JP6907816B2 - tire - Google Patents

Description

The present invention relates to a tire in which a groove portion and a sipe are formed in a tread portion.

Conventionally, there is known a problem of so-called stone biting, in which stones that have fallen on the road surface during running are bitten into a groove formed in a tread portion and cannot be removed. Stone biting can cause unpleasant vibrations and noise, and can damage the tire, for example, when the stone reaches the bottom of the groove. Therefore, Patent Document 1 below proposes a tire in which a saw blade-shaped protrusion is provided on the groove wall of the groove to discharge stones caught in the groove.

JP-A-2002-036822

However, the tire of Patent Document 1 is insufficient in the stone discharging action, and further improvement is required in order to discharge the stone bitten into the groove.

The present invention has been devised in view of the above circumstances, and provides a tire capable of efficiently discharging stones bitten into a groove based on forming a raised portion on the groove wall of the groove. Is the main purpose.

The present invention is a tire having a tread portion, wherein the tread portion includes a groove portion formed on a tread surface that comes into contact with the road surface during traveling and a sipe that communicates with the groove portion, and the groove portion is in the tire radial direction. It has a pair of groove walls extending to, and at least one of the groove walls is formed with a communication portion through which the sipe opens and at least one ridge portion adjacent to the communication portion. It extends from the first end on the communication portion side to the second end on the opposite side along the groove wall, and the ridge height of the first end is smaller than the ridge height of the second end. do.

In the tire according to the present invention, it is desirable that the raised portions are formed on both sides of the communicating portion.

In the tire according to the present invention, it is desirable that a plurality of the raised portions are formed so as to be separated from each other in the groove depth direction.

In the tire according to the present invention, it is desirable that the ridge width of the first end is smaller than the ridge width of the second end.

In the tire according to the present invention, it is desirable that the length of the raised portion from the first end to the second end is larger than the raised width of the second end.

In the tire according to the present invention, the first center, which is the center of the first end in the groove depth direction, is located closer to the tread surface side than the second center, which is the center of the second end in the groove depth direction. It is desirable to do.

In the tire according to the present invention, the raised portion center line connecting the first center and the second center forms an angle of 15 to 45 ° with respect to the tread surface when viewed from the groove side. Is desirable.

In the tire according to the present invention, it is desirable that the groove portion extends continuously in the tire circumferential direction.

In the groove portion of the tire of the present invention, a communication portion through which a sipe opens and at least one ridge portion adjacent to the communication portion are formed on at least one of the groove walls, and the ridge portion is on the communication portion side. It extends from the first end to the second end on the opposite side along the groove wall, and the ridge height of the first end is smaller than the ridge height of the second end.

Such a groove can move the bitten stone from the second end side where the ridge height is large to the first end side where the ridge height is small. Since the communication portion of the sipe is formed in the groove wall on the first end side, the groove wall on the first end side is easily deformed. Therefore, the stone that has moved to the first end side can be easily discharged due to the deformation of the groove wall. Therefore, the tire of the present invention can efficiently discharge the stones caught in the groove.

It is a developed view which shows one Embodiment of the tread part of the tire of this invention. It is sectional drawing of the line AA of FIG. It is a perspective view of the groove part of another embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a development view showing a tread portion 2 of the tire 1 of the present embodiment. As shown in FIG. 1, the tire 1 of the present embodiment has a tread portion 2 including a tread surface 2A that comes into contact with the road surface during traveling. The tire 1 is used as a heavy-duty tire suitable for, for example, a truck, a bus, or the like. The tread portion 2 of the present embodiment includes a groove portion 3 formed on the tread surface 2A, a land portion 4 adjacent to at least one of the groove portions 3, and a sipe 5 communicating with the groove portion 3.

The groove portion 3 of the present embodiment has a pair of groove walls 6 extending in the radial direction of the tire. It is desirable that at least one of the groove walls 6 is formed with a communication portion 6a through which the sipe 5 opens and at least one raised portion 7 adjacent to the communication portion 6a. Such a raised portion 7 can maintain the groove width and the groove depth of the groove portion 3 at appropriate sizes.

The raised portion 7 of the present embodiment extends along the groove wall 6 from the first end 7a on the communication portion 6a side to the second end 7b on the opposite side. It is desirable that the ridge height H1 of the first end 7a is smaller than the ridge height H2 of the second end 7b.

The groove portion 3 in which such a raised portion 7 is formed moves the bitten stone from the second end 7b having a large raised height H2 to the first end 7a having a small raised height H1. obtain. Since the communication portion 6a of the sipe 5 is formed in the groove wall 6 on the first end 7a side, the groove wall 6 on the first end 7a side is easily deformed. Therefore, the stone bitten into the groove 3 can be easily discharged as the groove wall 6 is deformed. Therefore, the tire 1 of the present embodiment can efficiently discharge the stones caught in the groove portion 3.

