JP5929437B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that improves durability associated with heat generation at a tire side portion.

  The tire side portion of the pneumatic tire has a high temperature due to concentration of deformation in the tire radial direction, and accordingly, deterioration of the rubber material is promoted, which greatly affects durability.

  Conventionally, for example, the pneumatic tire (pneumatic radial tire) described in Patent Document 1 maintains the tire damage prevention function and suppresses a decrease in durability due to heat generation. It is shown that a convex protector extending in the tire circumferential direction is formed in the buttress portion in the upper region in the direction, and numerous hemispherical or semi-elliptical spherical recesses are formed on the surface of the protector. Furthermore, this pneumatic tire is improving the heat dissipation effect by forming a small recess having a radius of 1/5 to 2/3 of the radius of the recess on the inner surface of the recess.

JP 2006-256433 A

  As in the pneumatic tire described in Patent Document 1 described above, it is known that when a small depression is provided on the inner surface of a depression such as a depression, the heat dissipation effect is improved because the surface area of the depression is increased. However, the increase in the surface area of the recess due to the small depression is because the rubber gauge is locally thinned, and the cut resistance may be reduced due to stress concentration. For this reason, the device for increasing the surface area of a recessed part is desired, without reducing cut resistance.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can improve the durability of a tire side part by increasing the surface area of a recessed part suitably.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention has a plurality of recesses disposed on at least one tire side portion, and at least one on the inner surface of the recess. A groove portion is disposed, and the groove portion is characterized in that a length L1 in the longitudinal direction is formed more than twice the width W1 in the short direction.

  According to this pneumatic tire, the surface area of the concave portion is increased by the groove portion, so that the cooling efficiency of the tire side portion is improved. As a result, the heat dissipation of the tire side portion is improved, and the durability can be improved. When the relationship between the length L1 and the width W1 of the groove is less than twice, the groove depth is increased to increase the surface area of the recess as much as twice or more, and stress concentration occurs in the groove. This may reduce the cut resistance. According to the pneumatic tire of the present invention, since the length L1 of the groove is formed more than twice the width W1, a reduction in cut resistance is suppressed.

  In the pneumatic tire of the present invention, the groove part increases the surface area in the concave part in the range of 10 [%] to 75 [%].

  If the increase rate of the surface area in the recess is 10% or more, a cooling effect for improving the durability can be sufficiently obtained. On the other hand, when the rate of increase of the surface area in the recess is set to 75 [%] or less, it is possible to suppress a situation where the cut resistance is reduced by suppressing the stress concentration in the groove.

  In the pneumatic tire of the present invention, the groove portion is formed such that the width W1 in the short direction is 0.02 ≦ W1 / W2 ≦ 0.50 with respect to the maximum opening width W2 of the concave portion. It is characterized by being.

  If the width W1 of the groove is 0.02 or more with respect to the maximum opening width W2 of the recess, a cooling effect for improving the durability can be sufficiently obtained. On the other hand, when the width W1 of the groove is 0.50 or less with respect to the maximum opening width W2 of the recess, it is possible to suppress a situation where the stress resistance to the groove is suppressed and the cut resistance is lowered.

  In the pneumatic tire of the present invention, the opening of the concave portion is formed in a circular shape or an elliptical shape.

  If there is no corner in the opening of the concave portion, it is possible to avoid the concentration of stress on the corner and to prevent the cut resistance from deteriorating. Moreover, since the diameter of the opening is uniform like a circular shape, the stress concentration in the radial direction can be evenly distributed, so that the situation where the cut resistance is lowered can be further suppressed. .

  In the pneumatic tire of the present invention, the groove is arranged along the shape of the opening of the recess.

  When the groove is arranged along the shape of the opening of the recess, local stress concentration in the groove can be suppressed, so that heat generation due to local deformation is suppressed and the cooling effect is improved. As a result, the heat dissipation of the tire side portion is further improved, and the durability can be further improved.

  In the pneumatic tire of the present invention, the concave portion is arranged in a range of 50 [%] of the tire cross-section height on the outer side in the tire radial direction from the rim check line.

  It is preferable to provide a recess around the cushion rubber around the rim where heat generation tends to be high in order to further improve the heat dissipation of the tire side portion and further improve the durability.

