JP2012035684A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an on-snow performance of a pneumatic tire.SOLUTION: A plurality of grooves 2 to 6 extending in a tire circumferential direction and tire width direction are disposed on a wheel tread of a tread part 1 and the plurality of grooves 2 to 6 cross each other, and thereby a plurality of blocks 7 are disposed. In addition, protrusions 11 (11A, 11B, and 11C) changing the height along a longitudinal direction thereof are disposed in the grooves 2 to 6.

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that improves steering stability, cornering performance, and braking performance while ensuring performance on snow.

  Conventionally, winter tires, for example, studless tires, are provided with a plurality of blocks by forming a large number of deep grooves in the ground contact portion to the road surface, and the snow is stepped on and solidified by these blocks (snow column shear force). And the resistance (edge effect) generated by scratching the snow that has been compacted by the corners of each block is increased to ensure the performance on snow.

  For example, a pneumatic tire for snowy and snowy road described in Patent Document 1 shown below has a circumferential narrow groove between a first see-through main groove on the tire equatorial plane side and a second see-through main groove on the tire ground contact end side. And a first lug groove that communicates from the first see-through main groove to the second see-through main groove and a second lug groove that extends from the second see-through main groove to the tire ground contact end are shifted in the tire circumferential direction. The first and second lug grooves and the first and second see-through main grooves and narrow grooves form a block, and a V-shaped transverse groove is arranged between the first see-through main grooves to form the block. It is. Therefore, the groove area is increased by the formed blocks, and the traction on snow can be improved.

Japanese Patent No. 4316569

  Although the pneumatic tire of Patent Document 1 described above can improve wet braking performance and on-snow traction, further improvement in on-snow performance is required in the future.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can improve performance on snow.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention includes a plurality of grooves extending in the tire circumferential direction and the tire width direction on the tread surface, and the plurality of grooves intersect. And a plurality of blocks formed in the groove, and a protrusion provided in the groove and changing in height along the longitudinal direction of the groove.

  According to this pneumatic tire, the protrusion provided in the groove changes in height along the longitudinal direction of the groove, so that the snow sandwiched between the road surface and the protrusion is formed by the protrusion. It is pushed out in the longitudinal direction and compressed while moving, so it can form a tougher snow column in the groove, this tough snow column increases the snow column shear force, and the edge effect due to tire corners Can increase the performance on snow.

  The pneumatic tire according to the present invention is characterized in that the protrusion is provided at an intersection where the plurality of grooves intersect.

  According to this pneumatic tire, the snow sandwiched between the road surface and the projecting portion by the projecting portion provided at the intersection is moved to the plurality of grooves by the projecting portion and compressed. Columns can be formed.

  Moreover, the pneumatic tire of the present invention is characterized in that the protruding portion has an extending portion that extends from the intersecting portion toward the passage side of the groove so as to decrease in height.

  According to this pneumatic tire, the snow sandwiched between the road surface and the projecting portion by the projecting portion provided at the intersection can be pushed out to the channel side of the groove to form a tough snow column in the groove.

  Moreover, the pneumatic tire of the present invention is characterized in that the extending portion is constituted by an inclined portion.

  According to this pneumatic tire, the snow sandwiched between the road surface and the protruding portion can be efficiently pushed and compressed in the longitudinal direction of the groove by the inclined portion, and a tougher snow column can be formed in the groove. Can do.

  In the pneumatic tire of the present invention, the inclined portion is provided with a guide portion on the surface along a direction in which the height changes.

  According to this pneumatic tire, when the snow sandwiched between the road surface and the protrusion is pushed out in the longitudinal direction of the groove by the inclined portion, the snow can be efficiently guided by the guide portion.

  In the pneumatic tire of the present invention, the height of the protrusion from the bottom of the groove is set in a range of 50% to 80% of the depth of the groove.

  According to this pneumatic tire, an appropriate amount of snow can be effectively guided into the groove and compressed by the protrusion.

  In the pneumatic tire of the present invention, the protrusion is provided at an intersection where the first groove and the second groove intersect, and is in contact with the bottom of the groove in the longitudinal direction of the first groove. Is set in the range of 200% to 400% of the opening length in the width direction of the second groove.

  According to this pneumatic tire, an appropriate amount of snow can be effectively guided into the groove and compressed by the protrusion.

  In the pneumatic tire of the present invention, the protrusion has two extending portions extending in a direction away from the intersecting portion, and the two extending portions have an asymmetric shape. And

  According to this pneumatic tire, it is possible to appropriately set the amount of snow induced into the groove by the protrusion and the edge effect by the protrusion.

  Further, in the pneumatic tire of the present invention, the degree of change in the height of the extending part on the front side in the tire rotating direction is larger than the degree of change in the height of the extending part on the rear side in the tire rotating direction. It is characterized by being set to.

  According to this pneumatic tire, an appropriate amount of snow can be secured and effectively compressed by the extending portion having a small degree of change in height on the rear side in the tire rotation direction, and on the front side in the tire rotation direction. The edge effect can be increased for a tough snow column compressed by an extension having a large degree of change in height.

