JP2016097830A - Stud and studdable tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stud that has a large edge effect to have satisfactory braking and driving performance, improves stud fall resisting performance, can increase strength of a pin part to suppress damage to the pin part, and has high durability of the pin part, and a studdable tire.SOLUTION: A stud 1 according to the present invention comprises: a columnar body part 2; a pin part 3Y provided at one end of the body part in a direction along a center axis; and a flange part 4 provided at the other end of the body part in the direction along the center axis. In the stud, the pin part 3Y is characterized in that a height dimension at one end in a pin part radial direction as a direction orthogonal to the center axis is different from a height dimension at the other end in the pin part radial direction.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a stud for a studable tire (hereinafter simply referred to as “stud”) and a studded tire formed by attaching the stud.

Conventionally, as shown in FIG. 13, a body portion 120, a pin portion 130 provided at one end in the direction along the central axis 100C, and a flange portion 140 provided at the other end in the direction along the central axis 100C, The pin portion 130 protrudes from the tread surface by being fitted with a mounting hole formed on the tread surface side of the tire from the flange portion 140 side. There is known a stud 100 embedded on the tread surface side, in which a cross-sectional shape orthogonal to the central axis 100C of the body portion 120, the pin portion 130, and the flange portion 140 is formed in a circle.
That is, the stud 100 has a body portion 120 and a pin portion 130 formed in a cylindrical shape extending in a direction along the central axis 100C, and one end surface (tip surface) 131 of the pin portion 130 has A groove 132 extending in a direction orthogonal to the central axis 100C is formed in a cross shape in plan view.
Here, the central axis 100C refers to the center of rotation of the stud in the radial direction (depth direction) embedded in the tire of the pin part, the body part, and the flange part, that is, the axis of the center of gravity in the cross section orthogonal to the radial direction. Say.
When the stud 100 is suddenly started / accelerated when the stud 100 is attached to a mounting hole formed on the tread surface side of the tire, the stud 100 comes off from the surface side of the tire tread. The situation is shown in FIG. In FIG. 14, W indicates the rolling direction of the studded tire 150, and the side of the stud 100 that contacts the ground first when the studded tire 150 rolls is called the stepping side F. The side that comes into contact with the ground later when rolling is called the kicking side R.
The studable tire 150 is required to have durability performance of the pin portion 130, edge performance that scratches ice on the road surface on the pin portion 130 side, anti-stud removal performance that suppresses the stud 100 from falling off, and the like.
The tire tread includes a body portion, a pin portion provided at one end in the direction along the central axis of the body portion, and a flange portion provided at the other end in the direction along the central axis of the body portion. There is known a stud in which a pin part is formed in an elliptical column shape in a stud embedded in a tread surface side so that the pin part protrudes from the tread surface by being fitted into a mounting hole formed on the surface side from the flange part side. (See Patent Document 1).

Japanese Patent No. 4088055

It is effective to reduce the scratching effect of the pin part to improve the anti-stud removal performance, while it is effective to increase the scratching effect of the pin part to improve the braking / driving performance. It has been difficult for the conventional pin portion to achieve both the anti-stud removal performance and the braking / driving performance, which are contradictory properties, and to increase the durability of the pin portion.
The present invention provides a stud with high durability of the pin portion, which has a large edge effect, improves braking / driving performance, improves anti-stud removal performance, can increase the strength of the pin portion and suppress damage to the pin portion, and An object is to provide a studded tire.

The stud according to the present invention includes a columnar body portion, a pin portion provided at one end in the direction along the central axis of the body portion, and a flange portion provided at the other end in the direction along the central axis of the body portion. Since the pin portion is characterized in that the height dimension at one end in the pin portion radial direction, which is a direction orthogonal to the central axis, is different from the height dimension at the other end in the pin portion radial direction. In addition to the large edge effect, the braking / driving performance can be improved, the stud removal resistance can be improved, the strength of the pin portion can be increased, and the pin portion can be prevented from being damaged.
In addition, since one end in the pin portion radial direction and the other end in the pin portion radial direction are located on the shortest pin portion radial line passing through the central axis, the edge effect is large and the braking / driving performance is good. At the same time, it is possible to provide a stud with high durability of the pin portion that can improve the anti-stud removal performance, increase the strength of the pin portion, and suppress damage to the pin portion.
In the studded tire according to the present invention, the short direction of the pin part that intersects the one end of the pin part radial direction and the other end of the pin part radial direction perpendicular to the central axis extends along the tire circumferential direction. In addition, since the stud is attached to a mounting hole formed on the tread surface side of the tire, the edge effect is large, the braking / driving performance is improved, the anti-stud removal performance is improved, and the strength of the pin portion is increased. A studded tire having high pin part durability that can suppress damage to the pin part can be provided.
In another studded tire according to the present invention, the short side direction of the pin part that intersects the one end of the pin part radial direction and the other end of the pin part radial direction orthogonal to the central axis extends along the tire width direction. As described above, since the stud is formed by being attached to a mounting hole formed on the tread surface side of the tire, the edge effect is great, the braking / driving performance is improved, and the anti-stud removal performance is improved. Therefore, it is possible to provide a studded tire with high durability, which can increase the strength of the pin and suppress damage to the pin.

(a) is a top view of a stud, (b) is a front view of a stud (embodiment 1). The perspective view of a stud (embodiment 1). The figure which shows the attachment method of a stud (embodiment 1). Sectional drawing which shows a studable tire (Embodiment 1). The figure which shows the tread surface of a studable tire (Embodiment 1). (a) is a top view of a stud, (b) is a front view of a stud (embodiment 3). (a) is a top view of a stud, (b) is a front view of a stud (embodiment 4). (a) is a top view of a stud, (b) is a front view of a stud (Embodiment 5). (a) is a top view of a stud, (b) is a front view of a stud (Embodiment 6). (a) is a top view of a stud, (b) is a front view of a stud (Embodiment 7). The front view of a stud (Embodiment 8). Front view of the stud (Embodiment 9). (a) is a top view of a stud, (b) is a front view of a stud (conventional example). Explanatory drawing which shows the condition at the time of a stud removing from the wear block of a tire (conventional example).

Embodiment 1
With reference to FIG. 1 thru | or FIG. 5, the stud of Embodiment 1 which is embedded in the surface side of the tread of a tire and forms a studable tire (spike tire) is demonstrated.

-Stud whole structure As shown in FIG.1 and FIG.2, the stud 1 is the body part 2, the pin part 3 provided in the end of the direction along the central axis of the body part 2, and the central axis of the body part 2. It is a columnar member long provided in the direction along the central axis of the body part 2 comprised including the flange part 4 provided in the other end of the direction along.
In the stud 1 according to the first embodiment, the central axis of the body part 2, the central axis of the pin part 3, and the central axis of the flange part 4 are formed by a continuous straight line, and the continuous straight line is the central axis 1C ( Hereinafter, it is simply referred to as “center axis 1 </ b> C”).
The central axis 1C refers to the rotational center of the radial (depth direction) stud embedded in the tire of the pin portion, the body portion, and the flange portion, that is, the axis of the center of gravity in the cross section orthogonal to the radial direction. . In other words, it refers to a central axis that is located at the center of gravity in the cross section of the stud 1 that is orthogonal to the extending direction of the stud 1, which is the direction in which the stud 1 is embedded in the tire, and extends along the extending direction of the stud 1.

  As shown in FIG. 3 and FIG. 4, the stud 1 is fitted into a mounting hole 14 b (see FIG. 3) formed on the surface 14 a side of the tread 14 in the tire from the flange portion 4 side which is the other end side of the stud 1. A stud portion tire (spike tire) 10 (see FIG. 4) is formed by being embedded on the surface 14a side of the tread 14 so that the pin portion 3 which is one end side of the stud 1 protrudes from the surface 14a of the tread 14.

-Body part As shown in Drawing 1 and Drawing 2, body part 2 is located in the upper part 2A located in one end side of the direction along central axis 1C, and the other end side of the direction along central axis 1C A lower portion 2B, and a middle portion 2C that connects the upper portion 2A and the lower portion 2B.
The upper portion 2A is formed in a columnar body whose cross-sectional shape orthogonal to the central axis 1C is equal over the entire length along the central axis 1C.
The lower portion 2B is formed in a columnar body whose cross-sectional shape orthogonal to the central axis 1C is the same over the entire length along the central axis 1C.
The relationship between the cross-sectional diameter of the upper part 2A and the cross-sectional diameter of the lower part 2B is the cross-sectional diameter of the upper part 2A> the cross-sectional diameter of the lower part 2B.
The middle part 2C is formed by a conical columnar body whose cross-sectional diameter perpendicular to the central axis 1C gradually decreases from the upper part 2A side toward the lower part 2B side.

  The outer peripheral surface of the body part 2 extends from the edge of the pair of plane parts 21A; 22A and the pair of plane parts 21A; 22A facing each other with the center axis 1C interposed therebetween, and is opposed and separated from each other with the center axis 1C interposed therebetween. It is comprised by a pair of curved surface part 23A; 24A which curves so that it may protrude in the direction, and the boundary part of plane part 21A; 22A and curved surface part 23A; 24A, and the said boundary part protrudes so that it may leave | separate from the central axis 1C. The curved boundary surfaces 25A; 26A; 27A; 28A are formed.

