JP5827661B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire that achieves both stable driving performance and performance on snow on a dry road surface.

  In recent years, pneumatic tires are required to have excellent running performance on snowy roads (hereinafter referred to as snow performance).

  In order to improve the performance on snow, a pneumatic tire in which grooves and sipes are provided in a tread portion has been proposed. However, such a pneumatic tire has a problem that the rigidity of the tread portion is lowered by the grooves and sipes, and the steering stability performance on the dry road surface is lowered.

  The following Patent Document 1 proposes a pneumatic tire in which a recess is provided at an edge of a land portion of a tread portion. Such a pneumatic tire maintains the rigidity of the land portion and ensures the steering stability performance on the dry road surface.

JP 2000-52715 A

  However, the pneumatic tire disclosed in Patent Document 1 has room for further improvement in terms of both the steering stability performance on the dry road surface and the on-snow performance.

  The present invention has been devised in view of the actual situation as described above, and is based on prescribing the arrangement of the recesses provided on the land, and achieves both stable driving performance on dry roads and on-snow performance. Its main purpose is to provide pneumatic tires.

In the present invention, the tread portion is provided with at least one main groove extending continuously in the tire circumferential direction, so that the first land portion is divided on one side of the main groove and the second land portion is divided on the other side. The first land portion and the second land portion are each provided with a recess, and the recess faces the main groove side of the first land portion. A plurality of first recesses provided on one edge, and a plurality of second recesses provided on a second edge facing the main groove of the second land portion, wherein each second recess is the respective first recess provided et been without intersecting the projection region projected on the second edge along the tire axial direction, wherein each recess is of substantially tetrahedral comprising a land portion of four triangular faces The substantially tetrahedron is recessed in space, the first surface on the tread surface side of the land portion, the second surface along the groove wall of the main groove, A third surface which forms a bottom side of the part, characterized in that it has a second surface facing the land portion side of the fourth surface.

  In the pneumatic tire according to the present invention, it is preferable that the third surface has a spherical triangular shape that is smoothly convex toward the outer side in the tire radial direction.

  In the pneumatic tire according to the present invention, the third surface of the first recess is inclined inward in the tire radial direction toward one side in the tire circumferential direction, and the third surface of the second recess is It is desirable to incline in the tire radial direction toward the other side in the tire circumferential direction.

In the second aspect of the present invention, the tread portion is provided with at least one main groove extending continuously in the tire circumferential direction, whereby the first land portion is provided on one side of the main groove and the second land is provided on the other side. A pneumatic tire in which two land portions are divided, wherein the first land portion and the second land portion are each provided with a recess, and the recess is the main groove of the first land portion. A plurality of first recesses provided on a first edge facing the side, and a plurality of second recesses provided on a second edge facing the main groove of the second land portion, Each of the second recesses is provided without intersecting with a projection area in which each of the first recesses is projected onto the second edge along the tire axial direction, and one end of the second land portion communicates with the main groove. A lug groove whose other end terminates in the second land portion is provided at a position where the lug groove intersects the projection region of the first recess. Vignetting wherein the are.

  In the pneumatic tire according to the present invention, the second land portion is provided with a lateral groove at an edge opposite to the second edge, and the lateral groove communicates with the second recess. desirable.

  In the pneumatic tire according to the present invention, it is desirable that the maximum depth of the concave portion is 0.5 to 0.95 times the groove depth of the main groove.

  In the pneumatic tire according to the present invention, it is desirable that the distance in the tire circumferential direction between the first recess and the second recess is 0.9 to 1.1 times the groove width of the main groove.

