JP5828258B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that improves airflow around the tire.

  Conventionally, for example, in Patent Document 1, a plurality of protrusions extending in the tire radial direction are provided at predetermined intervals in the tire circumferential direction on a tire side portion (tire side surface) that is the inner side in the width direction of the vehicle when the vehicle is mounted, There has been disclosed a pneumatic tire in which a large number of recesses are provided in a tire side direction and a tire radial direction on a tire side portion which is an outer side in the width direction of the vehicle when the vehicle is mounted. In the vehicle mounted state, air flows uniformly rearward on the outer side in the width direction of the vehicle, but the inner side in the width direction of the vehicle is arranged in the tire house and other parts such as an axle are arranged around the vehicle. Therefore, the air flow is likely to be disturbed. Therefore, according to this pneumatic tire, the air flow promoting effect and the rectifying effect are obtained by the protrusion provided on the tire side portion which is the inner side in the width direction of the vehicle in which the air flow is likely to be disturbed, and further the outer side in the width direction of the vehicle The dents on the tire side that creates turbulent flow around the tire when the vehicle travels, and the low-pressure part that occurs behind the tire during travel reduces the drag that is pulled back, improving fuel efficiency. ing.

JP 2010-260378 A

  Like the pneumatic tire described in Patent Document 1 described above, when a protrusion is provided on the tire side portion that is the inner side in the width direction of the vehicle when the vehicle is mounted, the effect of reducing aerodynamic resistance is great, but the vehicle and the tire It is necessary to narrow the tire width so as not to hinder the flow of air flowing in a narrow space. Moreover, because the rubber gauge at the location where the protrusion is provided is thicker than other locations, heat generation within the tire tends to accumulate, and the volume of rubber increases, so the amount of heat generation tends to increase and the durability of the tire May decrease. Furthermore, as described above, the inner side in the width direction of the vehicle is disposed in the tire house, and other parts such as an axle are disposed in the periphery, so that the exhaust heat of the engine and brakes flowing inside the vehicle has been obtained. The air tends to increase the temperature of the rubber of the tire, and the durability of the tire may be reduced.

  The present invention has been made in view of the above, and provides a pneumatic tire that improves the air flow around the tire and is not limited by the tire width and can suppress an increase in temperature. Objective.

  In order to solve the above-described problems and achieve the object, the pneumatic tire according to the present invention has a large number of pneumatic tires on the tire side portion on the outer side of the vehicle in a pneumatic tire in which the orientation of the inside and outside of the vehicle is specified when the vehicle is mounted. It is provided with the provided convex part and the recessed part provided many in the tire side part used as a vehicle inside.

  According to this pneumatic tire, the air flow from the front side to the rear side of the vehicle causes the air passing between the pneumatic tire and the vehicle to be turbulent by the concave portion inside the pneumatic tire. Further, even on the vehicle outer side of the pneumatic tire, the air passing through the vehicle outer side is made turbulent by the convex portion. For this reason, a turbulent boundary layer is generated around the pneumatic tire, and on the vehicle inner side, the expansion of air that escapes to the vehicle outer side behind the vehicle is suppressed, and on the vehicle outer side, the vehicle passes through the vehicle outer side of the pneumatic tire. Swelling of air is suppressed. As a result, the spread of the passing air can be suppressed, the air resistance of the vehicle can be reduced, and the fuel consumption can be further improved. In addition, according to this pneumatic tire, a convex portion that turbulent air is provided on the outside of the vehicle without being limited by the tire width, and heat is generated by reducing the rubber volume by the concave portion on the inside of the vehicle. It is possible to improve exhaust heat performance by turbulent air flow while suppressing tire heat generation and temperature rise.

  In the pneumatic tire of the present invention, the convex portions are formed in a longitudinal shape in the tire radial direction and are arranged at intervals in the tire circumferential direction.

  According to this pneumatic tire, air is made more turbulent by the protrusions formed in the tire radial direction, and the air is efficiently turbulent by being arranged in the circumferential direction. As a result, the effect of air turbulence can be remarkably obtained.

