JP5081465B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that is mounted on a heavy-duty vehicle having a large load capacity such as a truck or a bus or a vehicle body weight.

  Conventionally, in a pneumatic tire, not only the sidewall portion is greatly bent, but also a falling phenomenon, which is a phenomenon of falling outward in the tread width direction outside the tire radial direction of the bead portion contacting the rim flange of the rim wheel, is often seen. .

  Along with this collapse phenomenon, a failure such as separation occurs due to a shear strain (shear deformation) generated along a carcass layer formed by a carcass main body portion between bead cores and a folded portion folded around the bead core. There is a concern that the durability of the bead portion may deteriorate.

  In particular, when used under heavy load, the carcass layer from the bead portion to the sidewall portion is greatly deformed in the tire circumferential direction, and failure tends to occur near the end of the folded portion in the carcass layer. The durability of the part will deteriorate.

  As a method for improving the durability of such a bead portion, the following pneumatic tire is disclosed. For example, a pneumatic tire (hereinafter referred to as a first tire) including a carcass layer in which the position of the end of the folded portion in the carcass layer is folded back to the vicinity of the maximum tire width, and a carcass reinforcing layer that is folded around the bead core along the carcass layer. 1 tire) is disclosed (for example, refer to Patent Document 1).

  Further, a pneumatic tire (hereinafter referred to as a first tire) including a rubber reinforcing layer formed of two layers of rubber having a different hardness from each other is formed between the carcass body portion and the folded portion in the carcass layer so as to taper outward in the tire radial direction. 2 tires) is disclosed (for example, see Patent Document 2).

  Furthermore, a pneumatic tire (hereinafter referred to as a third tire) including at least two layers of chafers formed of a steel cord or an organic fiber cord and rubber on the outer side in the tread width direction of the folded portion in the carcass layer is disclosed. (For example, refer to Patent Document 3).

By the way, in recent pneumatic tires (especially, pneumatic tires mounted on heavy-duty vehicles such as trucks and buses with heavy loads and body weights), the load of the vehicles increases due to an increase in the load of the vehicles. As the tire is flattened and the tire is flattened, the load increases, and the deformation amount of the bead portion tends to increase (that is, the collapse deformation in the tire circumferential direction).
JP 2002-144826 A JP-A-8-222005 JP 2003-89305 A

  However, although the conventional first tire and the second tire described above are provided with a carcass reinforcing layer and a rubber reinforcing layer, the amount of deformation of the bead portion increases when used under heavy load. As a result, it is insufficient to improve the durability of the bead portion.

  On the other hand, the conventional third tire is provided with a chafer, but when used under heavy load, a failure is likely to occur between the carcass layer and the chafer, and the same as described above. It was insufficient to improve the durability of the bead portion.

  Then, it is made in view of the above-mentioned problem, and it aims at providing the pneumatic tire which can control the failure which occurs along a carcass layer, and can improve the endurance of a bead part. To do.

  In order to solve the above-described problems, the present invention has the following features. First, the invention according to the first aspect of the present invention includes a pair of bead portions including at least a bead core, a carcass layer folded between bead cores and folded around the bead core, and folded around the carcass layer in the bead portion. A first wire chafer formed of metal and rubber, and a second wire chafer formed of metal and rubber disposed on the inner side in the tread width direction of the carcass layer and the first wire chafer in the bead portion. And a first width direction inner end (P1) which is an end portion located on the inner side in the tread width direction of the first wire chafer is an end portion located on the outer side in the tread width direction of the first wire chafer. Located in the tire radial direction outer side than the first width direction outer end (P2), in the second wire chafer The second radial outer end (P3), which is the end most positioned on the outer side in the ear radial direction, passes through the surface position (P4) which is the position of the outer surface of the tire in contact with the rim flange of the rim wheel at the time of normal tire internal pressure, And the metal is inclined with respect to the tire radial direction in the second wire chafer, located on the inner side in the tire radial direction from the vertical line (L1) extending vertically from the surface position (P4) toward the tire inner surface. The gist is that the second inclination angle (α), which is an angle, is 85 to 90 degrees.

  Here, the tire normal internal pressure is an air pressure corresponding to the maximum load capacity of the Year Book 2004 version of JATMA (Japan Automobile Tire Association). Outside Japan, the internal pressure is the air pressure corresponding to the maximum load (maximum load capacity) of a single wheel described in the following standards.

  The standards are determined by industry standards that are valid in the region where the tire is produced or used. For example, in the United States, it is “The Year Book of The Tire and Rim Association Inc.”, and in Europe it is “The Standards Manual of the European Tire and Rim Technical Organization”.

  According to this feature, the deformation of the bead portion that contacts the rim flange of the rim wheel is suppressed by including the first wire chafer and the second wire chafer disposed on the inner side in the tread width direction of the carcass layer in the bead portion. Failure (which can be less susceptible to tire deformation) and occurring along the carcass layer (eg, separation due to shear strain between the carcass layer and the first wire chafer or the second wire chafer) And the durability of the bead portion can be improved.