A third aspect of the present invention is a pneumatic tire in which a land portion is divided between the main grooves by providing a plurality of main grooves continuously extending in a tire circumferential direction in the tread portion, The land portion is provided with a recess, and the recess is provided at a plurality of recesses provided at one edge of the land portion in the tire axial direction and at an edge on the other side in the tire axial direction. Each of the recesses provided on the edge on the one side includes a projection region projected on the edge on the one side along the tire axial direction. provided et been without intersecting, each recess is recessed in a substantially tetrahedral space of the land portion of four triangular faces, said generally tetrahedron, the first surface of the tread side of the land portion A second surface along the groove wall of the main groove, a third surface forming a bottom surface side of the recess, and the second surface Characterized in that it has a fourth surface of the land portion side of direction. According to a fourth aspect of the present invention, there is provided a pneumatic tire in which a land portion is divided between the main grooves by providing a plurality of main grooves extending continuously in the tire circumferential direction in the tread portion. The land portion is provided with a recessed portion, and the recessed portion is provided at a plurality of recessed portions provided on one edge of the land portion in the tire axial direction and on the other edge in the tire axial direction. Each of the recesses provided on the edge on the one side is projected on the edge on the one side along the tire axial direction. Provided without intersecting the area, the land portion includes a first land portion provided with the respective recesses, and a second land portion adjacent to one side of the tire land direction of the first land portion, The second land portion has one end communicating with the main groove between the first land portion and the second land portion, and the other end being A lug groove that terminates in the second land portion is provided, and the lug groove intersects with a projection region in which the concave portion provided at the edge on the one side is projected onto the second land portion along the tire axial direction. It is provided in.

  In the pneumatic tire according to the first aspect of the present invention, the tread portion is provided with at least one main groove extending continuously in the tire circumferential direction, whereby the first land portion is provided on one side of the main groove and the other is provided on the other side. The second land is divided on the side. Each of the first land portion and the second land portion is provided with a recess. Such a recess effectively compresses snow and shears it to obtain a large snow column shear force. For this reason, the traction performance at the time of running on snow improves.

  The recesses are a plurality of first recesses provided on the first edge facing the main groove side of the first land portion, and a plurality of recesses provided on the second edge facing the main groove side of the second land portion. A second recess. Each 2nd recessed part is provided without crossing the projection area | region which projected each 1st recessed part on the 2nd edge along the tire axial direction. Such first recesses and second recesses effectively maintain the rigidity of the land part while obtaining snow traction with good balance in the tire circumferential direction, and exhibit excellent steering stability performance on dry road surfaces.

  In the pneumatic tire according to the second aspect of the present invention, the tread portion is provided with a plurality of main grooves extending continuously in the tire circumferential direction, so that the land portion is divided between the main grooves. The land portion is provided with a recess. The recess includes a plurality of recesses provided at one edge in the tire axial direction and a plurality of recesses provided at the other edge in the tire axial direction. Such a recess obtains a large snow column shear force when traveling on a snowy road and improves the traction performance when traveling on snow.

  Each recess provided in the edge on one side is provided without intersecting with a projection region in which each recess provided in the edge on the other side is projected on the edge on the one side along the tire axial direction. Such a concave portion effectively maintains the rigidity of the land portion provided with the concave portion while obtaining snow traction with good balance in the tire circumferential direction, and exhibits excellent steering stability performance on a dry road surface.

  Therefore, the pneumatic tire of the present invention achieves both stable driving performance on dry road surfaces and on-snow performance.

It is an expanded view of the tread part of the pneumatic tire of this embodiment. It is AA sectional drawing of FIG. It is an expansion perspective view of the main groove and land part of FIG. It is an expansion perspective view of the recessed part of FIG. (A) is an enlarged perspective view which shows the 1st surface of a recessed part, (b) is an enlarged perspective view which shows the 2nd surface of a recessed part. (A) is an expanded perspective view which shows the 3rd surface of a recessed part, (b) is an enlarged perspective view which shows the 4th surface of a recessed part. It is an enlarged view of the 1st land part of FIG. It is an enlarged view of the 2nd land part of FIG. It is an enlarged view of the 3rd land part of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a development view of a tread portion 2 of a pneumatic tire (hereinafter sometimes simply referred to as “tire”) 1 of the present embodiment. The pneumatic tire 1 of this embodiment is suitably used as a radial tire for passenger cars, for example.