  Further, in the pneumatic tire according to the present invention, the height of the extending portion on the tire equatorial plane side in the tire width direction is changed in the tire width direction tire at the protrusion provided on the tire equatorial plane side. It is set so that it may become smaller than the change degree of the height of the said extension part in the earthing | grounding end side.

  According to the pneumatic tire, an appropriate amount of snow is pushed out and compressed to the tire equatorial plane side by the extending portion having a small change in height on the tire equatorial plane side in the tire width direction. A tough snow column can be formed.

  Further, in the pneumatic tire according to the present invention, in the protrusion provided on the tire ground contact end side, the degree of change in the height of the extending portion on the tire ground contact end side in the tire width direction is the tire in the tire width direction. It is set so that it may become smaller than the change degree of the height of the said extension part in the equatorial plane side.

  According to this pneumatic tire, snow can be pushed out and discharged to the tire ground contact end side by the extending portion having a small change in height on the tire ground contact end side in the tire width direction.

  The pneumatic tire according to the present invention is provided with a protrusion portion whose height changes in the longitudinal direction in the groove, so that a tough snow column is formed in the groove to increase the snow column shear force, and the tire The on-snow performance can be improved by increasing the edge effect due to the corners.

FIG. 1 is a developed plan view showing a part of a tread portion in a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a perspective view showing a protrusion. FIG. 3 is a schematic view showing a protrusion. FIG. 4 is an explanatory diagram illustrating the operation of the protrusion. FIG. 5 is a schematic diagram illustrating the formation direction of the protrusions on the tire. FIG. 6 is an explanatory diagram for explaining the formation direction of the protrusions in the tire circumferential direction. 7-1 is explanatory drawing for demonstrating the formation direction of the projection part in a tire width direction. 7-2 is explanatory drawing for demonstrating the formation direction of the projection part in a tire width direction. FIG. 8 is a perspective view showing a modification of the protrusion. FIG. 9 is a perspective view showing a modification of the protrusion. FIG. 10 is a perspective view showing a modification of the protrusion. FIG. 11 is a perspective view showing a modification of the protrusion. FIG. 12 is a perspective view showing a modification of the protrusion. FIG. 13 is a perspective view showing a modification of the protrusion. FIG. 14 is a perspective view showing a modification of the protrusion. FIG. 15-1 is a chart showing results of performance tests of pneumatic tires according to examples of the present invention. FIG. 15-2 is a chart showing the results of a performance test of a pneumatic tire according to an example of the present invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

  In the following description, the tire circumferential direction is a circumferential direction with the rotation axis of the pneumatic tire as the central axis. The tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction is the side toward the tire equatorial plane in the tire width direction, and the outer side in the tire width direction is the tire equatorial plane in the tire width direction. It is the side away from. Further, the tire radial direction means a direction orthogonal to the rotation axis, the tire radial direction inner side is a side toward the rotation axis in the tire radial direction, and the tire radial direction outer side is separated from the rotation axis in the tire radial direction. On the side. The tire equator plane is a plane that is orthogonal to the rotational axis of the pneumatic tire and passes through the center of the tire width of the pneumatic tire.

  The pneumatic tire according to the present embodiment is suitable as a studless tire corresponding to a snowy road surface, a mud & snow tire corresponding to an off-road such as a muddy ground or a snowy road surface, or a pneumatic tire such as an all-season tire.

  In the pneumatic tire of the present embodiment, as shown in FIG. 1, reference numeral 1 represents a tread portion in which the tire rotation direction R is designated as one direction, and the tread portion 1 is on the surface (tread surface). Four see-through main grooves (longitudinal grooves) 2 extending along the tire circumferential direction T are provided. The four see-through main grooves 2 are disposed symmetrically in the tire width direction with respect to the tire equatorial plane CL of the tread portion 1 and are paired with the first see-through main grooves 2A adjacent to the tire equatorial plane CL. And a pair of second see-through main grooves 2B adjacent to the tire ground contact width E.

  Further, the tread portion 1 has one circumferential narrow groove (vertical groove) 3 between the first see-through main groove 2A and the second see-through main groove 2B on both sides of the tire equatorial plane CL. They are arranged symmetrically to the left and right in the tire width direction with respect to CL. Each of the circumferential narrow grooves 3 is provided between the first see-through main groove 2A located on the left side of the tire equatorial plane CL and the second see-through main groove 2B located on the outside thereof, and is also located on the right side. Provided between the see-through main groove 2 </ b> A and the second see-through main groove 2 </ b> B located outside the see-through main groove 2 </ b> B, each extends linearly along the tire circumferential direction T and has a narrower groove width than the see-through main groove 2. ing.

  Further, the tread portion 1 has a plurality of first lug grooves (lateral grooves) 4 between the first see-through main groove 2A and the second see-through main groove 2B so that the two main grooves 2A and 2B communicate with each other. They are arranged symmetrically to the left and right in the tire width direction with respect to CL. The first lug grooves 4 extend from the first see-through main grooves 2A toward the tire counter-rotation direction while extending in the tire width direction, penetrate the circumferential narrow grooves 3, and pass through the second see-through main grooves. 2B communicates with each other and is arranged along the tire circumferential direction T at predetermined intervals.