  In the pneumatic tire according to the present invention, the concave portion has a maximum opening width W2 that is different at a position in the tire radial direction.

  In the tire side part, the rubber gauge (thickness of the rubber material) is different in the tire radial direction, and the rubber gauge is relatively small (relatively less heat generation) in the concave portion of the portion where the rubber gauge is relatively large (relatively heat generation). ) Increase the maximum opening width W2 with respect to the concave portion. As described above, by disposing the concave portion having the maximum opening width W2 suitable for the portion where the heat generation is different, the heat dissipation of the tire side portion is further improved, and the durability can be further improved. In addition, the opening width W2 is made smaller for the concave portion where the rubber gauge is relatively small than the concave portion where the rubber gauge is relatively large. For this reason, it can suppress that a rubber gauge becomes smaller (thinner) than necessary, and can suppress a fall of tire rigidity.

  Moreover, in the pneumatic tire of the present invention, the groove portion has a width W1 in the short direction that varies depending on the position of the concave portion in the tire radial direction.

  In the tire side portion, the rubber gauge (rubber material thickness) is different in the tire radial direction, and the rubber gauge is relatively small (relatively less heat generation) in the groove portion where the rubber gauge is relatively large (relatively heat generation). ) The width W1 is increased with respect to the groove portion. As described above, by disposing the groove portion having the width W1 suitable for the portion where the heat generation is different, the heat dissipation property of the tire side portion is further improved and the durability can be further improved. Moreover, the width W1 of the groove portion having a relatively small rubber gauge is made smaller than the groove portion having a relatively large rubber gauge. For this reason, it can suppress that a rubber gauge becomes smaller (thinner) than necessary, and can suppress a fall of tire rigidity.

  In the pneumatic tire of the present invention, the concave portion is disposed at least on the vehicle inner side when the vehicle is mounted.

  The tire side portion on the inside of the vehicle is a portion covered with the structure on the vehicle side, and the ambient temperature tends to be higher than that on the outside of the vehicle, and thermal degradation is likely to occur. For this reason, by disposing the recesses on the inner side of the vehicle, the heat dissipation of the tire side portion on the inner side of the vehicle can be improved, thermal degradation can be suppressed, and durability can be improved.

  The pneumatic tire of the present invention is characterized by being applied to a heavy duty pneumatic tire.

  In a heavy-duty pneumatic tire, since the rubber gauge on the tire side portion is relatively large, the influence of heat generation is large, and durability is regarded as important. Therefore, by applying it to a heavy duty pneumatic tire, the effect of improving the heat dissipation of the tire side portion and improving the durability can be remarkably obtained.

  The pneumatic tire according to the present invention can improve the durability of the tire side portion.

FIG. 1 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a partial external view of the pneumatic tire according to the embodiment of the present invention viewed from the tire width direction. FIG. 3 is a plan view of the recess viewed from the opening side. FIG. 4 is a cross-sectional view taken along the line AA in FIG. FIG. 5 is a cross-sectional side view of an example of a groove. FIG. 6 is a side sectional view of an example of the groove. FIG. 7 is a plan view of an example of the groove portion as viewed from the opening side. FIG. 8 is a plan view of another example of the concave portion when viewed from the opening side. FIG. 9 is a plan view of a recess of another example as viewed from the opening side. FIG. 10 is a side cross-sectional view of another example of a recess. FIG. 11 is a side cross-sectional view of another example of a recess. FIG. 12 is a side cross-sectional view of another example of a recess. FIG. 13 is a side cross-sectional view of another example of a recess. FIG. 14 is a plan view of another example of the recess when viewed from the opening side. FIG. 15 is a plan view of another example of the recess viewed from the opening side. FIG. 16 is a plan view of another example of the recess viewed from the opening side. FIG. 17 is a plan view of another example of the recess viewed from the opening side. FIG. 18 is a partial sectional side view of the recess. FIG. 19 is an explanatory diagram of an example of the arrangement of the recesses in the tire radial direction. FIG. 20 is an explanatory diagram of an example of the arrangement of the groove portions in the tire radial direction. FIG. 21 is a chart showing the results of the performance test of the pneumatic tire according to the example of the present invention. FIG. 22 is a chart showing the results of the performance test of the pneumatic tire according to the 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.