  As shown in FIG. 1, the tread portion 2 is provided with a plurality of main grooves 3 extending continuously in the tire circumferential direction. In the present specification, the “main groove” means a groove extending continuously in the tire circumferential direction and having a groove width of 2% or more of the tread ground contact width TW.

  The tread contact width TW is a distance in the tire axial direction between the tread contact ends Te and Te of the tire 1 in a normal state. The normal state is a state in which a tire is assembled on a normal rim (not shown) and filled with a normal internal pressure, and is not loaded.

  The “regular rim” is a rim determined for each tire in a standard system including a standard on which the tire is based. For example, “Standard Rim” for JATMA, “Design Rim” for TRA, ETRTO Then "Measuring Rim".

  The “regular internal pressure” is an air pressure determined by each standard for each tire in the standard system including the standard on which the tire is based. The maximum value described in “AT VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” in the case of ETRTO.

  The “tread contact end Te” is a contact position on the outermost side in the tire axial direction when a normal load is applied to the tire 1 in the normal state and the tire 1 contacts the plane with a camber angle of 0 °.

  The “regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. “JATMA” indicates “maximum load capacity”, and TRA indicates “TIRE LOAD”. The maximum value described in “LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “LOAD CAPACITY” in the case of ETRTO.

  The main groove 3 includes a center main groove 4 and a shoulder main groove 5.

  A pair of shoulder main grooves 5 are provided on both sides of the tire equator C and closest to the tread ground contact Te. The shoulder main groove 5 of the present embodiment extends, for example, linearly along the tire circumferential direction.

  A pair of center main grooves 4 are provided between the shoulder main grooves 5 and 5 and on both sides of the tire equator C. The center main groove 4 of the present embodiment extends, for example, linearly along the tire circumferential direction.

  The groove width W4 of the center main groove 4 and the groove width W5 of the shoulder main groove 5 are, for example, 2.5 to 7.5% of the tread ground contact width TW. The center main groove 4 and the shoulder main groove 5 as described above achieve both the steering stability performance on the dry road surface and the snow performance. In the present embodiment, the groove width W4 of the center main groove 4 and the groove width W5 of the shoulder main groove 5 are substantially constant.

  FIG. 2 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 2, the groove depth d4 of the center main groove 4 and the groove depth d5 of the shoulder main groove 5 are, for example, 5 to 15 mm in the case of the passenger car tire of this embodiment.

  As shown in FIG. 1, the tread portion 2 is provided with a plurality of main grooves 3, whereby a plurality of land portions 10 are formed between the main grooves 3 and 3. The land portion 10 includes, for example, a first land portion 11, a pair of second land portions 12 and 12, and a pair of third land portions 13 and 13. In the present embodiment, the first land portion 11 is provided between the pair of center main grooves 4 and 4. The second land portion 12 is provided between the center main groove 4 and the shoulder main groove 5. The third land portion 13 is provided outside the shoulder main groove 5 in the tire axial direction.

  FIG. 3 shows an enlarged perspective view of a region 20 surrounded by a two-dot chain line in FIG. In FIG. 3, a center main groove 4 as the main groove 3, a first land portion 11 provided on one side of the center main groove 4, and a second land portion 12 provided on the other side of the center main groove 4 It is shown.

  As shown in FIG. 3, the first land portion 11 and the second land portion 12 are each provided with a recess 30. Such a recessed part 30 obtains a large snow column shearing force by effectively pressing and solidifying the snow in the snow road and shearing it. For this reason, the traction performance at the time of running on snow improves.

  As shown in FIG. 1, the recess 30 includes a plurality of first recesses 31 provided on the first edge 11 e facing the main groove 3 side of the first land portion 11, and the main groove of the second land portion 12. It includes a plurality of second recesses 32 provided on the second edge 12e facing the third side and adjacent to the first edge.