  In the pneumatic tire of the present invention, the convex portion has a height protruding from the tire side portion of 0.5 [mm] or more and 10 [mm] or less.

  When the height of the convex portion is less than 0.5 [mm], since the range in which the convex portion contacts the air flow is small, the air flow behind the convex portion is not easily turbulent, and the air resistance of the vehicle The effect of reducing becomes smaller. In addition, when the height of the convex portion exceeds 10 [mm], since the range in which the convex portion contacts the air flow is large, the air flow behind the convex portion tends to swell, and the air resistance of the vehicle Reduction effect is reduced. In this regard, according to the pneumatic tire of the present invention, since the convex portion appropriately contacts the air flow, the air flow behind the convex portion is turbulent and the swelling of the air is reduced. The effect of reducing air resistance can be obtained remarkably.

  In the pneumatic tire of the present invention, the concave portion has a minimum distance of 0.5 [mm] or more between a bottom portion and a carcass cord.

  In order to make air turbulent and reduce heat generation, it is preferable to make the depth of the recess as deep as possible. However, if the bottom of the recess is too close to the carcass cord, the rubber volume between them becomes thin and the durability decreases. Is concerned. Therefore, the shortest distance between the bottom of the concave portion and the carcass cord is preferably 0.5 [mm] or more from the viewpoint of maintaining durability.

  Further, the pneumatic tire of the present invention is a ratio PH of the area PD not having the convex portion with respect to the area PH occupied by the convex portion in the range where the convex portion of the tire side portion on the vehicle outer side is provided. / PD is 0.05 or more and 0.45 or less.

  When PH / PD is less than 0.05, the number of protrusions is relatively small in the range where the protrusions are provided, so that the air flow is not easily turbulent and the effect of reducing the air resistance of the vehicle is reduced. . In addition, when PH / PD exceeds 0.45, since a relatively large number of convex portions are provided in the range where the convex portions are provided, the tire side portion has a thick rubber gauge portion, and the pneumatic tire rolls. Resistance tends to increase. In this regard, according to the pneumatic tire of the present invention, by making PH / PD in the range of 0.05 to 0.45, the rolling resistance of the pneumatic tire is reduced and the air flow is turbulent. By doing so, the swelling of the air is reduced, so that the effect of reducing the air resistance of the vehicle can be significantly obtained.

  The pneumatic tire of the present invention has a ratio DH / DD which is a ratio of the area DD not having the recess to the area DH occupied by the recess in the range where the recess on the tire side portion which is the inside of the vehicle is provided. 0.1 or more and 0.7 or less.

  When DH / DD is less than 0.1, since the number of recesses is relatively small in the range where the recesses are provided, the air flow is hardly turbulent and the effect of reducing heat generation is reduced. In addition, when DH / DD exceeds 0.7, since a relatively large number of recesses are provided in the range where the recesses are provided, the tire side portion has a thin rubber gauge, and the tire rigidity tends to decrease. Become. In this regard, according to the pneumatic tire of the present invention, by setting DH / DD in the range of 0.1 to 0.7, the generation of heat is suppressed by reducing the rubber volume while suppressing the decrease in tire rigidity. On the other hand, by making the air flow turbulent, exhaust heat can be improved, and the effect of suppressing tire heat generation and temperature rise can be significantly obtained.

  The pneumatic tire according to the present invention is characterized in that the projection and the recess overlap when the projection and the recess are projected onto a tire equatorial plane.

  In the portion provided with the convex portion, the tire rigidity tends to increase as the rubber gauge increases. On the other hand, in the portion provided with the recess, the tire rigidity tends to decrease due to the decrease in the rubber gauge. Therefore, according to the pneumatic tire of the present invention, the rigidity increasing portion and the decreasing portion are overlapped in the tire width direction on the basis of the tire equator plane, thereby suppressing the change in rigidity of the entire tire, and at the time of rotation. Can be reduced.

  The pneumatic tire according to the present invention can improve the air flow around the tire and can suppress an increase in temperature without being limited by the tire width.