  Further, the tread portion 1 has a plurality of second lug grooves (lateral grooves) 5 with respect to the tire equatorial plane CL so as to communicate with the second see-through main groove 2B on the outer side in the tire width direction from the second see-through main groove 2B. They are arranged symmetrically on the left and right in the tire width direction. The second lug grooves 5 extend outward from the respective second see-through main grooves 2B in the tire width direction, and communicate with the tire ground contact edge E while being inclined in the same direction as the first lug grooves 4, and further extend outward. And are provided at predetermined intervals along the tire circumferential direction T.

  Further, in the tread portion 1, the transverse groove 6 is in the tire width direction with respect to the tire equatorial plane CL so that the main grooves 2A communicate with each other between the first see-through main grooves 2A located on both sides of the tire equatorial plane CL. Are arranged symmetrically on the left and right of the. The transverse groove 6 has a V-shape (inverted V-shape in FIG. 1) having a vertex on the tire equatorial plane CL on the tire counter-rotation direction side, and has a predetermined interval along the tire circumferential direction T. Is arranged in.

  In addition, the 1st lug groove 4, the 2nd lug groove 5, and the crossing groove 6 are shifted and arrange | positioned in the tire circumferential direction T.

  The tread portion 1 includes the above-described see-through main groove 2 (first see-through main groove 2A, second see-through main groove 2B), circumferential narrow groove 3, first lug groove 4, second lug groove 5, and transverse groove 6. A number of blocks 7 are partitioned. This block 7 is between each first see-through main groove 2A, and on the tire equatorial plane CL, a plurality of first blocks 7A, each first see-through main groove 2A, and each circumferential narrow groove 3 A plurality of second blocks 7B disposed between the circumferential narrow grooves 3 and the second see-through main grooves 2B, and a plurality of second see-through main grooves 2B. And a plurality of fourth blocks 7D arranged on the outer side in the tire width direction.

  In each of the blocks 7A, 7B, 7C, and 7D, a plurality of sipes 8 extending in a zigzag shape in the tire width direction are formed on the respective ground contact surfaces.

  In the pneumatic tire according to the present embodiment, as a rubber used for the tread rubber layer having the tread portion 1 on the surface, a rubber having a JISA hardness of 40 to 60, preferably 43 to 55 is used from the viewpoint of performance on ice. It can be preferably used. The see-through width of the see-through main groove 2 is 2 mm to 10 mm, preferably 4 mm to 8 mm.

  In addition, the see-through main groove in the present embodiment is a main groove that can be seen from one end to the other when the tread portion 1 is developed over one circumference.

  In the pneumatic tire of the present embodiment configured as described above, the see-through main groove 2 (the first see-through main groove 2A and the second see-through main groove 2B), the circumferential narrow groove 3, the first lug groove 4, and the second In the lug groove 5 and the transverse groove 6, a protrusion 11 whose height changes along the longitudinal direction of each of the grooves 2 to 6 is provided. The protrusion 11 is provided at an intersection 12 where a plurality of grooves intersect, and extends from the intersection 12 toward the passage side of each of the grooves 2 to 6 so as to decrease in height. The extending part is constituted by an inclined part. In this case, the protruding portion 11 is formed of the same material with respect to the tread portion 1.

  The protrusion 11 includes a plurality of first protrusions 11A disposed in a plurality of first intersections 12A where the first see-through main grooves 2A, the first lug grooves 4, and the transverse grooves 6 intersect, and the circumferential narrow grooves 3 And a plurality of second protrusions 11B arranged at a plurality of second intersections 12B where the first lug grooves 4 intersect, and a plurality of third intersections where the second see-through main grooves 2B and the second lug grooves 5 intersect. And a plurality of third protrusions 11C arranged at 12C.

  The protrusion 11 and the intersection 12 will be described in detail. The protrusions 11A, 11B, and 11C and the intersections 12A, 12B, and 12C have substantially the same configuration. The protrusion 11B and the second intersection 12B will be described in detail.

  As shown in FIGS. 1 and 2, the second intersecting portion 12B is provided at a position where the circumferential narrow groove 3 and the first lug groove 4 intersect, and the circumferential narrow groove 3 is formed on the left and right sides of the bottom portion 3a. The first lug groove 4 is composed of a bottom 4a and left and right side walls 4b. The second protrusion 11 </ b> B is disposed at the second intersecting portion 12 </ b> B and has a shape that extends to the passage side of the circumferential narrow groove 3 and the first lug groove 4. In this case, a region where the circumferential narrow groove 3 and the first lug groove 4 intersect is referred to as a second intersecting portion 12B, whereas the circumferential narrow groove 3 and the first lug groove 4 do not intersect with other grooves. Is called a passage.