  Each 2nd recessed part 32 is provided, without crossing the projection area | region 17 which projected each 1st recessed part 31 on the 2nd edge 12e along the tire axial direction. Such first concave portion 31 and second concave portion 32 effectively maintain the rigidity of the land portion 10 while obtaining snow traction with good balance in the tire circumferential direction, and exhibit excellent driving stability performance on a dry road surface. The

  4, 5 and 6 are enlarged perspective views of the recess 30. As shown in FIG. 4, the recess 30 is formed by recessing the land portion 10 in a space of a substantially tetrahedron 40 composed of four triangular faces. As shown in FIGS. 5A and 5B and FIGS. 6A and 6B, the substantially tetrahedron 40 includes a first surface 41, a second surface 42, a third surface 43, and a fourth surface. A surface 44 is provided.

  As shown in FIG. 5A, the first surface 41 is a surface of the land portion 10 on the tread surface 10s side. In FIG. 5A, the first surface 41 is a surface indicated by hatching.

  The first surface 41 has a triangular shape having a first side 41a, a second side 41b, and a third side 41c. The 1st edge | side 41a consists of the virtual extension line 22 of the edge 10e of the land part 10, and has extended along the tire circumferential direction. The second side 41b is, for example, shorter than the first side 41a and is inclined with respect to the tire circumferential direction on the tread surface 10s of the land portion 10. The third side 41c is, for example, the shortest of the three sides and extends on the tread 10s of the land portion 10. An angle θ4 formed by the first side 41a and the second side 41b is, for example, 5 to 30 °.

  As shown in FIG. 5B, the second surface 42 is a surface along the groove wall 3 w of the main groove 3. In FIG. 5B, the second surface 42 is a surface indicated by hatching. The second surface 42 has a triangular shape having a first side 42a, a second side 42b, and a third side 42c. The first side 42a is composed of a virtual extension line 22 of the edge 10e of the land portion 10, and is common to the first side 41a (shown in FIG. 5A) of the first surface 41. The second side 42b extends from the tread surface 10s of the land portion 10 to the deepest portion 30d of the concave portion on the groove wall 3w of the main groove 3 while being inclined with respect to the tire circumferential direction. The third side 42 c is shorter than the first side 42 a and the second side 42 b, and extends on the groove wall 3 w of the main groove 3 along the depth direction of the main groove 3.

  As shown in FIG. 6A, the third surface 43 forms the bottom surface 33 of the recess 30. In FIG. 6A, the third surface 43 is a surface indicated by hatching.

  It is desirable that the third surface 43 is smoothly connected to the tread surface 10s of the land portion 10. The third surface 43 is inclined with respect to the tread surface 10s, and gradually increases the depth of the recess 30 toward one side or the other side in the tire circumferential direction. The third surface 43 of the present embodiment has a spherical triangular shape that is smoothly convex toward the outer side in the tire radial direction. Such a third surface 43 guides the snow into the recess 30 when driving on a snowy road, and effectively compresses the snow. Therefore, a large snow column shear force is obtained, and excellent on-snow performance is exhibited.

  The third surface 43 has a first side 43a, a second side 43b, and a third side 43c. The first side 43a extends from the tread surface 10s of the land portion 10 to the deepest portion 30d of the concave portion with an inclination on the groove wall 3w of the main groove 3 with respect to the tire circumferential direction. The first side 43a of the third surface 43 is common to the second side 43b (shown in FIG. 5B) of the second surface 42.

  The second side 43 b of the third surface 43 is the shortest side among the sides of the third surface 43, and extends on the tread 10 s of the land portion 10. The third side 43c extends from the tread surface 10s of the land portion 10 toward the deepest portion 30d of the recess 30 with an inclination with respect to the tire circumferential direction.

  The tip angle θ1 of the bottom surface 33 formed by the first side 43a and the third side 43c of the third surface 43 is preferably 5 ° or more, more preferably 15 ° or more, preferably 30 ° or less, more preferably 20 ° or less. Thereby, the volume of the recessed part 30 is ensured, and the snow in the recessed part 30 is effectively compacted when traveling on a snowy road.

  The edge side angle θ2 of the bottom surface 33 formed by the first side 43a and the third side 43c of the third surface 43 is preferably 45 ° or more, more preferably 60 ° or more, preferably 90 ° or less, more preferably 75. ° or less. Such a bottom surface 33 effectively guides snow into the recess 30 even when turning on a snowy road, and improves the turning performance on the snowy road.