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 as viewed from the outside of the vehicle. FIG. 3 is a partial external view of the pneumatic tire according to the embodiment of the present invention as viewed from the inside of the vehicle. FIG. 4 is an explanatory diagram showing the air flow in the vicinity of a general pneumatic tire. FIG. 5 is an explanatory view showing the air flow in the vicinity of the pneumatic tire according to the embodiment of the present invention. FIG. 6 is an explanatory diagram showing the flow of air in the vicinity of a convex portion having a height not exceeding a specified range. FIG. 7 is an explanatory diagram showing the air flow in the vicinity of the convex portion having a height not less than a specified range. FIG. 8 is an explanatory diagram showing the air flow in the vicinity of the convex portion having a height within a specified range. FIG. 9 is an explanatory diagram showing an area occupied by the convex portion and an area not having the convex portion in the tire side portion. FIG. 10 is an explanatory diagram showing an area occupied by the recesses and an area not having the recesses in the tire side portion. FIG. 11 is an explanatory diagram in which convex portions and concave portions are projected on the tire equatorial plane. FIG. 12 is an explanatory diagram in which convex portions and concave portions are projected on the tire equatorial plane. FIG. 13 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 1 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 rotation axis of the pneumatic tire 1 and 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, the pneumatic tire 1 according to the present embodiment includes a tread portion 2, shoulder portions 3 on both sides thereof, and a sidewall portion 4 and a bead portion 5 that are sequentially continuous from the shoulder portions 3. ing. The pneumatic tire 1 includes a carcass layer 6, a belt layer 7, and a belt reinforcing layer 8.

  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 disposed in a space formed by folding the end portion in the tire width direction of the carcass layer 6 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 organic fibers (polyester, rayon, nylon, etc.). The carcass layer 6 is provided as at least one layer.

  The belt layer 7 has a multilayer structure in which at least two belts 71 and 72 are laminated, and is disposed on the outer side in the tire radial direction which is the outer periphery of the carcass layer 6 in the tread portion 2 and covers the carcass layer 6 in the tire circumferential direction. It is. The belts 71 and 72 are made by coating a plurality of cords (not shown) arranged in parallel at a predetermined angle (for example, 20 degrees to 30 degrees) with a coat rubber with respect to the tire circumferential direction. The cord is made of steel or organic fiber (polyester, rayon, nylon, etc.). Further, the overlapping belts 71 and 72 are arranged so that the cords intersect each other.

  The belt reinforcing layer 8 is disposed on the outer side in the tire radial direction which is the outer periphery of the belt layer 7 and covers the belt layer 7 in the tire circumferential direction. The belt reinforcing layer 8 is formed by coating a plurality of cords (not shown) arranged substantially parallel (± 5 degrees) in the tire circumferential direction and in the tire width direction with a coat rubber. The cord is made of steel or organic fiber (polyester, rayon, nylon, etc.). The belt reinforcing layer 8 shown in FIG. 1 is disposed so as to cover the end of the belt layer 7 in the tire width direction. The configuration of the belt reinforcing layer 8 is not limited to the above, and is not clearly shown in the figure. However, the belt reinforcing layer 8 is configured to cover the entire belt layer 7 or has two reinforcing layers, for example, on the inner side in the tire radial direction. The reinforcing layer is formed so as to be larger in the tire width direction than the belt layer 7 and is disposed so as to cover the entire belt layer 7, and the reinforcing layer on the outer side in the tire radial direction is disposed so as to cover only the end portion in the tire width direction of the belt layer 7. Alternatively, for example, a configuration in which two reinforcing layers are provided and each reinforcing layer is disposed so as to cover only the end portion in the tire width direction of the belt layer 7 may be employed. That is, the belt reinforcing layer 8 overlaps at least the end portion in the tire width direction of the belt layer 7. The belt reinforcing layer 8 is provided by winding a strip-shaped strip material (for example, a width of 10 [mm]) in the tire circumferential direction.

  Moreover, when the pneumatic tire 1 of this Embodiment is mounted | worn with a vehicle (not shown), the direction with respect to the inner side and the outer side of a vehicle is designated 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. Hereinafter, the side facing the inner side of the vehicle when mounted on the vehicle is referred to as the inner side of the vehicle, and the side facing the outer side of the vehicle is referred to as the outer side of the vehicle. 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.

