WO2014006858A1

WO2014006858A1 - Pin, tire stud and studded tire

Info

Publication number: WO2014006858A1
Application number: PCT/JP2013/004027
Authority: WO
Inventors: 浩樹沢田; 川眞田　智; 祐貴渡辺; 智明伊藤
Original assignee: 株式会社ブリヂストン
Priority date: 2012-07-04
Filing date: 2013-06-27
Publication date: 2014-01-09
Also published as: JP2014012454A; JP5997518B2

Abstract

This pin (3) is used for studs to be embedded in a studdable tire, and is characterized by having grooves (5) disposed on one end surface (3a), and is further characterized in that the one end surface (3a) is divided into three or more parts by the grooves (5). Furthermore, this stud is provided with: a columnar body in which a recess is formed in the one end surface (3a) in the axis direction; and the abovementioned pin (3) which is inserted in the recess and has a part that includes the one end surface (3a) of the pin (3) that protrudes from one end surface (3a) of the body. Moreover, this studded tire is formed by embedding the abovementioned stud in multiple holes formed on a tread surface.

Description

Pins, tire studs and spike tires

The present invention relates to a pin used for a stud driven into a studded tire, a tire stud, and a spike tire.

Conventionally, a spike tire in which metal studs are driven into a plurality of holes formed on a tread surface is known as a winter tire with improved running performance on a frozen road (ice road) or a snowy road.

Here, as a stud used for a studded tire, generally, a cylindrical body having a small hole formed in one end face, a hard pin press-fitted into a small hole in the body, and the body on the other end face side of the body And a stud provided with a flange for preventing slippage provided integrally therewith.

Then, the stud is embedded in the tread portion from the flange to one end surface of the body, and is driven into a hole formed in the tread portion tread surface so that the pin protrudes from the tire surface.
Normally, the pin is formed using an ultra-hard metal such as tungsten steel, and the body and the flange are formed using a metal such as an aluminum alloy or steel.

By the way, in the spike tire in which the stud is driven into a plurality of holes formed in the tread portion tread, the stud that has been driven scratches ice and snow, increasing the frictional resistance of the tire.
Specifically, in the spike tire, as shown in FIG. 1, first, in this figure, the pin 12 of the stud 11 embedded in the tread portion 10 of the tire rotating clockwise is a road surface 13 (ice road or snowy road). ). Next, when the body 15 whose corners protrude from the hole 14 due to the contact between the pin 12 and the road surface 13 comes into contact with the road surface 13, the stud 11 scratches ice and snow, and the running performance is improved.

In order to improve the on-ice performance of the spike tire as described above, it is necessary to increase the frictional resistance of the tire by increasing the force with which the stud scratches the ice.

In this regard, a technique has been proposed in which two or more pins are provided on the stud to enhance the grip performance on an icy road (see Patent Document 1).

International publication 2012/004452 pamphlet

However, in the method described in Patent Document 1, it is necessary to manufacture two or more pins and press-fit them into the small holes in the stud body, which increases the manufacturing process and increases the cost and man-hours. Since a plurality of pins are provided, there is a problem that the weight of the entire stud increases.
In addition, it is necessary to provide a plurality of small holes for press-fitting a plurality of pins in the body, which also leads to an increase in manufacturing process, cost, and man-hour.
Accordingly, there has been a demand for the development of a technique for improving the performance on ice without causing these problems.

The present invention is intended to solve the above-described problem, and provides a pin and a stud for a tire that can improve the braking performance on ice of a spike tire, and a spike tire that improves the braking performance on ice. Objective.

The inventors have intensively studied to solve the above problems.
As a result, it was found that providing a groove on one end face of the pin to increase the edge component is extremely effective for improving the braking performance on ice, and that the pin itself can be reduced in weight.