  The inclination angle θ3 of the bottom surface 33, which is the angle between the first surface 41 (shown in FIG. 5A) and the third surface 43, is preferably 5 ° or more, more preferably 8 ° or more, and preferably 15 ° or less. More preferably, it is 12 ° or less. Such a 3rd surface 43 secures the volume of the recessed part 30, suppressing the rigidity fall of a land part. For this reason, the handling stability performance on dry road and the performance on snow are compatible.

  It is desirable that the inclination angle θ3 gradually increases from the tread surface 10s side toward the deepest portion 30d side of the recess 30. As a result, the snow that has entered the recess 30 is more effectively pressed when traveling on a snowy road. Therefore, a large snow column shear force is obtained, and excellent on-snow performance is exhibited.

  As shown in FIG. 6B, the fourth surface 44 is a surface on the land portion 10 side facing the second surface 42 (shown in FIG. 5B). In FIG. 6B, the fourth surface 44 is a surface indicated by oblique lines.

  The fourth surface 44 is substantially perpendicular to the third surface 43 (shown in FIG. 6A). The fourth surface 44 extends along the tire radial direction. The fourth surface 44 is, for example, a flat surface or a curved surface that is gently curved. Such a fourth surface 44 strongly compresses the snow that has entered the recess 30 along the third surface to the main groove 3 side when traveling on a snowy road. Therefore, a large snow column shearing force is obtained, and in particular, the turning performance on a snowy road is improved.

  The fourth surface 44 has a triangular shape having a first side 44a, a second side 44b, and a third side 44c. The first side 44a is inclined with respect to the tire circumferential direction and extends on the tread surface 10s of the land portion 10. The second side 44 b extends along the depth direction of the main groove 3 on the groove wall 3 w of the main groove 3. The third side 44c is inclined with respect to the tire circumferential direction from the tread surface 10s of the land portion 10 toward the deepest portion 30d of the recess 30.

  As shown in FIG. 4, the width W1 of the recess 30 in the tire axial direction is preferably 0.2 times or more, more preferably 0, the width W2 of the land portion 10 where the recess 30 is provided in the tire axial direction. .25 times or more, preferably 0.4 times or less, more preferably 0.35 times or less. Such a recess 30 improves on-snow performance while maintaining the rigidity of the land portion 10.

  The ratio W1 / L1 between the width W1 in the tire axial direction of the recess 30 and the length L1 in the tire circumferential direction is preferably 0.15 or more, more preferably 0.18 or more, and preferably 0.25 or less. Preferably it is 0.22 or less. Such a recess 30 improves the traction performance and turning performance on snow in a well-balanced manner.

  The maximum depth d1 of the recess 30 is preferably 0.5 times or more, more preferably 0.6 times or more, preferably 0.95 times or less, more preferably 0. 0 or more times the groove depth d2 of the main groove 3. 75 times or less. Such a recessed part 30 balances the steering stability performance on a dry road surface and the performance on snow.

  As shown in FIG. 1, the distance L2 in the tire circumferential direction between the first recess 31 and the second recess 32 adjacent in the tire circumferential direction is preferably 0.9 times or more the groove width W3 of the main groove 3 and more. Preferably it is 0.95 times or more, preferably 1.1 times or less, more preferably 1.05 times or less. The first concave portion 31 and the second concave portion 32 exhibit a large snow column spring force while making the rigidity distribution of the land portion 10 uniform.

  As shown in FIG. 3, the third surface 43a of the first recess 31 is inclined inward in the tire radial direction toward one side in the tire circumferential direction, and the third surface 43b of the second recess 32 is the tire It is desirable to incline in the tire radial direction toward the other side in the circumferential direction. Such first concave portion 31 and second concave portion 32 can obtain a large snow column shear force both during acceleration and deceleration. Therefore, the performance on snow is improved in a more balanced manner.