  The second projecting portion 11B has two inclined portions (extending portions) 21a and 21b extending from the substantially center position of the second intersecting portion 12B to the respective passages in the longitudinal direction in the circumferential narrow groove 3, Two inclined portions (extending portions) 22a and 22b extending from the inclined portions 21a and 21b in the second intersecting portion 12B to the respective passages in the longitudinal direction of the first lug groove 4 are provided. Each inclined portion 21a, 21b is located at a substantially central position of the second intersecting portion 12B from the top portion 21c having the same height in the width direction of the circumferential narrow groove 3 toward each passage side of the circumferential narrow groove 3. The shape extends so as to be low. On the other hand, each inclination part 22a, 22b is each position of the 1st lug groove 4 from the top part 22c, 22d which has the same height in the width direction of the 1st lug groove 4 in the position which touches the side surface of this inclination part 21a, 21b. It has a shape extending in an inclined manner so that its height decreases toward the side. In this case, the top portion 21c and the top portions 22c and 22d have the same height.

  In this case, each of the inclined portions 21 a and 21 b has a height set lower than the depth of the circumferential narrow groove 3 and the depth of the first lug groove 4, and the width is larger than the width of the circumferential narrow groove 3. Is set too narrow. Similarly, each of the inclined portions 22 a and 22 b has a height set lower than the depth of the circumferential narrow groove 3 and the depth of the first lug groove 4, and the width is larger than the width of the first lug groove 4. Is set too narrow. Therefore, each inclined part 21a, 21b is located on the bottom part 3a of the circumferential narrow groove on the inner side in the tire radial direction with respect to the tread surface, and a predetermined interval so that the side surface does not contact with each side wall 3b of the circumferential narrow groove 3 Is arranged. On the other hand, the inclined portions 22a and 22b are located on the bottom portion 4a of the first lug groove 4 on the inner side in the tire radial direction with respect to the tread surface, and the side surfaces do not contact the side walls 4b of the first lug groove 4. Arranged at intervals.

Here, the ideal size of the inclined portions 21a, 21b, 22a, and 22b (second projecting portion 11B) with respect to the sizes of the circumferential narrow groove 3 and the first lug groove 4 (second intersecting portion 12B) will be described. . As shown in FIGS. 2 and 3, the second protrusion 11 </ b> B has a height H from the bottom 3 a, 4 a of each groove 3, 4 within a range of 50% to 80% of the depth D of the groove 3, 4. It is preferable to set to.
That is, 0.5D <H <0.8D.

  In this case, if the height H of the second protrusion 11B is lower than 50% of the depth D of the grooves 3 and 4, there is a risk that the second protrusion 11B cannot efficiently push snow into the grooves 3 and 4. . Further, if the height H of the second protrusion 11B is greater than 80% of the depth D of the grooves 3 and 4, the distance from the second protrusion 11B to the tread surface (tire contact surface) becomes short, and a sufficient amount May not be able to collect snow.

In addition, the second protrusion 11B has a length L1 in contact with the bottom 3a in the longitudinal direction of the circumferential narrow groove 3 in the inclined portions 21a and 21b at the second intersecting portion 12B, and the width direction of the first lug groove 4 The opening length W1 is preferably set in the range of 200% to 400%. The second protrusion 11B has a length L2 in contact with the bottom 4a in the longitudinal direction of the first lug groove 4 in the inclined portions 22a and 22b at the second intersecting portion 12B. It is preferable to set in the range of 200% to 400% of the length W2.
That is, 2W1 <L1 <4W1, 2W2 <L2 <4W2.

  In this case, if the lengths L1 and L2 of the inclined portions 21a and 21b and the inclined portions 22a and 22b are shorter than 200% of the opening lengths W1 and W2 of the grooves 3 and 4 in the second protrusion 11B, There is a possibility that snow may not be efficiently pushed into the grooves 3 and 4 by the protrusion 11B. If the lengths L1 and L2 of the inclined portions 21a and 21b and the inclined portions 22a and 22b are longer than 400% of the opening lengths W1 and W2 of the grooves 3 and 4 in the second protrusion 11B, the grooves 3 and 4 This may cause a decrease in the volume of snow and may not compress a sufficient amount of snow.

  Here, a gap is provided between the side surface of each inclined portion 21a, 21b and each side wall 3b of the circumferential narrow groove 3 in relation to the second projecting portion 11B and the second intersecting portion 12B. Although gaps are provided between the side surfaces of the portions 22a and 22b and the side walls 4b of the first lug grooves 4, the present invention is not limited to this configuration. For example, due to the relationship between the second protrusion 11B and the second intersecting portion 12B, the side surfaces of the inclined portions 21a and 21b are brought into contact with the side walls 3b of the circumferential narrow groove 3, or the side surfaces of the inclined portions 22a and 22b. May be configured to contact each side wall 4b of the first lug groove 4.

  As described above, the second projecting portion 11B and the second intersecting portion 12B have been described in detail, but the other projecting portions 11A and 11C and the intersecting portions 12A and 12C have substantially the same configuration. However, the protrusion 11C has three inclined portions (extending portions) because the intersection C is a three-way. Moreover, since each groove | channel 2-6 does not cross | intersect so that it may orthogonally cross in each cross | intersection part 12A, 12B, 12C, in each protrusion part 11A, 11B, 11C, each sloping part 21a, 21b and each sloping part The inclined portions 21a, 21b, 22a, and 22b may be arranged so as to be parallel to each other along the paths of the grooves 2-6.

