JP4559179B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire with improved driving performance on snow.

  For pneumatic tires such as studless tires that have a block pattern on the tread surface, when the blocks are kicked off the road surface as a factor to ensure a stable grip when driving on snowy road surfaces, It is important to efficiently drain the snow that has entered the ditch.

Therefore, as a pneumatic tire aimed at improving the performance of discharging snow that has entered the groove of the block pattern, 1) the groove angle (the angle of the side wall rising from the groove to the land) has been increased (slowly). 2) Adjust the negative ratio between the groove and land of the block pattern (for example, increase the groove area), and use the centrifugal force and block deformation when kicking the road surface to discharge the snow that has entered the groove A pneumatic tire has been proposed (see, for example, Patent Document 1).
JP 2001-39121 A

  However, in the above-described method, the land area of the block pattern is reduced as the snow discharge performance is further improved. When the land area is reduced, the wear resistance performance of the land area is reduced and the grip force when traveling on a dry road surface is reduced, so there is a limit to improving the snow discharge performance.

  The present invention has been made in view of the above-mentioned facts, and has improved air discharging performance of snow entering the block pattern groove without affecting the negative ratio between the block pattern groove and the land portion. An object is to provide a tire entering.

  Therefore, the inventors of the present invention, as a method of improving the snow discharge performance without affecting the negative ratio between the groove of the block pattern and the land portion, to block deformation from the time of stepping on the road surface to the time of kicking out Attention has been paid to the fact that snow discharge performance can be improved by controlling the deformation direction of the block, and the present invention has been completed.

  In order to achieve the above-described object, the present invention has the following features. First, a feature of the present invention is that a plurality of blocks (for example, block 10) formed by being partitioned by grooves (for example, circumferential section 5 and lateral grooves 6) provided on a tread surface (for example, tread surface 1). A pneumatic tire provided, wherein the block is a linear portion that is inclined at an angle α (for example, an angle α1) in a tire width direction with respect to a circumferential line (for example, the circumferential line L1) parallel to the tire equator line. (E.g., a sipe 15) having (e.g., a straight portion 11), and the block expands in a road surface first arrival direction (e.g., road surface first arrival direction P) with respect to the circumferential line by the sipe. The first sub-block (for example, the sub-block 10a) on the side where the inclination angle of the straight line portion is an acute angle and the road surface rearward direction (for example, the direction opposite to the road surface first-arrival direction P) with respect to the circumferential line. Said straight The first sub-block is divided into second sub-blocks (for example, sub-block 10b) on the side where the inclination angle of the line portion becomes an obtuse angle, and the first sub-block reaches the road surface first before the second sub-block ( For example, the gist is to have a road surface first arrival surface 16).

  According to such a feature, when the rotating pneumatic tire block is stepped on the road surface, the first sub-block having the road surface first landing surface reaches the road surface first. Since the first sub-block and the second sub-block are separated by a sipe having a linear portion inclined at an angle α, the first sub-block begins to bend in the direction of the road surface after the second sub-block, When both the first sub-block and the second sub-block are in contact with the road surface, the first sub-block is bent more greatly in the direction of landing on the road surface than the second sub-block. If this is seen as a deformation of the entire block, it becomes a twisted state in which the block is deformed so as to be twisted. Then, when the block kicks out the road surface, the block is deformed so as to return to the original block shape from the twisted state.

  When driving on icy and snowy road surfaces, snow enters the grooves that define the block when the road surface is stepped on, but the snow that has entered the groove due to the return deformation from the twisted state when the road surface is kicked and the outer wall of the block (i.e., the groove A gap is formed between the inner wall and the inner wall of one side, and the area of the snow closely contacting the groove is reduced, so that the snow discharging performance by the centrifugal force of the rotating pneumatic tire is improved.

  Therefore, it is possible to provide a pneumatic tire with improved performance of discharging snow that has entered the groove of the block pattern without affecting the negative ratio between the groove of the block pattern and the land portion.

  Further, in the pneumatic tire according to the features of the present invention, the groove depth (for example, groove depth D) of the sipe (for example, sipe 15) is such that the groove (for example, block 10) divides the block (for example, block 10). It is preferable that the width is shallower than the groove depth (for example, block height H) of the lateral groove 6) and is ½ or more of the groove depth of the groove.

  According to such a pneumatic tire, the amount of deformation in which the block is twisted when the road surface is stepped on becomes moderate, and the performance of discharging snow that has entered the groove of the block pattern can be further improved.