This invention is made | formed based on said knowledge, The summary structure is as follows.
The pin of the present invention is used for a stud that is driven into a studded tire. A groove is provided on one end surface, and the one end surface is divided into three or more portions by the groove.
This is because the edge component can be increased and the braking performance on ice of the tire can be improved.

In the pin of the present invention, it is preferable that the one end face is divided into three or more and five or less portions by the groove.
This is because the edge component can be further increased while preventing pin chipping, and the braking performance on ice of the tire can be further improved.

Furthermore, in the pin of the present invention, when the groove width of the groove is W (mm) and the maximum outer diameter of one end surface of the pin is OD (mm),
0.15 ≦ W / OD ≦ 0.5 and 2.0 ≦ OD ≦ 4.0
It is preferable to satisfy.
This is because by setting the above range, it is possible to achieve both braking performance on ice and anti-stud off performance.
Here, “stud off resistance” means that the stud is difficult to fall off during traveling.
Further, the “groove width” means a width in a direction perpendicular to the extending direction of the groove, and when the groove width is not constant, it means the maximum width of the groove.
Further, the “maximum outer diameter” means the largest interval when one end face of the pin is sandwiched between two parallel lines contacting the end face.

Furthermore, in the pin of the present invention, it is preferable that the one end face is divided at an equal angle by the groove.
This is because the strength of the pin can be improved.

Here, the stud of the present invention includes a columnar body in which a concave portion is formed on one end surface in the axial direction, and a part including one end surface of the pin protruding from the one end surface of the body. The above-mentioned pin is provided.
This is because the on-ice braking performance of the spike tire can be improved by using the stud having the above pin by driving it into a plurality of holes formed on the tread surface of the studded tire.

In the tire stud of the present invention, the maximum depth of the groove from one end face of the pin is D (mm), and the height from one end face of the body to one end face of the pin is H ( mm)
0.15 ≦ D / H ≦ 0.5 and 0.8 ≦ H ≦ 2.0
It is preferable to satisfy.
This is because by setting the above range, it is possible to achieve both braking performance on ice and anti-stud off performance.
If the height from one end face of the body to one end face of the pin is not constant, the height from the position of the maximum height of one end face of the body to the position of the maximum height of one end face of the pin It shall be said. The maximum height position refers to the position on the uppermost axial direction when the direction in which the pin is provided is the upper side and the direction in which the flange is provided is the lower side in the axial direction of the body.

Furthermore, the spike tire of the present invention is characterized in that the tire stud is driven into a plurality of holes formed in the tread surface.
This is because the on-ice braking performance of the spike tire can be improved.

According to the present invention, it is possible to provide a pin and a tire stud that can improve the on-ice braking performance of a spike tire, and therefore it is possible to improve the on-ice braking performance of a spike tire.

It is a figure for demonstrating a mode that a spike tire scratches a road surface. It is a front view which shows the stud for tires concerning one Embodiment of this invention. (A) It is a top view of the pin concerning one Embodiment of this invention. (B) It is a front view of the pin concerning one Embodiment of this invention. (A) It is a top view of the pin concerning other embodiment of this invention. (B) It is a front view of the pin concerning other embodiment of this invention. It is a tread development view showing a tread part tread of a studable tire concerning one embodiment of the present invention. (A) It is a top view of the pin concerning further another embodiment of this invention. (B) It is a front view of the pin concerning other embodiment of this invention. (A) It is an upper side figure of the pin concerning other embodiment of this invention. (B) It is a front view of the pin concerning other embodiment of this invention. (A) It is a top view of the pin concerning another embodiment of this invention. (B) It is a front view of the pin concerning another embodiment of this invention. (A) It is a top view of the pin concerning another embodiment of this invention. (B) It is a front view of the pin concerning another embodiment of this invention. (A) It is a top view of the pin concerning another embodiment of this invention. (B) It is a front view of the pin concerning another embodiment of this invention. It is a front view which shows the stud for tires concerning other embodiment of this invention. (A) It is a top view of the pin concerning a comparative example. (B) It is a front view of the pin concerning a comparative example. (A) It is a top view of the pin concerning a prior art example. (B) It is a front view of the pin concerning a prior art example. (A) It is a top view of the pin concerning another embodiment of this invention. (B) It is a front view of the pin concerning another embodiment of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 2 is a front view showing a tire stud (hereinafter also simply referred to as a stud) according to an embodiment of the present invention.
As shown in FIG. 2, a stud 1 according to the present invention is formed on a substantially cylindrical body 2 and one end face 2a in the direction of an axis C of the body 2 (a central axis C extending in the longitudinal direction of the body). A pin 3 disposed in a concave portion (indicated by a dotted line in the figure), and a flange 4 for preventing slipping provided integrally with the body 2 on the other end surface side in the axial direction of the body 2 are provided.
In the illustrated example, the edge portion on the one end surface 2a side in the axial direction of the body 2 is chamfered.