  Therefore, when the tire rotates, snow on the road surface is sandwiched between the tread surface, and at this time, the projections 11A, 11B, and 11C provided at the intersections 12A, 12B, and 12C are between the road surface. The sandwiched snow is pushed into each of the grooves 2 to 6 and compressed. That is, as shown in FIG. 4, when the snow on the road surface is sandwiched between the projections 11A, 11B and the road surface, the snow is separated into the grooves 2, 3, 4 by the inclined portions 21a, 21b, 22a, 22b. It is pushed out to the passage side and is compressed here.

  For example, in the first lug groove 4, in the protrusion 11 </ b> A at the intersection 12 </ b> A with the first see-through main groove 2 </ b> A, the inclined portion 22 b causes the snow on the road surface to pass by the inclination direction (left side in FIG. 4). Extrude into. On the other hand, in the first lug groove 4, in the protrusion portion 11 </ b> B at the intersection 12 </ b> B with the circumferential narrow groove 3, the inclined portion 22 a causes the snow on the road surface to pass toward the passage side (right side in FIG. 4). Extrude. Then, in the first lug groove 4, a large amount of snow is collected and compressed in the passage of the first lug groove 4 between the protruding portion 11 </ b> A (inclined portion 22 b) and the protruding portion 11 </ b> B (inclined portion 22 a). Thus, a tougher snow column can be formed by the first lug groove 4.

  Moreover, since each groove | channel 2-6 is a see-through groove, a noise can be reduced with the projection part 11 on a dry road surface. In this case, if the intervals between the plurality of projections 11 are not equal, but are arranged at unequal intervals, the sound passing through the grooves 2 to 6 collides with the projections 11 to disturb the air column resonance. Pattern noise can be reduced.

  And the snow column shear force increases by this tough snow column, and the edge effect generated by scratching this tough snow column by the corners of the tire (the corners of the tops 21c, 22c, 22d and the block 7) increases, The performance on snow can be improved.

  By the way, in this Embodiment, the projection part mentioned above has two inclination parts (extension part) extended in the direction spaced apart from an intersection part, and makes these two inclination parts asymmetrical shape. Thus, a new effect can be produced. That is, the degree of change (inclination angle) of the height of the inclined part on the front side in the tire rotation direction is set to be larger than the degree of change (inclination angle) on the rear side in the tire rotation direction. As shown in FIGS. 5 and 6, in the tire 30, the protrusions 34 are arranged at the intersections 33 between the longitudinal grooves 31 along the circumferential direction of the tread portion and the lateral grooves 32 along the width direction. And in the protrusion part 34, the inclination angle (theta) a of the inclination part 35a in the front side of a tire rotation direction is set larger than the inclination angle (theta) b of the inclination part 35b in the rear side of a tire rotation direction. That is, θa> θb.

  Accordingly, when the tire 30 rotates, snow on the road surface is sandwiched between the rear inclined portion 35b of the protrusion 34, and is pushed out and compressed along the vertical groove 31 in the tire rotation direction. In this case, since the inclination angle θb of the inclined portion 35b on the rear side is small, the surface area of the inclined surface is increased, and a large amount of snow can be pushed into the vertical groove 31 to be compressed. Can be formed. After that, since the inclined portion 35a on the front side of the next protrusion 34 has a large inclination angle θa, the edge effect by the top formed by the inclined portions 35a and 35b is large, and this strong snow column is easily scratched and resisted. Can be increased, and the performance on snow can be improved.

  Further, at the protrusion provided on the tire equatorial plane CL side, the degree of change (inclination angle) of the height of the inclined portion on the tire equatorial plane CL side in the tire width direction is on the tire ground contact edge E side in the tire width direction. It sets so that it may become smaller than the change degree (inclination angle) of the height of an inclination part. On the other hand, the degree of change (inclination angle) of the height of the inclined portion on the tire ground contact end E side in the tire width direction on the tire ground contact end E side is on the tire equatorial plane CL side in the tire width direction. It sets so that it may become smaller than the change degree (inclination angle) of the height of an inclination part.

  As shown in FIG. 7A, on the tire equatorial plane CL side of the tread portion, the protruding portion 44A is disposed at the intersection 43A between the longitudinal groove 41A along the circumferential direction and the lateral groove 42A along the width direction. Then, at the protrusion 44A, the inclination angle θb of the inclined portion 45Ab on the tire equatorial plane CL side is set smaller than the inclination angle θa of the inclined portion 45Aa on the tire ground contact end E side. That is, θa> θb. On the other hand, as shown in FIG. 7-2, on the tire ground contact end E side, the protrusions 44B are arranged at the intersections 43B of the longitudinal grooves 41B along the circumferential direction of the tread portion and the lateral grooves 42B along the width direction. . Then, at the protrusion 44B, the inclination angle θa of the inclined portion 45Ba on the tire ground contact end E side is set smaller than the inclination angle θb of the inclined portion 45Bb on the tire equatorial plane CL side. That is, θa <θb.

