JP5237675B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire in which spike pins are driven into a tread surface.

  A pneumatic tire in which spike pins are driven on a tread surface is generally referred to as a spike tire or a stud tire, and is mainly used for running on icy and snowy roads. Patent Document 1 below describes a spike tire in which a non-slip spike pin is driven into a tread block and a plurality of sipes are provided on the block. In this tire, traveling performance such as braking performance and steering stability performance when turning is improved by the effect (edge effect) that the edge of the sipe scratches the road surface when traveling on icy and snowy roads.

  By the way, in said spike tire, in order to ensure the rigidity required for holding | maintaining a spike pin, the area | region which does not have a sipe is formed around the spike pin. Therefore, due to the formation of a region having no sipe, there is a problem that a sufficient edge effect cannot be obtained when traveling on an icy and snowy road, and the braking performance and the like are lowered.

  In order to solve the above problem, in the pneumatic tire described in Patent Document 2 below, the width in the tire circumferential direction and the width in the tire width direction with respect to the region having no sipe formed around the spike pin. The relationship is adjusted to ensure the holding force of the spike pin. However, even in this tire, the edge effect cannot be obtained around the spike pin, and the running performance on icy and snowy roads tends to deteriorate.

Further, Patent Document 3 below describes a tire in which a large number of protrusions are integrally provided on the tread surface. This tire is intended to give a studless tire the same performance as a spiked tire. However, it does not disclose a solution to the problems specific to the spike tire described above. Moreover, since a relatively large protrusion is employed and the height of the protrusion is considered to be practically 1 to 5 mm, if the protrusion is applied to a spike tire, the road surface is scratched by a spike pin. We are anxious about impairing action.
JP 62-94402 A JP 2008-24213 A JP-A-61-81206

  This invention is made | formed in view of the said situation, The objective is to provide the pneumatic tire which can heighten an edge effect, without reducing the holding force of a spike pin.

  The above object can be achieved by the present invention as described below. That is, the pneumatic tire of the present invention is a pneumatic tire in which spike pins are driven into the tread surface, and a plurality of sipes are provided on the tread surface, and a region not having the sipes is formed around the spike pins. The protrusion is provided in the region that does not have the sipes.

  According to the above configuration, since the protrusion is provided in the region that does not have the sipe formed around the spike pin, the edge effect due to the protrusion is expressed when traveling on an icy and snowy road. And since the area | region which does not have a sipe is formed in the circumference | surroundings of a spike pin, the holding force of a spike pin is not reduced.

  In the present invention, it is preferable that the projection includes a surrounding portion surrounding the spike pin. Thereby, since the edge effect by a protrusion is expressed along various directions, various running performances, such as braking / driving performance and turning performance on an icy and snowy road, can be improved effectively.

  In the above, it is preferable that the surrounding portion forms a polygon surrounded by four to seven line segments. As a result, the edge effect due to the protrusion can be expressed along various directions, and the length of the edge component contributing to the edge effect can be ensured. As a result, various running performances such as braking / driving performance and turning performance on icy and snowy roads can be improved more effectively.

  In the above, it is preferable that the plurality of surrounding portions are arranged concentrically. Thereby, the edge effect by the surrounding part of protrusion can be improved.

  In the above, it is preferable that the projection includes a reinforcing portion extending radially from the spike pin and continuing to the surrounding portion from the inside. Thereby, the rigidity of an enclosure part can be improved and the edge effect by the enclosure part of a processus | protrusion can be improved.

  In the above, what the height of the said protrusion is 0.3-0.7 mm is preferable. Thereby, the effect of this invention can be show | played more appropriately. That is, if the height of the protrusion is less than 0.3 mm, the edge effect due to the protrusion tends to be small, and if the height of the protrusion exceeds 0.7 mm, the anti-slip action by the spike pin may be reduced. There is.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partial plan view of a tread portion of a pneumatic tire according to the present invention. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a cross-sectional view taken along the line AA of FIG.

