JP2016210388A - Pneumatic tire for passenger car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for further saving weight than ever, in a pneumatic tire for a passenger car, in which a steel cord is used within a belt structure.SOLUTION: A pneumatic tire for a passenger car includes a circumferential belt 3 of at least one layer, which is made of a rubber-covered layer of a steel cord wound around a crown part in the circumferential direction of the tire in a sequential order from the radial inside of the tire, and inclined belts 4a and 4b of at least one layer, which is made of a rubber-covered layer of an organic fiber cord arranged in a direction making an angle of ±20-60° with respect to the circumferential direction of the tire.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire for passenger cars (hereinafter, also simply referred to as “tire”), and more particularly, to a pneumatic tire for passenger cars according to an improvement in a reinforcing structure of a crown portion.

  In general, a tire has a basic structure in which a carcass extending between a pair of bead portions is used as a skeleton, and one or more belts that reinforce the crown portion are provided outside the crown portion of the carcass in the tire radial direction. . On the premise of such a basic structure, various technologies aimed at reducing the weight of tires have been studied under the recent demand for low fuel consumption of tires.

  For example, Patent Document 1 discloses that at least one carcass layer is provided for the purpose of providing a pneumatic tire that can be reduced in weight by improving a belt and is excellent in durability, steering stability, and uneven wear. A first belt in which a first cord in which an angle with respect to the equator of the tire is inclined in a range of 15 ° to 75 ° is arranged as a belt layer, and a first belt extending in parallel with the equator of the tire. A technique is disclosed in which the first belt has a lower tensile strength than the second belt using the second belt in which the cords 2 are arranged.

International Publication No. 2011/016215

  As in the tire described in Patent Document 1, an inclined belt whose cord direction is inclined with respect to the tire equator and a circumferential belt whose cord direction extends substantially parallel to the tire equator are stacked one by one. When using such a belt structure, a steel cord having high rigidity and low cost may be used as a cord for the circumferential belt. However, even in a tire for a passenger car using such steel, further weight reduction is achieved. It is demanded.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above problems and provide a technique for further reducing the weight of a pneumatic tire for a passenger car using a steel cord in a belt structure.

  As a result of intensive studies, the inventor has provided a layer made of an organic fiber cord together with a layer made of a steel cord in the belt structure, the layer made of the organic fiber cord is placed outside in the tire radial direction, and the layer made of the steel cord is made of It has been found that the above-mentioned problems can be solved by disposing each inside in the radial direction, and the present invention has been completed.

  That is, the pneumatic tire for a passenger car according to the present invention includes at least one circumferential belt composed of a rubberized layer of a steel cord wound around the crown portion in the tire circumferential direction sequentially from the inner side in the tire radial direction. And at least one inclined belt made of a rubberized layer of organic fiber cords arranged in a direction that makes ± 20 ° to 60 ° with respect to the direction.

  The tire according to the present invention preferably includes one layer of the circumferential belt and two layers of the inclined belt in which cord angles intersect with each other. In the tire of the present invention, the ratio H / TW between the drop height H along the tire radial direction from the tire equator to the tread edge and the tread width TW in the tire width direction cross section is 0.005 or more and 0.3. The following is preferable.

  Furthermore, in the tire of the present invention, it is preferable that a ratio w / W between the circumferential belt width w and the tire maximum width W is 0.59 or more and 0.98 or less. Furthermore, in the tire of the present invention, the ratio TW / W between the tread width TW and the tire maximum width W is preferably 0.60 or more and 0.98 or less.

  According to the present invention, with the above-described configuration, it is possible to further reduce the weight of the pneumatic tire for a passenger car using a steel cord in the belt structure as compared with the conventional one.

(A) The width direction sectional view which shows an example of the pneumatic tire for passenger cars of this invention, (b) It is explanatory drawing which shows the belt structure which concerns on this invention. It is explanatory drawing which concerns on an example of the inclination belt which concerns on this invention. It is explanatory drawing which concerns on the other example of the inclination belt which concerns on this invention. It is explanatory drawing which concerns on the further another example of the inclination belt which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1A is a cross-sectional view in the width direction showing an example of a pneumatic tire for passenger cars of the present invention, and FIG. 1B is an explanatory view showing a belt configuration according to the present invention. The illustrated pneumatic tire 10 for a passenger car includes a pair of left and right bead portions 11, a pair of sidewall portions 12 connected to the outer side in the tire radial direction, and a tread portion 13 extending between the sidewall portions 12. ing. In addition, the illustrated tire has at least one carcass 2 extending in a toroid shape extending between the bead cores 1 embedded in the pair of bead portions 11, and in the illustrated example, the carcass 2 including one carcass ply is used as a skeleton. A tread rubber 5 that forms a tread surface portion is disposed outside the crown portion of the carcass 2 in the tire radial direction.