  Furthermore, the pneumatic tire according to the feature of the present invention is the pneumatic tire in a state in which the tread surface (for example, the tread surface 100) is viewed in a plan view with the road surface first arrival direction (for example, the road surface first arrival direction P) of the pneumatic tire being upward. In the plurality of blocks (for example, the blocks 110 and 120), the inclination directions of the straight portions (for example, the straight portions 113a and the straight portions 123a) are respectively left and right with respect to the circumferential line (for example, the circumferential line L3). The first block and the second block include a first block (for example, block 110) and a second block (for example, block 120), and the first block and the second block are separated by the groove (for example, the main groove 105). It is preferable that they are provided adjacent to each other.

  According to such a pneumatic tire, the sipes having linear portions in different inclination directions are provided in the first block and the second block provided adjacent to each other, so when stepping on the road surface The first block and the second block are deformed into a twisted state in opposite directions with respect to the groove.

  When the road surface is kicked out, the first block and the second block undergo reverse deformations in the opposite directions, so that the snow that has entered the groove that divides the two blocks and the outer walls of the two blocks (that is, A gap is formed between the inner wall and the inner wall of the groove, and the area of the snow in close contact with the groove is further reduced, so that the snow discharging performance due to the centrifugal force of the rotating pneumatic tire is further improved.

  Furthermore, the pneumatic tire according to the feature of the present invention is adjacent to the pneumatic tire in a state in which the tread surface (for example, the tread surface 100) is viewed in plan with the road surface first arrival direction (for example, the road surface first arrival direction P) of the pneumatic tire being upward. The first block (e.g., block 100) and the second block (e.g., block 120) provided in the above have outer walls (e.g., outer walls 116 and 126) facing each other, and In each of the one block and the second block, the outer wall has a left and right inclination angle (angles α2 and α3) of the straight portions (for example, the straight portions 113a and 123a) of the sipe (for example, the sipes 113 and 123). It is preferable to have inclined surfaces (inclined surfaces 115 and 125) inclined in the opposite direction.

According to such a pneumatic tire, the outer wall of the first block and the outer wall of the second block facing each other across the groove are each in the rotational direction of torsional deformation when the road surface is stepped on the circumferential line. When the road surface is stepped on, the inclination of each inclined surface is further inclined with respect to the circumferential line in accordance with the torsional deformation of the first block and the second block. Become.

  As a result, the snow that has entered the groove that divides the first block and the second block when the road surface is depressed receives a force in the common vector direction of the rotational direction of the two blocks that are torsionally deformed from the inclined surface. A snow pillar is formed, and the grip force of the pneumatic tire on the road surface on snow can be increased.

  Furthermore, a pneumatic tire according to a feature of the present invention includes at least one main groove (for example, the main groove 105) continuously extending in the tire circumferential direction and a plurality of horizontal grooves (for example, the horizontal groove 101 and the cross groove) that intersect the main groove. A horizontal groove 102), a first block row (eg, block row 160) having a plurality of the first blocks (eg, block 110) partitioned by the horizontal groove (eg, horizontal groove 101), and the horizontal groove (eg, horizontal groove). 102) and a second block sequence (for example, block sequence 170) having a plurality of the second blocks (for example, block 120), and the first block sequence and the second block sequence are the main blocks. It is preferable that the right and left direction is divided by the groove.

  According to such a pneumatic tire, since the first block row and the second block row are partitioned by the main groove in the tire circumferential direction and arranged in the left-right direction, the first tire row extends over the entire circumference in the tire circumferential direction. The block and the second block are divided by the main groove, and a plurality of blocks are provided, and the performance of discharging the snow that has entered the main groove can be improved over the entire circumference in the tire circumferential direction.

  It is possible to provide a pneumatic tire that improves the performance of discharging snow that has entered the groove of the block pattern without affecting the negative ratio between the groove of the block pattern and the land portion.

  Next, an example of an embodiment of a pneumatic tire according to the present invention will be described with reference to the drawings. It should be noted that the drawings described in the following description are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description.

(First embodiment)
FIG. 1 is a plan view of a part of a tread surface 1 of a pneumatic tire according to a first embodiment of the present invention, with the road surface first arrival direction P of the pneumatic tire being upward.

