A tire stud according to the present invention is manufactured from ceramic, and thus has characteristics of causing the strength of ceramics to recover through crack healing while lowering residual stress by improving a sintering process. In addition, abrasion resistance is improved by further adding a sintering aid and an organic oxide during sintering, and thus friction with a road surface can always be maintained to be constant and life span can be greatly increased.

A tire stud according to the present invention is manufactured from ceramic, and thus has characteristics of causing the strength of ceramics to recover through crack healing while lowering residual stress by improving a sintering process. In addition, abrasion resistance is improved by further adding a sintering aid and an organic oxide during sintering, and thus friction with a road surface can always be maintained to be constant and life span can be greatly increased.

Disclosed is a tire stud comprising a stainless steel body with a flange and a blind hole and further comprising a spike installed in said hole, wherein the cross-sectional shape of the hole is different from the cross-sectional shape of the spike at least at one of: the opening, the lower surface of the spike, and a depth between the opening lower surface of the spike; whereby only protrusions of the spike are attached to the side wall of the hole with friction joints where the cross-sectional shape of the hole is different from the cross-sectional shape of the spike.

A stud is inserted into a tread portion of a tire. The first stud includes a tip end protruding from the tread portion for contacting a surface, the tip end comprising a radially outer portion with a first surface, a second surface, a third surface, a fourth surface, a fifth surface, a sixth surface, and a seventh surface, the first surface defining an irregular quadrilateral and extending radially inward from the fourth surface toward a planar side of the tip end; and a base including a flanged bottom portion provided on an end opposite the tip end and extending radially outward, a stump portion provided between the bottom portion and the tip end, and a shank portion interconnecting the stump portion and the bottom portion, the base being embedded and secured in the tread portion of the tire in which the first stud is installed, the bottom portion having a tear-drop shape comprising three planar sides and one semi-cylindrical side.

In a stud pin, a flange contour shape of a lower flange is an anisotropic shape in which, among imaginary rectangles circumscribing the contour shape, the smallest rectangle includes short sides and long sides having different lengths. The flange contour shape includes first recess portions on each of portions of the flange contour shape extending along the short sides, the first recess portions being curved toward a centroid of the flange contour shape, and the flange contour shape includes a second recess portion on portions of the flange contour shape extending along the long sides, the second recess portions being curved toward the centroid of the flange contour shape. A body contour shape of a body portion is a polygonal shape including vertex angles in a same number as the first and second recess portions, and the vertex angles are disposed facing the first and second recess portions.

A stud pin and a pneumatic tire are provided. A tip portion of the stud pin includes an end surface with a concave polygonal profile shape including one recessed portion and one protrusion portion on a side opposite the recessed portion. The stud pin is mounted in a stud pin installation hole with the protrusion portion facing a leading side in a tire circumferential direction and the recessed portion face a trailing side.

A tire has a tread having a first tread edge, a second tread edge on the opposite side, and multiple inclined main grooves formed such that each inclined main groove is obliquely extending from one of the first and second tread edges toward a tire equator and is terminated without reaching the other one of the first and second tread edges. The inclined main grooves are formed such that each of the inclined main grooves includes a tire axial direction outer side portion obliquely extending in an inclined direction, a tire axial direction inner side portion inclining in the inclined direction, and a middle portion formed between the tire axial direction outer side portion and the tire axial direction inner side portion and inclining in the opposite inclined direction with respect to the inclined direction of the tire axial direction outer side portion and tire axial direction inner side portion.

A tire has a tread having a first tread edge, a second tread edge on the opposite side, and multiple inclined main grooves formed such that each inclined main groove is obliquely extending from one of the first and second tread edges toward a tire equator and is terminated without reaching the other one of the first and second tread edges. The inclined main grooves are formed such that each of the inclined main grooves includes a tire axial direction outer side portion obliquely extending in an inclined direction, a tire axial direction inner side portion inclining in the inclined direction, and a middle portion formed between the tire axial direction outer side portion and the tire axial direction inner side portion and inclining in the opposite inclined direction with respect to the inclined direction of the tire axial direction outer side portion and tire axial direction inner side portion.

A stud is configured to be inserted into a tread portion of a tire. The stud includes a tip end protruding from the tread portion for contacting a surface, and a base including a flanged bottom portion provided on an end opposite the tip end and extending radially outward, a stump portion provided between the bottom portion and the tip end, and a shank portion interconnecting the stump portion and the bottom portion. The base is embedded and secured in the tread portion of the tire in which the stud is installed. The bottom portion has a tear-drop shape consisting of three planar sides and one semi-cylindrical side. The stump portion has a polygonal shape consisting of three concave sides, two convex sides, and one planar side.

A stud pin includes a tip, a body portion that supports the tip, and a lower flange connected to the body portion at an end on an opposite side to the end surface. A profile shape of the lower flange and a body profile shape of the body portion are anisotropic shape. The flange profile shape includes four or more first flange protrusion portions projecting toward the longitudinal direction and two second flange protrusion portions projecting toward the lateral direction. The body profile shape includes four or more first body protrusion portions projecting toward the lateral direction and two second body protrusion portions projecting toward the longitudinal direction.