  As shown in FIG. 1 (b), in the tire of the present invention, at least one layer, in the illustrated example, one layer is sequentially formed between the carcass 2 and the tread rubber 5 in the crown portion from the inner side in the tire radial direction. A circumferential belt 3 and at least one layer, in the example shown, two layers of inclined belts 4a, 4b are provided. Of these, the circumferential belt 3 is made of a rubberized layer of a steel cord wound in the tire circumferential direction, and the inclined belts 4a and 4b are arranged in a direction of ± 20 ° to 60 ° with respect to the tire circumferential direction. It consists of a rubberized layer of an organic fiber cord.

  As a result of studying a structure having a circumferential belt layer made of steel cord and an inclined belt layer made of organic fiber cord as an example of a belt structure including a layer made of steel cord, the present inventor has found such a result. In a tire including steel, steel may be deteriorated due to moisture entering from the tire surface. Therefore, it is difficult to make the tread rubber 5 forming the tread portion sufficiently thin, which hinders further weight reduction. I found out. On the other hand, in the present invention, the inclined belts 4a and 4b made of organic fiber cords are arranged on the outer side in the tire radial direction of the circumferential belt 3 made of steel cords. Therefore, even when the tread rubber 5 is thinned, the weight can be further reduced without impairing the durability.

  In the tire of the present invention, it is important only that the circumferential belt 3 using steel and the inclined belts 4a and 4b using organic fibers are provided in a predetermined order. The material and the like of the member are not particularly limited, and can be appropriately selected from conventionally known materials.

  In the present invention, the circumferential belt 3 may be provided with at least one layer, for example, with 2 to 4 layers. As the steel cord constituting the circumferential belt 3, for example, a cord having a cord diameter of 0.1 to 5.0 mm can be used, and the number of drivings can be set to 10 to 250/50 mm, for example.

  In the present invention, the inclined belts 4a and 4b may be provided in at least one layer, for example, in two to four layers. As the organic fiber cords constituting the inclined belts 4a and 4b, for example, those having a total fineness of 940 to 4000 dtex can be used, and the number of drivings can be set to 10 to 60 (lines / 50 mm), for example. Examples of the material of the organic fiber cord include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), nylon (aliphatic polyamide), aramid (aromatic polyamide), and the like.

  FIG. 2 is an explanatory view according to another example of the inclined belt according to the present invention. In the present invention, as shown in the drawing, the inclined belts 4a and 4b are formed by arranging rubber strips S formed by aligning a plurality of cords and covering them with rubber in a direction inclined with respect to the tire circumferential direction at both ends in the width direction. Those having an endless structure formed by winding while being folded can also be used.

  In this case, the rubber strip S constituting the inclined belts 4a and 4b is formed by rubber coating a plurality of, for example, 2 to 20, organic fiber cords or steel cords, and the width thereof is, for example, 3 to 30 mm. can do.

  As the cord for forming the rubber strip S, in the case of an organic fiber cord, the material is polyester such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), nylon (aliphatic polyamide), aramid (aromatic polyamide), etc. For example, one having a total fineness of 940 to 4000 dtex can be used. Further, the number of implantations can be set to, for example, 10 to 60 (lines / 50 mm).