That is, the outer peripheral surface of the body portion 2 is curved at one end edge of one curved surface portion 23A of the pair of curved surface portions 23A; 24A and one end edge of one flat surface portion 21A of the pair of flat surface portions 21A; 22A. It is connected via the boundary surface portion 25A, the other end edge of one curved surface portion 23A and one end edge of the other flat surface portion 22A are connected via a curved boundary surface portion 26A, and one end of the other curved surface portion 24A and one flat surface portion 21A. The other end edge of the other curved surface portion 24A is connected via the curved boundary surface portion 27A, and the other end edge of the other curved surface portion 24A is connected to the other end of the other flat surface portion 22A via the curved boundary surface portion 28A. The curved boundary surface portion has one end in contact with the flat surface portion and the other end in contact with the curved surface portion.
The curved surface portions 23A and 24A may have a configuration in which the curved surface portion and the flat surface portion are combined.
Moreover, the outer peripheral surface of the body part 2 means the surface in the outer periphery of the side of the same direction as the central axis 1C. In other words, the outer peripheral surface of the body part 2 refers to a surface that extends along the central axis 1C and surrounds the central axis 1C.

Further, as shown in FIG. 1A, the body portion 2 has an outer peripheral contour line in a cross section orthogonal to the central axis 1C and an end face in a direction along the central axis 1C (hereinafter referred to as a front end face 2t). A direction in which the outer peripheral edges (edges) extend from the ends of the pair of linear portions 21; 22 facing each other with the central axis 1C and the pair of linear portions 21; And a pair of curved portions 23; 24 that are curved so as to project inward, and a boundary portion between the straight portions 21; 22 and the curved portion 23; 24, and the boundary portion is curved so as to project away from the central axis 1C. The configuration formed by the boundary portions 25; 26; 27; 28 is most preferable. One end of the curved boundary portion is in contact with the linear portion, and the other end is in contact with the curved portion.
In addition, the structure by which the bending part 23; 24 combined the bending part and the linear part may be sufficient.

  The front end surface 2t of the body portion 2 is, for example, a plane orthogonal to the central axis 1C, a curved surface that curves toward one end in the direction along the central axis 1C, or the central axis 1C. It is formed in the curved surface which curves so that it may become depressed toward the other end of a direction.

The pair of flat surface portions 21A; 22A constituting the outer peripheral surface of the upper portion 2A are formed by flat surfaces facing each other in parallel with the central axis 1C interposed therebetween. The pair of curved surface portions 23A; 24A constituting the outer peripheral surface of the upper portion 2A are formed by curved surfaces having the same curvature around the central axis 1C, and the distance between the central axis 1C and each curved surface portion 23A; 24A Are the same. The length of the pair of plane portions 21A; 22A of the upper portion 2A in the plane orthogonal to the central axis 1C (in other words, the length of the pair of plane portions 21A; 22A of the upper portion 2A that intersects the plane orthogonal to the central axis 1C) The length of each linear portion 21; 22 equal to the length (hereinafter referred to as the width length) is the same length, and the length of the pair of curved surface portions 23A; 24A of the upper portion 2A in the plane orthogonal to the central axis 1C. (In other words, the length of each of the curved portions 23; 24 equal to the length of the curved line that intersects the plane orthogonal to the central axis 1C in the pair of curved surface portions 23A; 24A of the upper portion 2A (hereinafter referred to as the width length)). Are the same length. That is, the shape of the outer peripheral edge (edge) on the tip surface 2t of the upper portion 2A and the shape of the outer peripheral contour line of the cross section orthogonal to the central axis 1C of the upper portion 2A are congruent.
The pair of flat surface portions 21A and 22A constituting the outer peripheral surface of the lower portion 2B are formed by flat surfaces facing each other in parallel with the central axis 1C interposed therebetween. The pair of curved surface portions 23A; 24A constituting the outer peripheral surface of the lower portion 2B are formed by curved surfaces having the same curvature around the central axis 1C, and the distance between the central axis 1C and each curved surface portion 23A; 24A. Are the same. The straight portions 21; 22 equal in width to the pair of flat portions 21A; 22A of the lower portion 2B have the same length, and the curves equal to the width of the pair of curved surface portions 23A; 24A in the lower portion 2B. The lengths of the portions 23; 24 are the same length.
The pair of flat surface portions 21A; 22A constituting the outer peripheral surface of the middle portion 2C is formed by flat surfaces facing each other across the central axis 1C so that the distance between the facing portions decreases as the distance from the upper portion 2A side approaches the lower portion 2B side. It is formed. The pair of curved surface portions 23A; 24A constituting the outer peripheral surface of the middle portion 2C are formed by curved surfaces having the same curvature around the central axis 1C, and the distance between the central axis 1C and each curved surface portion 23A; 24A. Are the same. The straight portions 21; 22 having the same width as the pair of flat portions 21A; 22A of the middle portion 2C have the same length, and the curves having the same length as the pair of curved surface portions 23A; 24A of the middle portion 2C. The lengths of the portions 23; 24 are the same length.

The shape of the outer peripheral edge of the distal end surface 2t of the upper portion 2A (the distal end surface 2t of the body portion 2), the shape of the outer peripheral contour of the cross section perpendicular to the central axis 1C of the upper portion 2A, and the central axis 1C of the lower portion 2B The shape of the outer peripheral contour line of the cross section and the shape of the outer peripheral contour line of the cross section orthogonal to the central axis 1C of the middle portion 2C are formed in a 180 ° rotationally symmetric shape with the central axis 1C as the rotation center axis.
The 180 ° rotationally symmetric shape is a shape in which four corners of a quadrangle are rounded by the curved boundary portions 25; 26; 27; 28, and a pair of opposite sides of the quadrangle are formed by curved sides.
That is, the shape of the outer peripheral edge on the distal end surface 2t of the body portion 2 and the shape of the outer peripheral contour line of the body portion 2 are a pair of straight portions 21; A pair of curved portions 23; 24 extending from the ends of the portions 21; 22 and facing each other across the central axis 1C and projecting away from each other, and the straight portions 21; 22 and the curved portions 23; 24 The boundary portion is formed in a curved boundary portion 25; 26; 27; 28 that protrudes away from the central axis 1C, and the central axis 1C is 180 as a rotation center axis. ° It is rotationally symmetric.

In other words, the cross-sectional shape of the body portion 2 orthogonal to the central axis 1C and the shape of the distal end surface 2t are the long axis 1L and the short axis 1S passing through the central axis 1C and orthogonal to each other on the cross section orthogonal to the central axis 1C. And has a line-symmetric shape with the long axis 1L or the short axis 1S as the axis of symmetry. The direction along the long axis 1L is the longitudinal direction of the stud 1, and the direction along the short axis 1S is the short direction of the stud 1.
The maximum distance between the curved portion 23 and the curved portion 24 that intersects the long axis 1L is defined as the major axis dimension, and the distance between the straight portion 21 and the straight section 22 that intersects the minor axis 1S is defined as the minor axis dimension. , The flatness of the cross-sectional shape of the body portion 2 defined by the major axis dimension and the minor axis dimension is greater than 0 and equal to or less than 0.2.
However, flatness ratio = 1− (b / a)
a: major axis dimension b: minor axis dimension

That is, on the cross section orthogonal to the central axis 1C, the long diameter dimension a which is the maximum separation distance between the pair of curved surface portions 23A; 24A and the short diameter dimension which is the maximum separation distance between the pair of plane portions 21A; The relationship with b is a> b.
The planar portions 21A and 22A of the upper portion 2A, the lower portion 2B, and the middle portion 2C are planar portions that extend along the long axis 1L described above while extending along the central axis 1C.
The curved surface portions 23A and 24A of the upper portion 2A, the lower portion 2B, and the middle portion 2C are curved surface portions that extend along the central axis 1C and extend along the short axis 1S described above.

  The curved surface portion 23A of the upper portion 2A, the lower portion 2B, and the middle portion 2C; the length of the arc of 24A (the length extending along the short axis 1S) is a circle having a radius of curvature of the curved surface portion 23A; 24A. It is shorter than half of the circumference, that is, the length of the semicircle of the circle. That is, the cross-sectional shape of the body part 2 orthogonal to the central axis 1C and the shape of the tip surface 2t are not oval or elliptical.

-Pin part The pin part 3 is formed in the column which the cross-sectional shape orthogonal to the central axis 1C is equal over the full length along the central axis 1C.

As shown in FIG. 2, the outer peripheral surface of the pin portion 3 extends from the edge of the pair of plane portions 31A; 32A and the pair of plane portions 31A; 32A facing each other with the center axis 1C interposed therebetween and extends the center axis 1C. It is composed of a pair of curved surface portions 33A; 34A that are curved so as to face each other and protrude away from each other, and a boundary portion between the flat surface portion 31A; 32A and the curved surface portion 33A; 34A. It is formed by curved boundary surfaces 35A; 36A; 37A; 38A that protrude away from 1C. The curved boundary surface portion has one end in contact with the flat surface portion and the other end in contact with the curved surface portion.
The curved surface portion 33A; 34A may have a configuration in which the curved surface portion and the flat surface portion are combined.

That is, the outer peripheral surface of the pin portion 3 is curved at one end edge of one curved surface portion 33A of the pair of curved surface portions 33A; 34A and one end edge of one flat surface portion 31A of the pair of flat surface portions 31A; 32A. The other end edge of one curved surface portion 33A and one end edge of the other flat surface portion 32A are connected via a curved boundary surface portion 36A, and one end of the other curved surface portion 34A and one flat surface portion 31A are connected via the boundary surface portion 35A. The other end edge of the other curved surface portion 34A is connected via a curved boundary surface portion 37A, and the other end edge of the other curved surface portion 34A is connected to the other end of the other flat surface portion 32A via a curved boundary surface portion 38A.
In addition, the outer peripheral surface of the pin part 3 means the surface in the outer periphery of the side side of the same direction as the central axis 1C. In other words, the outer peripheral surface of the pin portion 3 refers to a surface that extends along the central axis 1C and surrounds the central axis 1C.