  FIG. 7 shows a partially enlarged view of the first land portion 11. The tread portion 2 of the present embodiment is formed in a point-symmetric pattern with an arbitrary point on the tire equator C as the center. Therefore, as shown in FIG. 7, a plurality of recesses 30 are provided on the first edges 11 e on both sides of the first land portion 11. Such a recess 30 exhibits a large snow column shear force in the vicinity of the tire equator C where the contact pressure is large when traveling on a snowy road, and further improves the traction performance when traveling on snow.

  Each of the first recesses 31A provided on the first edge 11e on the one side has each first recess 31B provided on the first edge 11e on the other side in the first edge 11e on the one side along the tire axial direction. It is provided without intersecting the projected projection area 18. Such a concave portion 30 effectively maintains the rigidity of the land portion provided with the concave portion while obtaining a snow traction with good balance in the tire circumferential direction, and exhibits excellent steering stability performance on a dry road surface.

  The distance L3 in the tire circumferential direction between the first recess 31A provided on the first edge 11e on one side and the second recess 31B provided on the first edge 11e on the other side is preferably that of the first land portion 11. The width W6 is 1.05 times or more, more preferably 1.1 times or more, preferably 1.2 times or less, more preferably 1.15 times or less. Such a recess 30 exhibits a large snow column spring force while making the rigidity distribution of the first land portion 11 uniform.

  In the present embodiment, the first land portion 11 is preferably a rib that is continuous in the tire circumferential direction. The width W6 of the first land portion 11 in the tire axial direction is, for example, 0.1 to 0.15 times the tread ground contact width TW (shown in FIG. 1 and the same hereinafter). Such a first land portion 11 has high rigidity in the tire circumferential direction and exhibits excellent steering stability performance.

  It is desirable that a circumferential sub-groove 34 extending continuously in the tire circumferential direction is provided at the center of the first land portion 11 in the tire axial direction. The circumferential sub-groove 34 of the present embodiment extends linearly on the tire equator C. Such a circumferential sub-groove 34 effectively compresses snow when traveling on a snowy road. Therefore, turning performance especially on snowy roads is improved.

  The width W7 of the circumferential sub-groove 34 is 6 to 12% of the width W6 of the first land portion 11, for example. The groove depth d6 (shown in FIG. 2) of the circumferential sub-groove 34 is, for example, 4 to 6 mm. Such a circumferential sub-groove 34 exhibits excellent on-snow performance while maintaining the rigidity of the first land portion 11.

  FIG. 8 shows an enlarged view of the second land portion 12. The width W8 of the second land portion 12 in the tire axial direction is, for example, 0.1 to 0.15 times the tread ground contact width TW.

  The second land portion 12 is provided with a recess 30, a lug groove 46, a lateral groove 47, and an inclined sipe 48.

  A plurality of the recesses 30 provided in the second land portion 12 are provided on the edge 45a of the second land portion 12 on the center main groove 4 side.

  The lug groove 46 has one end 46 a communicating with the center main groove 4 and the other end 46 b terminating in the second land portion 12. Such a lug groove 46 improves wet performance and on-snow performance while maintaining the rigidity of the second land portion 12.

  It is desirable that the lug groove 46 is provided at a position intersecting with a projection region extending in the tire axial direction of the recess 30 provided in the first land portion 11. Such a lug groove 46 makes the rigidity distribution of the first land portion 11 and the second land portion 12 uniform, and maintains the steering stability performance on the dry road surface.

  The lateral groove 47 communicates with the shoulder main groove 5 and extends obliquely in the tire axial direction. An angle θ5 of the lateral groove 47 with respect to the tire axial direction is, for example, 20 to 30 °.

  It is desirable that the lateral groove 47 communicates with the concave portion 30 through the connection sipe 49. Such a lateral groove 47 further improves the performance on snow. In this specification, the “sipe” is a cut having a width of about 1 mm or less, which is substantially free of width, and is distinguished from a draining groove.