  As shown in the figure, a plurality of rubber strips S are formed directly around a molding core 100 such as a belt-tread molding drum or a molding drum, or indirectly via a circumferential belt material or other tire components. It can be formed by circumferential winding. Specifically, for example, first, one rubber strip S is moved from a position E1 corresponding to one widthwise end of the formed inclined belts 4a and 4b to a position E2 corresponding to the other widthwise end. The rubber strip S is bent at the position E2 by being inclined at an angle α with respect to the circumferential direction of the molded core 100. Thereafter, the rubber strip S extends toward the position E1 by being inclined at an angle β that is the same size as the angle α and in the opposite direction with respect to the circumferential direction of the molded core 10, and is bent at the position E1. This process is repeated to wind the rubber strip S. After one round of winding is completed, the rubber strip S is shifted from the winding start position of the first round in the circumferential direction by the width of the rubber strip S to start winding the rubber strip S. By winding the strip S around the molded core 100 without a gap, the inclined belts 4a and 4b can be formed. Since the inclined belts 4a and 4b formed in this way do not have many cut ends of the cord at the end portions in the width direction, belt end separation caused by such cut ends is effectively prevented. be able to.

  The winding direction of the rubber strip S can be set to, for example, 5 ° to 30 ° at an angle α (β) with respect to the tire circumferential direction.

  Since the cord is laminated in two layers by winding the rubber strip S as described above, the two-layer inclined belts 4a and 4b in which the cord angles cross each other between the layers are substantially obtained. Will be formed. When the inclined belt has four or more layers, the above steps may be repeated.

  In the present invention, it is preferable to dispose the rubber member G between the rubber strips S laminated at the edges in the tire width direction of the inclined belts 4a and 4b. In this portion, since the rubber strip S is folded back, the cord is arranged substantially over the tire circumferential direction, and the rigidity in the tire circumferential direction tends to be high, and the tire tread surface is not sufficiently stretched in the tire circumferential direction, There is a possibility that premature wear may occur due to an increase in tire circumferential shear strain. However, between the laminations at the tire width direction edge portions of the rubber strips S constituting the inclined belts 4a and 4b, that is, the inclination laminated at this portion. By arranging the rubber member G between the cords of the belt, the tire circumferential rigidity in this portion can be reduced. Accordingly, this portion of the tread extends in the tire circumferential direction on the tread surface, thereby delaying the progress of wear. As a result, the tread surface can be more evenly worn and the wear performance can be improved. In addition, what is necessary is just to stick this rubber member G to the said predetermined location so that it may arrange | position sequentially between layers, winding the rubber strip S. FIG. Specifically, when the number of turns of the currently wound rubber strip S is the Nth turn, after the rubber strip S is folded back at the position where the end of the inclined belt in the width direction is formed, the N-1th turn It is assumed that at least the rubber member G is disposed at a location overlapping the rubber strip S in the radial direction (N ≧ 2).

  Here, in the present invention, the edge portions in the tire width direction of the inclined belts 4a and 4b on which the rubber member G is disposed are folded at both ends of the belt in the tire width direction of the rubber strip S as shown in FIG. A region including at least a portion (hatched portion) laminated on the rubber strip S one round before. In the illustrated example, the rubber member G1 is disposed between the laminations of the rubber strip S1 and the rubber strip S2, and the rubber member G2 is disposed between the laminations of the rubber strip S2 and the rubber strip S3. Therefore, in the tire of the present invention, when viewed in a cross section in the tire width direction, the portion where the rubber member G is disposed is only the thickness of the rubber member G compared to the portion where only the rubber strip S is disposed. The belt is thicker.

  In the present invention, as the rubber member G, it is preferable to use a member having a 100% modulus equal to or smaller than the 100% modulus of the coating rubber of the inclined belts 4a and 4b, and in particular, the inclined belts 4a and 4b. A coating rubber having a 100% modulus smaller than the 100% modulus is used. That is, by using a rubber member that is softer than the coating rubber of the inclined belts 4a and 4b, the tire circumferential rigidity at the edge in the tire width direction of the belt can be more effectively reduced. In particular, the ratio of the 100% modulus of the rubber member G to the 100% modulus of the coating rubber of the inclined belts 4a and 4b is preferably 0.3 to 0.8. Here, the 100% modulus of rubber can be a value measured at a temperature of 30 ° C. using a dumbbell-shaped test piece in accordance with JIS K-6251.

  Moreover, there is no restriction | limiting in particular as thickness of the rubber member G, For example, it can be 0.3 mm-1.5 mm. If the thickness of the rubber member G is smaller than the above range, the effect of reducing the rigidity in the tire circumferential direction may be insufficient. If it is thicker than the above range, the rubber member G generates heat and the temperature rises, and the tire is also tired. There is a possibility that the effect of reducing the circumferential rigidity is insufficient.