Further, as shown in FIG. 1 (a), the pin portion 3 has an outer peripheral contour line in a cross section orthogonal to the central axis 1C and an end surface in the direction along the central axis 1C (hereinafter referred to as a distal end surface 3t). A direction in which the outer peripheral edges (edges) extend from the ends of the pair of linear portions 31; 32 facing each other with the central axis 1C therebetween and the ends of the pair of linear portions 31; And a pair of curved portions 33; 34 that are curved so as to project inward, and a boundary portion between the straight portions 31; 32 and the curved portion 33; 34, and the boundary portion is curved so as to project away from the central axis 1C. The configuration formed by the boundary portions 35; 36; 37; 38 is most preferable. One end of the curved boundary portion is in contact with the linear portion, and the other end is in contact with the curved portion.
In addition, the structure by which the bending part 33; 34 combined the bending part and the linear part may be sufficient.

  The tip surface 3t of the pin portion 3 is, for example, a plane orthogonal to the central axis 1C, a curved surface curved so as to protrude toward one end in the direction along the central axis 1C, or the central axis 1C. It is formed in the curved surface which curves so that it may become depressed toward the other end of a direction.

  The pair of flat surface portions 31A and 32A constituting the outer peripheral surface of the pin portion 3 are formed by flat surfaces facing each other in parallel with the central axis 1C interposed therebetween. The pair of curved surface portions 33A; 34A constituting the outer peripheral surface of the pin portion 3 are formed by curved surfaces having the same curvature around the central axis 1C, and the distance between the central axis 1C and each curved surface portion 33A; 34A. Are the same. The lengths of the straight portions 31; 32 equal to the length (hereinafter referred to as the width length) in the plane orthogonal to the central axis 1C of the pair of plane portions 31A; 32A of the pin portion 3 are the same length. The length of each of the curved portions 33; 34 equal to the length (hereinafter referred to as the width length) in the plane orthogonal to the central axis 1C of the pair of curved surface portions 33A; 34A is the same length. That is, the shape of the outer peripheral edge (edge) of the tip surface 3t of the pin portion 3 and the shape of the outer peripheral contour line of the cross section orthogonal to the central axis 1C of the pin portion 3 are congruent.

The shape of the outer peripheral edge of the tip surface 3t of the pin portion 3 and the shape of the outer peripheral contour line of the cross section orthogonal to the central axis 1C of the pin portion 3 are formed in a 180 ° rotationally symmetric shape with the central axis 1C as the rotation center axis. .
The 180 ° rotationally symmetric shape is a shape in which four corners of a quadrangle are rounded by curved boundary portions 35; 36; 37; 38, and a pair of opposite sides of the quadrangle are formed by curved sides. In other words, the 180 ° rotationally symmetric shape is a shape in which curved portions located on both sides of the long axis of the ellipse are replaced with straight lines orthogonal to the long axis (both ends of the long axis of the rugby ball in plan view). A shape with a straight portion with the side cut off).
In other words, the shape of the outer peripheral edge of the pin portion 3 and the shape of the outer peripheral contour line are as follows: a pair of linear portions 31; 32 facing each other with the central axis 1C interposed therebetween, and end portions of the pair of linear portions 31; A pair of curved portions 33; 34 which extend and bend so as to face each other across the central axis 1C and protrude away from each other, and a boundary portion between the straight portions 31; 32 and the curved portions 33; 34, The boundary portion is formed in curved boundary portions 35; 36; 37; 38 projecting away from the center axis 1C, and has a 180 ° rotationally symmetric shape with the center axis 1C as the rotation center axis.
Further, the length of the arc of the curved surface portion 33A; 34A of the pin portion 3 (the length extending along the long axis 1L) is 1/2 of the circumference of the circle having the radius of curvature of the curved surface portion 33A; 34A. That is, it is shorter than the semicircular length of the circle. That is, the cross-sectional shape of the pin portion 3 orthogonal to the central axis 1C and the shape of the tip surface 3t are not oval or elliptical.

In other words, the cross-sectional shape of the pin portion 3 orthogonal to the central axis 1C includes a long axis 1L and a short axis 1S that pass through the central axis 1C and are orthogonal to each other on a cross section orthogonal to the central axis 1C. The shape is axisymmetric with respect to the short axis 1S as an axis of symmetry.
And the distance between the linear part 31 and the linear part 32 which cross | intersects a major axis is defined as a major axis dimension, The distance between the curved part 33 and the curved part 34 which intersects a minor axis is defined as a minor axis dimension. In the case, the flatness of the cross-sectional shape of the pin portion 3 defined by the major axis dimension and the minor axis dimension is 0.3 or more and 0.6 or less.
However, flatness ratio = 1− (b / a)
a: major axis dimension b: minor axis dimension

Flange portion vertical cross-sectional shape The flange portion 4 is formed in a shape that the outer peripheral surface 4F expands from one end side to the other end side in the direction along the central axis 1C and then decreases in diameter, and the outer peripheral surface of the flange portion 4 The maximum outer peripheral diameter position 4M of 4F is configured to be located on the other end face 4E side of the flange portion 4 with respect to a position that is 1/2 the dimension in the thickness direction of the flange portion that is the direction along the central axis 1C. .
In other words, the cross-sectional shape of the flange portion 4 along the center axis 1C is such that the diameter of the cross section perpendicular to the center axis 1C gradually increases from the lower portion 2B side of the body portion 2 toward the maximum outer peripheral diameter position 4M of the flange portion 4. And the diameter of the cross section perpendicular to the central axis 1C gradually decreases from the maximum outer peripheral diameter position 4M of the flange portion 4 toward the other end surface 4E of the flange portion 4. .
The maximum outer peripheral diameter position 4M is formed on the curved surface, and the curved surface 4G protrudes so that the boundary between the maximum outer peripheral diameter position 4M of the outer peripheral surface 4F and the other end surface 4E of the flange portion 4 is separated from the central axis 1C. It is the structure formed by.
The flange portion 4 is composed of a curved curved boundary portion in which the outer peripheral surface 4F and the other end surface 4E protrude in a direction away from the central axis 1C. The curved boundary portion has one end in contact with the outer peripheral surface 4F and the other. The end is in contact with the other end surface 4E.

-Flange part As shown in FIG. 1; FIG. 2, the outer peripheral surface 4F of the flange part 4 is a radial direction of a pair of plane part 41A; 42A and a pair of plane part 41A; 42A which opposes on both sides of the central axis 1C ( A pair of curved surface portions 43A; 44A, a flat surface portion 41A; 42A, and a curved surface portion 43A that extend from one edge in the central axis direction) and are curved so as to face each other across the central axis 1C and protrude away from each other. 44A, and the boundary portion is formed by a curved boundary surface portion 45A projecting away from the central axis 1C; 46A; 47A; 47A; the curvature radius of the curved surface portion and the curvature of the curved boundary surface portion It is comprised so that a radius may differ.

That is, the outer peripheral surface 4F of the flange portion 4 has one end edge of one curved surface portion 43A of the pair of curved surface portions 43A; 44A and one end edge of one flat surface portion 41A of the pair of flat surface portions 41A; It is connected via a curved boundary surface portion 45A (see FIG. 1A), and the other edge of one curved surface portion 43A and one end edge of the other flat surface portion 42A are connected via a curved boundary surface portion 46A, and the other curved surface portion. One end of 44A and the other end edge of one flat surface portion 41A are connected via a curved boundary surface portion 47A, and the other end edge of the other curved surface portion 44A and the other end of the other flat surface portion 42A are connected via a curved boundary surface portion 48A. It is formed to be connected.
In addition, the outer peripheral surface 4F of the flange part 4 means the surface in the outer periphery of the side of the same direction as the central axis 1C. In other words, the outer peripheral surface 4F of the flange portion 4 refers to a surface that extends along the central axis 1C and surrounds the central axis 1C.

In other words, as shown in FIG. 1 (a), the flange portion 4 has a pair of linear portions 41; 42 having an outer peripheral contour line in a cross section orthogonal to the central axis 1C and facing the central axis 1C, and a pair of A pair of curved portions 43; 44 that extend from the ends of the straight portions 41; 42 and that face each other across the central axis 1C and protrude away from each other, and the straight portions 41; 42 and the curved portions 43; 44 The boundary portion is formed by curved boundary portions 45; 46; 47; 48 projecting away from the central axis 1C, and the curvature radius of the curved portion and the curvature radius of the curved boundary portion are Are configured differently. One end of the curved boundary portion is in contact with the linear portion, and the other end is in contact with the curved portion.
In addition, the structure by which the bending part 43; 44 combined the bending part and the linear part may be sufficient.

  The other end surface 4E of the flange portion 4 is formed, for example, on a plane orthogonal to the central axis 1C.

