JP5355040B2 - Spike tire - Google Patents

Description

  The present invention relates to a spike tire in which spike pins are driven into a tread surface, and particularly relates to a shape around the pins of the spike tire.

As a winter tire, a spike tire is known in which a land sipe of a tire tread is provided and spike pins are driven into a land portion where the sipe is formed. As the spike pin, generally, as shown in FIG. 6A, a cylindrical body 20a, a tip 20b press-fitted to the distal end side of the body 20a, and a drop provided on the proximal end side of the body 20a. The spike pin 20 provided with the flange 20c for prevention is used. As shown in FIGS. 6A and 6B, the spike pin 20 is driven into a pin hole 42 opened in advance on the surface of the land portion 41 of the tread. The spike pin 20 is usually driven with the tip of the tip 20b and the tip of the body 20a protruding from the surface of the land portion 41 by about h = 1 mm, so that when the tire travels on an icy road Since the tip 20b protruding from the tread surface and the body 20a scratch the ice and increase the frictional resistance of the tire, high on-ice performance can be ensured (see, for example, Patent Documents 1 and 2).
JP 2000-142036 A JP 10-53009 A

By the way, since the spike pin 20 protrudes from the tread surface, as shown in FIG. 7, when the spike pin 20 is in the ground contact surface of the running tire 40, the spike pin 20 instantaneously Pressed from. Therefore, the spike pin 20 is in a state where the rubber under the pin is crushed and submerged in the rubber. At this time, the rubbers 43p and 43q around the spike pin 20 are pulled to the inner surface side of the tread by the sinking of the spike pin 20, so that they float from the road surface 50. Actually, when the ground contact print of the spike tire is observed, it can be seen that an ungrounded portion larger than the diameter of the body 20a of the spike pin 20 is generated.
As described above, when an ungrounded portion is generated around the spike pin 20, there is a problem that the ground contact area of the tread is reduced and the grip force on the icy road is decreased. Incidentally, the reduction of the ground contact area is about 1 to 3%, although it depends on the number of spike pins in the ground contact surface. In addition, as described above, if an ungrounded portion is formed around the spike pin 20, there is a problem that the fall of the spike pin 20 due to the impact force from the road surface 50 becomes large and the spike pin 20 is easily dropped. It was.

  The present invention has been made in view of conventional problems, and it is an object of the present invention to improve the performance of spike tires on ice and to suppress the dropping of spike pins.

The invention according to claim 1 of the present application includes a plurality of grooves formed on a tread surface of a tire, a land portion partitioned by the grooves, a pin hole formed in the land portion, and a pin hole formed in the pin hole. a spike tire provided with a driven spike pins, around the pin holes are raised portion is provided that is raised from the surface of the land portion tread rubber the pin hole is formed, The protruding portion has an annular shape when viewed from the extending direction of the center line of the pin hole, and a cross section when cut by a plane including the center line of the pin hole and parallel to the center line is the land portion. A slope portion that rises from the opposite side of the pin hole and increases in height as it approaches the pin hole, and the spike pin is driven in a state where the tip protrudes from the bump portion . It is characterized by this . As a result, it is possible to prevent the rubber around the spike pin from lifting off from the road surface due to the sinking of the spike pin, thereby minimizing the reduction of the ground contact area and suppressing the collapse of the spike pin. can do. Therefore, it is possible to suppress a decrease in grip force on icy roads and snowy roads and a drop of spike pins .
The invention according to claim 2, in spike tire according to claim 1, the inclined surface portion, with the inclined surface which rises linearly or arcuate or stepped from the surface of the land portion, of the slope portion on the opening side of the pin hole has the same height as the end of the opening side of the pin hole of the slope portion, which is provided with a plane parallel portion on the surface of the land portion in which the pin hole is formed It is.
Further, an invention according to claim 3, in spiked tire according to claim 1, the inclined surface portion, with the arc-shaped slope portion which rises from the surface of the land portion, the arc of the slope portion, the The inclination of the tangent on the opening side of the pin hole is an arc parallel to the surface of the land portion where the pin hole is formed.
By making the shape of the raised portion as described above, the spike pin can be securely held, so that the fall of the spike pin can be further suppressed.