  FIG. 2 is a partial external view of the pneumatic tire according to the present embodiment as viewed from the outside of the vehicle. As shown in FIG. 2, the pneumatic tire 1 configured as described above is provided with a large number of convex portions 9 that protrude from the surface of the tire side portion S to the outside of the tire in the tire side portion S outside the vehicle. ing.

  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, a maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO.

  For example, as shown in FIG. 2, the convex portion 9 is a rubber material formed in the tire radial direction in the range of the tire side portion S (even if the rubber material constituting the tire side portion S is The rubber material may be a rubber material different from the rubber material), and is disposed at a predetermined interval in the tire circumferential direction. The convex portion 9 has a cross-sectional shape intersecting in the longitudinal direction formed in a semicircular shape, a semi-elliptical shape, a semi-ellipse shape, a triangular shape, a quadrangular shape, a trapezoidal shape, or a cross-sectional outer shape having an arc. Has been. Moreover, the convex part 9 may be formed in a cross-sectional shape uniformly in the longitudinal direction, or may be formed by changing the cross-sectional shape in the longitudinal direction. Further, the end of the convex portion 9 may protrude smoothly from the surface of the tire side portion S, or may protrude from the surface of the tire side portion S. In FIG. 2, the convex portion 9 is formed as one protrusion in the tire radial direction in the range of the tire side portion S, but may be divided into a plurality of portions in the longitudinal direction. When the convex part 9 is divided, another convex part 9 arranged in the tire circumferential direction may be arranged so as to overlap with a divided part of the convex part 9 adjacent in the tire circumferential direction in the tire circumferential direction. Good. Moreover, although the convex part 9 is formed in linear form in FIG. 2, you may be bent or curved on the way, and the said bending | flexion and curve may be plural. Moreover, although the convex part 9 is formed in the tire radial direction in FIG. 2, it may be inclined and formed with respect to the tire radial direction.

  FIG. 3 is a partial external view of the pneumatic tire according to the present embodiment as viewed from the inside of the vehicle. As shown in FIG. 3, the pneumatic tire 1 configured as described above is provided with a large number of recesses 10 that are recessed from the surface of the tire side portion S to the inside of the tire in the tire side portion S inside the vehicle. Yes.

  For example, as shown in FIG. 3, the recesses 10 are arranged at predetermined intervals in the tire radial direction and the tire circumferential direction in the range of the tire side portion S. The recess 10 has an opening shape that opens on the surface of the tire side portion S in a circular shape, an elliptical shape, an oval shape, a polygonal shape, or the like. 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. In FIG. 3, the recesses 10 are arranged in a staggered manner in the tire radial direction and the tire circumferential direction. Good.

  As described above, the pneumatic tire 1 of the present embodiment is directed to the inside and outside of the vehicle when the vehicle is mounted, and includes a plurality of convex portions 9 provided on the tire side portion S that is the outside of the vehicle, and the inside of the vehicle. A plurality of recesses 10 provided in the tire side portion S.

  As shown in FIG. 4 showing the flow of air in the vicinity of a general pneumatic tire, the pneumatic tire 101 having no convex portion 9 or concave portion 10 is in front of the vehicle in the direction of arrow A in FIG. An air flow is generated from the rear side toward the rear side. This air flow passes between the pneumatic tire 101 and the vehicle 100 so as to swell toward the outside of the vehicle inside the pneumatic tire 101. Moreover, on the vehicle outer side of the pneumatic tire 101, the air flow passes so as to swell toward the vehicle outer side. These air flows become vehicle resistance.