3 (a) and 3 (b) are diagrams for explaining the pin 3, FIG. 3 (a) is a top view of the pin 3, and FIG. 3 (b) is an end view of the pin 3. FIG. .
As shown in FIG. 3A, a groove 5 is formed in one end face 3a of the pin 3, and the pin 3 is thus divided into four discontinuous portions.
In the illustrated example, the groove 5 is provided so that two grooves extending from one end to the other at one end face 3 a of the pin 3 intersect each other perpendicularly, and one end face 3 a of the pin 3 is formed by the groove 5. It is divided into four equal angles (90 ° in the illustrated example).
Further, as shown in FIG. 3B, the groove 5 has a semicircular cross section, in other words, the bottom is rounded. In the present invention, as shown in FIGS. 4A and 4B, the bottom of the groove can be flat.
In the illustrated example, one end face 3a is flat, but may be curved so as to have a center of curvature inside the pin (that is, may be curved in a shape convex in the protruding direction of the pin). ).
In the following, the pin shown in FIGS. 3 (a) and 3 (b) is in the concave portion of the body, and the one end surface is on the upper side in the axial direction as shown in FIG. The tire stud inserted and fixed (in this example, press-fitted) so as to be on the lower side, as shown in FIG. 5, is a spiked tire that is driven into a plurality of holes 7 formed in the tread surface 6 The effect will be described.

According to the present invention, since the end surface of the pin that contacts the road surface is divided into three or more by the groove, the edge component can be increased and the braking performance on ice can be improved.
Furthermore, since the groove is provided in the pin, the pin can be reduced in weight.
Further, since it is not necessary to increase the number of pins and it is not necessary to perform special processing on the stud body, it is possible to suppress an increase in cost.

Moreover, in this invention, it is preferable that one end surface 3a is divided | segmented into 3 or more and 5 or less parts by the groove | channel.
This is because the edge component is increased by dividing it into three or more parts, while the chipping is prevented by dividing into five or less parts, and the braking performance on ice can be improved in this range. .
And in this invention, it is especially preferable to divide | segment one end surface 3a into four parts by a groove | channel. This is because the effect of increasing the edge component while preventing pin chipping can be exhibited in a well-balanced manner, and the braking performance on ice can be particularly improved.
Here, FIGS. 6A and 6B, FIGS. 7A and 7B, and FIGS. 8A and 8B are diagrams for explaining pins according to other embodiments of the present invention, respectively. is there.
In the present invention, as in the example shown in FIGS. 6A and 6B, the end surface 3a can be divided into six parts at equal angles (60 ° in the illustrated example) by the grooves 5. 7 (a) and 7 (b), the end surface 3a can be divided into eight parts at equal angles (45 ° in the illustrated example) by the grooves 5, and further, FIG. As in the example shown in b), the end surface 3a can also be divided into ten portions at equal angles (36 ° in the illustrated example) by the grooves 5.
On the other hand, as shown in FIGS. 9A and 9B, the end surface 3 a can be divided into three parts by the groove 5.