Hereinafter, the best mode of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration of a spike tire 10 according to the best mode, in which 11 is a bead portion, 11C is a bead core, 12 is a carcass layer, 13a and 13b are belt layers, 14 is a tread, Reference numeral 15 denotes a side tread.
The carcass layer 12 is a member that forms a skeleton of the spike tire 10 provided so as to straddle a pair of bead cores 11 </ b> C arranged in the bead portion 11, and the tire in the crown portion of the carcass layer 12. Two belt layers 13a and 13b are arranged on the radially outer side. Each of the belt layers 13a and 13b is formed by arranging steel cords or cords made by twisting organic fibers so as to cross each other at an angle of 20 ° to 70 ° with respect to the equator direction. The extending direction of the cord of the belt layer 13a and the extending direction of the cord of the belt layer 13b disposed 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. A plurality of treads 14 are provided on the surface of the tread 14 so as to extend along the tire circumferential direction. Main grooves 16 are formed, and a plurality of land portions 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 in the tire width direction of the central land portion 17A, and the land portion 18 is a tire width of the outer land portion 17B. It is a shoulder side land part located in the both outer sides of a direction. A plurality of sipes 19 are formed on the surfaces of the land portions 17A, 17B, and 18, and a plurality of spike pins 20 are driven into the shoulder-side land portion 18 and the outer land portion 17B. In this example, the spike pin 20 shown in FIG. 6 is the same as the spike pin 20.
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.
In the figure, reference numeral 13c indicates that the spike pin 20 is prevented from sinking into the belt layer 13b on the outer side in the tire radial direction due to a rubber sag under the pin (in the tire radial direction) by the spike pin 20. This is a belt protective layer provided with a cord made of an organic fiber or the like.

In this example, the shoulder side land portion 18 is a block row in which a plurality of shoulder blocks 22 partitioned by the main groove 16 and a lug groove 21 intersecting the main groove 16 are arranged along the tire circumferential direction. Configured. As shown in FIG. 2A, the shoulder block 22 is formed with a plurality of sipes 19 and pin holes 23 for driving spike pins 20. As shown in FIG. 2B, the pin hole 23 includes an introduction portion 23a and a pin holding portion 23b. The introduction portion 23a is a void portion having a substantially trapezoidal cross-sectional shape that opens to the tread surface side, and whose diameter decreases in a tapered shape as it goes inside the tread. The pin holding portion 23b communicates with the introduction portion 23a and has a diameter smaller than the diameter of the body 20a of the spike pin 20. The diameter of the pin holding portion 23b slightly increases in the portion where the flange 20c of the spike pin 20 is accommodated. ing. A pin hole similar to the pin hole 23 is also formed in the outer land portion 17B.
The tread rubber around the pin hole 23 of the shoulder block 22 of this example is raised from the surface 22k of the shoulder block 22 which is a land portion where the pin hole 23 is formed. A portion where the tread rubber around the pin hole 23 is raised is hereinafter referred to as a raised portion 24. The surface 22k of the shoulder block specifically refers to the surface of the tread rubber constituting the shoulder block 22 excluding the pin hole 23 and its periphery and the portion where the sipe 19 is formed.
As shown in FIGS. 2A and 2B, the shape of the raised portion 24 is annular when viewed from the tread surface side, which is the extending direction of the center line of the pin hole 23, and the center of the pin hole 23. The cross-sectional shape when it is cut by a plane including a line and parallel to the center line is a trapezoid. That is, the raised portion 24 includes a slope portion 24a that rises linearly from the surface 22k of the shoulder block, and a flat portion 24b provided between the slope portion 24a and the opening portion 23s of the pin hole 23. Yes. The plane portion 24b is parallel to the surface 22k of the shoulder block 22 which is a land portion where the pin hole is formed, and the height of the bulge is the maximum height of the slope portion 24a. It is equal to the height of the end side of the pin hole 23. The tread rubber around the pin hole formed in the outer land portion 17B also has a raised portion similar to the raised portion 24.