  3 and 4 are explanatory views according to still another example of the inclined belt according to the present invention. In the present invention, as the inclined belts 4a and 4b, reinforcing members 20A and 20B having a network structure composed of a plurality of reinforcing members 21A and 21B as shown in the figure can be used. In the reinforcing members 20A and 20B, the network structure is a knotted network or a knotless network. In a tire using such a net-like reinforcing member, since a shearing force is not generated between belt layers as in a normal belt crossing layer, durability and the like are improved. Further, the reinforcing members 20A and 20B have a net-like structure composed of a knot net or a knotless net. The nodes 22A and 22B corresponding to the intersections of the reinforcing materials 21A and 21B are connected to each other. Rather than being fixed by fusion or the like, they are joined together by restraining each other. Therefore, the bending deformation of the reinforcing members 21A and 21B at the portions other than the nodes 22A and 22B can absorb the change in the angle between the belt cords accompanying the rolling of the tire, and the reinforcing materials 21A and 22B can be absorbed at the nodes 22A and 22B. No stress is concentrated on 21B. Therefore, the fatigue strength of the reinforcing members 21A2 and 1B can be maintained as compared with the conventional structure, the durability can be improved, and the occurrence of fatigue failure can be suppressed. Further, by using the reinforcing members 20A and 20B as the inclined belts 4a and 4b, the reinforcing effect conventionally obtained by the two crossing belt layers can be obtained by the single reinforcing member, thereby reducing the weight of the tire. The effect which improves an effect more is also acquired.

  The reinforcing member 20A shown in FIG. 3 has a net-like structure composed of a knot net in which nodes 22A are formed by connecting different reinforcing materials 21A. In this case, there is no particular limitation on how to connect the reinforcing members 21A, and any generally known method may be used. Thus, by forming a network structure in a state where a plurality of reinforcing members 21A are constrained by a knot, it is possible to suppress the occurrence of breakage due to stress concentration as in the case of a fused network structure.

  Further, the reinforcing member 20B shown in FIG. 4 is formed by twisting a plurality of reinforcing cords 23 as the reinforcing member 21B, and twisting the reinforcing cords 23 constituting the different reinforcing members 21B to form the nodes 22B. It has a net-like structure composed of a knotless net. In the example shown in the drawing, two reinforcing members 21B obtained by twisting two reinforcing cords 23 are replaced with one of the reinforcing cords 23 constituting one reinforcing member 21B at the node 22B, and the other reinforcing member 21B. The reinforcing cords 23 constituting the wire are constrained by being twisted so as to pass through each other. Also in this case, by forming the network structure in a state in which the plurality of reinforcing members 21B are constrained by twisting, the occurrence of breakage due to stress concentration as in the case of the fused network structure can be suppressed. .

  As the reinforcing members 21A and 21B constituting the reinforcing members 20A and 20B, a monofilament made of various organic fibers or a twisted cord obtained by appropriately twisting a plurality of monofilaments, which is usually used for a tire reinforcing member, is used. it can. Examples of such organic fibers include nylon, aramid fiber, polyester, and the like.

  In particular, as the reinforcing material 21B, a material obtained by twisting a plurality of reinforcing cords 23 is used. As the reinforcing cord 23 in this case, the same monofilament as described above or a twisted cord obtained by appropriately twisting a plurality of monofilaments can be used. Further, the number of the reinforcing cords 23 constituting the reinforcing member 21B can be two or more, for example, 3 to 6.

  As the reinforcing materials 21A and 21B, for example, those having a total fineness of 1100 to 3300 dtex can be used. In addition, the number of reinforcements 21A and 21B driven in the reinforcement members 20A and 20B can be, for example, 8 to 80 pieces / 50 mm in a direction orthogonal to the arrangement direction of the reinforcements.

  The reinforcing members 20A and 20B can be used for tire manufacture in a state where they are coated with rubber after being subjected to an adhesive treatment. The adhesive treatment can be performed according to a conventional method, and may be performed after the reinforcing member is manufactured, or may be performed at the stage of the reinforcing member or the reinforcing cord.

