Stud pin and studded tire
A stud pin includes a tip, a body portion, and a lower flange. A flange profile shape of the lower flange is an anisotropic shape includes short sides and long sides of different lengths, and includes four or more first flange protrusion portions that project in the longitudinal direction parallel with the long sides and two second flange protrusion portions that project in the lateral direction parallel with the short sides. A body profile shape of the body portion is a shape including body linear portions extending in a linear manner. The body linear portions are disposed facing a portion of the flange profile shape between two adjacent protrusion portions of the first flange protrusion portion and the second flange protrusion portion along the outer circumference of the flange profile shape.
1. A stud pin installable in a studdable tire, comprising:
a tip comprising an end surface that comes into contact with a road surface;
a body portion that supports the tip so that the tip projects from an end surface on one side of the body portion; and
a lower flange connected to an end of the body portion on an opposite side to the end surface; wherein
a flange profile shape of the lower flange as viewed from an arrangement direction of the tip, the body portion, and the lower flange is an anisotropic shape in which, of imaginary rectangles circumscribing the flange profile shape, a first smallest rectangle with a shortest side of its four sides being a smallest and/or a second smallest rectangle with a longest side of its four sides being a smallest comprise short sides and long sides of different lengths;
the flange profile shape comprises four or more first flange protrusion portions that project toward a longitudinal direction parallel with the long sides and two second flange protrusion portions that project toward a lateral direction parallel with the short sides;
a body profile shape of the body portion as viewed from the arrangement direction is a shape comprising body linear portions extending in a linear manner;
the body linear portions are disposed facing a portion of the flange profile shape along an outer circumference of the flange profile shape between two adjacent protrusion portions of the first flange protrusion portions;
the first flange protrusion portions are constituted by two pairs of the first flange protrusion portions;
the flange profile shape comprises two first flange recess portions curved toward a centroid of the flange profile shape and disposed between each of the pairs of the first flange protrusion portions and at least one second flange recess portion curved toward the centroid, disposed between each of the second flange protrusion portions and one of the first flange protrusion portions, and smoothly connect to one of the first flange protrusion portions; and
a radius of curvature of the first recess portions is smaller than a radius of curvature of the at least one second flange recess portion.
2. The stud pin according to claim 1 , wherein
the body profile shape comprises, as the body linear portions, two first body linear portions disposed facing a portion of the flange profile shape between each of the two pairs of the first flange protrusion portions and four second body linear portions disposed facing a portion of the flange profile shape between each of the second flange protrusion portions and one of the first flange protrusion portions.
3. The stud pin according to claim 2 , wherein
the at least one second flange recess portion of the flange profile shape comprises four second flange recess portions; and
the first body linear portions are disposed facing the first flange recess portions, and the second body linear portions are disposed facing the four second flange recess portions.
4. The stud pin according to claim 3 , wherein
the two second flange protrusion portions comprise two flange linear portions parallel with the longitudinal direction; and
the flange linear portions are portions projecting most in the lateral direction.
5. The stud pin according to claim 4 , wherein
the body portion is encompassed within the flange profile shape when viewed from the arrangement direction;
the body profile shape comprises two body protrusion portions projecting toward the second flange protrusion portions; and
the body protrusion portions each comprises two of the second body linear portions connected together.
6. The stud pin according to claim 5 , wherein
the body portion is encompassed within the flange profile shape when viewed from the arrangement direction;
the body profile shape comprises two body protrusion portions projecting toward the short sides of the smallest rectangle;
the body protrusion portions comprise the first body linear portions; and
the first body linear portions are portions projecting most in a longitudinal direction parallel with the long sides of the smallest rectangle.
7. A studded tire that is a studdable tire installed with a stud pin, comprising:
a tread portion installed with the stud pin described in claim 6 with the longitudinal direction or the lateral direction facing a tire circumferential direction.
8. The stud pin according to claim 2 , wherein
the body portion is encompassed within the flange profile shape when viewed from the arrangement direction;
the body profile shape comprises two body protrusion portions projecting toward the second flange protrusion portions; and
the body protrusion portions each comprises two of the second body linear portions connected together.
9. The stud pin according to claim 2 , wherein
the body portion is encompassed within the flange profile shape when viewed from the arrangement direction;
the body profile shape comprises two body protrusion portions projecting toward the short sides of the smallest rectangle;
the body protrusion portions comprise the first body linear portions; and
the first body linear portions are portions projecting most in a longitudinal direction parallel with the long sides of the smallest rectangle.
10. The stud pin according to claim 1 , wherein
the two second flange protrusion portions comprise two flange linear portions parallel with the longitudinal direction; and
the flange linear portions are portions projecting the most in the lateral direction.
11. A studded tire that is a studdable tire installed with a stud pin, comprising:
a tread portion installed with the stud pin described in claim 1 with the longitudinal direction or the lateral direction facing a tire circumferential direction.