Stud pin and pneumatic tire
View Patent ↗A stud pin configured to be installed in a stud pin installation hole in a tread portion of a pneumatic tire includes a tip end which makes contact with a road surface; and a buried base embedded in the tread portion; pressure from the side surface of the stud pin installation hole on the bottom portion and the trunk portion securing the stud pin. The buried base extends in one direction and includes a flanged trunk portion provided between the bottom portion and the tip portion. The bottom portion includes a plurality of first recesses formed on and along an outer peripheral surface thereof that is in contact with a side surface of the stud pin installation hole. The trunk portion includes a plurality of second recesses formed on and along an outer peripheral surface thereof that is in contact with the side surface of the stud pin installation hole.
1. A stud pin configured to be inserted into a stud pin installation hole in a tread portion of a pneumatic tire, the stud pin comprising:
a tip end protruding from the tread portion to make contact with a road surface; and
a buried base including a flanged bottom portion provided on an end opposite the tip end and extending in one direction; a flanged trunk portion provided between the bottom portion and the tip end; the buried base being embedded in the tread portion of the pneumatic tire in which the stud pin is installed, and pressure from a side surface of the stud pin installation hole on the bottom portion and the trunk portion securing the stud pin;
the bottom portion including a plurality of first recesses formed on and along an outer peripheral surface thereof that comes into contact with the side surface of the stud pin installation hole;
the trunk portion including a plurality of second recesses formed on and along an outer peripheral surface thereof that comes into contact with the side surface of the stud pin installation hole;
the first recesses provided on the bottom portion and the second recesses provided on the trunk portion being provided at a same peripheral position on the outer peripheral surface of the buried base; and
wherein a first projection is formed between the first recesses on the periphery of the outer peripheral surface of the bottom portion of the buried base, and a shape of the first projection along the bottom portion is a first arc having a radius of curvature of R1 larger than half L 1 of the bottom portion in a width direction orthogonal to the extending direction of the buried base.
2. The stud pin according to claim 1 , wherein, at least one cavity is formed along the periphery of the outer peripheral surface of the tip end; and the cavity, the first recesses, and the second recesses are formed at the same peripheral position on the outer peripheral surface of the tip end and the outer peripheral surface of the buried base.
3. The stud pin according to claim 2 , wherein a shape of the first recesses along the outer peripheral surface is a third arc, and a radius of curvature R 3 of the third arc is larger than the radius of curvature R 1 of the first arc.
4. The stud pin according to claim 3 , wherein a length of the first recesses along the outer peripheral surface is greater than a length of the first projection along the outer peripheral surface of the buried base.
5. The stud pin according to claim 4 , wherein a second projection is formed between the second recesses on the periphery on the outer peripheral surface of the trunk portion of the buried base, and a shape of the second projection along the trunk portion is a second arc having a radius of curvature of R 2 equivalent to half a maximum size of the trunk portion in the width direction orthogonal to the extending direction of the buried base or larger than half the maximum size.
6. The stud pin according to claim 5 , wherein the shape of the second recesses along the outer peripheral surface is a fourth arc, and a radius of curvature R 4 of the fourth arc is larger than the radius of curvature R 2 of the second arc.
7. The stud pin according to claim 1 , wherein a shape of the first recesses along the outer peripheral surface is a third arc, and a radius of curvature R 3 of the third arc is larger than the radius of curvature R 1 of the first arc.
8. The stud pin according to claim 1 , wherein a length of the first recesses along the outer peripheral surface is greater than a length of the first projection along the outer peripheral surface of the buried base.
9. The stud pin according to claim 1 , wherein a second projection is formed between the second recesses on the periphery on the outer peripheral surface of the trunk portion of the buried base, and a shape of the second projection along the trunk portion is a second arc having a radius of curvature of R 2 equivalent to half a maximum size of the trunk portion in a width direction orthogonal to the extending direction of the buried base or larger than half the maximum size.