  Since the reinforcing members 20A and 20B have a net-like structure and the reinforcing members are not fixed at the nodes, it is possible to freely set the angle formed between the reinforcing members, that is, the two in the tire The reinforcing direction can be arbitrarily selected. The direction in which the reinforcing member is disposed when the reinforcing member of the present invention is disposed on the tire is not particularly limited, and can be, for example, in the range of 5 to 65 ° with respect to the tire circumferential direction.

  In the tire of the present invention, it is preferable to provide one layer of the circumferential belt 3 and two layers of inclined belts 4a and 4b whose cord angles cross each other, as shown in the figure. By adopting such a belt configuration, it is possible to obtain the greatest weight reduction effect while ensuring the desired tire performance, which is preferable.

  In the present invention, the ratio H / TW between the drop height H along the tire radial direction from the tire equator CL to the tread edge TE and the tread width TW in the tire width direction cross section is 0.005 or more and 0.3. The following is preferable. When the ratio H / TW is less than the above range, the ground pressure increases, heat generation increases, and high-speed durability tends to decrease. On the other hand, when the ratio H / TW exceeds the above range, the elongation of the cord at the time of grounding increases, and the fatigue strength of the cord tends to decrease.

  Here, the tread end means the ground contact end in the tire width direction of the tire when the tire is mounted on the applicable rim, the specified internal pressure is filled, and the maximum load is applied, and the tread width is between the tread ends. Means the distance in the tire width direction. “Applicable rim” is an industrial standard effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) YEAR BOOK is used. In Europe, ETRTO (European Tire and Rim Technical Organization) is used. STANDARD MANUAL, in the United States, TRA (THE TIRE and RIM ASSOCATION INC.) YEAR BOOK specified rim, etc., "specified internal pressure" refers to the standard of JATMA etc. for tires of the applicable size when the tire is attached to the applicable rim The internal pressure (maximum air pressure) corresponding to the tire maximum load capacity is referred to, and the “maximum load load” refers to a load corresponding to the maximum load capacity.

  Furthermore, in this invention, it is preferable that ratio w / W of the width w of the circumferential belt 3 and the tire maximum width W is 0.59 or more and 0.98 or less. If the ratio w / W is less than the above range, the tagging effect is insufficient, the contact pressure of the shoulder portion becomes high, and the high-speed durability tends to decrease. On the other hand, if the ratio w / W exceeds the above range, the tire weight becomes heavy. Here, the width of the circumferential belt 3 means a width measured in the tire width direction.

  Furthermore, in the present invention, the ratio TW / W between the tread width TW and the tire maximum width W is preferably 0.60 or more and 0.98 or less. When the ratio TW / W is less than the above range, the ground pressure increases and the high-speed durability tends to decrease. On the other hand, if the ratio TW / W exceeds the above range, the tire weight becomes heavy.

  In the present invention, the carcass 2 is composed of one or more, for example, 2 to 5, carcass plies. The carcass ply can be formed of organic fiber or steel, and the same organic fiber as that used for the inclined belts 4a and 4b can be used. The thickness of the tread rubber 5 is preferably about 3 mm or more in terms of the distance from the bottom of the groove provided in the tread portion to the steel cord surface from the viewpoint of suppressing deterioration of the steel. By securing the rubber thickness from the groove bottom to the steel cord to this extent, the permeation of moisture can be suppressed and the deterioration of the steel can be satisfactorily suppressed. On the other hand, the organic fiber cord is superior to the steel cord in terms of water resistance and the like, and therefore no problem due to moisture intrusion occurs.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Example 1>
A pneumatic tire for a passenger car having a tire size 155 / 65R17 having a structure as shown in FIG. 1 was produced according to the conditions shown in the following table. The carcass was formed from a single carcass ply made of a rubberized layer of polyester cord. Further, on the crown portion of the tire, on the conditions shown in the following table, one layer composed of a rubberized layer of a steel cord having a cord diameter of 0.3 mm wound in the tire circumferential direction sequentially from the inner side in the tire radial direction. Two layers of slanting belts consisting of a circumferential belt (110 driven / 50 mm) and a rubberized layer of polyester cord (cord structure: 1100 dtex) arranged in a direction of ± 45 ° with respect to the tire circumferential direction (51 shots / 50 mm).