  In this case, the protrusion 44A provided on the tire equatorial plane CL side is, for example, the protrusions 11A and 11B in FIG. 1, and the protrusion 44B provided on the tire ground contact end E side is, for example, In FIG. 1, the protrusion 11C. Specifically, it is preferable that the protrusion provided closest to the tire ground contact end E has the shape of the protrusion 44B described above, and the other protrusions have the shape of the protrusion 44A described above.

  Therefore, when the tire rotates, the snow on the road surface is sandwiched between the inclined portions 45Aa and 45Ab of the protrusion 44A on the tire equatorial plane CL side, and this snow is pushed out and compressed along the longitudinal direction of the lateral groove 42A. In this case, since the inclination angle θb of the inclined portion 45Ab on the tire equatorial plane CL side is small, the surface area of the inclined plane increases, and a large amount of snow can be pushed into the lateral groove 42A to be compressed. A tougher snow column can be formed in the lateral groove 42A. Therefore, the edge effect is increased and the performance on snow can be improved.

  Further, when the snow on the road surface is sandwiched between the inclined portions 45Ba and 45Bb in the projection 44B on the tire ground contact end E side, the snow is pushed out and compressed along the longitudinal direction of the lateral groove 42B. In this case, since the inclination angle θa of the inclined portion 45Ba on the tire ground contact end E side is small, the surface area of the inclined surface is increased, and a large amount of snow can be discharged from the lateral groove 42B to the outer side in the tire width direction, improving on-snow performance. it can.

  Moreover, the shape of the protrusion part of this invention is not limited to embodiment mentioned above. For example, as shown in FIG. 8, the protrusion 51 has a regular quadrangular pyramid shape, and is formed with four inclined portions 51a, 51b, 51c, 51d having a flat surface and a top 51e. Yes. By setting it as such a shape, the shape of the projection part 51 is simplified and a moldability can be improved. Further, as shown in FIG. 9, the protrusion 52 has a regular quadrangular pyramid shape, and four inclined portions 52a, 52b, 52c, and 52d are formed, and a top portion 52e is formed, but each inclined portion 52a is formed. , 52b, 52c, 52d are curved surfaces that are recessed so as to be recessed. In this case, it is good also as a curved surface which protruded so that the surface of each inclination part 52a, 52b, 52c, 52d may become a convex part. By setting it as such a shape, the shape of the projection part 52 is simplified and a moldability can be improved. The curved surface may be an inclined surface composed of a plurality of planes.

  Further, as shown in FIG. 10, the protrusion 53 has a hemispherical shape, and an inclined portion 53a having a three-dimensional curved surface is formed on the surface. A semi-elliptical sphere shape may be used instead of the hemispherical shape. By setting it as such a shape, the shape of the projection part 53 is simplified and a moldability can be improved further. As shown in FIG. 11, the protrusion 54 has three inclined portions 54a, 54b, 54c having a flat surface on the surface and a top portion 54d. In this case, it is effective to be provided at the intersection of the three-way crossing where the vertical groove and the horizontal groove intersect. By adopting such a shape, the three inclined portions 54a, 54b, 54c are continuous without a step, so that snow can be efficiently pushed into the groove and compressed.

  Further, as shown in FIG. 12, the protrusion 55 is arranged so that the two inclined portions 21a and 21b and the two inclined portions 22a and 22b intersect each other, like the protrusion 11B described above. A plurality of guide grooves 55a and 55b are provided on the surfaces (inclined surfaces) of the portions 22a and 22b as guide portions along the direction in which the height changes. Each of the guide grooves 55a and 55b is a plurality of parallel grooves provided along the inclination direction of the inclined portions 22a and 22b, and more snow that is sandwiched between the road surface and the inclined portions 22a and 22b. It can be actively guided to the groove. In this case, you may provide a guide groove (guide part) in inclination part 21a, 21b.

  The shape of the guide portion is not limited to the guide groove, and may be a guide protrusion or a ridge. Further, the guide groove does not need to be provided in the entire area of the inclined surface, and may be provided in a part thereof so as to gradually become shallower from the top side.

  Further, as shown in FIG. 13, the protrusion 56 is arranged so that the two inclined portions 21a and 21b and the two inclined portions 22a and 22b intersect each other in the same manner as the protrusion 11B described above. The chamfered portions 56a are provided at the four corners where the side walls of the portions 21a, 21b, 22a, and 22b come into contact. The chamfered portion 56a can positively guide the snow sandwiched between the protruding portion 56 and the road surface to the groove without accumulating on the corners of the inclined portions 21a, 21b, 22a, and 22b.

  Further, as shown in FIG. 14, a groove (vertical groove or horizontal groove) 61 is provided in the tread portion, and protrusions 62 and 63 are provided in the longitudinal direction of the groove 61 in the passage of the groove 61. ing. The protrusions 62 and 63 are formed with inclined portions (extending portions) 64 and 65 so as to face each other, and top portions 66 and 67 are formed. In this case, the protrusions 62 and 63 are not opposed to each other, that is, the opposite sides of the inclined portions 64 and 65 across the top portions 66 and 67 are not inclined portions but vertical portions 68 and 69.