10. The stud pin according to claim 9 , wherein the shape of the second recesses along the outer peripheral surface is a fourth arc, and a radius of curvature R 4 of the fourth arc is larger than the radius of curvature R 2 of the second arc.
11. The stud pin according to claim 9 , wherein a length of the second recesses along the outer peripheral surface is greater than a length of the second projections along the outer peripheral surface of the buried base.
12. The stud pin according to claim 1 , wherein the maximum size L 1 of the bottom portion in the width direction orthogonal to the extending direction of the buried base is greater than a maximum size L 2 of the trunk portion in the width direction, and a minimum size L 4 of the bottom portion in a width direction orthogonal to the extending direction of the base is greater than a minimum size L 5 of the trunk portion in the width direction; and
the maximum size L 2 of the trunk portion is greater than the minimum size L 4 of the bottom portion.
13. The stud pin according to claim 1 , wherein a ratio L 1 /L 2 of the maximum size L 1 of the bottom portion in a width direction to a maximum size L 2 of the trunk portion in the width direction is greater than 1.0 and less than or equal to 1.5, the width direction being orthogonal to the extending direction of the buried base.
14. The stud pin according to claim 13 , wherein a ratio L 2 /L 3 of the maximum size L 2 of the trunk portion in the width direction to a maximum size L 3 of the tip end in the width direction orthogonal to the extending direction of the buried base of the stud pin is not less than 1.5 and not greater than 3.5.
15. The stud pin according to claim 1 , wherein upon the extending direction of the buried base of the stud pin being a height direction, a height from a bottom surface of the bottom portion of the buried base opposite the tip end is H 1 , and a height from the bottom surface to a top end of the bottom portion is H 2 , and a ratio H 1 /H 2 of the height H 1 to the height H 2 is from 6.0 to 9.0.
16. A pneumatic tire comprising a tread portion provided with a stud pin installation hole and a stud pin installed in the stud pin installation hole, the stud pin comprising:
a tip end protruding from the tread portion to make contact with a road surface; and
a buried base including a flanged bottom portion provided on an end opposite the tip end and extending in one direction; a flanged trunk portion provided between the bottom portion and the tip end; the buried base being embedded in the tread portion of the pneumatic tire in which the stud pin is installed, and pressure from a side surface of the stud pin installation hole on the bottom portion and the trunk portion securing the stud pin;
the bottom portion including a plurality of first recesses formed on and along an outer peripheral surface thereof that comes into contact with the side surface of the stud pin installation hole;
the trunk portion including a plurality of second recesses formed on and along an outer peripheral surface thereof that comes into contact with the side surface of the stud pin installation hole; and
the first recesses provided on the bottom portion and the second recesses provided on the trunk portion being provided at a same peripheral position on the outer peripheral surface of the buried base; and wherein a first projection is formed between the first recesses on the periphery of the outer peripheral surface of the bottom portion of the buried base, and a shape of the first projection along the bottom portion is a first arc having a radius of curvature of R1 larger than half a maximum size L 1 of the bottom portion in a width direction orthogonal to the extending direction of the buried base.
17. The pneumatic tire according to claim 16 , wherein the side surface of the stud pin installation hole abutting the bottom portion of the stud pin installation hole is a cylindrical curved surface along the periphery of the stud pin installation hole; and
a minimum size L 4 of the bottom portion in a width direction orthogonal to the extending direction of the buried base is greater than a diameter of the cylindrical shape of the curved surface abutting the bottom portion of the stud pin installation hole.
18. The pneumatic tire according to claim 16 , wherein the side surface of the stud pin installation hole abutting the trunk portion of the stud pin installation hole is a cylindrical curved surface along the periphery of the stud pin installation hole; and
a minimum size L 5 of the trunk portion in a width direction orthogonal to the extending direction of the buried base is greater than a diameter of the cylindrical shape of the curved surface abutting the trunk portion of the stud pin installation hole.