Since the tread rubber in which the pin hole 23 is formed has elasticity, as shown in FIG. 3 (a), the body 20a of the spike pin 20 is held by a nail 60 of a driving tool (not shown) such as a spike gun. The spike pin 20 can be easily driven into the pin hole 23 by press-fitting into the pin hole 23. Thereby, as shown in FIG. 3B, the spike pin 20 has a raised portion 24 (or a surface of the outer land portion 17B) in which the tip of the tip 20b and the tip of the body 20a are raised from the surface 22k of the shoulder block 22. Will be driven in a state of protruding from the raised part). At this time, it is preferable that the spike pin 20 is driven so as to protrude about 1 mm from the surface 22k of the shoulder block 22 (or the surface of the outer land portion 17B) as usual. For example, when the height of the raised portion 24 from the surface 22k of the shoulder block 22 is 0.2 mm, the tip of the spike pin 20 may be driven so as to protrude from the raised portion 24 by about 0.8 mm. .
In the spike tire 10 of the present example, the rubber around the spike pin 20 protrudes from the surface 22k of the shoulder block 22, and therefore, as shown in FIG. Even when pushed from the road surface 50 and sunk into the rubber, the amount of sunk of the rubbers 22p and 22q around the spike pin 20 is much smaller than in the prior art. Therefore, the width of the annular ungrounded portion indicated by the width w shown in the figure when the spike pin 20 is on the ground plane is significantly reduced from the width of the conventional annular ungrounded portion indicated by the width W shown in the figure. can do. As a result, the reduction in the contact area of the tread can be minimized, so that the grip force on the icy road can be improved and the fall of the spike pin 20 can be suppressed to prevent the spike pin 20 from falling off. Can be reduced.

  As described above, in this best mode, the cross-sectional shape is trapezoidal when viewed from the tread surface side around the pin hole 23 for driving the spike pin 20 formed in the shoulder block 22 of the spike tire 10. Even when the tread rubber is provided with the raised portion 24 where the shoulder block surface 22k is raised and the spike pin 20 is submerged in the rubber during running, the rubber around the spike pin 20 is provided. Since the sinking amounts of 22p and 22q are reduced, the ungrounded portion around the spike pin 20 can be greatly reduced. Accordingly, it is possible to suppress a decrease in the contact area of the tread and improve the grip force on the icy road, and it is possible to suppress the collapse of the spike pin 20, so that the spike pin 20 is also prevented from falling off. be able to.

In the best mode described above, the spike tire 10 in which the spike pin 20 is driven into the shoulder block 22 and the outer land portion 17B has been described. However, the present invention is not limited to this, and the spike pin 20 may be driven only into the shoulder block 22. Good.
Needless to say, the tread pattern of the spike tire is not limited at all. Also, the form of the spike pin to be driven into the pin hole 23 is not limited to the spike pin 20 shown in FIG. 3, and other forms of spike pins are used, such as no tip and a cylindrical body. Also good.
In the above example, the cross-sectional shape of the raised portion 24 is a trapezoidal shape, but the present invention is not limited to this. For example, as shown in FIG. It is good also as circular arc shape that inclination becomes large as it approaches the plane part 24b, or as shown in FIG.5 (b), it is good also as circular arc shape that inclination becomes small as it approaches the plane part 24b. Alternatively, as shown in FIG. 5C, the same effect can be obtained even when the slope portion 24a of the raised portion 24 is stepped.
Moreover, as shown in FIG.5 (d), it is good also considering the cross-sectional shape as circular arc shape which has a center in the inner side of a tread. In this case, if the inclination of the tangent on the opening 23s side of the pin hole 23 of the circular arc is made substantially parallel to the surface 22k of the shoulder block, the periphery of the pin hole 23 becomes substantially flat, so that a separate flat portion 24b is provided. There is no need to provide.

初期氷上性能は発進トラクション性能により評価した。具体的には、車速１０ｋｍ／ｈで氷上を走行した後、アクセルを踏んで加速し車速が３５ｋｍ／ｈに到達するのに要する時間(加速時間)を測定し、従来例を１００とした指数で評価した。数字が高い程加速時間が短く、発進トラクション性能が高い。
ピン抜け試験条件は、ピン打ち込み本数を１１０本／タイヤとし、１５０００ｋｍ走行後のピン残存本数から、ピン抜け率（％）を算出し、従来例を１００とした指数で評価した。なお、ピン抜け率（％）＝（ピン残存本数／ピン打ち込み本数）×１００である。数字が高い程ピン残存本数が多い。
表１から明らかなように、ピン孔周りに隆起部を有する本発明のスパイクタイヤの方が、従来のスパイクタイヤに比べて、初期氷上性能が高く、ピン抜け率についても同等以上であることが確認された。 As shown in FIG. 6 (a), a spike tire (conventional example) having a flat shape around the pin hole and a tire according to the present invention (present invention) provided with a raised portion around the pin hole are prepared, Table 1 below shows the results of the initial on-ice performance test and the pin-out test performed by mounting each of the tires on a test vehicle. In addition, the shape of the said protruding part produced and tested the tire which has 5 types of pin holes shown in FIG.2 (b) and FIG.5 (a)-(d), respectively. The outermost diameter of the ring when the raised portion is viewed from the tread surface is in the range of 9 to 10 mm, and the height from the tread surface is in the range of 0.1 to 0.3 mm. Moreover, in the raised part which has a plane part shown in FIG.2 (b) and FIG.5 (a)-(c), the outermost diameter of a plane part exists in the range of 6-7 mm.