  The block 10 is defined by two main grooves 5 extending in the tire circumferential direction of the tread surface 1 of the pneumatic tire and lateral grooves 6 provided in the tire width direction. Further, the pneumatic tire includes a plurality of blocks 10 in the tire circumferential direction of the tread surface 1.

  The peripheral block 4 provided adjacent to the block 10 across the main groove 5 is a block having the same block height as the block 10.

  FIG. 2 is an enlarged view of the block 10 in plan view in FIG. The road surface first arrival direction P indicates the rotation direction of the pneumatic tire 1 when the vehicle moves forward. The block 10 includes a sipe 15 that is a narrow groove having a straight portion 11 inclined at an angle α1 in the tire width direction with respect to a circumferential line L1 parallel to the tire equator line CL. And sub-block 10b.

  The sub-block 10a is a sub-block located on the side (left side in the figure) where the inclination angle of the linear portion 11 expanding in the road first arrival direction P with respect to the circumferential line L1 is an acute angle (angle α1). In the block 10b, the inclination angle of the linear portion 11 that expands in the road rearward arrival direction (the direction opposite to the road first arrival direction P) with respect to the circumferential line L1 is an obtuse angle (180 degrees−angle α1) (in FIG. It is a sub-block located on the right side.

  Further, the sub-block 10a is arranged so as to be shifted from the sub-block 10b by the width G toward the road surface first arrival direction side. When the pneumatic tire rotates toward the road surface first arrival direction P, the sub-block 10a It has a road surface first arrival surface 16 that reaches the road surface first.

  In the present embodiment, the entire shape of the sipe 15 in the plan view of the block 10 is configured to be the straight portion 11, but the present invention is not limited to this. For example, the shape of the sipe 15 in plan view may be a combination of a plurality of straight or curved line segments. In this case, the present invention is applied as long as the sipe 15 has at least the linear portion inclined at the angle α1 described above.

  FIG. 3 is a three-dimensional perspective view of the block 10 according to the first embodiment of the present invention. As shown in the figure, the groove depth D of the sipe 15 provided in the block 10 is shallower than the block height H (that is, the groove depth of the lateral groove 6 defining the block 10), and The groove depth is ½ or more of the block height H.

  Further, the inner wall 15a and the inner wall 15b of the sipe 15 are one side wall of the sub-block 10a and the sub-block 10b, respectively.

  For convenience of explanation, the groove width w of the sipe 15 in FIG. 3 is shown to be a little wider than a general sipe, but in practice, the block 10 is grounded to the road surface as described later. Thus, the groove width is so narrow that the sipe side wall 15a and the sipe side wall 15b are in contact with each other when bent in the road surface arrival direction (the direction opposite to the road surface first arrival direction P).

  Next, block deformation of the block 10 in this embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating a deformation of the block shape when the block 10 provided on the tread surface 1 of the rotating pneumatic tire is stepped on the road surface. In addition, the road surface first arrival direction P shows the rotation direction of the pneumatic tire in the vehicle which advances similarly to each figure mentioned above. Further, the road boundary line B shown in FIGS. 4B and 4C is a ground boundary line between the block 10 and the road surface, and the grounding area E indicates an area where the block 10 is grounded to the road surface. ing.

  Fig.4 (a) is a figure which shows the shape of the block 10 before road surface grounding.

4 (b) is a diagram showing a time of depression subblock 10a is to the road surface (i.e., the state began to grounded road surface). As shown in the figure, at the time of depression of the road surface of the block 10, the road surface arrival surface 16 of the sub-block 10a before the sub-block 10b is grounded to reach the road surface.

  A shear force a generated in the direction opposite to the road surface first arrival direction P is applied from the road surface to the sub-block 10a that has begun to contact the road surface. However, since the sub-block 10a and the sub-block 10b are separated by the sipe 15, Only the block 10a bends in the direction opposite to the road surface first arrival direction P (road surface rearward direction) (bending displacement amount: X1). At this time, the sub-block 10a and the sub-block 10b are displaced along the inclined linear portion 11 of the sipe 15.

  FIG. 4C is a diagram showing a state where both the sub-block 10a and the sub-block 10b are grounded to the road surface. In this state, a shearing force generated in the direction opposite to the road surface arrival direction P is also applied to the grounded sub-block 10b from the road surface, and the sub-block 10b is bent by the bending displacement amount Y2. The amount Y2 is smaller than the bending amount X2 of the sub-block 10a.