  On the other hand, as shown in FIG. 5 showing the air flow in the vicinity of the pneumatic tire according to the present embodiment, the pneumatic tire 1 having many concave portions 10 on the vehicle inner side and many convex portions 9 on the vehicle outer side. According to the above, the air flow A from the front side to the rear side of the vehicle causes the air passing between the pneumatic tire 1 and the vehicle 100 to be turbulent by the recess 10 inside the pneumatic tire 1. Further, even on the vehicle outer side of the pneumatic tire 1, the air passing through the vehicle outer side is turbulent by the convex portion 9. For this reason, a turbulent boundary layer is generated around the pneumatic tire 1, and on the vehicle inner side, the expansion of air that escapes to the vehicle outer side behind the vehicle is suppressed, and on the vehicle outer side, the vehicle outer side of the pneumatic tire 1 is restricted. Swelling of the passing air is suppressed. As a result, the spread of the passing air is suppressed, the air resistance of the vehicle is reduced, and the fuel consumption can be further improved.

  Moreover, according to the pneumatic tire 1 of the present embodiment, the convex portion 9 is provided on the vehicle outer side and the concave portion 10 is provided on the vehicle inner side, so that the air is disturbed on the vehicle outer side without being limited by the tire width. Protrusions 9 to be fluidized are provided, and on the inside of the vehicle, the rubber volume is reduced by the recesses 10, so that heat generation is suppressed by turbulent air flow while suppressing heat generation, and tire heat generation and temperature increase are achieved. It becomes possible to suppress.

  Further, in the pneumatic tire 1 of the present embodiment, the convex portions 9 are formed in a longitudinal shape in the tire radial direction and are arranged at intervals in the tire circumferential direction.

  According to the pneumatic tire 1, the air is more turbulent by the protrusions formed in the tire radial direction, and the air is efficiently turbulent by being arranged in the tire circumferential direction. As a result, the effect of turbulence of air can be remarkably obtained.

  Moreover, in the pneumatic tire 1 of the present embodiment, the height of the protruding portion 9 protruding from the tire side portion S is 0.5 [mm] or more and 10 [mm] or less.

  When the height of the convex portion 9 is less than 0.5 [mm], the convex portion 9 has an air flow as shown in an explanatory diagram showing the flow of air in the vicinity of the convex portion having a height not more than the specified range in FIG. Therefore, the air flow behind the convex portion 9 is not easily turbulent and the effect of reducing the air resistance of the vehicle is reduced. In addition, when the height of the convex portion 9 exceeds 10 [mm], the convex portion 9 has an air flow as shown in the explanatory diagram showing the flow of air in the vicinity of the convex portion having a height equal to or higher than the specified range in FIG. Therefore, the air flow behind the convex portion 9 tends to swell, and the effect of reducing the air resistance of the vehicle is reduced. In this regard, according to the pneumatic tire 1 of the present embodiment, as shown in the explanatory view showing the flow of air in the vicinity of the convex portion having a height within the specified range in FIG. By contacting, the air flow behind the convex portion 9 becomes turbulent and air bulge is reduced, so that the effect of reducing the air resistance of the vehicle can be remarkably obtained.

  Moreover, in the pneumatic tire 1 of the present embodiment, the recess 10 has a shortest distance between its bottom and the carcass cord of 0.5 [mm] or more.

  In order to make air turbulent and reduce heat generation, it is preferable to make the depth of the recess 10 as deep as possible. However, if the bottom of the recess 10 is too close to the carcass cord of the carcass layer 6, the rubber volume between them is reduced. There is concern about the decrease in durability due to thinning. Therefore, the shortest distance between the bottom of the recess 10 and the carcass cord is preferably 0.5 [mm] or more in order to maintain durability. In addition, it is preferable that the minimum depth of the recessed part 10 is 0.3 [mm] or more in order to make air turbulent.

  Further, the pneumatic tire 1 of the present embodiment has an area PD that does not have the convex portion 9 with respect to the area PH occupied by the convex portion 9 in the range in which the convex portion 9 of the tire side portion S that is the vehicle outer side is provided. The ratio PH / PD is 0.05 or more and 0.45 or less.

  Here, FIG. 9 is an explanatory diagram showing an area occupied by the convex portion and an area not having the convex portion in the tire side portion. The area PH occupied by the convex portion 9 is the area of the root portion of the convex portion 9 on the surface of the tire side portion S, as shown in FIG. On the other hand, as shown in FIG. 9, the area PD that does not have the convex portion 9 is an imaginary line that connects the tire radial direction outermost portions of the root portion of each convex portion 9, and the root portion of each convex portion 9. In an area surrounded by a virtual line connecting the innermost portions in the tire radial direction, the area excluding the area PH. Further, the area PH and area PD are determined when the pneumatic tire 1 is assembled with a normal rim and filled with a normal internal pressure and is not loaded (no load).