The pair of flat surface portions 41A; 42A constituting the outer peripheral surface 4F of the flange portion 4 are centered so that the distance between the opposing surfaces increases as the distance from the lower portion 2B side of the body portion 2 approaches the maximum outer peripheral diameter position 4M of the flange portion 4. It is formed by planes facing each other across the shaft 1C. The pair of curved surface portions 43A and 44A constituting the outer peripheral surface 4F of the flange portion 4 have the same curvature with the center axis 1C as the center, and are located from the lower portion 2B side of the body portion 2 to the maximum outer peripheral diameter position 4M of the flange portion 4. It is formed by curved surfaces facing each other across the central axis 1C so that the distance between the opposing surfaces increases as it approaches. The length of each straight line portion 41; 42 equal to the length (hereinafter referred to as the width length) of the pair of flat surface portions 41A; 42A of the flange portion 4 in the plane orthogonal to the central axis 1C is the same length. The lengths of the curved portions 43; 44 equal to the length (hereinafter referred to as the width length) of the pair of curved surface portions 43A; 44A perpendicular to the central axis 1C are the same.
That is, the shape of the outer peripheral edge of the other end surface 4E of the flange portion 4 and the shape of the outer peripheral contour line of the cross section orthogonal to the central axis 1C of the flange portion 4 are similar shapes with the central axis 1C as the center.

The shape of the outer peripheral edge of the other end surface 4E of the flange portion 4 and the shape of the outer peripheral contour line of the cross section orthogonal to the central axis 1C of the flange portion 4 are formed into a 180 ° rotationally symmetric shape with the central axis 1C as the rotation center axis. Is done.
The 180 ° rotationally symmetric shape is a shape in which four corners of a quadrangle are rounded by curved boundary portions 45; 46; 47; 48, and a pair of opposite sides of the quadrangle are formed by curved sides.
That is, the shape of the outer peripheral edge and the shape of the outer peripheral contour line on the other end surface 4E of the flange portion 4 described above are a pair of linear portions 41; 42 and a pair of linear portions 41; A pair of curved portions 43; 44 that are extended from the ends of the first curved portion and curved so as to protrude opposite to each other across the central axis 1C, and a boundary portion between the linear portions 41; 42 and the curved portions 43; 44 180 [deg.] Rotationally symmetrical shape with the central axis 1C as the rotation center axis, wherein the boundary portion is formed in the curved boundary portions 45; 46; 47; 48 projecting away from the central axis 1C It is.
The length of the arc of the curved surface portion 43A; 44A of the flange portion 4 (the length extending along the short axis 1S) is ½ of the circumference of the circle having the radius of curvature of the curved surface portion 43A; 44A. That is, it is shorter than the semicircular length of the circle. That is, the cross-sectional shape of the flange portion 4 orthogonal to the central axis 1C and the shape of the other end surface 4E are not oval or elliptical.

In other words, the cross-sectional shape of the flange portion 4 orthogonal to the central axis 1C includes a long axis 1L and a short axis 1S that pass through the central axis 1C and are orthogonal to each other on a cross section orthogonal to the central axis 1C. The shape is axisymmetric with respect to the short axis 1S as an axis of symmetry.
The maximum distance between the curved portion 43 and the curved portion 44 intersecting with the long axis 1L is defined as the long diameter dimension, and the distance between the straight portion 41 and the straight section 42 intersecting with the short axis 1S is defined as the short diameter dimension. In this case, the flatness of the cross-sectional shape of the flange portion 4 defined by the major axis dimension and the minor axis dimension is 0.1 or more and 0.25 or less.
However, flatness ratio = 1− (b / a)
a: major axis dimension b: minor axis dimension

The relationship between the pin part, the body part, and the flange part. The stud 1 has the long axis 1L of the pin part 3, the long axis 1L of the body part 2, and the long axis 1L of the flange part 4, and the short axis of the pin part 3. 1S, the short axis 1S of the body part 2 and the short axis 1S of the flange part 4 are formed to coincide with each other.
That is, in the plan view shown in FIG. 1A, the stud 1 has the straight portions 31; 32 of the pin portion 3, the curved portions 23; 24 of the body portion 2, and the curved portions 43; 44 of the flange portion 4 facing each other. In addition, the curved portions 33; 34 of the pin portion 3, the straight portions 21; 22 of the body portion 2, and the straight portions 41; 42 of the flange portion 4 are formed to face each other.
That is, the body portion 2 is configured as a pair of longitudinal side portions in which the outer peripheral contour line of the cross section orthogonal to the central axis 1C is opposed to the central axis 1C and extends along the longitudinal direction orthogonal to the central axis 1C. The straight portions 21; 22 and a pair of curved portions 23; 24 as side portions extending in the short direction perpendicular to the longitudinal direction so as to face each other with the center axis 1C interposed therebetween.
Further, the flange portion 4 serves as a pair of longitudinal side portions in which the outer peripheral contour line of the cross section orthogonal to the central axis 1C faces the central axis 1C and extends along the longitudinal direction orthogonal to the central axis 1C. The straight portion 41; 42 and a pair of curved portions 43; 44 as side portions extending in the short direction perpendicular to the longitudinal direction so as to face each other across the central axis 1C.
Further, the outer peripheral edge of one end surface in the direction along the central axis 1C and the outer peripheral contour line of the cross section orthogonal to the central axis 1C are opposed to the pin portion 3 across the central axis 1C and orthogonal to the central axis 1C. A pair of short sides extending along a short direction perpendicular to the longitudinal direction opposite to the central axis 1C with a pair of curved portions 33; 34 extending as a pair of longitudinal sides extending along the longitudinal direction Most preferably, it is composed of straight portions 31; 32 as side portions.
The stud 1 has the longitudinal direction of the pin portion 3, the longitudinal direction of the flange portion 4, and the longitudinal direction of the body portion 2, and the short direction of the pin portion 3, the short direction of the flange portion 4, and the body portion. It is formed so that the width direction of 2 coincides.
The longitudinal direction and the short direction are the same. The long axes 1L of the respective parts and the short axes 1S of the respective parts are completely matched, as well as the long axes 1L of the respective parts and the short axes 1S of the respective parts. This includes the case where they are offset by about ± 10 ° about the central axis 1C.

-Studded tire Referring to Fig. 4, a studded tire 10 configured by fitting the stud 1 into a mounting hole 14b formed in the tread 14 will be described.
The studded tire 10 includes a bead portion 11, a bead core 11 </ b> C, a carcass layer 12, belt layers 13 a and 13 b, a tread 14, a side tread 15, and a stud 1.
The carcass layer 12 is a member that forms a skeleton of the studded tire 10 that is provided so as to straddle a pair of bead cores 11 </ b> C disposed in the bead portion 11. An inner belt layer 13a and an outer belt layer 13b are disposed on the outer side in the tire radial direction. Each of the belt layers 13a and 13b is formed by arranging steel cords or cords made by twisting organic fibers so as to intersect at an angle of, for example, 20 ° to 70 ° with respect to the equator direction of the tire. The extending direction of the cord of the belt layer 13a arranged on the inner side and the extending direction of the cord of the belt layer 13b arranged on the outer side in the tire radial direction intersect with each other.
The tread 14 is a rubber member (tread rubber) disposed on the outer side in the tire radial direction of the belt layers 13a and 13b. The tread 14 extends on the surface 14a of the tread 14 along the tire circumferential direction 10Y (see FIG. 5). A plurality of provided main grooves 16 are formed, and a plurality of land portions (blocks) 17A, 17B, and 18 are partitioned by these main grooves 16. The land portion 17A is a central land portion located in the tire center portion, the land portion 17B is an outer land portion located on both outer sides of the central land portion 17A in the tire width direction 10X (see FIG. 5), and the land portion 18 is the outer side. It is a shoulder side land portion located on both outer sides in the tire width direction 10X of the land portion 17B.
A plurality of sipes 19 are formed on the surfaces of the land portions 17A, 17B, and 18.
The side tread 15 is a rubber member that extends from the end of the tread 14 to the side of the tire and covers the carcass layer 12.
Between the tread 14 and the outer belt layer 13b, a belt protective layer for preventing the stud 1 from sinking into the outer belt layer 13b due to a rubber sag under the stud 1 (inner side in the tire radial direction). 13c is provided. The belt protective layer 13c is configured to include a cord made of organic fiber or the like.
A mounting hole 14b is formed on the surface side of the tread 14, and the stud 1 is fitted and mounted in the mounting hole 14b. The attachment hole 14b is provided in the shoulder side land portion 18 and the outer land portion 17B, for example.

As shown in FIG. 3A, the mounting hole 14b is formed by, for example, a cylindrical bottomed hole extending from the surface 14a of the tread 14 of the studded tire 10 toward the center of the tire circle. The mounting hole 14b includes, for example, an inlet portion 14c, a bottom portion 14e, and an intermediate portion 14d that connects the inlet portion 14c and the bottom portion 14e. The inlet portion 14c, the bottom portion 14e, and the intermediate portion 14d are formed coaxially so that the central axes of the mounting holes 14b are the same. The intermediate part 14d is a cylindrical mounting hole having a constant diameter. The inlet portion 14c is surrounded by a conical surface that expands from the circular inlet side end of the intermediate portion 14d toward the surface 14a of the tread 14 (conical surface having the center line of the hole of the mounting hole 14b as the center line). This is a funnel-shaped cylindrical mounting hole. The bottom portion 14e is a bottomed mounting hole portion surrounded by a surface forming a bottom surface 14k by reducing the diameter from the circular bottom side end of the intermediate portion 14d toward the center of the tire circle.
In addition, in order to improve the anti-stud removal performance, the shape on the bottom surface 14k side of the bottom portion 14e is preferably a shape corresponding to the shape of the flange portion 4 of the stud 1.