  Therefore, when the tire rotates, snow on the road surface is sandwiched between the inclined portions 64 and 65, and this snow is pushed out along the longitudinal direction of the groove 61 by the inclination of the inclined surface and compressed. In this case, since the inclined portions 64 and 65 are opposed to each other, the snow pushed out by the inclined portions 64 and 65 is collected in the passage between the grooves 61 and is compressed. A snow column can be formed, the edge effect is increased, and the performance on snow can be improved.

  That is, the protrusion on the pneumatic tire of the present invention can improve the performance on snow even if it is provided in a groove other than the intersection. The shape of the protrusions 62 and 63 is not limited to the shape in which the inclined portions 64 and 65 are formed on one side, and may be a shape in which inclined portions are provided on both sides in the longitudinal direction of the groove 61.

  In the above-described embodiment, the extending portion provided in the protruding portion has been described as an inclined portion having an inclined surface. However, the present invention is not limited to this configuration. For example, it is good also as a shape where height changes along the longitudinal direction of a groove | channel by making the surface of an extension part into step shape.

  As described above, in the pneumatic tire according to the present embodiment, a plurality of grooves 2 to 6 extending in the tire circumferential direction and the tire width direction are provided on the tread surface of the tread portion 1 and the plurality of grooves 2 to 6 are provided. Protrusions 11 (11A, 11B, 11C), 34, 44A, 44B, 51 whose height changes along the longitudinal direction in the grooves 2-6 are configured by providing a plurality of blocks 7 by intersecting. , 52, 53, 54, 55, 56, 62, 63 are provided.

  Accordingly, the protrusions 11 (11A, 11B, 11C), 34, 44A, 44B, 51, 52, 53, 54, 55, 56, 62, 63 provided in the grooves 2-6 are formed in the grooves 2-6. By changing the height along the longitudinal direction, the road surface and the projections 11 (11A, 11B, 11C), 34, 44A, 44B, 51, 52, 53, 54, 55, 56, 62, 63 The snow sandwiched between the two is pushed out in the longitudinal direction of the grooves 2 to 6 and is compressed while moving, so that a tougher snow column can be formed in the grooves 2 to 6. The column shear force is increased, the edge effect due to the corner of the tire is increased, and the performance on snow can be improved.

  Further, in the pneumatic tire of the present embodiment, the protrusions 11 (11A, 11B, 11C), 34, 44A, 44B, 51, 52, 53, 54, 55, 56, 62, 63 are formed in a plurality of grooves 2 to 2. 6 are provided at intersections 12 (12A, 12B, 12C), 33, 43A, 43B where 6 intersect. Therefore, the snow of the intersections 12 (12A, 12B, 12C), 33, 43A, 43B is moved to the plurality of grooves 2-6 and compressed, and a strong snow column is formed in the grooves 2-6. Can do.

  Further, in the pneumatic tire of the present embodiment, the projecting portions 11 (11A, 11B, 11C), 34, 44A, 44B, 51, 52, 53, 54, 55, 56, 62, 63 and the intersecting portion 12 ( 12A, 12B, 12C), 33, 43A, 43B, inclined portions 21a, 21b, 22a, 22b, 35a as extending portions extending so as to decrease in height toward the passage side of the grooves 2-6. 35b, 45Aa, 45Ab, 45Ba, 45Bb, 51a-51d, 52a-52d, 53a, 54a-54c, 64, 65 are provided. Accordingly, the snow at the intersections 12 (12A, 12B, 12C), 33, 43A, 43B is inclined to the inclined portions 21a, 21b, 22a, 22b, 35a, 35b, 45Aa, 45Ab, 45Ba, 45Bb, 51a-51d, 52a-52d. , 53a, 54a to 54c, 64, 65 can be efficiently extruded and compressed in the longitudinal direction of the grooves 2-6, and a tougher snow column can be formed in the grooves 2-6.

  The pneumatic tire of the present invention improves on-snow performance. This on-snow performance is not only for road surfaces on which snow has accumulated, but also on road surfaces on which muddy soil has accumulated. And braking performance can be improved.

  15-1 and 15-2 are charts showing the results of the performance test of the pneumatic tire according to the example of the present invention. In this example, a performance test related to performance on snow was performed on a plurality of types of pneumatic tires having different conditions.

  In this performance test, a pneumatic tire with a tire size of 225 / 65R17 102Q is assembled to a normal rim, filled with 95% of the normal internal pressure, 97% of the normal load is added, and the front steering of a 2-D / 4 test vehicle is performed. The test was carried out with the shaft attached. The regular rim here refers to “standard rim” defined in JATMA, “Design Rim” defined in TRA, or “Measuring Rim” defined in ETRTO. The normal internal pressure means “maximum air pressure” defined by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The normal load means “maximum load capacity” defined in JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined in TRA, or “LOAD CAPACITY” defined in ETRTO.