Furthermore, in the present invention, as shown in FIGS. 3A and 3B, the width of the groove formed on one end surface 3a of the pin is W (mm), and the maximum outer diameter of the one end surface 3a of the pin is set. When OD (mm)
0.15 ≦ W / OD ≦ 0.5 and 2.0 ≦ OD ≦ 4.0
It is preferable to satisfy.
This is because by ensuring the groove width by setting the ratio W / OD to be 0.15 or more, the edge effect can be sufficiently exerted when the pin is dragged on ice, When the ratio W / OD is 0.5 or less, the area of the land section defined by the groove on one end face of the pin is secured, the strength of the pin is secured, and the pin is dragged on the road surface on ice. This is because it is possible to suppress the occurrence of pin chipping during running on a dry road surface, thereby avoiding a decrease in braking performance on ice due to chipping and a decrease in edge components.
Further, by setting the OD to 2.0 (mm) or more, the contour of the pin itself can be enlarged to ensure basic performance on ice, while the OD (mm) is set to 4.0 or less. This is because it is possible to avoid a decrease in basic anti-stud-off performance due to an excessively large pin and a large road surface reaction force.

Furthermore, in the present invention, at least two grooves are provided on one end surface of the pin, and the at least two grooves are formed so that the groove divides the one end surface of the pin at an equal angle. Is preferred.
This is because by dividing into equal intervals, the area of the land portion divided by the groove becomes uniform, the land portion having a small area and small strength is not formed, the pin is missing, and the edge component decreases. This is because a decrease in braking performance on ice can be prevented.

Further, in the present invention, a columnar body in which a recess is formed on one end surface in the axial direction, and a pin that is inserted into the recess and a part of which includes one end surface protrudes from one end surface of the body. 3 (a) and 3 (b) and the like, the maximum depth of the groove from one end face 3a of the pin is D (mm), and as shown in FIG. When the height from the end surface 2a to one end surface 3a of the pin is H (mm),
0.15 ≦ D / H ≦ 0.5 and 0.8 ≦ H ≦ 2.0
It is preferable to satisfy.
This is because by setting the ratio D / H to be 0.15 or more, it is possible to sufficiently secure the groove depth and sufficiently exhibit the effect as an edge when the pin is dragged on ice. On the other hand, by setting the ratio D / H to 0.5 or less, the groove is appropriately shallow with respect to the land area defined by the groove to ensure the strength of the pin, and the pin is placed on the road surface on ice. This is because it is possible to suppress the occurrence of chipping at the time of dragging or on a dry road surface, thereby preventing a decrease in braking performance on ice due to chipping and a decrease in edge components.
In addition, by setting H to 0.8 (mm) or more, it is possible to secure the protruding height of the pin from the body and ensure basic performance on ice, while H is set to 2.0 (mm This is because, by setting the following, it is possible to avoid a decrease in basic anti-stud-off performance due to the projecting height of the pin from the body being too large and the road surface reaction force becoming large.

Here, the top surface shape of the pin, that is, the planar shape of one end surface 3a of the pin can be various shapes other than a circular shape, for example, as shown in FIGS. 10 (a) and 10 (b). It is particularly preferable to have a shape provided with the notch 3b.
Since the rectangular corner is close to point contact, the ground contact pressure can be made extremely high locally, and as a result, the amount of biting into the icy road surface increases compared to the case of line contact with a cylindrical edge. This is because an actual edge effect greater than the size calculated from the shape can be obtained, so that the braking performance on ice is particularly improved.

Furthermore, in the present invention, as shown in FIG. 11, a part of the body has a recess (shown by a dotted line in the drawing) on the upper end surface of the body 2 having a notch 2 b reaching the upper end surface on the side surface. A pin can be press-fitted so as to protrude from the upper end surface.