  The inclined sipe 48 has one end 48 a communicating with the shoulder main groove 5 and the other end 48 b terminating in the second land portion 12. The inclined sipe 48 is inclined in the same direction as the lateral groove 47, for example. For example, the inclined sipe 48 is inclined at an angle θ6 of 20 to 30 ° with respect to the tire axial direction. Such an inclined sipe 48 improves the running performance on an icy road while maintaining the rigidity on the inner side of the second land portion 12 in the tire axial direction.

  FIG. 9 shows an enlarged view of the third land portion 13. The width W10 of the third land portion 13 in the tire axial direction is, for example, 0.15 to 0.25 times the tread ground contact width TW.

  The third land portion 13 includes a rib region 51 and a block region 52. The rib region 51 has a rib shape extending continuously in the tire circumferential direction. In the block region 52, blocks divided by lateral grooves and sipes are provided in the tire circumferential direction.

  The ratio W11 / W12 of the width W11 of the rib region 51 in the tire axial direction and the width W12 of the block region 52 in the tire axial direction is preferably 0.2 or more, more preferably 0.23 or more, and preferably 0.2. 3 or less, more preferably 0.27 or less. Such rib region 51 and block region 52 improve wandering performance while maintaining steering stability performance.

  The third land portion 13 is provided with a ground contact end lateral groove 53, a vertically long sipe 54, and a horizontally long sipe 55.

  The ground contact lateral groove 53 extends, for example, at least from the tread ground contact Te to the inside in the tire axial direction. It is desirable that the ground contact end lateral groove 53 terminates in the third land portion 13. The grounding end lateral groove 53 of the present embodiment is gently curved. Such a grounding end lateral groove 53 achieves both steering stability performance and wandering performance.

  The vertically long sipe 54 communicates between the grounding end lateral grooves 53 and 53, for example. The vertically long sipe 54 of the present embodiment communicates with the inner end 53 i of the ground contact end lateral groove 53 in the tire axial direction. Such a vertically long sipe 54 improves the turning performance especially on ice.

  For example, the horizontally long sipe 55 is provided between the grounding end lateral grooves 53 and 53, and extends along the grounding end lateral groove 53. The horizontally long sipe 55 extends, for example, at least from the tread ground contact end Te inward in the tire axial direction, and terminates in the third land portion 13. Such a horizontally long sipe 55 improves wandering performance.

  As mentioned above, although the pneumatic tire of this invention was demonstrated in detail, this invention is not limited to said specific embodiment, It changes and implements to various aspects. For example, the first land portion 11 and the second land portion 12 may be provided on one side and the other side of the main grooves other than the center main groove 4.

A pneumatic tire of size 225 / 65R17 having the basic pattern of FIG. 1 was prototyped based on the specifications in Table 1. As a comparative example, a tire having the basic pattern shown in FIG. These tires were installed in the following test vehicles, and the driving stability performance on dry road surfaces and the performance on snow were tested. The common specifications and test methods for each tire are as follows.
Wearing rim: 17 × 6.5J
Tire internal pressure: 220kPa
Test vehicle: 4-wheel drive vehicle, displacement 2400cc
Tire mounting position: all wheels

<Operation stability on dry road>
The driving stability performance when the test vehicle was run on the test course consisting of a dry asphalt road surface was evaluated based on the driver's sensory performance. A result is a score which makes the comparative example 100, and shows that the steering stability performance on a dry road surface is excellent, so that a numerical value is large.

<Snow performance>
The on-snow performance when running on a snowy road with the test vehicle was evaluated based on the driver's sensuality. A result is a score which makes a comparative example 100, and shows that performance on snow is excellent, so that a numerical value is large.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the pneumatic tire of the example achieved both the stable driving performance on the dry road surface and the performance on snow.