  FIG. 1 is a meridional sectional view of a pneumatic tire according to the present embodiment. In the following description, the tire radial direction refers to a direction orthogonal to the rotation axis (not shown) of the pneumatic tire 1, and the tire radial direction inner side refers to the side toward the rotation axis in the tire radial direction, the tire radial direction outer side. Means the side away from the rotation axis in the tire radial direction. Further, the tire circumferential direction refers to a direction around the rotation axis as a central axis. Further, the tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction means the side toward the tire equator plane (tire equator line) CL in the tire width direction, and the outer side in the tire width direction means the tire width direction. Is the side away from the tire equatorial plane CL. The tire equatorial plane CL is a plane that is orthogonal to the rotational axis of the pneumatic tire 1 and that passes through the center of the tire width of the pneumatic tire 1. The tire width is the width in the tire width direction between the portions located outside in the tire width direction, that is, the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equator line is a line along the tire circumferential direction of the pneumatic tire 1 on the tire equator plane CL. In the present embodiment, the same sign “CL” as that of the tire equator plane is attached to the tire equator line.

  As shown in FIG. 1, a pneumatic tire 1 according to the present embodiment includes a tread portion 2, shoulder portions 3 on both outer sides in the tire width direction, sidewall portions 4 and beads that are sequentially continuous from the shoulder portions 3. Part 5. The pneumatic tire 1 includes a carcass layer 6 and a belt layer 7.

  The tread portion 2 is made of a rubber material (tread rubber), is exposed at the outermost side in the tire radial direction of the pneumatic tire 1, and the surface thereof is the contour of the pneumatic tire 1. A tread surface 21 is formed on the outer peripheral surface of the tread portion 2, that is, on the tread surface that contacts the road surface during traveling. The tread surface 21 is provided with a plurality of (four in this embodiment) main grooves 22 that are straight main grooves extending along the tire circumferential direction and parallel to the tire equator line CL. The tread surface 21 extends along the tire circumferential direction by the plurality of main grooves 22, and a plurality of rib-like land portions 23 parallel to the tire equator line CL are formed. Although not shown in the figure, the tread surface 21 is provided with a lug groove that intersects the main groove 22 in each land portion 23. The land portion 23 is divided into a plurality of portions in the tire circumferential direction by lug grooves. Further, the lug groove is formed to open to the outer side in the tire width direction on the outermost side in the tire width direction of the tread portion 2. Note that the lug groove may have either a form communicating with the main groove 22 or a form not communicating with the main groove 22.

  The shoulder portion 3 is a portion on both outer sides in the tire width direction of the tread portion 2. Further, the sidewall portion 4 is exposed at the outermost side in the tire width direction of the pneumatic tire 1. The bead unit 5 includes a bead core 51 and a bead filler 52. The bead core 51 is formed by winding a bead wire, which is a steel wire, in a ring shape. The bead filler 52 is a rubber material arranged in a space formed by folding the end portion in the tire width direction of the carcass layer 6 outward in the tire width direction at the position of the bead core 51.

  The carcass layer 6 is configured such that each tire width direction end portion is folded back from the tire width direction inner side to the tire width direction outer side by a pair of bead cores 51 and is wound around in a toroidal shape in the tire circumferential direction. It is. The carcass layer 6 is formed by coating a plurality of carcass cords (not shown) arranged in parallel at an angle in the tire circumferential direction with an angle with respect to the tire circumferential direction being along the tire meridian direction. The carcass cord is made of steel or organic fiber (polyester, rayon, nylon, etc.).

  The belt layer 7 has, for example, a multilayer structure in which four layers of belts 71, 72, 73, and 74 are laminated, and is disposed on the outer side in the tire radial direction that is the outer periphery of the carcass layer 6 in the tread portion 2. It covers in the circumferential direction. The belts 71, 72, 73, and 74 are formed by coating a plurality of cords (not shown) arranged in parallel at a predetermined angle with respect to the tire circumferential direction with a coat rubber. The cord is made of steel or organic fiber (polyester, rayon, nylon, etc.).

  FIG. 1 shows a heavy duty pneumatic tire. Not only this but the pneumatic tire of this Embodiment may be a pneumatic tire for passenger cars.