  In the pneumatic tire of the present embodiment, the tread portion Tr formed on the tire outer peripheral surface side is provided with a vertical groove 1a extending along the tire circumferential direction PD and a horizontal groove 1b extending along the tire width direction WD. The land portion of the tread surface is divided into a plurality of blocks 1 and ribs 4. Reference symbol C denotes a tire equator line passing through the center of the tread portion Tr in the width direction.

  Spike pins 2 are driven into the surface of the block 1 serving as the tread surface. The block 1 is provided with a plurality of sipes 3 at intervals in the tire circumferential direction PD. Each sipe 3 extends along the tire width direction WD and is inclined with respect to the tire width direction WD in the present embodiment.

  A region 10 having no sipe 3 is formed around the spike pin 2. The region 10 is formed in a range of 6 to 10 mm from the center of the spike pin 2, for example. As shown in FIG. 2, the protrusion 5 is disposed in a region 10 that does not have the sipe 3 and is integrally provided on the surface of the block 1. With this configuration, the edge effect due to the protrusions 5 is exhibited when traveling on an icy and snowy road, and the region 10 without the sipe 3 is formed around the spike pin 2, so that the holding force of the spike pin 2 can be reduced. Absent.

  The protrusion 5 includes surrounding portions 6a and 6b that surround the spike pin 2. In this embodiment, the surrounding portions 6a and 6b form a hexagonal pattern. As described above, when the surrounding portions 6a and 6b surround the spike pin 2, the edge effect by the protrusion 5 is expressed along various directions. For example, a portion adjacent to the spike pin 2 in the tire circumferential direction becomes an edge component during driving braking, and a portion adjacent to the spike pin 2 in the tire width direction becomes an edge component during turning. For this reason, various driving performances such as braking / driving performance and turning performance on icy and snowy roads can be effectively improved.

  The surrounding portions 6a and 6b are preferably polygonal from the viewpoint of securing the length of the edge component that contributes to the edge effect, and in particular, polygons (four to heptagon) surrounded by four to seven line segments. It is preferable to make it. If this is a triangle, the edge effect may not be exerted depending on the direction in which the force acts. In the case of a polygon or circle surrounded by eight or more line segments, the length of the edge component that contributes to the edge effect. Tend to be shorter. The hexagonal shape is considered to have the best balance in achieving both the direction dependency of the edge effect and ensuring the length of the edge component.

  In the present embodiment, the protrusion 5 has two surrounding portions 6a and 6b arranged concentrically so that the edge effect by the protrusion 5 is enhanced. Further, the projection 5 is provided with reinforcing portions 7a and 7b extending radially from the center of the spike pin 2 and connected to the surrounding portions 6a and 6b from the inside, thereby increasing the rigidity of the surrounding portions 6a and 6b. The edge effect is further improved.

  The surrounding portion 6a has a trapezoidal cross section as shown in FIG. 3, and the surrounding portion 6b and the reinforcing portions 7a and 7b are formed in the same manner. The height H of the protrusion 5 is preferably 0.3 to 0.7 mm in order to more appropriately achieve the above-described effects. Since the protrusion amount of the spike pin 2 from the tread surface is determined to be about 1.2 mm on average by the standard such as STRO, the height H of the protrusion 5 is set to 0.7 mm or less. An anti-slip action can be secured appropriately. Since the spike pin 2 is stuck into the road surface when traveling on an icy and snowy road, even when the height H is about 0.3 mm, the protrusion 5 comes into contact with the road surface and exhibits an edge effect.

  The width W of the protrusion 5 is preferably 0.3 to 1.0 mm. When the width W is less than 0.3 mm, the edge effect by the protrusion 5 tends to be small. On the other hand, if the width W exceeds 1.0 mm, a large number of protrusions 5 cannot be arranged in the region 10 and the increase of the edge component tends to be difficult.

  The sipe 3 is provided in the periphery of the region 10 on the surface of the block 1, but it is preferable that an interval X 1 of 1 mm or more is secured between the sipe 3 and the protrusion 5. Moreover, it is preferable that the space | interval X2 of 1 mm or more is ensured between the wall surface of the block 1 and the protrusion 5. FIG. Thereby, in the mold for molding the tire, it is possible to avoid the blades for forming the sipe 3 or the bones for forming the grooves (vertical grooves 1a and transverse grooves 1b) coming into contact with the recesses for forming the protrusions 5. Moreover, in order to reduce the area | region where an edge effect is not expressed, it is preferable that the space | interval X1 is 2 mm or less.