  Here, focusing on the deformation of the entire block 10, the shape of the block 10 with respect to the reference position S in the non-grounded state of the block 10 is directed to the rotation direction R1 (clockwise direction in the figure) shown in FIG. The twisted state is deformed so as to be twisted.

  When the pneumatic tire further rotates and the block 10 is kicked off from the road surface (that is, when the block 10 starts to be separated from the road surface), the block 10 returns to the twisted state due to the property of rubber as an elastic body. Further, it is deformed so as to return to the original block shape S in the direction opposite to the rotation direction R1 (counterclockwise direction in the figure).

  As described above, the block 10 is deformed into a twisted state when stepped on the road surface due to the difference in bending amount between the two sub-blocks divided by the sipe 15, and returns to the original block shape S when kicked. Transforms into

  The series of deformations of the block 10 as described above acts on the snow on the road surface that enters the grooves that define the block 10 as follows.

  Here, as an example, a main groove 5 that partitions the block 10 and the peripheral block 4 will be described as an example of a groove that partitions the block 10 as shown in FIG.

  When the block 10 steps into the road surface, snow on the road surface enters the main groove 5 and, as described above, the block 10 starts torsional deformation in the direction of the rotation direction R1 shown in FIG. Then, the snow that has entered the main groove 5 receives pressure from the outer wall 12 of the block 10 that is torsionally deformed, and forms a snow column that is compacted between the peripheral block 4 and the block 10 that is torsionally deformed. .

  When the pneumatic tire gradually rotates in the road surface first arrival direction P and the block 10 kicks off the road surface, the block 10 tries to return to the original block shape S from the twisted state. At this time, the outer wall 12 of the block 10 is deformed in a direction opposite to the direction in which the snow that has entered the main groove 5 is compacted, so that the snow column that is compacted in the main groove 5 is peeled off from the outer wall 12. Become.

  As a result, when the road surface of the block 10 is kicked out, the degree of adhesion of the snow column to the main groove 5 is lowered, and the snow discharging performance due to the centrifugal force of the rotating pneumatic tire is improved.

  Moreover, in this embodiment, the some block 10 is provided adjacent to the tire circumferential direction. Even for the snow that has entered the lateral grooves 6 that define the plurality of blocks 10, the snow discharge performance is improved by the same action as that of the main groove 5 described above, and the effects of the present invention can be obtained.

  More specifically, since the groove shape of the lateral groove 6 sandwiched between the two blocks 10 that are twisted and deformed in the same direction from the stepping on the road surface to the kicking of the block 10 is greatly deformed, the block 10 At this time, the snow column formed by entering the lateral groove 6 can be greatly deformed to destroy the snow column.

  As a result, when the road surface of the block 10 is kicked out, the snow column that has entered the lateral groove 6 can be effectively destroyed, and the snow discharging performance due to the centrifugal force of the rotating pneumatic tire can be improved.

  The angle α1 that is the inclination angle of the straight portion 11 of the sipe 15 is preferably in the range of 5 degrees or more and less than 30 degrees. By setting the angle α1 in such a range, the snow discharging performance is improved. More effective torsional deformation of the block 10 can be obtained.

(Operations and effects according to the first embodiment)
According to the pneumatic tire according to the first embodiment, when the rotating pneumatic tire block 10 steps into the road surface, the sub-block 10a having the road surface first landing surface 16 reaches the road surface first. Since the sub-block 10a and the sub-block 10b are separated by the sipe 15 having the linear portion 11 inclined at the angle α1, the sub-block 10a is ahead of the sub-block 10b in the road surface arrival direction (opposite the road surface arrival direction P). When the sub-block 10a and the sub-block 10b both come into contact with the road surface, the sub-block 10a is bent more greatly in the direction of landing after the road than the sub-block 10b. If this is viewed as a deformation of the entire block 10, a twisted state is formed in which the block 10 is deformed so as to be twisted in the rotational direction R1. Then, when the block 10 is kicked out, the block 10 is deformed so as to return to the original block shape S from the twisted state.

  When running on an icy and snowy road surface, snow enters the main groove 5 that defines the block 10 when the road surface is stepped on, but the snow and the outer wall 12 that have entered the main groove 5 due to return deformation from the twisted state when the road surface is kicked out. (In other words, a gap is formed between the main groove 5 and the inner wall of one side of the main groove 5), and the area of the snow closely contacting the main groove 5 is reduced. Therefore, the snow discharging performance by the centrifugal force of the rotating pneumatic tire is improved. To do.