  FIG. 2 is a partial external view of the pneumatic tire according to the present embodiment as viewed from the tire width direction. As shown in FIG. 2, the pneumatic tire 1 configured as described above has a plurality of concave portions 10 that are recessed from the surface of the tire side portion S in at least one tire side portion S.

  Here, the tire side portion S in FIG. 1 refers to a surface that is uniformly continuous from the ground contact end T of the tread portion 2 to the outer side in the tire width direction and from the rim check line L to the outer side in the tire radial direction. Further, the ground contact T is a tread surface 21 of the tread portion 2 of the pneumatic tire 1 when the pneumatic tire 1 is assembled on a regular rim and filled with a regular internal pressure and 70% of the regular load is applied. In the region where the road contacts the road surface, it means both outermost ends in the tire width direction and continues in the tire circumferential direction. The rim check line L is a line for confirming whether or not the tire rim is assembled normally. Generally, on the front side surface of the bead portion 5, the rim check line L is outside the rim flange in the tire radial direction. However, it is shown as an annular convex line that continues in the tire circumferential direction along the portion that is in the vicinity of the rim flange.

  The regular rim is “standard rim” defined by JATMA, “Design Rim” defined by TRA, or “Measuring Rim” defined by ETRTO. The normal internal pressure is “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The normal load is “maximum load capacity” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO.

  In the recess 10, the opening shape of the opening that opens on the surface of the tire side portion S is formed in a circular shape, an elliptical shape, an oval shape, a polygonal shape, or the like (shown as a circular opening shape in FIG. 2). ). If there are corners in the opening shape, stress concentration may occur and cut resistance may be reduced. To suppress stress concentration, the opening shape should be circular, elliptical, or oval, or the corners may be circular arcs. It is preferable to use a shape or a chamfered shape. In addition, the recess 10 is formed in a semicircular shape, a semi-elliptical shape, a semi-elliptical shape, a mortar shape, a rectangular shape, or the like. If there are corners in the cross-sectional shape, stress concentration may occur. To suppress stress concentration, the cross-sectional shape should be semicircular, semi-elliptical, semi-ellipsoidal, or the corners may be arc-shaped or chamfered. A shape is preferable.

  Moreover, the recessed part 10 is arrange | positioned at equal intervals by the tire circumferential direction and a tire radial direction, as shown in FIG. 2, and may be arrange | positioned along a tire radial direction. Moreover, the recessed part 10 may be arrange | positioned by mixing the thing from which opening shape and cross-sectional shape differ. Moreover, the recessed part 10 may be arrange | positioned at zigzag form, and may be arrange | positioned on the basis of a square or a triangle.

  In addition, the recess 10 may be formed as a corner (opening edge) as a boundary between the opening and the surface of the tire side portion S, but there is a risk of stress concentration if there is a corner, In order to suppress stress concentration, the portion is preferably formed in an arc shape or a chamfered shape.

  3 is a plan view of the recess viewed from the opening side, FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, and FIGS. 5 and 6 are side cross-sectional views of examples of the groove. 7 is a plan view of an example of the groove portion as viewed from the opening side.

  As shown in FIG. 3 and FIG. 4, at least one groove 11 is disposed on the inner surface of the recess 10. The groove 11 shown in FIGS. 3 and 4 is formed so as to form a circle along the shape of the opening of the recess 10 with respect to the recess 10 whose opening has a circular shape and an elliptical cross-sectional shape. And triple. And the groove part 11 is formed in the length L1 of the longitudinal direction more than twice with respect to the width W1 of the transversal direction.

  Here, the length L1 of the groove 11 is a length that passes through the position D of the maximum depth of the groove 11 as shown in FIGS. Further, the width W1 of the groove 11 is the maximum width of the groove 11 as shown in FIG. That is, the width W1 of the groove 11 may change as shown in FIG.