A more preferred embodiment of the tread portion 2 will be described below.

As a preferred embodiment, the tread portion 2 includes three groove portions 3 continuously extending in the tire circumferential direction and four land portions 4 separated by the three groove portions 3. The groove portion 3 includes, for example, a crown main groove 3A located on the tire equator C and a shoulder main groove 3B located between the crown main groove 3A and the tread end Te. The groove portion 3 may include, for example, a lateral groove extending in the tire axial direction and an inclined groove inclined in the tire circumferential direction.

Here, the "tread end" Te is the outermost end of the ground contact surface in the tire axial direction when a normal load is applied to the tire 1 in a normal state and the tire 1 is grounded on a flat surface at a camber angle of 0 °. The central position of the tread end Te in the tire axial direction is the "tire equator" C.

The "normal state" is a state in which the tire 1 is rim-assembled on a normal rim (not shown) and is adjusted to a normal internal pressure without load. Hereinafter, unless otherwise specified, the dimensions and the like of each part of the tire 1 are values measured in this normal state.

A "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire 1 is based. For example, "standard rim" for JATTA and "Design Rim" for TRA. If it is ETRTO, it is "Measuring Rim".

"Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which Tire 1 is based. For JATMA, "maximum air pressure", and for TRA, the table "TIRE LOAD". The maximum value described in "LIMITS AT VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO.

"Regular load" is the load defined for each tire in the standard system including the standard on which Tire 1 is based. For JATTA, "maximum load capacity", for TRA, the table "TIRE" The maximum value described in "LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", or "LOAD CAPACITY" for ETRTO.

The land portion 4 includes, for example, a crown land portion 4A located between the crown main groove 3A and the shoulder main groove 3B, and a shoulder land portion 4B located between the shoulder main groove 3B and the tread end Te. There is.

The crown land portion 4A of the present embodiment is formed with a sipe 5 communicating with the crown main groove 3A and the shoulder main groove 3B, and a narrow groove 8 having a groove width smaller than that of the groove portion 3 and extending in the tire circumferential direction. ing. The sipe 5 includes a first sipe 5A that connects the narrow groove 8 and the crown main groove 3A, and a second sipe 5B that connects the narrow groove 8 and the shoulder main groove 3B. Such a crown land portion 4A can maintain appropriate rigidity in a crown region where the contact pressure is large.

The shoulder land portion 4B of the present embodiment does not have a lateral groove or a sipe that crosses in the tire axial direction. Such a shoulder land portion 4B can maintain appropriate rigidity in a shoulder region where a large load is applied during turning.

In the present embodiment, the raised portion 7 is formed on a pair of groove walls 6 of the crown main groove 3A. Since such a raised portion 7 has a large contact pressure and a large groove width, the bitten stone can be discharged in the crown main groove 3A where the stone is easily bitten. The raised portion 7 may be formed on the groove wall of the shoulder main groove 3B.

The ridge height H1 of the first end 7a of the ridge portion 7 is preferably 0.05 to 0.50 mm. The ridge height H2 of the second end 7b of the ridge portion 7 is preferably 1.0 to 2.0 mm. Such a raised portion 7 can move the stone bitten into the groove portion 3 from the second end 7b side toward the first end 7a side without affecting the drainage property or the like.

FIG. 2 is a cross-sectional view taken along the line AA of FIG. As shown in FIG. 2, the raised portion 7 of the present embodiment is centered at the first center 7ac, which is the center of the first end 7a in the groove depth D direction, and at the center of the second end 7b in the groove depth D direction. It has a second center 7 bc. It is desirable that the first center 7ac is located closer to the tread surface 2A of the tread portion 2 than the second center 7bc.

The raised portion center line 7c connecting the first center 7ac and the second center 7bc preferably forms an angle θ of 15 to 45 ° with respect to the tread surface 2A when viewed from the groove 3 side. In such a raised portion 7, when the stone bitten into the groove portion 3 is moved from the second end 7b side to the first end 7a side, the stone is moved to the tread surface 2A side, so that the stone can be discharged more easily. Can be.

It is desirable that the ridge width W1 of the first end 7a is smaller than the ridge width W2 of the second end 7b. In this case, the raised portion 7 has a substantially trapezoidal shape when viewed from the side of the groove portion 3. In such a raised portion 7, since the rigidity of the first end 7a side is smaller than the rigidity of the second end 7b side, the movement of the stone from the second end 7b side to the first end 7a side can be facilitated. .. The raised portion 7 may have a substantially rectangular shape when viewed from the side of the groove portion 3.

The ridge width W1 of the first end 7a is preferably 0.5% to 20% of the groove depth D of the groove portion 3. The ridge width W2 of the second end 7b is preferably 10% to 20% of the groove depth D of the groove portion 3. Such a raised portion 7 can discharge the stone bitten into the groove portion 3 without affecting the drainage property or the like.