  Accordingly, there is provided a pneumatic tire having improved performance of discharging snow that has entered the main groove 5 of the block pattern formed on the tread surface 1 without affecting the negative ratio of the groove and land portion of the block pattern. be able to.

  Furthermore, according to the pneumatic tire according to the first embodiment, the groove depth of the sipe 15 is shallower than the groove depth of the main groove 5 that defines the block 10 and is ½ or more of the groove depth of the main groove 5. Therefore, the amount of deformation that causes the block 10 to be twisted when the road surface is stepped on is moderate, and the performance of discharging snow that has entered the groove of the block pattern of the tread surface 1 can be further improved.

(Second Embodiment)
FIG. 5 is a diagram illustrating a state in which a part of the tread surface 100 of the pneumatic tire according to the second embodiment of the present invention is viewed in plan view. Here, the road surface first arrival direction P indicates the rotation direction of the pneumatic tire.

  The tread surface 100 of the pneumatic tire includes a plurality of blocks 110, 120, and 130, which are blocks to which the features of the present invention are applied, on the tread surface. As shown in the figure, the tread surface 100 is provided with three main grooves 104 to 107 extending in the tire circumferential direction and a plurality of lateral grooves 101 to 103 intersecting any of the main grooves 104 to 107. Yes.

  A plurality of blocks 110 are partitioned by the lateral grooves 101 and are continuously provided in the tire circumferential direction, and a block row 160 is constituted by the plurality of blocks 110.

  Further, a plurality of blocks 120 are defined by the lateral grooves 102 and are provided in the tire circumferential direction and continuously on the tire equator line CL, and the plurality of blocks 120 constitute a block row 170.

  Further, a plurality of blocks 130 are partitioned by the lateral grooves 103 and continuously provided in the tire circumferential direction, and a block row 180 is constituted by the plurality of blocks 130.

Further, in FIG. 5 showing a state in which the tread surface 100 is viewed in plan with the road surface first arrival direction P as an upper side, a block row 160 and a block row 170 are partitioned in the left-right direction by the main groove 105. (That is, when viewed for each individual block, the block 110 and the block 120 are provided adjacent to each other in the left-right direction by the main groove 105.)
Further, the block row 170 and the block row 180 are similarly partitioned in the left-right direction by the main groove 106. (That is, when viewed for each individual block, the block 120 and the block 130 are provided adjacent to each other in the left-right direction by the main groove 106.)
The block 110, the block 120, and the block 130 according to the second embodiment are all auxiliary blocks (FIG. 6 and FIG. 6) formed on the block with the shape of the block 10 according to the first embodiment as a basic type. It is a block configured by combining two basic types in the tire circumferential direction with a pinch (to be described later with reference to FIG. 7).

  FIG. 6 is an enlarged view of the block row 160 and the block row 170 shown in FIG.

  First, the block 110 included in the block sequence 160 will be described. The block 110 has four sub blocks 110a to 110c. Of the four sub-blocks of the block 110, the sub-block 110a and the sub-block 110b are based on the shape of the block 10 according to the first embodiment described above. Similarly, the sub-block 110c and the sub-block 110d have the basic shape of the block 10 according to the first embodiment described above.

  The sub-block 110a and the sub-block 110b are separated by a sipe 113 having a straight portion 113a that is inclined at an angle α2 in the tire width direction with respect to a circumferential line L3 parallel to the tire equator line CL. The groove depth of the sipe 113 is shallower than the groove depth of the lateral groove 101 defining the block 110 and is not less than ½ of the groove depth of the lateral groove 101.

  The sub-block 110a is a sub-block on the side where the inclination angle of the linear portion 113a expanding in the road first arrival direction P with respect to the circumferential line L3 becomes an acute angle (angle α2), and the sub-block 110b This is a sub-block on the side where the inclination angle of the straight line portion 113a that expands in the road surface arrival direction (opposite to the road surface arrival direction P) with respect to the direction line L3 is an obtuse angle (180 degrees−angle α2).

  Further, the sub-block 110a has a road surface first arrival surface 111 that reaches the road surface before the sub-block 110b.

  As described above, in the block 110, the sub-block 110a and the sub-block 110b have substantially the same configuration as the sub-block 10a and the sub-block 10b in the first embodiment described above, and the block 110 is in contact with the road surface. First, the sub-block 110a contacts the road surface before the sub-block 110b, and starts bending in the direction of landing on the road surface.