  In addition, the cross-sectional shape of the groove part 11 is formed in a semicircle shape, a semi-elliptical shape, a semi-oval shape, a mortar shape, or a rectangular shape. If there are corners in the cross-sectional shape, stress concentration may occur. To suppress the stress concentration, the cross-sectional shape is semicircular, semi-elliptical, semi-ellipsoidal, or the corners are arc-shaped or surfaces. It is preferable to make it a shape. In addition, the groove 11 may be formed with a corner (opening edge) as a boundary between the opening and the inner surface of the recess 10, but if there is a corner, stress concentration may occur, In order to suppress concentration, it is preferable that the portion is formed in an arc shape or a chamfered shape. In addition, as long as the length 11 of the groove portion 11 is more than twice the width W1, the opening shape of the opening portion that opens to the inner surface of the recess portion 10 is not limited, and an elliptical shape, an oval shape, etc. It may be formed. If there is a corner in the opening shape, stress concentration may occur. To suppress the stress concentration, the opening shape may be elliptical or oval, or the corner may be arc or chamfered. preferable.

  Here, it supplements about the form of the recessed part 10 or the groove part 11. FIG. FIGS. 8 and 9 are plan views of the recesses of another example as viewed from the opening side, FIGS. 10 to 13 are side sectional views of the recesses of the other examples, and FIGS. It is the top view which looked at the recessed part of the other example from the opening part side.

  In FIG. 8, the recess 10 is formed in an elliptical shape, and the groove 11 is formed in an elliptical shape along the shape of the opening of the recess 10 and is formed in a triple. Has been. In FIG. 9, the concave portion 10 is formed such that the opening shape of the opening portion is rectangular (rectangular shape), and the groove portion 11 has a rectangular shape (rectangular shape) along the shape of the opening portion of the concave portion 10. And is formed in a triple. In addition, the groove part 11 may be formed intermittently in FIG. 8 and FIG.

  In FIG. 10, the recess 10 has a semi-elliptical cross section, and the groove 11 has a triangular cross section. In FIG. 11, the recess 10 has a rectangular cross-sectional shape, and the groove 11 has a semicircular cross-sectional shape. In FIG. 12, the recess 10 has a trapezoidal cross section, and the groove 11 has a semicircular cross section. In FIG. 13, the recess 10 has a triangular cross-sectional shape, and the groove 11 has a semicircular cross-sectional shape.

  In FIG. 14, the concave portion 10 is formed such that the opening shape of the opening portion is circular, and one groove portion 11 is formed so as to form a spiral shape along the shape of the opening portion of the concave portion 10. In FIG. 15, the recess 10 is formed such that the opening shape of the opening is circular, and the eight grooves 11 are formed so as to intersect with each other so as to pass through the center of the recess 10. . In FIG. 16, the recess 10 is formed so that the opening shape of the opening is circular, and two grooves 11 are formed in a C shape along the shape of the opening of the recess 10. . Moreover, in FIG. 17, the recessed part 10 is formed in the circular opening shape of the opening part, and the five groove parts 11 are provided linearly and in parallel. In addition, the groove part 11 may be formed intermittently in FIGS.

  As described above, in the pneumatic tire 1 of the present embodiment, a plurality of recesses 10 are disposed in at least one tire side portion S, and at least one groove portion 11 is disposed on the inner surface of the recess 10. The groove 11 is formed such that the length L1 in the longitudinal direction is more than twice the width W1 in the short direction.

  According to the pneumatic tire 1, the surface area of the recess 10 is increased by the groove portion 11, so that the cooling efficiency of the tire side portion S is improved. As a result, the heat dissipation of the tire side portion S is improved, and the durability can be improved. When the relationship between the length L1 and the width W1 of the groove 11 is less than twice, the groove depth is increased in order to increase the surface area of the recess 10 equivalent to twice or more, and stress is applied to the groove 11. Concentration may occur and cut resistance may be reduced. According to the pneumatic tire 1 of the present embodiment, since the length L1 of the groove 11 is formed to be twice or more than the width W1, it is possible to suppress a reduction in cut resistance.

  Moreover, in the pneumatic tire 1 of the present embodiment, it is preferable that the groove portion 11 increases the surface area in the concave portion 10 in a range of 10 [%] to 75 [%]. For example, as shown in a partial sectional side view of the recess in FIG. 18, the recess 10 has a circular opening shape (see FIG. 3) and a semicircular cross-sectional shape. Further, in FIG. 18, the groove portions 11 are formed in multiple circles along the opening shape of the recess 10 (see FIG. 3), and the cross-sectional shape forms a part of a circle. FIG. 18A shows a form in which the surface area in the recess 10 is increased by 10 [%] with respect to the form without the groove 11. FIG. 18B shows a form in which the surface area in the recess 10 is increased by 30 [%] with respect to the form without the groove 11. FIG. 18C shows a form in which the surface area in the recess 10 is increased by 50 [%] with respect to the form without the groove 11. FIG. 18D shows a form in which the surface area in the recess 10 is increased by 75 [%] with respect to the form without the groove 11.