  When PH / PD is less than 0.05, since the projections 9 are provided in a relatively small amount in the range in which the projections 9 are provided, the air flow is not easily turbulent and the effect of reducing the air resistance of the vehicle is achieved. Get smaller. Moreover, when PH / PD exceeds 0.45, since the convex part 9 will be provided comparatively many in the range which provided the convex part 9, the part with the thick rubber gauge of the tire side part S will increase, and it will be pneumatic The rolling resistance of the tire 1 tends to increase. In this regard, according to the pneumatic tire 1 of the present embodiment, the rolling resistance of the pneumatic tire 1 is reduced and the flow of air by setting PH / PD in the range of 0.05 to 0.45. Since the air bulge is reduced by making the air turbulent, the effect of reducing the air resistance of the vehicle can be remarkably obtained.

  Further, the pneumatic tire 1 of the present embodiment has a ratio of the area DD having no recess 10 to the area DH occupied by the recess 10 in a range where the recess 10 of the tire side portion S which is the inside of the vehicle is provided. DH / DD is 0.1 or more and 0.7 or less.

  Here, FIG. 10 is explanatory drawing which shows the area which a recessed part occupies in a tire side part, and the area which does not have a recessed part. The area DH occupied by the recess 10 is the area of the opening of the recess 10 on the surface of the tire side S, as shown in FIG. On the other hand, as shown in FIG. 10, the area DD not having the recesses 10 is an imaginary line connecting the tire radial direction outermost portions of the opening portions of the recesses 10 and the tire radial direction of the opening portions of the recesses 10. In an area surrounded by an imaginary line connecting innermost portions, the area excluding the area DH. Further, the area DH and the area DD are when the pneumatic tire 1 is assembled on a regular rim and filled with a regular internal pressure and is unloaded (no load).

  When DH / DD is less than 0.1, since the recesses 10 are provided in a relatively small amount in the range where the recesses 10 are provided, the air flow is hardly turbulent and the effect of reducing heat generation is reduced. In addition, when DH / DD exceeds 0.7, the recesses 10 are provided in a relatively large number in the range where the recesses 10 are provided, so that the tire side portion S has a thin portion of the rubber gauge, and the tire rigidity is reduced. Will tend to. In this regard, according to the pneumatic tire 1 of the present embodiment, by setting DH / DD in the range of 0.1 to 0.7, heat is generated by reducing the rubber volume while suppressing a decrease in tire rigidity. It is possible to improve the exhaust heat performance by making the air flow turbulent while suppressing the tire, and to obtain the effect of suppressing the tire heat generation and the temperature rise.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 11 in which the convex portion and the concave portion are projected on the tire equator plane, when the convex portion 9 and the concave portion 10 are projected on the tire equator plane CL, the convex portion 9 And the recess 10 overlap.

  In the portion provided with the convex portion 9, the tire rigidity tends to increase as the rubber gauge increases. On the other hand, in the portion where the recess 10 is provided, the tire rigidity tends to decrease due to a decrease in the rubber gauge. Therefore, according to this pneumatic tire 1, by changing the rigidity increasing portion and the decreasing portion in the tire width direction on the basis of the tire equatorial plane CL, a change in rigidity of the entire tire is suppressed, and at the time of rotation It becomes possible to reduce the vibration. Note that it is not necessary for all the convex portions 9 and the concave portions 10 to overlap, and this effect can be obtained if at least 50% or more of the convex portions 9 and the concave portions 10 overlap.

  In addition, the pneumatic tire 1 mentioned above is applied not only for passenger cars but also for heavy loads and run-flat pneumatic tires. In the case of a passenger car, the effect is obtained as described above. Further, in the case of heavy loads, particularly at a heavy load, the convex portion 9 suppresses the deformation of the tire when the tire side portion S is compressed, and the concave portion 10 increases the temperature when the tire side portion S is compressed. Suppress and improve durability. Also in the case of run-flat, particularly during puncture, the convex portion 9 further suppresses the deformation of the tire when the tire side portion S is compressed, and the concave portion 10 increases the temperature when the tire side portion S is compressed. To improve durability.