  Similarly, the sub-block 110c and the sub-block 110d have substantially the same configuration as the sub-block 10a and the sub-block 10b in the first embodiment described above, and when the block 110 is grounded to the road surface, Prior to 110d, the sub-block 110c comes into contact with the road surface and starts bending in the direction of landing on the road surface.

  In block 110, sub-block 110a and sub-block 110c are partitioned by auxiliary block 119 formed on block 110, and sub-block 110b and sub-block 110d are auxiliary block 118 formed on block 110. It is divided by. In addition, the sub-block 110b and the sub-block 110c are partitioned by a sipe 117. The groove depth of the sipe 117 is substantially the same as that of the sipe 113 or sipe 114.

  FIG. 7 is a view showing an A-A ′ cross section that is a cross section parallel to the tire equatorial plane of the auxiliary block 118. As shown in the figure, the auxiliary block 118 is partitioned by sipes 190 that partition the sub-block 110b and the sub-block 110d, respectively. The block surface of the auxiliary block 118 is a surface that is lower than the tread surface 100 (the tread surface of the sub block 110d or the sub block 110b) by a depth D2. The depth D2 of the tread surface 100 of the present embodiment is 1.0 mm when the pneumatic tire is new. Further, the groove depth D3 of the sipe 190 is preferably in the range of 50% to 70% of the groove depth H from the groove bottom 104b of the main groove 104. By setting the groove depth D3 of the sipe 190 in such a range, it is possible to generate a good torsional deformation in the block 110 at the time of grounding while ensuring the rigidity of the entire block 110.

  Note that the cross-sectional shape and dimensions of the auxiliary block 119 parallel to the tire equatorial plane are the same as those of the auxiliary block 118.

  In the present embodiment, the sipe 113 is entirely a straight portion 113a, but the present invention is not limited to this. For example, the sipe 113 has a different inclination angle between the straight portion 113a and the straight portion 113a. The shape may be a combination of other linear portions or curved portions. The same applies to the sipe 114 and the straight portion 114a.

  According to the block 110 as described above, when the pneumatic tire rotates in the road first landing direction P and the block 110 contacts the road surface, the entire block 110 is deformed so as to be twisted in the rotation direction R2. When the block 110 is kicked off, the block 110 rotates in the direction opposite to the rotation direction R2 and returns to the original shape from the state of torsional deformation.

  Next, the block 120 will be described with reference to FIG. The block 120 included in the block row 170 has four sub-blocks 120a to 120d.

  The block 120 is a block in which the configuration of the block 110 described above is configured and arranged in a shape that is symmetrical in the tire width direction. Of the four sub-blocks of the block 120, the sub-block 120a and the sub-block 120b have a basic shape that is symmetrical in the tire width direction of the block 10 according to the first embodiment described above. Similarly, the sub-block 120c and the sub-block 120d have a basic shape that is symmetrical in the tire width direction of the block 10 according to the first embodiment described above.

  The difference between the block 120 and the block 110 is that the straight portion 123a of the sipe 123 that divides the sub block 120a and the sub block 120b is inclined with respect to the tire equator CL direction, and the sub block 120c and the sub block 120d are divided. The inclination direction of the straight portion 124a of the sipe 124 with respect to the tire equator line CL direction is that the straight portion of the block 110 is expanded in the left and right direction.

  Similarly to the block 110, the block 120 includes a road surface first surface 121 of the sub block 120a, a road surface first surface 125 of the sub block 120c, an auxiliary block 128, and an auxiliary block 129. The cross-sectional shape of the auxiliary block 128 and the auxiliary block 129 parallel to the tire equatorial plane is the same as the cross-sectional shape of the auxiliary block 118 described above.

  With such a configuration, the block 120 undergoes torsional deformation in the rotation direction R3 that is the opposite direction to the sub-block 110 when contacting the road surface.

  As described above, the tread surface 100 according to this embodiment includes the block 110 that causes torsional deformation in the rotation direction R2 (clockwise in FIG. 6) when stepped on the road surface, and the rotation direction R3 when stepped on the road surface. A block 120 that causes torsional deformation (counterclockwise in FIG. 6) is provided by being divided in the left-right direction by the main groove 105.

  The angle α2 that is the inclination angle of the straight portion 113a of the sipe 113 (and the inclination angle of the straight portion 114a of the sipe 114), and the angle that is the inclination angle of the straight portion 123a of the sipe 123 (and the inclination angle of the sipe 124). α3 is preferably in the range of 5 degrees or more and less than 30 degrees as in the first embodiment described above.