As shown in FIG. 3B, the stud 1 is driven into the mounting hole 14b from the flange portion 4 side by a driving machine not shown, so that the stud 1 is mounted in a state of being fitted into the mounting hole 14b.
The height dimension of the stud 1 is formed longer than the depth dimension of the mounting hole 14b, and the stud 1 is mounted such that one end surface side of the pin portion 3 and the body portion 2 protrudes from the surface 14a of the tread 14, for example.
The stud 1 of Embodiment 1 is attached to the attachment hole 14b so that the long axis 1L extends in parallel with the tire width direction 10X and the short axis 1S extends in parallel with the tire circumferential direction 10Y.
The stud 1 may be attached to the attachment hole 14b such that the long axis 1L extends in parallel with the tire circumferential direction 10Y and the short axis 1S extends in parallel with the tire width direction 10X.

-Effect by body part shape According to the stud 1 of Embodiment 1, the body part 2 is extended from the edge of a pair of plane part 21A; 22A and a pair of plane part 21A; 22A which oppose on both sides of the central axis 1C. When the stud 1 is mounted in the mounting hole 14b, it is formed in a shape having a pair of curved surface portions 23A and 24A that are curved so as to face each other across the central axis 1C and protrude away from each other. The contact mode between the inner wall surface (rubber surface) of the mounting hole 14b and the flat portion 21A; 22A and the contact mode between the inner wall surface (rubber surface) of the mounting hole 14b and the curved surface portion 23A; 24A are different. In addition, the falling deformation of the stud 1 can be suppressed, and the anti-stud removal performance is improved.

  Further, the body portion 2 is formed by the curved boundary surface portions 25A; 26A; 27A; 28A in which the boundary portion between the flat surface portions 21A; 22A and the curved surface portions 23A; 24A protrudes away from the central axis 1C. Since the corner portion is eliminated on the outer peripheral surface of the columnar body portion 2 and the corner portion and the inner wall surface of the mounting hole 14b are in contact with each other, it is possible to suppress a situation in which the inner wall surface of the mounting hole 14b is likely to crack. Stud 1 can be prevented from being deformed by falling, and the stud removal resistance is improved.

The stud removal phenomenon that tends to occur as the wear of the tire tread 14 progresses is a phenomenon that frequently occurs when the tire is kicked from the road surface when the vehicle suddenly starts or accelerates. It is effective to increase the area of the outer peripheral surface of the body part 2 that contacts the inner wall surface (rubber surface) of the tire mounting hole 14b.
Further, when the above-described flatness ratio is larger than 0.2, the length of the plane portion 21A; 22A (the width in the direction along the long axis 1L) becomes too short, and the plane portion 21A; 22A and the mounting hole Since the contact force with the inner wall surface of 14b is relatively smaller than the contact force between the curved surface portions 23A; 24A and the inner wall surface of the mounting hole 14b, the deformation of the stud 1 is increased during braking and acceleration. , There is a possibility that it may lead to deterioration of the stud removal resistance.
Further, when the flatness of the cross-sectional shape of the body part 2 is smaller than 0, the diameter difference (clearance) between the major axis of the pin part 3 and the major part of the upper part 2A of the body part 2 becomes too small, and the upper part 2A Damage to the pin 3 due to the wall thickness (≈ robustness against external inputs other than ground contact during normal driving) is reduced, and problems such as damage to the pin 3 and loss of the pin 3 are likely to occur. There is a fear.
Therefore, in the stud 1 of the first embodiment, in the cross-sectional shape orthogonal to the central axis 1C of the body part 2, the flatness defined by the major axis dimension and the minor axis dimension is greater than 0 and less than or equal to 0.2. Therefore, the longitudinal direction orthogonal to the central axis 1C and intersecting with the pair of curved surface portions 23A; 24A extends along the tire width direction 10X, and the short direction perpendicular to the longitudinal direction extends along the tire circumferential direction 10Y. When the stud 1 is mounted in the tire mounting hole 14b so as to extend, the area of the outer peripheral surface of the body portion 2 that contacts the inner wall surface of the tire mounting hole 14b increases, and the tire width direction The contact force between the flat surface portions 21A; 22A located on both ends of the 10X and the inner wall surface of the mounting hole 14b can be maintained well, and the stud removal resistance is improved and the pin portion 3 is protected from damage. There it is possible to provide a stack twin wheels 10 to increase.
The stud 1 is formed on the tread surface side of the tire so that the longitudinal direction of the body portion 2 extends along the tire circumferential direction and the short side direction of the body portion 2 extends along the tire width direction. A studded tire formed by being attached to the mounting hole may be used.

-Effect by pin part shape The outer periphery (edge) in the front end surface 3t of the pin part 3 is extended from the edge part of a pair of linear part 31; 32, and it protrudes in the direction which opposes on both sides of the center axis 1C, and leaves | separates mutually Thus, the peripheral edge length, that is, the pin edge length can be increased, and the pin edge performance for scratching the frozen road surface is improved.
The outer peripheral edge of the tip surface 3t of the pin portion 3 includes a pair of linear portions 31; 32 facing each other with the central axis 1C interposed therebetween, and both end portions of the long axis 1L of the pin portion 3 are not curved in a direction away from the central axis 1C. It is formed as follows. That is, since both ends of the major axis 1L of the pin portion 3 are not formed in a sharp shape, the thickness of the member along the minor axis 1S can be increased at both ends of the major axis 1L in the pin portion 3, The strength in the direction along the minor axis 1S can be increased. That is, the member thickness in the direction along the straight portion 31; 32 can be increased, and the strength in the direction along the straight portion 31; 32 of the pin portion 3 can be increased.
Accordingly, as shown in FIG. 5, the long axis 1L of the tip surface 3t of the pin portion 3 extends along the tire width direction 10X, and the short shaft 1S of the tip surface 3t of the pin portion 3 extends along the tire circumferential direction 10Y. When the stud 1 is mounted in the mounting hole 14b so as to extend, the pin edge length in the drag direction during braking / driving can be increased, the braking / driving performance can be improved, the strength of the pin portion 3 can be increased, and braking and acceleration can be performed. It is possible to provide a studable tire 10 that can suppress damage to the pin portion 3 such as initial pin breakage due to insufficient strength in the front-rear direction of the pin when starting.

  Further, the outer peripheral edge of the pin portion 3 on the distal end surface 3t has a curved boundary portion 35; 36; 37; 38 where the boundary portion between the straight portion 31; 32 and the curved portion 33; 34 protrudes away from the central axis 1C. Therefore, compared with the case where the boundary portion is formed at the corner portion, the stress is less likely to concentrate on the boundary portion, so that wear deterioration and damage of the pin portion 3 can be reduced.

Further, when the flatness of the pin portion 3 described above is smaller than 0.3, the cross-sectional shape is not significantly different from a circular shape, and the braking / driving performance may not be improved as compared with the pin portion having a circular cross-sectional shape. .
Also, when the flatness of the pin portion 3 is larger than 0.6, the short diameter of the pin portion 3 becomes too small compared to the long diameter, and the initial pin breakage due to insufficient strength in the longitudinal direction of the pin during braking and acceleration start, etc. There is a risk that it will easily occur.
Therefore, in the stud 1 of the first embodiment, the flat shape defined by the major axis dimension a and the minor axis dimension b in the shape of the tip surface 3t of the pin part 3 and the cross-sectional shape orthogonal to the central axis 1C of the pin part 3. Since the rate is 0.3 or more and 0.6 or less, the longitudinal direction orthogonal to the central axis 1C and intersecting the pair of linear portions 31; 32 extends along the tire width direction 10X, and the longitudinal direction When the stud 1 is mounted in the tire mounting hole 14b so that the transverse direction perpendicular to the tire extends in the tire circumferential direction 10Y, the pin edge length can be made longer and braking / driving performance can be improved, and braking can be performed. In addition, it is possible to provide the studded tire 10 that can increase the strength in the longitudinal direction of the pin during acceleration start and suppress the damage of the pin portion 3 such as the initial break of the pin.
The stud 1 is formed on the tread surface side of the tire so that the longitudinal direction of the pin portion 3 extends along the tire circumferential direction and the short side direction of the pin portion 3 extends along the tire width direction. A studded tire formed by being attached to the mounting hole may be used.

-Effect by flange part shape According to the stud 1 of Embodiment 1, as for the flange part 4, the shape of the outer periphery outline of the cross section orthogonal to the central axis 1C has a pair of linear part 41 which opposes on both sides of the central axis 1C; 42 and a pair of curved portions 43; 44 that extend from the ends of the pair of linear portions 41; 42, and are curved so as to face each other across the central axis 1C and protrude away from each other. Therefore, when the stud 1 is attached to the attachment hole 14b, the contact state between the inner wall surface (rubber surface) of the attachment hole 14b and the linear portion 41; 42, the inner wall surface (rubber surface) of the attachment hole 14b, and the curve. Since the contact mode with the portions 43 and 44 is different, it is possible to provide the studded tire 10 that can suppress the falling deformation of the stud 1 at the time of braking and acceleration and can improve the resistance to pulling out the stud.

  Further, the flange portion 4 is formed by the curved boundary portions 45; 46; 47; 48 projecting away from the central axis 1C at the boundary portion between the straight portions 41; 42 and the curved portions 43; 44. Since the corner portion of the outer peripheral surface 4F of the flange portion 4 is eliminated and the corner portion and the inner wall surface of the mounting hole 14b are in contact with each other, it is possible to suppress a situation in which the inner wall surface of the mounting hole 14b is likely to crack. The studded tire 10 that can suppress the falling deformation of the stud 1 at the time of acceleration and start of acceleration and improve the anti-stud removal performance can be provided.