  If the increasing rate of the surface area in the recess 10 is 10% or more, it is possible to sufficiently obtain a cooling effect for improving durability. On the other hand, when the increase rate of the surface area in the recess 10 is 75% or less, it is possible to suppress the situation where the cut resistance is reduced by suppressing the stress concentration in the groove 11. In addition, it is preferable that the opening part of the recessed part 10 and the opening part of the groove part 11 do not overlap (do not coincide) in order to suppress the situation where the cut resistance is lowered. In addition, in order to further suppress the situation where the stress concentration in the groove portion 11 is further suppressed and the cut resistance is lowered, the groove portion 11 increases the surface area in the concave portion 10 in a range of 25% to 50%. It is preferable.

  In the pneumatic tire 1 of the present embodiment, the groove 11 has a width W1 in the short direction of 0.02 ≦ W1 / W2 ≦ 0 with respect to the maximum opening width W2 of the recess 10 (see FIG. 4). It is preferably formed in the range of .50.

  If the width W1 of the groove 11 is 0.02 or more with respect to the maximum opening width W2 of the recess 10, it is possible to sufficiently obtain a cooling effect for improving the durability. On the other hand, when the width W1 of the groove portion 11 is 0.50 or less with respect to the maximum opening width W2 of the concave portion 10, it is possible to suppress the situation where the stress resistance to the groove portion 11 is suppressed and the cut resistance is lowered. In order to obtain a sufficient cooling effect for improving the durability, the groove 11 is formed in a range where the width W1 is 0.05 ≦ W1 / W2 ≦ 0.20 with respect to the opening width W2 of the recess 10. It is preferable.

  Moreover, in the pneumatic tire 1 of the present embodiment, it is preferable that the opening of the recess 10 is formed in a circular shape or an elliptical shape.

  If the opening of the recess 10 has no corners, it is possible to avoid the concentration of stress on the corners and suppress the situation where the cut resistance is lowered. Moreover, since the diameter of the opening is uniform, such as a circular shape, the stress concentration in the radial direction can be evenly distributed, so it is possible to further suppress the situation where the cut resistance decreases. It is. In addition, even if the opening portion has a polygonal shape and the corner portion has a circular arc shape, the stress resistance to the corner is avoided and the cut resistance is reduced. It is possible to suppress the situation. Moreover, if it is a regular polygon, since the diameter of an opening part will become a substantially uniform form and the stress concentration in radial direction can be disperse | distributed uniformly, it can suppress the situation where cut resistance falls. It is.

  In the pneumatic tire 1 according to the present embodiment, the groove 11 is preferably arranged along the shape of the opening of the recess 10.

  When the groove 11 is arranged along the shape of the opening of the recess 10, local stress concentration on the groove 11 is suppressed, so that heat generation due to local deformation is suppressed and the cooling effect is improved. As a result, the heat dissipation of the tire side portion S is further improved, and the durability can be further improved.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 1, the recess 10 is arranged in a range H2 of 50 [%] of the tire cross-sectional height H1 on the outer side in the tire radial direction from the rim check line L. It is preferable.

  The tire cross-section height H1 is a tread that is the outermost tread in the tire radial direction from the tire radial inner end (rim base position) of the bead portion 5 when the rim is assembled to a normal rim and the internal pressure is 5% of the normal internal pressure. The height of the tire along the tire radial direction to the surface 21 (crown center). It is preferable to provide the recesses 10 around the cushion rubber around the rim where heat generation tends to be high in order to further improve the heat dissipation of the tire side portion S and further improve the durability. In order to further improve heat dissipation and durability, the recess 10 is preferably disposed within a range of 35 [%] of the tire cross-section height H1 on the outer side in the tire radial direction from the rim check line L. .

  Moreover, in the pneumatic tire 1 of the present embodiment, it is preferable that the maximum opening width W2 of the recess 10 is different at a position in the tire radial direction.