  The evaluation method is that the driver sensuously evaluates on-snow performance consisting of driving stability on the snow, cornering performance, and braking performance on a snow test road at a predetermined speed on a test vehicle equipped with pneumatic tires. To do. The evaluation result is indicated by a performance index with the evaluation result of the conventional example as 100, and the larger the performance index (the above value), the better the performance on snow.

  15-1 and 15-2, the conventional pneumatic tire has a plurality of grooves and blocks, but has no protrusions. On the other hand, the pneumatic tire of Example 1 is provided with a plurality of protrusions in the groove, and the pneumatic tires of Examples 2 to 14 are provided with protrusions at the intersections. Moreover, the pneumatic tire of Example 2 is provided with inclined portions (extending portions) on both sides of the protrusions symmetrically in the tire circumferential direction and the tire width direction, and the pneumatic tire of Example 3 has protrusions. Inclined portions (extending portions) are provided asymmetrically in the tire circumferential direction and symmetrical in the tire width direction on both sides of the tire portion, and the pneumatic tire of Example 4 has inclined portions (extending portions) on both sides of the protruding portion. ) Is provided symmetrically in the tire circumferential direction and asymmetrically in the tire width direction.

  Moreover, the pneumatic tires of Examples 5 to 9 were obtained by changing the ratio of the height of the protrusions, and the pneumatic tires of Examples 10 to 14 were changed by the ratio of the length of the protrusions. Is. In the pneumatic tires of Examples 1 to 5, the inclined portion (extending portion) of the protruding portion does not have a guide portion, and the pneumatic tires of Examples 6 to 14 are inclined portions (extended) of the protruding portion. The guide part is provided in the existing part).

  As is clear from the tables of FIGS. 15-1 and 15-2, the pneumatic tires of Examples 1 to 14 have protrusions at grooves and intersections, and each condition is optimized. This shows that the performance on snow is improved.

  As described above, the pneumatic tire according to the present invention is suitable for a pneumatic tire that improves performance on snow.

1 tread portion 2 see-through main groove 2A first see-through main groove 2B second see-through main groove 3 circumferential narrow groove 4 first lug groove 5 second lug groove 6 transverse groove 7 block 7A first block 7B second block 7C third Block 8 Sipe 11 Projection 11A First Projection 11B Second Projection 11C Third Projection 12 Crossing 12A First Cross 12B Second Cross 12C Third Cross 21a, 21b, 22a, 22b Present)
21c, 22c, 22d Top part 31, 41A, 41B Vertical groove 32, 42A, 42B Horizontal groove 33, 43A, 43B Intersection part 34, 44A, 44B Protrusion part 35a, 35b, 45Aa, 45Ab, 45Ba, 45Bb Inclined part (extension part) )
51, 52, 53, 54, 55, 56 Protrusion 51a-51d, 52a-52d, 53a, 54a-54c Inclined part (extending part)
51e, 52e, 54d Top 55a, 55b Guide groove (guide part)
61 Groove 62, 63 Protruding part 64, 65 Inclined part (extending part)
66,67 top

Claims (11)

A plurality of grooves extending in the tire circumferential direction and the tire width direction on the tread surface;
A plurality of blocks formed by intersecting the plurality of grooves;
A protrusion provided in the groove and having a height that varies along the longitudinal direction of the groove;
A pneumatic tire characterized by comprising:   The pneumatic tire according to claim 1, wherein the protrusion is provided at an intersection where the plurality of grooves intersect.   3. The pneumatic tire according to claim 2, wherein the protrusion has an extending portion that extends from the intersecting portion toward a passage side of the groove so as to decrease in height.   The pneumatic tire according to claim 3, wherein the extending portion is configured by an inclined portion.   The pneumatic tire according to claim 4, wherein the inclined portion is provided with a guide portion along a direction in which a height changes on the surface.   6. The projection according to claim 1, wherein a height of the protrusion from a bottom of the groove is set in a range of 50% to 80% of a depth of the groove. Pneumatic tire.   The protrusion is provided at an intersection where the first groove and the second groove intersect, and the length in contact with the bottom of the groove in the longitudinal direction of the first groove is the width direction of the second groove. The pneumatic tire according to any one of claims 1 to 6, wherein the pneumatic tire is set in a range of 200% to 400% of an opening length.   The pneumatic structure according to claim 3, wherein the protrusion has two extending portions extending in a direction away from the intersecting portion, and the two extending portions have an asymmetric shape. tire.   The height change degree of the extension part on the front side in the tire rotation direction is set to be larger than the change degree of the height of the extension part on the rear side in the tire rotation direction. Item 9. The pneumatic tire according to Item 8.   In the protrusion provided on the tire equatorial plane side, the degree of change in the height of the extending section on the tire equatorial plane side in the tire width direction is the height of the extending section on the tire ground contact end side in the tire width direction. The pneumatic tire according to claim 8, wherein the pneumatic tire is set to be smaller than a degree of change in height.   In the protrusion provided on the tire ground contact end side, the degree of change in the height of the extending portion on the tire ground contact end side in the tire width direction is the height of the extension portion on the tire equatorial plane side in the tire width direction. The pneumatic tire according to claim 8, wherein the pneumatic tire is set to be smaller than a degree of change in height.

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