Further, when the flatness of the flange portion 4 described above is larger than 0.25, the width of the straight portion 41; 42 in the direction along the long axis 1L becomes too short, and the straight portion 41; 42 and the mounting hole 14b. Since the contact force with the inner wall surface of the stud is relatively smaller than the contact force between the curved portions 43; 44 and the inner wall surface of the mounting hole 14b, the falling deformation of the stud 1 during braking and acceleration starts increases. There is a possibility that it may lead to deterioration of the stud removal resistance.
Further, when the flatness of the flange portion 4 is smaller than 0.1, the diameter difference (clearance) between the short diameter of the pin portion 3 and the short diameter of the flange portion 4 becomes too small, and braking and acceleration start are performed. Sometimes, the stud 1 falls down and becomes deformed, which may lead to deterioration of the stud removal resistance.
Therefore, in the stud 1 of the first embodiment, in the cross-sectional shape orthogonal to the central axis 1C of the flange portion 4, the flatness defined by the major axis dimension a and the minor axis dimension b is 0.1 or more and 0.25 or less. Therefore, the longitudinal direction perpendicular to the central axis 1C and intersecting the pair of curved portions 43; 44 extends along the tire width direction 10X, and the short direction perpendicular to the longitudinal direction is the tire circumferential direction 10Y. When the stud 1 is attached to the tire mounting hole 14b so as to extend along the tire, the stud 1 can be prevented from falling down at the time of braking and acceleration and the studded tire 10 can be provided with improved anti-stud removal performance. .
The stud 1 is formed on the tread surface side of the tire so that the longitudinal direction of the flange portion 4 extends along the tire circumferential direction and the short side direction of the flange portion 4 extends along the tire width direction. A studded tire formed by being attached to the mounting hole may be used.

-Effect by flange part perpendicular cross-sectional shape According to the stud 1 of Embodiment 1, the flange part 4 is reduced in diameter after the outer peripheral surface 4F is enlarged from one end side to the other end side in the direction along the central axis 1C. The flange portion 4 has a maximum outer peripheral diameter position 4M of the outer peripheral surface 4F of the flange portion 4 in a direction along the central axis 1C, and the flange portion 4 is more than a position that is ½ of the thickness direction dimension of the flange portion. Since it is configured to be positioned on the end face 4E side, when the stud 1 is driven into the mounting hole 14b, the maximum outer peripheral diameter position 4M of the flange portion 4 is installed at a position close to the belt layers 13a and 13b of the tire. As a result, the residual stress by which the rubber around the stud 1 attached to the attachment hole 14b is pulled inward (in the stud 1 side) increases and the stud 1 becomes difficult to come out, so that the anti-stud removal performance is improved.
When the stud 1 is driven into the mounting hole 14b, the rubber around the stud 1 attached to the mounting hole 14b is closer to the inner side as the maximum outer peripheral diameter position 4M of the flange 4 is closer to the belt layers 13a and 13b of the tire. Since the residual stress pulled toward the stud 1 side becomes large and the stud 1 is difficult to come off, it is preferable that the maximum outer peripheral diameter position 4M of the flange portion 4 is set as close as possible to the other end face 4E of the flange portion 4. .

  Further, the flange portion 4 has a maximum outer peripheral diameter position 4M formed in a curved surface, and a boundary portion between the maximum outer peripheral diameter position 4M of the outer peripheral surface 4F and the other end surface 4E of the flange portion 4 is separated from the central axis 1C. Since it is formed by the protruding curved surface 4G, there is no corner at the boundary between the outer peripheral surface 4F and the other end surface 4E and the outer peripheral surface 4F, and the mounting hole 14b is brought into contact with the corner and the inner wall surface of the mounting hole 14b. Since it becomes possible to suppress a situation in which a crack is likely to occur in the inner wall surface of the steel plate, the stud 1 can be prevented from being collapsed during braking and acceleration start, and the anti-stud removal performance is improved.

・ Effects of direction matching When the stud 1 comes off from a land portion (block) where the tire is worn during sudden start / acceleration, the tip surface 3t side of the pin portion 3 or the tip surface 2t side of the upper portion 2A is caught on the road surface. As a result, the stud 1 falls off while rotating (see the states C and D in FIG. 14). The main factors that determine the ease of rotation of the stud 1 are the resistance force of the flange portion 4 and the resistance force on the tip side of the upper portion 2A. When the resistance force of one side is large and the resistance force of the other is small, the stud 1 is likely to be rotationally deformed. When the magnitudes of the two resistance forces are the same, the stud 1 is translationally deformed rather than rotationally deformed. Becomes difficult to fall off.
The magnitude of the resistance force is considered to be approximately proportional to the size of the diameter of the flange portion 4 and the diameter of the upper portion 2A, and the difference between the diameter of the flange portion 4 and the diameter of the upper portion 2A approaches zero. It is considered that the anti-stud removal performance is improved.

According to the stud 1 of the first embodiment, the longitudinal direction of the pin portion 3, the longitudinal direction of the flange portion 4, and the longitudinal direction of the body portion 2 coincide with each other, and the short direction of the pin portion 3 and the short side of the flange portion 4 Is formed so that the short direction of the body portion 2 coincides with the direction of the body portion 2, so that the difference in diameter between the diameter of the flange portion 4 and the diameter of the upper portion 2A can be reduced, and the anti-stud removal performance is improved. it can.
In other words, in the first embodiment, the body portion 2 and the flange portion 4 are formed in such a shape that a large edge effect can be obtained in the direction in which the pin portion 3 is required.
Further, the stud according to the first embodiment is configured so that an edge effect is obtained at the straight portion, and the curved portion can easily cope with the pin durability and the weight limit.
And the longitudinal direction of the pin part 3, the flange part 4, and the body part 2 extends along the tire width direction 10X, and the short direction of the pin part 3, the flange part 4, and the body part 2 is the tire circumferential direction 10Y. The studded tire 10 in which the stud 1 is mounted in the mounting hole 14b of the tire so as to extend along the tire is most desirable, and it is possible to provide the studded tire 10 with improved resistance to stud removal.
In addition, since the diameter difference between the diameter of the flange portion 4 and the diameter of the upper portion 2A can be reduced, the anti-stud removal performance can be improved, so that at least the longitudinal direction of the pin portion 3 and the longitudinal direction of the flange portion 4 coincide. In addition, the stud may be formed so that the short direction of the pin portion 3 and the short direction of the flange portion 4 coincide.
Moreover, the longitudinal direction of the pin part 3, the flange part 4, and the body part 2 extends along the tire circumferential direction 10Y, and the short direction of the pin part 3, the flange part 4, and the body part 2 is the tire width direction 10X. The stud 1 may be a studable tire 10 attached to the tire attachment hole 14b so as to extend along the tire.

Embodiment 2 (Relationship between the diameter of the upper part and the diameter of the flange part (the smaller the diameter difference, the better))
In the second embodiment, the direction along the short axis 1S of the stud 1 so that the diameter difference between the diameter of the flange portion 4 and the diameter of the upper portion 2A in the direction along the short axis 1S of the stud 1 is as small as possible. The short shaft 1S of the stud 1 extends along the tire circumferential direction 10Y, and the long shaft 1L of the stud 1 is Since the studded tire 10 in which the stud 1 is attached to the tire attachment hole 14b is formed so as to extend along the tire width direction 10X, the stud removal resistance is improved.

Embodiment 3 (Cross-sectional shape deformation of body part)
As shown in FIG. 6, the outer peripheral contour line of the cross section orthogonal to the central axis 1C and the lengths of a pair of straight lines forming the outer peripheral edge (edge) of the tip surface 2t, in other words, a pair forming the outer peripheral surface. The stud 1 may be provided with a body portion 2X having a configuration in which the width of the flat portion (the length in the direction along the long axis 1L) is varied.
That is, the stud 1 of the third embodiment extends from the edges of the pair of plane portions 21Aa; 22Aa and the pair of plane portions 21Aa; 22Aa opposite to each other across the center axis 1C and having the center axis 1C. It is composed of a pair of curved surface portions 23Aa; 24Aa that are opposed to each other and project in a direction away from each other, and a boundary portion between the flat surface portions 21Aa; 22Aa and the curved surface portions 23Aa; 24Aa. The stud 1 includes a body portion 2X having an outer peripheral surface formed by curved boundary surface portions 25Aa, 26Aa, 27Aa, and 28Aa projecting away from 1C.
Further, the body portion 2X includes a pair of linear portions whose outer peripheral contour line having a cross section orthogonal to the central axis 1C and the outer peripheral edge (edge) of the distal end surface 2t are opposed to each other with the central axis 1C interposed therebetween and have different lengths. A pair of curved portions 23a; 24a that extend from the ends of the pair of linear portions 21a; 22a and that protrude so as to face each other across the central axis 1C and protrude away from each other; and the linear portions 21a; 22a and a boundary portion between the curved portions 23a and 24a, and the boundary portion is formed by curved boundary portions 25a; 26a; 27a; 28a projecting away from the central axis 1C. In addition, the outer peripheral contour of the cross section orthogonal to the central axis 1C and the shape of the outer peripheral edge (edge) of the distal end surface 2t are formed in a body-symmetrical shape with the short axis 1S as the symmetry axis. .