  Specifically, as shown in the explanatory diagram of the example of the arrangement of the recesses in the tire radial direction in FIG. 19, a plurality (four in FIG. 19) of the recesses 10 are gradually different in the opening width W2 in the tire radial direction. In the tire side portion S, in the tire radial direction, the rubber gauge is different (thickness of the rubber material), and the rubber gauge is relatively small (relatively heat generation) in the concave portion 10 where the rubber gauge is relatively large (relatively high heat generation). The opening width W <b> 2 is increased with respect to the concave portion 10 of the portion having a small amount). As described above, by disposing the concave portion 10 having the opening width W2 suitable for the portion where the heat generation is different, the heat dissipation of the tire side portion S is further improved, and the durability can be further improved. In addition, the opening width W2 of the concave portion 10 having a relatively small rubber gauge is made smaller than the concave portion 10 having a relatively large rubber gauge. For this reason, it is possible to suppress a decrease in tire rigidity by suppressing the rubber gauge from becoming smaller (thinner) than necessary.

  Moreover, in the pneumatic tire 1 of the present embodiment, it is preferable that the groove portion 11 has a width W1 in the short-side direction depending on the position of the recess 10 in the tire radial direction.

  Specifically, as shown in the explanatory diagram of the example of the arrangement of the concave portions in the tire radial direction in FIG. 20, a plurality of (four in FIG. 20) concave portions 10 having the same opening width are provided in the tire radial direction. Thus, the width W1 of the groove 11 is gradually different. In the tire side portion S, the rubber gauge is different in the tire radial direction, and the rubber gauge is relatively small (relatively heat generation) in the groove portion 11 where the rubber gauge is relatively large (relatively heat generation). The width W <b> 1 is increased with respect to the groove portion 11 of the portion with a small amount). As described above, by disposing the groove portion 11 having the width W1 suitable for the portion where the heat generation is different, the heat dissipation of the tire side portion S is further improved, and the durability can be further improved. In addition, the width W1 of the groove 11 having a relatively small rubber gauge is made smaller than that of the groove 11 having a relatively large rubber gauge. For this reason, it is possible to suppress a decrease in tire rigidity by suppressing the rubber gauge from becoming smaller (thinner) than necessary.

  Moreover, in the pneumatic tire 1 of the present embodiment, it is preferable that the recess 10 is disposed at least on the vehicle inner side when the vehicle is mounted.

  In this case, when the pneumatic tire 1 is mounted on a vehicle (not shown), the directions with respect to the inner side and the outer side of the vehicle are specified in the tire width direction. The designation of the direction is not clearly shown in the figure, but is indicated by, for example, an index provided on the sidewall portion 4. And when it mounts | wears with a vehicle, the side which faces the inner side of a vehicle is called vehicle inner side, and the side which faces the outer side of a vehicle is called vehicle outer side. In addition, designation | designated of a vehicle inner side and a vehicle outer side is not restricted to the case where it mounts | wears with a vehicle. For example, when the rim is assembled, the direction of the rim with respect to the inside and outside of the vehicle is determined in the tire width direction. For this reason, when the rim is assembled, the pneumatic tire 1 is designated with respect to the inner side (vehicle inner side) and the outer side (vehicle outer side) of the vehicle in the tire width direction.

  The tire side portion S on the inner side of the vehicle is a portion covered with the structure on the vehicle side, and the ambient temperature tends to be higher than that on the outer side of the vehicle, and thermal degradation is likely to occur. For this reason, by disposing the recess 10 on the inside of the vehicle, it is possible to improve the heat dissipation of the tire side portion S on the inside of the vehicle, suppress thermal degradation, and improve durability.

  Moreover, it is preferable that the pneumatic tire 1 of this Embodiment is applied to the heavy load pneumatic tire.

  In a heavy-duty pneumatic tire, since the rubber gauge of the tire side portion S is relatively large, the influence of heat generation is large, and durability is regarded as important. Therefore, by applying the pneumatic tire 1 of the present embodiment to a heavy duty pneumatic tire, it is possible to significantly obtain the effect of improving the heat dissipation of the tire side portion S and improving the durability.

  In this example, a durability performance test was performed on a plurality of types of pneumatic tires having different conditions (see FIGS. 21 and 22).