  The tread pattern of the pneumatic tire of the present invention is not particularly limited, and the block may be a polygon other than a rectangle, a V shape, or the like. In addition, the spike pin may be driven into a rib extending in the tire circumferential direction. However, in the present invention, since the holding force of the spike pin can be ensured as described above, the spike pin is driven into a block having a large rigidity reduction due to sipe. It is particularly useful when

  The pneumatic tire of the present invention is the same as a normal pneumatic tire except that a projection as described above is provided in a region not having a sipe formed around a spike pin, and a conventionally known material, shape, and structure. Any manufacturing method can be used in the present invention.

[Other Embodiments]
(1) The protrusion shown in FIGS. 4-6 is a modification of the protrusion in this invention. The protrusion 8 shown in FIG. 4 and the protrusion 9 shown in FIG. 5 are examples in which the width is larger than the protrusion 5 described above, and the width W1 of the protrusion 8 is 1 mm and the width W2 of the protrusion 9 is 1.5 mm. Illustrated. Further, the protrusions 8 and 9 have surrounding portions 8a and 9a and reinforcing portions 8b and 9b continuous from the inside thereof. The protrusion 11 shown in FIG. 6 is an example having two surrounding portions 11a and 11b having a circular shape and a reinforcing portion 11c.

  (2) In the above-described embodiment, an example in which a sipe extends linearly is shown, but the present invention is not limited to this, and the sipe may extend in a wave shape or a zigzag shape.

  The braking performance was evaluated in order to specifically show the configuration and effects of the present invention. The braking performance was evaluated by measuring the braking distance when the tire was mounted on a real vehicle (3000 cc class FR sedan) and the ABS was operated by applying braking force from a speed of 40 km / h while running on an icy and snowy road. . Two ice roads were prepared: a snow road with snow and an ice road with ice on the surface. The result of the comparative example is shown as an index with the value of 100, and the larger the value, the better the braking performance.

  The tire according to the above-described embodiment described with reference to FIGS. The height of the protrusion was 0.5 mm, and the width of the protrusion was 15 mm. Moreover, as shown in FIG. 7, a tire from which protrusions were removed from the example was used as a comparative example. In any of the examples and comparative examples, the tire size was 195 / 65R15. The evaluation results are shown in Table 1.

  As shown in Table 1, in the example, by providing a protrusion in a region having no sipe formed around the spike pin, the braking performance on the icy and snowy road is superior to the comparative example.

The fragmentary top view of the tread part of the pneumatic tire which concerns on this invention 1 is an enlarged view of the main part of FIG. AA arrow sectional view of FIG. The figure which shows the modification of the protrusion in this invention The figure which shows the modification of the protrusion in this invention The figure which shows the modification of the protrusion in this invention Partial plan view of a tread portion of a pneumatic tire according to a comparative example

Explanation of symbols

1 Block 2 Spike Pin 3 Sipe 5 Protrusions 6a and 6b Enclosures 7a and 7b Reinforcement 10 Regions without sipes

Claims (6)

  In a pneumatic tire in which spike pins are driven into the tread surface, a plurality of sipes are provided on the tread surface, and a region not having the sipes is formed around the spike pins and protrudes into the region having no sipes. A pneumatic tire characterized in that is provided.   The pneumatic tire according to claim 1, wherein the protrusion includes a surrounding portion surrounding the spike pin.   The pneumatic tire according to claim 2, wherein the surrounding portion forms a polygon surrounded by four to seven line segments.   The pneumatic tire according to claim 2 or 3, wherein the plurality of surrounding portions are arranged concentrically.   The pneumatic tire according to any one of claims 2 to 4, wherein the protrusion includes a reinforcing portion that extends radially around the spike pin and continues to the surrounding portion from the inside.   The pneumatic tire according to any one of claims 1 to 5, wherein a height of the protrusion is 0.3 to 0.7 mm.

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