The stud removal phenomenon that tends to occur as the tire tread wear progresses is a phenomenon that often occurs when the tire is kicked off the road surface at the time of sudden start / acceleration of the vehicle, so the longest time until just before the stud removal, It is effective to increase the area of the outer peripheral surface of the kicking side of the body portion (upper portion 2A) that contacts the inner wall surface (rubber surface) of the tire mounting hole.
Therefore, in the stud 1 of the third embodiment, the short straight portion 22a, in other words, the short width long flat portion 22Aa is positioned on the stepping side, and the long straight portion 21a, in other words, the long width long flat portion 21Aa is provided. Provided is a studded tire 10 in which the stud 1 is mounted in the mounting hole 14b so as to be positioned on the kicking side, so that the stud 1 can be prevented from falling down during braking and acceleration start, and the anti-stud removal performance is improved. become able to.
Here, the short straight portion 22a of the upper portion 2A is positioned on the block stepping side, and the long straight portion 21a is mounted on the block kicking side, so that there is a certain constraint on the weight per stud. Because there is. That is, when the short straight portion 22a of the upper portion 2A is positioned on the block stepping side and the long straight portion 21a is mounted on the block kicking side, the edge effect and durability are maintained within the same weight constraint conditions. And improvement of anti-stud removal performance.
Even when the short straight portion 22a of the upper portion 2A is positioned on the block kicking side and the long straight portion 21a is positioned on the block stepping side, the body does not depend on the tire rotation direction as shown in FIG. When comparing the shape of the part and the volume (weight), it is possible to improve the stud removal resistance. This is because, in the stud removal phenomenon (see FIG. 14), the attachment hole catching effect of the step-side body end that is first pulled out from the kicked block is improved.

Embodiment 4 (deformation of cross-sectional shape of pin part)
As shown in FIG. 7, the outer peripheral contour line of the cross section orthogonal to the central axis 1C and the pin portion 3X having a configuration in which the curvatures of the pair of curved portions forming the outer peripheral edge (edge) on the tip surface 3t are different are provided. The stud 1 may be used.
That is, the stud 1 according to the fourth embodiment extends from the end edges of the pair of plane portions 31Aa; 32Aa and the pair of plane portions 31Aa; 32Aa and sandwiches the center axis 1C. It is composed of a pair of curved surface portions 33Aa; 34Aa, which are curved so as to protrude in directions away from each other and have different radii of curvature, and a boundary portion between the flat surface portion 31Aa; 32Aa and the curved surface portion 33Aa; 34Aa. The stud 1 is provided with a pin portion 3X having an outer peripheral surface formed by curved boundary surface portions 35Aa, 36Aa, 37Aa, and 38Aa projecting away from the shaft 1C.
In addition, the pin portion 3X includes a pair of linear portions 31a; 32a in which the outer peripheral contour line of the cross section orthogonal to the central axis 1C and the outer peripheral edge (edge) of the distal end surface 3t face each other with the central axis 1C interposed therebetween; A pair of straight portions 31a; a pair of curved portions 33a; 34a extending from the ends of the straight portions 31a; 32a and facing each other across the central axis 1C and projecting away from each other, and the straight portions 31a; 32a and the curved portions 33a 34a, and the boundary portion is formed by curved boundary portions 35a; 36a; 37a; 38a projecting away from the central axis 1C.

In order to improve the anti-stud removal performance, it is effective to reduce the scratching effect on the stepping side of the pin portion that first contacts the ground when accelerating. On the other hand, in order to improve the braking performance, it is effective to increase the scratching effect on the kick side of the pin portion that is dragged forward during braking.
Therefore, in the fourth embodiment, the studs are formed such that the curved portion 34a having a small radius of curvature of the pin portion 3X is positioned on the stepping side and the curved portion 33a having a large radius of curvature of the pin portion 3X is positioned on the kicking side. 1 is attached to the mounting hole 14b, so that the curved portion 34a having a small radius of curvature is positioned on the stepping side when the tire rolls, and the scratching effect of the pin portion 3X is reduced when stepping on. Furthermore, since the curved portion 33a having a large radius of curvature is positioned on the kicking side at the time of rolling of the tire and the scratching effect of the pin portion 3X is increased at the time of kicking, the studable tire 10 with improved braking performance can be provided. become.
Here, it is the stud 1 that the curved portion 34a with a small curvature radius of the pin portion 3X is positioned on the block stepping side and the curved portion 33a with a large curvature radius of the pin portion 3X is positioned on the block kicking side. This is because there are certain restrictions on the weight per book. That is, when the small curved portion 34a is positioned on the block stepping side and the curved portion 33a having the large radius of curvature of the pin portion 3X is mounted on the block kicking side, the edge is subject to the same weight constraint condition. The effect, durability, and resistance to stud removal can be improved.
Even when the curved portion 34a having a small curvature radius of the pin portion 3X is positioned on the block kicking side and the curved portion 33a having a large curvature radius of the pin portion 3X is positioned on the block stepping side, FIG. As described above, when comparing the pin portion shape independent of the tire rotation direction and a constant volume (weight), the stud removal resistance can be improved. This is because, in the stud removal phenomenon (see FIG. 14), the attachment hole catching effect of the stepping-side pin end that is pulled out first from the kicked-out block is improved.

Embodiment 5 (Cross-sectional shape deformation of flange portion)
As shown in FIG. 8, the flange portion 4X having a configuration in which the length of the outer peripheral contour line of the cross section orthogonal to the central axis 1C and the pair of linear portions forming the outer peripheral edge (edge) in the other end surface 4E is different. The provided stud 1 may be sufficient.
That is, the stud 1 according to the fifth embodiment extends from the edge of the pair of plane portions 41Aa; 42Aa and the pair of plane portions 41Aa; 42Aa opposite to each other across the center axis 1C, and extends the center axis 1C. It is composed of a pair of curved surface portions 43Aa; 44Aa that are opposed to each other and protrude in a direction away from each other, and a boundary portion between the flat surface portion 41Aa; 42Aa and the curved surface portion 43Aa; 44Aa, and the boundary portion is a central axis The stud 1 was provided with a flange portion 4X having an outer peripheral surface formed by curved boundary surface portions 45Aa, 46Aa, 47Aa, and 48Aa projecting away from 1C.
In addition, the flange portion 4X has a pair of linear portions 41a; 42a and a pair of linear portions 41a; 42a whose outer peripheral contour lines having a cross section orthogonal to the central axis 1C are opposed to each other with the central axis 1C interposed therebetween. A pair of curved portions 43a; 44a that are extended from the ends of the curved portion and are curved so as to protrude opposite to each other across the central axis 1C, and a boundary portion between the linear portions 41a; 42a and the curved portions 43a; 44a The boundary portion is formed by curved boundary portions 45a; 46a; 47a; 48a that protrude away from the central axis 1C.

The stud removal phenomenon that easily occurs as the wear of the tread surface progresses is a phenomenon that occurs particularly frequently at the time of kicking during sudden start / acceleration. Therefore, it is effective to widen the contact area on the kicking side of the flange portion that is in contact with the longest time until just before the stud is pulled out at the time of kicking.
Therefore, in the stud 1 of the fourth embodiment, the short straight portion 42a, in other words, the short width flat surface portion 42Aa is positioned on the stepping side, and the long straight portion 41a, in other words, the long width long flat surface portion 41Aa is provided. Provided is a studded tire 10 in which the stud 1 is mounted in the mounting hole 14b so as to be positioned on the kicking side, so that the stud 1 can be prevented from falling down during braking and acceleration start, and the anti-stud removal performance is improved. become able to.
Here, the short straight portion 42a of the flange portion 4 is positioned on the block stepping side, and the long straight portion 41a is mounted on the block kicking side, so that there is a certain constraint on the weight per stud. Because there is. That is, when the short straight portion 42a of the flange portion 4 is positioned on the block stepping side and the long straight portion 41a is mounted on the block kicking side, the edge effect and durability are maintained under the same weight constraints. And improvement of anti-stud removal performance.
Even in the case where the short straight portion 42a of the flange portion 4 is positioned on the block kicking side and the long straight portion 41a of the flange portion 4 is mounted on the block stepping side, the tire rotation direction as shown in FIG. When comparing the flange portion shape and the volume (weight) constant without depending on the above, it is possible to improve the anti-stud removal performance. This is because, in the stud removal phenomenon (see FIG. 14), the attachment hole catching effect of the step-side flange end that is first pulled out from the kicked block is improved.

Embodiment 6 (Cross-sectional shape deformation of body part, pin part, flange part)
As shown in FIG. 9, the stud 1 is configured to include the body portion 2X of the third embodiment, the pin portion 3X of the fourth embodiment, and the flange portion 4X of the fifth embodiment. The stud 1 is attached to the attachment hole 14b so that the curved portion 34a having a small curvature radius at 3X and the short straight portion 42a at the flange portion 4X are located on the stepping side. Thus, it is possible to provide the studded tire 10 that can achieve the effect.
Here, the short straight portion 22a in the body portion 2X, the curved portion 34a having a small radius of curvature in the pin portion 3X, and the short straight portion 42a in the flange portion 4X are attached so as to be positioned on the block stepping side. This is because there are certain restrictions on the weight. That is, when the straight portion 22a in the body portion 2X, the curved portion 34a having a small radius of curvature in the pin portion 3X, and the short straight portion 42a in the flange portion 4X are mounted so as to be positioned on the block stepping side, Among them, it is possible to improve the edge effect, durability, and stud removal resistance.
Even when the short straight portion 22a in the body portion 2X, the curved portion 34a having a small radius of curvature in the pin portion 3X, and the short straight portion 42a in the flange portion 4X are mounted so as to be positioned on the block kicking side, as shown in FIG. Furthermore, when compared with a shape and volume (weight) that does not depend on the tire rotation direction, the stud removal resistance can be improved. This is because, in the stud removal phenomenon (see FIG. 14), the attachment hole catching effect of the stepping side end that is first pulled out from the kicked block is improved.

