, and
• a first distance, in the radial direction, from the reference surface of the tread-forming surface to the end of the first contour is greater than a second distance, in the radial direction, from the reference surface of the tread-forming surface to the end of the second contour.

A production method for a tire including a tread having a tread surface that comes into contact with a road surface, at least two circumferential grooves having a groove width of not less than 9 mm being formed on the tread so as to extend in a circumferential direction, thereby forming at least three land portions in the tread, the tread surface including the at least two circumferential grooves and at least three land surfaces that are outer surfaces of the at least three land portions, the production method comprising:

• providing tire material in a tire mold;
• and
• pressurizing and heating the tire material in the tire mold, wherein the tire mold includes a tread-forming surface to shape the tread surface,
• wherein the tread-forming surface includes at least two projections to respectively form the at least two circumferential grooves, and at least three land surface-forming portions to respectively form the at least three land surfaces,
• wherein a contour of a land surface-forming portion between two projections among the at least three land surface-forming portions is represented by a single, continuous circular arc that is convex outward in a radial direction,
• of the two projections, a first projection is a wide projection having a larger width than a second projection, and the second projection is a narrow projection having a smaller width than the first projection,
• wherein a surface that is tangent to the at least three land surface-forming portions is defined as a reference surface of the tread-forming surface, and
• wherein a wide-side drop distance, which is a first distance, in the radial direction, from the reference surface of the tread-forming surface to a first end of the contour of the land surface-forming portion between the two projections on a wide projection side, is greater than a narrow-side drop distance, which is a second distance, in the radial direction, from the reference surface of the tread-forming surface to a second end of the contour of the land surface-forming portion between the two projections on a narrow projection side.