In order to confirm the effect of the present invention, the pins according to the inventive examples 1 to 9 and the pin according to the comparative example were prototyped, and the pins according to the conventional example were prepared.
Each pin is inserted into a recess in the upper end surface of the body, studs that are press-fitted so that a part protrudes from the upper end surface of the body are inserted into a plurality of holes formed in the tread portion tread surface, and the upper end surface of the body is Spike tires were produced by driving to a standard.
The specifications of each tire are shown in Table 1 below.

Each of the tires having a tire size of 195 / 65R15 was incorporated into a rim having a rim size of 6J × 15 inches, filled with an internal pressure of 210 kPa, and the following evaluation was performed.
<Ice braking performance>
After running on general roads on ice and snow and dry roads (preliminary driving of about 80 km in mileage), the test driver suddenly braked the vehicle from the initial speed of 20 km / h on the course on the ice roads. And the braking distance until a vehicle became a stationary state was measured, and the braking performance on ice of a spike tire was evaluated from the reciprocal number. The evaluation is an index evaluation with a relative value where the evaluation result of the conventional example is 100, and the larger the value, the higher the braking performance on the icy road surface.
<Stud-off resistance>
The snow and dry road surface was run 30000 km from the time of a new tire. Then, the number of studs dropped after running was measured, and the ratio of the number of dropped studs to the total number of initial studs was calculated to evaluate the stud slip-off property of the spike tire. The evaluation is an index evaluation with a relative value where the evaluation result of the conventional example is 100, and the smaller the value, the higher the stud-off resistance performance.
Table 1 below shows the evaluation results together with the tire specifications.

As shown in Table 1, it can be seen that each of Invention Examples 1 to 9 is superior in braking performance on ice than the conventional tire, while ensuring anti-stud off performance similarly to the conventional tire.

Next, tires according to Invention Examples 10 to 21 were manufactured by changing the groove width W, groove depth D, pin outer diameter OD, and pin protrusion height H, and evaluated in the same manner as described above.
The specifications and evaluation results of each tire are shown in Tables 2 and 3 below.
The tires described above have common specifications that are not shown in the tables.

As shown in Table 2, it can be seen that the invention example in which the OD and the ratio W / OD are optimized can achieve both the braking performance on ice and the anti-stud off performance.
Moreover, as shown in Table 3, it can be seen that the invention example in which H and the ratio D / H are optimized can achieve both the braking performance on ice and the anti-stud off performance.

1 Stud (Stud for tire)
2 Body 2a end face (one end face of the body)
2b Notch 3 Pin 3a End face (one end face of the pin)
3b Notch part 4 Flange 5 Groove 10 Tread part 11 Stud 12 Pin 13 Road surface 14 Hole 15 Body TE Tread end

Claims

A pin used for a stud driven into a studded tire,
A pin provided with a groove on one end face, and the one end face is divided into three or more portions by the groove.
The pin according to claim 1, wherein the one end face is divided into three or more and five or less portions by the groove.
When the groove width of the groove is W (mm) and the maximum outer diameter of one end surface of the pin is OD (mm),
0.15 ≦ W / OD ≦ 0.5 and 2.0 ≦ OD ≦ 4.0
The pin according to claim 1 or 2, satisfying
The pin according to any one of claims 1 to 3, wherein the one end face is divided at an equal angle by the groove.
A columnar body having a recess formed on one end face in the axial direction;
A tire stud comprising: the pin according to any one of claims 1 to 4, wherein the pin is inserted into the recess and a part including one end face of the pin protrudes from one end face of the body.
When the maximum depth of the groove from one end face of the pin is D (mm), and the height from one end face of the body to one end face of the pin is H (mm),
0.15 ≦ D / H ≦ 0.5 and 0.8 ≦ H ≦ 2.0
The tire stud according to claim 5, wherein:
A spike tire, wherein the tire stud according to claim 5 or 6 is driven into a plurality of holes formed in a tread surface.