It is desirable that the length L from the first end 7a to the second end 7b of the raised portion 7 is larger than the raised width W2 of the second end 7b. Such a raised portion 7 can smoothly move the stone bitten into the groove portion 3. Therefore, the groove portion 3 is less damaged due to the movement of the stone, and the durability of the tire 1 can be improved.

FIG. 3 is a perspective view showing the groove portion 13 of another embodiment. The configurations common to the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 3, the groove portion 13 of this embodiment has a groove wall 16 extending in the radial direction of the tire. It is desirable that the groove wall 16 is formed with a communication portion 16a formed on the tread surface 2A through which the sipe 5 opens, and a plurality of raised portions 17 adjacent to the communication portion 16a.

The raised portions 17 of this embodiment are formed on both sides of the communicating portion 16a. That is, the raised portion 17 includes, for example, a first raised portion 17A and a second raised portion 17B located on one side of one communication portion 16a, and a third raised portion 17C and a fourth raised portion 17D located on the other side. Includes. Even when such a raised portion 17 is formed only on one groove wall 16 of the groove portion 13, the stone bitten into the groove portion 13 can be moved in the direction in which the sipe 5 is formed.

It is desirable that a plurality of raised portions 17 are formed so as to be separated from each other in the groove depth direction. That is, the raised portion 17 includes, for example, the first raised portion 17A and the third raised portion 17C located on the tread surface 2A side, and the second raised portion 17B and the fourth raised portion 17B located on the lower side in the groove depth direction. Includes 17D and. Such a raised portion 17 has a second raised portion 17B and a fourth raised portion 17D even when the first raised portion 17A and the third raised portion 17C lose their functions due to the wear of the tread surface 2A. As a result, the stone bitten into the groove 13 can be moved in the direction in which the sipe 5 is formed.

The first raised portion 17A and the third raised portion 17C preferably have a gap of 1 to 5 mm. Further, the second raised portion 17B and the fourth raised portion 17D preferably have a gap of 1 to 5 mm. Such a raised portion 17 can quickly discharge the stone bitten into the groove portion 3.

Although the particularly preferable embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments, and can be modified into various embodiments.

A tire having the tread pattern shown in FIG. 1 was prototyped based on the specifications shown in Table 1. These prototype tires were mounted on a test vehicle and tested for stone biting resistance. The common specifications and test methods for each test tire are as follows.

Vehicle used: Domestic medium-duty truck (loading capacity 3t)
Tire size: 205 / 85R16 117 / 115L
Rim size: 16 x 5.5J
Internal pressure: 600 kPa
Load capacity: 3t
Groove width of groove: 10 mm
Groove depth of groove: 10 mm

<Stone biting resistance>
The test vehicle equipped with the test tires traveled 10 km on a road surface with small stones and then 5 km on a road surface without such stones. The number of stones biting into the groove per tire after running was measured. The result is displayed as an index with Comparative Example 1 as 100, and the smaller the value, the better the stone biting resistance. If the value is 0, it means that there are no stones that have been bitten after running.

The test results are shown in Table 1.

As a result of the test, it was confirmed that the tire of the example was superior in stone biting resistance to the comparative example.

1 Tire 2 Tread part 2A Tread surface 3 Groove part 5 Sipe 6 Groove wall 6a Communication part 7 Raised part 7a 1st end 7b 2nd end

Claims (7)

A tire with a tread
The tread portion includes a groove portion formed on the tread surface that comes into contact with the road surface during traveling and a sipe that communicates with the groove portion.
The groove has a pair of groove walls extending in the radial direction of the tire.
At least one of the groove walls is formed with a communication portion through which the sipe opens and at least one raised portion adjacent to the communication portion.
The raised portion extends along the groove wall from the first end on the communication portion side to the second end on the opposite side.
The protrusion height of the first end, rather smaller than the protrusion height of said second end,
The raised portion is a tire formed on both sides of the communicating portion. The tire according to claim 1 , wherein a plurality of the raised portions are formed so as to be separated from each other in the groove depth direction. The tire according to claim 1 or 2 , wherein the ridge width at the first end is smaller than the ridge width at the second end. The tire according to any one of claims 1 to 3 , wherein the length of the raised portion from the first end to the second end is larger than the raised width of the second end. The first center, which is the center of the first end in the groove depth direction, is located on the tread surface side of the second center, which is the center of the second end in the groove depth direction, according to claims 1 to 4 . Tires listed in either. The tire according to claim 5 , wherein the raised portion center line connecting the first center and the second center forms an angle of 15 to 45 ° with respect to the tread surface when viewed from the groove side. The tire according to any one of claims 1 to 6 , wherein the groove portion continuously extends in the tire circumferential direction.

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