  Further, as shown in FIG. 6, the block 110 and the block 120 in the present embodiment are adjacent to each other with the main groove 105 interposed therebetween, and have outer walls facing each other.

  More specifically, the block 110 has an outer surface having an inclined surface 115 inclined in the left-right opposite direction in a plan view of the tread surface with respect to the inclination angle of the sipe straight portion 113a and the straight portion 114a provided in the block 110. A wall 116 is provided. On the other hand, the block 120 has an outer wall 126 having an inclined surface 125 that is inclined in the left-right opposite direction in a plan view of the tread surface with respect to the inclination angles of the sipe straight portion 123a and the straight portion 124a provided in the block 120. is doing.

  In the present invention, the groove depth and groove width of the main groove and the lateral groove, the size of the block, the groove depth and groove width of the sipe, etc. should be appropriately designed and changed within the range satisfying the above conditions. Is possible.

(Operations and effects according to the second embodiment)
According to the pneumatic tire according to the second embodiment, when the rotating pneumatic tire block 110 steps on the road surface, the sub-block 110a having the road surface first landing surface 111 reaches the road surface first. Since the sub-block 110a and the sub-block 110b are separated by a sipe 113 having a linear portion 113a inclined at an angle α2, the sub-block 110a is ahead of the sub-block 110b in the road surface arrival direction (opposite the road surface arrival direction P). When the sub-block 110a and the sub-block 110b both come into contact with the road surface, the sub-block 110a is bent more greatly in the direction of landing on the road than the sub-block 110b. Similarly, the sub-block 110c and the sub-block 110d divided by the sipe 114 are in a state where the sub-block 110c is bent more greatly in the direction of landing on the road than the sub-block 110d when the block 110 steps on the road surface.

  If this is viewed as a deformation of the entire block 110, the twisted state is formed so that the block 110 is twisted in the rotational direction R2. When the block 110 kicks out the road surface, the block 110 is deformed so as to return to the original block shape from the twisted state.

  Further, since the block 120 is a block having a symmetrical shape with the block 110, the block 120 is in a twisted state that is deformed so as to be twisted in the rotation direction α3 opposite to the block 110 when the road surface is stepped on. When the road surface is kicked out, the block 120 is deformed so as to return to the original block shape from the twisted state.

  Further, the groove depth of the sipe 113 and the sipe 114 of the block 110 is shallower than the groove depth of the lateral groove 101 that defines the block 110 and is ½ or more of the groove depth of the lateral groove 101, and the sipe 123 of the block 120 and Since the groove depth of the sipe 124 is shallower than the groove depth of the lateral groove 102 that defines the block 120 and is 1/2 or more of the groove depth of the lateral groove 102, the block 110 and the block 120 are twisted when the road surface is depressed. The amount of deformation becomes moderate.

  Therefore, the block 120 and the block 110 have the same operations and effects as those of the first embodiment described above, and are formed on the tread surface 100 without affecting the negative ratio between the groove of the block pattern and the land portion. It is possible to provide a pneumatic tire with improved performance for discharging snow that has entered the main groove 105 of the block pattern.

  According to the pneumatic tire according to the second embodiment, the block 110 and the block 120 provided adjacent to each other are sipe (sipe 113 and sipe 114, sipe having linear portions in different inclination directions, respectively. 123 and sipe 124) are provided, and when the road surface is stepped on, the main groove 105 is sandwiched so as to be deformed into a twisted state in opposite directions (rotational direction R2 and rotational direction R3).

  When the road surface is kicked out, the block 110 and the block 120 undergo reverse deformations in opposite directions, so that the snow that has entered the main groove 105 that divides the two blocks and both outer walls (outer walls) of the two blocks 116 and the outer wall 126), a gap is generated, and the snow area in close contact with the main groove 105 is further reduced, so that the snow discharging performance due to the centrifugal force of the rotating pneumatic tire is further improved.

  According to the pneumatic tire according to the second embodiment, the outer wall 116 of the block 110 and the outer wall 126 of the block 120 that are opposed to each other across the main groove 105 are further provided with circumferential lines (circumferential lines L4). Alternatively, it has inclined surfaces (inclined surface 115 and inclined surface 125) inclined toward the rotational direction (rotational direction R2 or rotational direction R3) of torsional deformation when the road surface is stepped on the circumferential line L5). At the time of stepping on, the torsional deformation of the block 110 and the block 120 causes the inclination of the inclined surfaces to be inclined further with respect to the circumferential line.