  In this example, performance tests on the fuel efficiency improvement rate and the temperature increase rate were performed for a plurality of types of pneumatic tires with different conditions (see FIG. 13).

  In this performance test, a pneumatic tire having a tire size of 185 / 65R15 was assembled on a regular rim, filled with a regular internal pressure, and mounted on a small front wheel drive vehicle with a displacement of 1500 [cc] + motor assist.

  As a method for evaluating the fuel efficiency improvement rate, the fuel efficiency was measured when the test vehicle traveled 50 laps at 100 [km / h] at a speed of 100 [km / h] on a test course of 2 [km] on the entire circumference. Based on this measurement result, the fuel efficiency improvement rate is index-evaluated using the conventional pneumatic tire as a reference (100.0). This index evaluation shows that the fuel efficiency improvement rate is improved as the value increases.

  In addition, the temperature rise rate evaluation method is that the temperature rise rate of the tire surface when traveling 50 laps at a speed of 100 [km / h] on a test course of 2 [km] on the entire circumference is infrared radiation. It was measured with a thermometer. And based on this measurement result, the pneumatic tire of the conventional example is used as a reference (100), and the temperature rise rate is index-evaluated. This index evaluation shows that the temperature increase rate is reduced as the numerical value is smaller.

  In FIG. 13, the conventional pneumatic tire does not have a convex portion and a concave portion. Moreover, the pneumatic tires of Comparative Examples 1 to 3 have a convex portion on the inner side of the vehicle and a concave portion on the outer side of the vehicle. On the other hand, in FIG. 13, the pneumatic tires of Examples 1 to 10 have convex portions on the vehicle outer side and concave portions on the vehicle inner side.

  And as shown to the test result of FIG. 13, it turns out that the pneumatic tire of Example 1- Example 10 improves the air flow around a tire, improves fuel consumption, and suppresses the temperature rise. .

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 9 Convex part 10 Concave part S Tire side part CL Tire equatorial plane

Claims (6)

For pneumatic tires that have a specified orientation inside and outside the vehicle when mounted on the vehicle,
A plurality of convex portions provided on the tire side portion on the vehicle outer side;
A plurality of recesses provided in the tire side portion which is the inside of the vehicle;
With
PH / PD, which is the ratio of the area PD not having the convex portion to the area PH occupied by the convex portion in the range where the convex portion of the tire side portion on the vehicle outer side is provided, is 0.05 or more and 0.00. air-filled tire, characterized in that it is 45 or less. For pneumatic tires that have a specified orientation inside and outside the vehicle when mounted on the vehicle,
A plurality of convex portions provided on the tire side portion on the vehicle outer side;
A plurality of recesses provided in the tire side portion which is the inside of the vehicle;
With
DH / DD, which is the ratio of the area DD not having the recess to the area DH occupied by the recess, is 0.1 to 0.7 in the range where the recess is provided in the tire side portion which is the inside of the vehicle. air-filled tire it said that there. For pneumatic tires that have a specified orientation inside and outside the vehicle when mounted on the vehicle,
A plurality of convex portions provided on the tire side portion on the vehicle outer side;
A plurality of recesses provided in the tire side portion which is the inside of the vehicle;
With
If the convex portion and the concave portion is projected to the tire equatorial plane, air-filled tire you, characterized in that said said protrusion recess overlap. The pneumatic tire according to any one of claims 1 to 3, wherein the convex portions are formed in a longitudinal shape in the tire radial direction and are arranged at intervals in the tire circumferential direction. The air according to any one of claims 1 to 4 , wherein a height of the convex portion protruding from the tire side portion is 0.5 [mm] or more and 10 [mm] or less. Enter tire. The pneumatic tire according to any one of claims 1 to 5 , wherein the concave portion has a shortest distance of 0.5 [mm] or more between a bottom portion and a carcass cord.

Images