Initial ice performance was evaluated by starting traction performance. Specifically, after running on ice at a vehicle speed of 10 km / h, step on the accelerator and accelerate to measure the time (acceleration time) required for the vehicle speed to reach 35 km / h. evaluated. The higher the number, the shorter the acceleration time and the higher the starting traction performance.
The pin drop test condition was evaluated by an index where the number of pins driven was 110 / tire, the pin drop rate (%) was calculated from the number of remaining pins after running 15000 km, and the conventional example was 100. Note that the pin omission rate (%) = (number of remaining pins / number of pins driven) × 100. The higher the number, the more pins remaining.
As is clear from Table 1, the spike tire of the present invention having a raised portion around the pin hole has higher initial ice performance than the conventional spike tire, and the pin omission rate is equal or higher. confirmed.

  As described above, according to the present invention, it is possible to obtain a spike tire capable of improving the performance on ice while suppressing the dropout of the spike pin, so that the traveling safety of the vehicle can be further improved.

It is a figure which shows the structure of the spike tire which concerns on the best form of this invention. It is a figure which shows the shape of the pin hole which concerns on this best form. It is a figure which shows the driving | running state of a spike pin. It is a figure for demonstrating the grounding state of the tread rubber around the spike pin in driving | running | working. It is a figure which shows the other shape of the pin hole by this invention. It is a figure which shows the shape of the conventional pin hole, and the driving | running state of a spike pin. It is a figure for demonstrating the grounding state of the tread rubber around the spike pin in driving | running | working in the conventional spike tire.

Explanation of symbols

10 spike tires, 11 bead parts, 11C bead core, 12 carcass layers,
13a, 13b Belt layer, 14 tread, 15 side tread, 16 main groove,
17A Central land, 17B Outer land, 18 Shoulder land, 19 Sipe,
20 spike pin, 20a body, 20b tip, 20c flange,
21 lug groove, 22 shoulder block, 22k surface of shoulder block,
22p, 22q rubber around spike pin, 23 pin hole, 23a introduction part,
23b Pin holding part, 23s opening part, 24 protuberance part, 24a slope part,
24b Plane portion, 50 road surface.

Claims (3)

A spike tire comprising a plurality of grooves formed on a tread surface of a tire, a land portion defined by the grooves, a pin hole formed in the land portion, and a spike pin driven into the pin hole. There,
Around the pin holes, and the raised portion is provided that is raised from the surface of the land portion tread rubber the pin hole is formed,
The protuberance is
The shape when viewed from the extending direction of the center line of the pin hole is annular,
The cross section when cut by a plane that includes the center line of the pin hole and is parallel to the center line rises from the opposite side of the land portion from the pin hole, and the height of the protrusion increases as the pin hole approaches. Having a slope,
The spike pin is
A spike tire characterized in that it is driven in a state in which a tip protrudes from the raised portion . The slope portion, with an inclined surface portion which rises linearly or arcuate or stepped from the surface of the land portion, the opening side of the pin hole of the slope portion, the opening of the pin hole of the slope portion spike tire according to claim 1, characterized in that a plane parallel portion on the surface of the land portion having the same height as the ends of the side, the pin holes are formed. The slope portion, with the arc-shaped slope portion which rises from the surface of the land portion, the arc of the slope portion, the gradient of tangent to the opening side of the pin hole of the land portion of the pin hole is formed The spike tire according to claim 1 , wherein the tire is an arc parallel to the surface.

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