  As a result, the snow that has entered the main groove 105 that divides the block 110 and the block 120 when the road surface is stepped down exerts a force in the common vector direction D in the rotation direction of the two blocks that undergo torsional deformation (inclined surface 115). And the inclined surface 125), a strong snow column is formed, and the gripping force of the pneumatic tire on the road surface on snow can be increased.

  According to the pneumatic tire according to the second embodiment, the block row 160 and the block row 170 are further partitioned in the tire circumferential direction by the main groove 105 and arranged in the left-right direction. Thus, the block 110 and the block 120 are divided by the main groove 105, and a plurality of blocks 110 are provided, so that the performance of discharging the snow that has entered the main groove 105 can be improved over the entire circumference in the tire circumferential direction.

It is the figure which planarly viewed a part of tread surface 1 of the pneumatic tire concerning a 1st embodiment of the present invention. It is an enlarged view of the block 10 which concerns on the 1st Embodiment of this invention. It is a three-dimensional perspective view of the block 10 which concerns on the 1st Embodiment of this invention. It is a figure which shows block deformation | transformation at the time of the block 10 which concerns on the 1st Embodiment of this invention grounding with respect to a road surface. It is the figure which planarly viewed a part of tread surface 100 of the pneumatic tire concerning a 2nd embodiment of the present invention. It is the enlarged view of the block row | line | column 160 and the block row | line | column 170 which concern on the 2nd Embodiment of this invention. It is a figure which shows the A-A 'cross section of the auxiliary block 118 which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Tread surface, 4 ... Block, 5 ... Circumferential cross section, 6 ... Cross groove, 10 ... Block, 10a, 10b ... Side block, 11 ... Straight part, 15 ... Sipe, 15a, 15b ... Inner side wall, 16 ... Road surface arrival 100, tread surface, 101-103, transverse groove, 104-107, circumferential cross section, 104b, groove bottom, 110a, 110d, 120a-120d, sub-block, 111, 112, 121, 122, road surface landing surface, 113,114,123,124 ... Sipe, 113a, 114a, 123a, 124a ... Straight portion, 115,125 ... Inclined surface, 116,126 ... Outer wall, 117,127 ... Sipe, 118,119,128,129 ... Auxiliary Block, 110, 120, 130 ... Block, 160, 170, 180 ... Block row, 190 ... Sipe, D ... Sipe groove depth , D2 ... depth, D3 ... groove depth, H ... block height, w ... sipe groove width, CL ... tire equator line, L1 to L5 ... circumferential line, R1-R3 ... twist direction

Claims (3)

A pneumatic tire having a plurality of blocks formed by being partitioned by grooves provided on a tread surface,
The block includes a sipe having a straight portion inclined at an angle α in the tire width direction with respect to a circumferential line parallel to the tire equator line,
The block is divided by the sipe, and the first sub-block on the side where the inclination angle of the linear portion that expands in the road first arrival direction with respect to the circumferential line is an acute angle, and the circumferential line A second sub-block on the side where the inclination angle of the straight line portion that expands in the rearward direction of the road surface becomes an obtuse angle;
The first sub-block, have a road arrival surface to reach the road surface earlier than the second sub-block,
In a state where the tread surface is viewed in plan with the road surface first arrival direction as an upper direction,
The plurality of blocks include a first block and a second block in which an inclination direction of the linear portion is different in a left-right direction with respect to the circumferential line, and the first block and the second block are the grooves. Are provided adjacent to each other,
The first block and the second block provided adjacent to each other have outer walls facing each other, and in each of the first block and the second block, the outer wall is the straight line that the sipe has. A pneumatic tire characterized by having an inclined surface that is inclined opposite to the inclination angle of the right and left direction .   2. The pneumatic tire according to claim 1, wherein a groove depth of the sipe is shallower than a groove depth of the groove defining the block and is ½ or more of a groove depth of the groove. At least one main groove extending continuously in the tire circumferential direction;
A plurality of lateral grooves intersecting the main groove;
A first block row having a plurality of the first blocks partitioned by the lateral grooves;
A second block row having a plurality of the second blocks partitioned by the lateral grooves,
The pneumatic tire according to claim 1 , wherein the first block row and the second block row are partitioned in the left-right direction by the main groove .

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