  As for the performance test, in FIG. 21, a drum tester having a drum diameter of 1701 [mm] in an environment in which a pneumatic tire having a tire size of 195 / 85R16 is assembled on a regular rim and the ambient temperature is controlled to be constant. Then, the internal pressure was inflated to 75 [%] of the normal internal pressure, the test was conducted at a speed of 81 [km / h], and the load was 150 [%] of the normal load until the pneumatic tire was damaged, The mileage when it was damaged was measured. In this durability test, index evaluation is performed using the conventional example as a reference (100). In this evaluation, the larger the value, the better the durability.

  Also, in the performance test, with respect to FIG. 22, a drum diameter 1701 [mm] in an environment in which a heavy-duty pneumatic tire having a tire size of 11R22.5 is assembled on a regular rim and the ambient temperature is controlled to be constant. The pneumatic tire for heavy loads was damaged when the internal pressure was inflated to 75% of the normal internal pressure, the speed was 45 km / h, and the load was 150% of the normal load. The test was conducted until the test was completed, and the distance traveled when it was damaged was measured. In this durability test, index evaluation is performed using the conventional example as a reference (100). In this evaluation, the larger the value, the better the durability.

  21 and 22, the pneumatic tires of Conventional Examples 1 and 2, Comparative Examples 1 and 2, and Examples 1 to 12 have a recess in the tire side portion. And the pneumatic tire of the prior art examples 1 and 2 does not have a groove part in the inner surface of a recessed part. Moreover, although the pneumatic tire of Comparative Examples 1 and 2 has a groove part, L1 / W1 is not in a specified range.

  On the other hand, the pneumatic tires of Examples 1 to 12 have a groove portion with L1 / W1 as a specified range. And as for the pneumatic tire of Example 1 (Example 7), the opening shape of a recessed part is a square. Moreover, as for the pneumatic tire of Example 2 (Example 8) and Example 3 (Example 9), a recessed part and a groove part are the forms which are shown in FIG. Moreover, as for the pneumatic tire of Example 4 (Example 10), a recessed part and a groove part are the forms which are shown in FIG. Moreover, as for the pneumatic tire of Example 5 (Example 11) and Example 6 (Example 12), a recessed part and a groove part are the forms which are shown in FIG.

  And as shown to the test result of FIG. 21 and FIG. 22, it turns out that the pneumatic tire of Example 1- Example 12 is excellent in durability, and the durability of a tire side part is improved.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 10 Concave part 11 Groove part L Rim check line S Tire side part T Grounding end L1 Length in the longitudinal direction of the groove part W1 Short width of the groove part W2 Maximum opening width of the concave part

Claims (9)

A plurality of recesses are disposed on at least one tire side portion, and at least one groove portion is disposed on the inner surface of the recess, and the groove portion has a length L1 in the longitudinal direction thereof and a short length thereof. A pneumatic tire characterized in that it is formed at least twice the width W1 in the hand direction and is arranged along the shape of the opening of the recess .   2. The pneumatic tire according to claim 1, wherein the groove portion increases a surface area in the concave portion in a range of 10 [%] to 75 [%]. The groove portion is formed such that a width W1 in a short side direction is 0.02 ≦ W1 / W2 < 0.50 with respect to a maximum opening width W2 of the concave portion. 2. The pneumatic tire according to 2.   The pneumatic tire according to any one of claims 1 to 3, wherein an opening of the recess is formed in a circular shape or an elliptical shape. The recess, the pneumatic tire according to any one of claims 1-4, characterized in that it is arranged from the rim check line in the range of 50 [%] of the tire section height in the tire radial direction outside . The pneumatic tire according to any one of claims 1 to 5 , wherein the concave portion has a maximum opening width W2 that is different at a position in a tire radial direction. The pneumatic tire according to any one of claims 1 to 6 , wherein the groove portion has a width W1 in a short side direction different depending on a position of the concave portion in a tire radial direction. The recess, the pneumatic tire according to any one of claims 1-7, characterized in that it is arranged inside the vehicle during at least the vehicle mounting. The pneumatic tire according to any one of claims 1 to 8 , wherein the pneumatic tire is applied to a heavy duty pneumatic tire.

Images