2 tread portion 3 main groove 11 first land portion 12 second land portion 11e first edge 12e second edge 17 projection region 30 recessed portion 31 first recessed portion 32 second recessed portion 32

Claims (9)

By providing at least one main groove extending continuously in the tire circumferential direction in the tread portion, the first land portion is divided on one side of the main groove and the second land portion is divided on the other side. Tire,
Each of the first land portion and the second land portion is provided with a recess,
The recesses are provided on a first edge of the first land portion facing the main groove and a second edge of the second land portion facing the main groove. A plurality of second recesses formed,
Wherein each of the second recesses is provided et been without intersecting the projection area of each first recess and projection to the second edge along the tire axial direction,
Each of the concave portions has a land portion recessed with a substantially tetrahedral space composed of four triangular surfaces,
The substantially tetrahedron includes a first surface on the tread surface side of the land portion, a second surface along a groove wall of the main groove, a third surface forming a bottom surface side of the recess, and the second surface. A pneumatic tire characterized by having a fourth surface on the land portion side facing each other . The pneumatic tire according to claim 1, wherein the third surface has a spherical triangular shape that is smoothly convex toward the outer side in the tire radial direction. The third surface of the first recess is inclined inward in the tire radial direction toward one side in the tire circumferential direction,
The pneumatic tire according to claim 1 or 2, wherein the third surface of the second recess is inclined inward in the tire radial direction toward the other side in the tire circumferential direction. By providing at least one main groove extending continuously in the tire circumferential direction in the tread portion, the first land portion is divided on one side of the main groove and the second land portion is divided on the other side. Tire,
Each of the first land portion and the second land portion is provided with a recess,
The recesses are provided on a first edge of the first land portion facing the main groove and a second edge of the second land portion facing the main groove. A plurality of second recesses formed,
Each of the second recesses is provided without intersecting with a projection region in which each of the first recesses is projected onto the second edge along the tire axial direction.
The second land portion is provided with a lug groove having one end communicating with the main groove and the other end terminating in the second land portion,
The pneumatic tire according to claim 1, wherein the lug groove is provided at a position intersecting the projection area of the first recess. In the second land portion, a lateral groove is provided on an edge opposite to the second edge,
  The pneumatic tire according to claim 1, wherein the lateral groove communicates with the second recess. The pneumatic tire according to any one of claims 1 to 5, wherein a maximum depth of the concave portion is 0.5 to 0.95 times a groove depth of the main groove. The pneumatic tire according to any one of claims 1 to 6, wherein a distance in a tire circumferential direction between the first recess and the second recess is 0.9 to 1.1 times a groove width of the main groove. A pneumatic tire in which a land portion is divided between the main grooves by providing a plurality of main grooves continuously extending in the tire circumferential direction in the tread portion,
The land portion is provided with a recess,
The recess includes a plurality of recesses provided at one edge of the land portion in the tire axial direction, and a plurality of recesses provided at the other edge in the tire axial direction,
Each recess provided in the edge on the one side is provided without intersecting with the projection area projected on the edge on the one side along the tire axial direction of each recess provided in the edge on the other side,
Each of the concave portions has a land portion recessed with a substantially tetrahedral space composed of four triangular surfaces,
The substantially tetrahedron includes a first surface on the tread surface side of the land portion, a second surface along a groove wall of the main groove, a third surface forming a bottom surface side of the recess, and the second surface. A pneumatic tire characterized by having a fourth surface on the land portion side facing each other. A pneumatic tire in which a land portion is divided between the main grooves by providing a plurality of main grooves continuously extending in the tire circumferential direction in the tread portion,
The land portion is provided with a recess,
The recess includes a plurality of recesses provided at one edge of the land portion in the tire axial direction, and a plurality of recesses provided at the other edge in the tire axial direction,
Each recess provided in the one side edge is provided et been without intersecting the other side projection area of the recesses and projections on the one side edge along the tire axial direction provided on the edges of,
The land portion includes a first land portion provided with the recesses, and a second land portion adjacent to one side of the tire land direction of the first land portion,
The second land portion is provided with a lug groove having one end communicating with the main groove between the first land portion and the second land portion, and the other end terminating in the second land portion,
The pneumatic tire according to claim 1, wherein the lug groove is provided at a position intersecting with a projection region obtained by projecting the concave portion provided at the edge on the one side onto the second land portion along the tire axial direction.

Images