<Example 2>
A pneumatic tire for a passenger car having a tire size 255 / 35R20 having a structure as shown in FIG. 1 was produced according to the conditions shown in the following table. The carcass was formed from a single carcass ply made of a rubberized layer of polyester cord. Further, on the crown portion of the tire, on the conditions shown in the table below, one layer composed of a rubberized layer of a steel cord having a cord diameter of 0.6 mm wound in the tire circumferential direction sequentially from the inner side in the tire radial direction. An endless slope consisting of a rubber belt of a circumferential belt (number of driven 25/50 mm) and an aramid (Kevlar) cord (cord structure: 1270 dtex) arranged in a direction of ± 30 ° with respect to the tire circumferential direction And a belt (24 driven / 50 mm). This inclined belt was formed by winding a rubber strip formed by aligning six cords and covering them with rubber in a direction of ± 30 ° with respect to the tire circumferential direction while turning back at both ends in the width direction.

<Example 3>
A pneumatic tire for a passenger car having a tire size 235 / 60R18 having a structure as shown in FIG. 1 was produced according to the conditions shown in the following table. The carcass was formed from a single carcass ply made of a rubberized layer of polyester cord. Further, on the crown portion of the tire, on the conditions shown in the following table, one layer composed of a rubberized layer of a steel cord having a cord diameter of 0.9 mm wound in the tire circumferential direction sequentially from the inner side in the tire radial direction. It consists of a rubberized layer of a reinforcing member having a net structure composed of a circumferential belt (20 shots / 50 mm) and a nylon cord (cord structure: 1400 dtex) arranged in a direction forming ± 45 ° with respect to the tire circumferential direction. An intersecting inclined belt (49 driven / 50 mm) (see FIG. 4) was provided.

  In addition, as an inclined belt, it consists of a rubberized layer of a steel cord (cord structure: 1 × 5 × 0.2, number of driving 39/50 mm) with a cord diameter of 0.65 mm arranged at the same angle as each test tire. Test tires of Comparative Examples 1 to 3 were produced in the same manner as the test tires of the examples except that one layer was used.

  The weight of the test tire of each example is shown in the table below in a weight ratio where the weight of the test tire of each comparative example having the same tire size is 1. The smaller the weight ratio, the lighter and better. The rubber thicknesses from the groove bottom to the surface of the steel cord located on the outermost side in the tire radial direction were the same in each example and the corresponding comparative examples.

  As shown in the above table, in the test tires of each example in which a circumferential belt using a steel cord and an inclined belt using an organic fiber cord are arranged in a predetermined stacking order, durability is obtained. It was confirmed that even if the thickness of the tread rubber was secured, the lightness could be improved as compared with the conventional one.

DESCRIPTION OF SYMBOLS 1 Bead core 2 Carcass 3 Circumferential belt 4a, 4b Inclined belt 5 Tread rubber 10 Pneumatic tire for passenger cars 11 Bead part 12 Side wall part 13 Tread part 20A, 20B Reinforcement member 21A, 21B Reinforcement material 22A, 22B Node 23 Reinforcement cord 100 Molded core S Rubber strip G Rubber member E1 Position corresponding to one widthwise end of the inclined belt E2 Position corresponding to the other widthwise end of the inclined belt

Claims (5)

  At least one circumferential belt composed of a rubberized layer of a steel cord wound in the tire circumferential direction sequentially from the inner side in the tire radial direction on the crown portion, and ± 20 ° to 60 ° with respect to the tire circumferential direction A pneumatic tire for a passenger car, comprising: at least one inclined belt made of a rubberized layer of organic fiber cords arranged in a direction.   The pneumatic tire for a passenger car according to claim 1, comprising: one layer of the circumferential belt; and two layers of the inclined belt in which cord angles intersect with each other.   The ratio H / TW of the drop height H along the tire radial direction from the tire equator to the tread edge and the tread width TW in the tire width direction cross section is 0.005 or more and 0.3 or less. Pneumatic tires for passenger cars.   The pneumatic tire for a passenger car according to any one of claims 1 to 3, wherein a ratio w / W between the width w of the circumferential belt and the maximum tire width W is 0.59 or more and 0.98 or less.   The pneumatic tire for a passenger car according to any one of claims 1 to 4, wherein a ratio TW / W between the tread width TW and the tire maximum width W is 0.60 or more and 0.98 or less.

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