Embodiment 7 (Cross section shape deformation + center axis deviation of body part, pin part, flange part)
As shown in FIG. 10, the stud 1 has a configuration in which the central axis 4Z of the flange portion 4X, the central axis 3Z of the pin portion 3X, and the central axis 2Z of the body portion 2X described in the sixth embodiment are shifted. In this case, the stud 1 having a configuration in which the central axis 3Z of the pin portion 3X and the central axis 2Z of the body portion 2X are located closer to the straight portion 41a of the flange portion 4X than the central axis 4Z of the flange portion 4X, The stud 1 is mounted in the mounting hole 14b so that the short straight portion 22a in the body portion 2X, the curved portion 34a having a small radius of curvature in the pin portion 3X, and the short straight portion 42a in the flange portion 4X are positioned on the stepping side. Thus, the studded tire 10 is provided with the stud 1 in which the central axis 3Z of the pin portion 3X and the central axis 2Z of the body portion 2X are offset to the kicking side with respect to the central axis 4Z of the flange portion 4X.
According to the studded tire 10, the difference in the tire side radial direction of the upper portion 2A, the flange portion 4X, and the pin portion 3X of the body portion 2X is smaller than the stepping-side diameter difference, and the stud-side tire diameter difference is smaller. Since the rotational deformation of the stud 1 is suppressed on the kicking side that has been in contact for the longest time just before 1 falls off, the anti-stud removal performance is improved.

In the present invention, the configuration of the stud is different in the length of the outer peripheral contour line and the outer peripheral edge of the body portion as in the above-described embodiment 6 (see FIG. 9) and embodiment 7 (see FIG. 10). A pair of straight portions 21a; 22a, a peripheral contour line of the pin portion, and a peripheral edge include a pair of curved portions 33a; 34a having different curvature radii, and the peripheral contour line of the flange portion has a different length. A pair of straight portions 41a; 42a, and a short straight portion 22a, a curved portion 34a having a small radius of curvature, and a short straight portion 42a are all arranged on the same side, and the stud is used to form the stud. The short straight portion 22a in the body portion 2X, the curved portion 34a having a small radius of curvature in the pin portion 3X, and the short straight portion 42a in the flange portion 4X are provided on the tire block depression side or block kick side. It is preferable to configure the stack twin wheels mounted so as to be positioned on the side.
The short straight portion 22a, the curved portion 34a having a small radius of curvature, and the short straight portion 42a are all disposed on the same side, that is, the center of the short straight portion 22a, the center of the curved portion 34a having a small radius of curvature, and the center of the short straight portion 42a. The short axis 1S passes, and the short straight part 22a, the curved part 34a having a small radius of curvature, and the short straight part 42a are located on one side with the long axis 1L as a boundary.
The short axis 1S passes through the center of the short straight portion 22a, the center of the curved portion 34a having a small curvature radius, and the center of the short straight portion 42a, and the short straight portion 22a of the body portion and the curvature radius of the pin portion are small. A stud configured such that the curved portion 34a is located on one side with the long axis 1L as a boundary, and the short straight portion 42a of the flange portion is located on the other side with the long axis 1L as a boundary. There may be. That is, with the long axis 1L as a boundary, the short straight portion 42a of the flange portion is a stud provided on the opposite side of the short straight portion 22a in the body portion 2X and the curved portion 34a having a small curvature radius in the pin portion 3X. There may be.

Embodiment 8 (Side shape of pin part)
Instead of the pin portion described in each embodiment, as shown in FIG. 11, the height dimension (the length dimension in the direction along the central axis 1C) at one end of the pin portion radial direction, which is a direction orthogonal to the central axis 1C. ) And the height of the other end in the pin portion radial direction may be a stud 1 having a pin portion 3Y configured to be different.
For example, one end in the pin portion radial direction and the other end in the pin portion radial direction are the shortest pin portion radial lines passing through the central axis, that is, both end positions on the short axis 1S (see FIG. 1 and the like).
For example, at one of the radial ends of the pin portion 3Y intersecting the short axis 1S, the boundary portion 3s between the tip surface 3t of the pin portion 3Y and the outer peripheral surface 3r of the pin portion 3Y is separated from the central axis 1C. It is assumed that the pin portion 3Y has a configuration formed by a curved boundary surface portion that protrudes in the direction.
Specifically, one curved portion 33 of the pair of curved portions 33; 34 that form the outer peripheral edge (edge) of the distal end surface 3t of the pin portion 3 described in the first embodiment is formed by the above-described curved boundary surface portion. The formed structure is assumed.
That is, the curvature radius of the boundary portion 3s between the tip surface 3t of the pin portion 3Y and the outer peripheral surface 3r of the pin portion 3Y in one of the pair of bending portions 33; 34 is r1, and the pair of bending portions 33; When the radius of curvature of the boundary portion 3e between the tip surface 3t of the pin portion 3Y and the outer peripheral surface 3r of the pin portion 3Y in the other curved portion is r2, r1> r2.

  Then, the stud 1 is mounted on the vehicle by configuring the studded tire 10 in which the stud 1 is mounted in the mounting hole 14b so that the boundary portion 3s side of the configuration formed by the curved boundary surface portion becomes the stepping end.

  According to the eighth embodiment, the vertical section curvature radius of the boundary portion 3s between the one end surface (tip surface 3t) of the stepped side of the pin portion 3Y and the outer peripheral surface 3r is increased (≈the pin edge is rounded). The scratching effect on the stepping side of the pin portion 3Y to be grounded first can be reduced, the stud removal resistance can be improved, and the vertical cross section of the boundary portion 3e between the tip end surface 3t on the kick side of the pin portion 3Y and the outer peripheral surface 3r Since the radius of curvature is small (= the pin edge is sharp and sharp), the scratching effect on the kicking side of the pin portion 3Y that is dragged forward during braking is increased, and the braking performance is improved.

  The boundary portion 3s may be a slope instead of a curved surface. In short, if it is a stud with a pin portion formed so that the height dimension at one end in the pin portion radial direction and the height dimension at the other end in the pin portion radial direction are different, the stud-resistant stud is a reverse performance Both slipping performance and braking performance can be achieved.

Embodiment 9 (Vertical sectional shape of the lower part)
As shown in FIG. 12, the diameter of the cross-sectional shape orthogonal to the central axis 1 </ b> C is formed so that the diameter gradually increases from the middle part 2 </ b> C side toward the flange part 4, and the cone shape is continuous with the outer peripheral surface of the flange part 4. It is good also as the stud 1 provided with the body part 2Y which has the lower part 2B1 which has the outer peripheral surface.
The angle α formed by the cross section perpendicular to the central axis 1C of the lower portion 2B1 and the inclined surface forming the outer peripheral surface of the lower portion 2B1 is preferably 20 deg ≦ α ≦ 60 deg.

  When the outer peripheral surface is a surface parallel to the central axis 1C as in the lower portion 2B described above, the outer peripheral surface becomes a portion that is difficult to contact the inner peripheral surface of the mounting hole 14b, and resists the collapse deformation of the stud 1. If it is formed on an inclined surface that gradually increases from the middle portion 2C side toward the flange portion 4 like the outer peripheral surface of the lower portion 2B1 of the ninth embodiment, The rubber on the inner peripheral surface of the mounting hole 14b can be easily brought into contact with each other and a frictional force can be expressed, and the resistance force against the falling deformation of the stud 1 can be increased, so that the anti-stud removal performance is improved.

Embodiment 10
The stud which formed the groove | channel as demonstrated in FIG. 13 in the front end surface of the pin part in each embodiment may be sufficient. The groove may have a cross shape or a straight line shape as shown in FIG.
When such a groove is provided, the ice powder scratched and scraped off by the pin portion 3 is discharged through the groove, and is difficult to stay on one end surface of the pin portion 3, which is preferable.

1 Stud, 1C central axis, 2 body part, 3Y pin part, 4 flange part,
10 Studded tires,
14 tread, 14a tread surface, 14b mounting hole.

Claims (4)

In a stud provided with a columnar body part, a pin part provided at one end in the direction along the central axis of the body part, and a flange part provided at the other end in the direction along the central axis of the body part,
The stud portion is characterized in that a height dimension at one end in the pin portion radial direction which is a direction orthogonal to the central axis is different from a height dimension at the other end in the pin portion radial direction.   2. The stud according to claim 1, wherein one end in the pin portion radial direction and the other end in the pin portion radial direction are positioned on a shortest pin portion radial line passing through the central axis.   The stud is a tread surface of the tire so that the short direction of the pin portion perpendicular to the central axis and intersecting one end of the pin portion radial direction and the other end of the pin portion radial direction extends along the tire circumferential direction. A studded tire formed by being attached to a mounting hole formed on the side.   The tread surface of the tire is such that the short direction of the pin portion that intersects the central axis and intersects one end of the pin portion radial direction and the other end of the pin portion radial direction extends along the tire width direction. A studded tire formed by being attached to a mounting hole formed on the side.

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