  Specifically, the carcass layer serving as a skeleton of the pneumatic tire is formed by the first width direction inner end (P1) being positioned on the outer side in the tire radial direction than the first width direction outer end (P2). It can reinforce and can suppress a deformation to the tire peripheral direction.

  Along with the suppression of the deformation in the tire circumferential direction, the temperature rise of the bead portion during vehicle travel can be suppressed, so that the durability of the bead portion can be improved.

  In addition, the second radially outer end (P3) is located on the inner side in the tire radial direction from the vertical line (L1) extending vertically from the surface position (P4) toward the tire inner surface, and the second inclination angle. When (α) is 85 to 90 degrees, shear strain around the carcass layer due to the collapse phenomenon can be relieved, and failures such as separation can be suppressed.

  In particular, when the second inclination angle (α) is 85 to 90 degrees, deformation in the tire circumferential direction can be suppressed, and deformation of the bead portion (deformation around the bead core) can be suppressed. Therefore, since the shear strain around the carcass layer due to the collapse phenomenon can be relieved, it is possible to suppress failures such as separation and the temperature rise of the bead part during vehicle travel, The durability of the bead portion can be improved.

The invention according to another aspect of the present invention is disposed in the tread width direction in the side of the second wire chafer and covers toward the second radially outer end portion (P3) to the outside tread width direction, The gist is to further include a third wire chafer formed of metal and rubber.

  According to this feature, the third wire chafer covers the second radially outer end (P3) toward the outer side in the tread width direction, whereby the carcass layer can be further reinforced, and the tire circumferential direction can be increased. Deformation can be further suppressed.

The invention according to another aspect of the present invention is disposed in the tread width direction in the side of the third wire chafer and the third wire chafer covers toward the tread lateral direction outer side, by a metal and rubber The gist is to further include a fourth wire chafer to be formed.

  According to this feature, the fourth wire chafer covers the third wire chafer toward the outer side in the tread width direction, whereby the carcass layer can be further reinforced and deformation in the tire circumferential direction can be further suppressed. be able to.

  The invention according to another feature of the present invention is the third radial outer side which is disposed at the inner side in the tread width direction of the third wire chafer and is the end most positioned on the outer side in the tire radial direction of the third wire chafer. The gist is to further include a nylon chafer that covers the end (P5) toward the outside in the tread width direction and is formed of nylon and rubber.

  According to this feature, the nylon chafer covers the third radially outer end (P5) toward the outer side in the tread width direction, thereby causing a failure that occurs along the carcass layer (for example, adjacent to the carcass layer). Separation due to shear strain between the second wire chafer and the carcass layer) can be suppressed, and the durability of the bead portion can be further improved.

  The invention according to another feature of the present invention is arranged on the outer side in the tire radial direction than the third radial outer end (P5), which is the end most positioned on the outer side in the tire radial direction in the third wire chafer, The gist is to further include a rubber member formed of rubber having A hardness of 70 degrees or more.

  According to such a feature, a failure that occurs along the carcass layer (for example, the second adjacent to the carcass layer) due to the rubber member being disposed on the outer side in the tire radial direction from the second radially outer end (P4). Separation due to shear strain between the wire chafer and the carcass layer) can be suppressed, and the durability of the bead portion can be further improved.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to suppress the failure which generate | occur | produces along a carcass layer, the pneumatic tire which can improve the durability of a bead part can be provided.

  Next, an example of a pneumatic tire according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

  Note that the pneumatic tire 1 described below is a heavy-duty pneumatic tire that is mounted on a heavy-duty vehicle having a large load capacity such as a truck or a bus or a vehicle body weight.

[First Embodiment]
FIG. 1 is a cross-sectional view in the tread width direction of the pneumatic tire according to the first embodiment, and FIG. 2 is an enlarged cross-sectional view in the tread width direction of a bead portion constituting the pneumatic tire according to the first embodiment. FIG. 3 is a view showing only the chafer constituting the pneumatic tire according to the first embodiment (the arrow A diagram in FIG. 2).

  As shown in FIG. 1, the pneumatic tire 1 has a pair of bead portions 3 including a bead core 3a and a bead filler 3b. Moreover, the pneumatic tire 1 has a carcass layer 5 that is folded back from the inner side in the tread width direction to the outer side in the tread width direction around the bead core 3a across the bead cores 3a.

  A plurality (four layers in FIG. 1) of belt layers 7 are arranged outside the carcass layer 5 in the tire radial direction. A tread portion 9 that is in contact with the road surface is disposed outside the belt layer 7 in the tire radial direction.

  The pneumatic tire 1 has a first wire chafer 11 that is folded around the carcass layer 5 in the bead portion 3 and is formed of metal and rubber. A second wire chafer 13 made of metal and rubber is disposed on the inner side in the tread width direction of the carcass layer 5 and the first wire chafer 11 in the bead portion 3.

  A third wire chafer 15 formed of metal and rubber is disposed on the inner side in the tread width direction of the second wire chafer 13. A fourth wire chafer 17 formed of metal and rubber is disposed inside the third wire chafer 15 in the tread width direction.

  Here, the end located on the inner side in the tread width direction in the first wire chafer 11 is referred to as a “first width direction inner end (P1)”, and the end located on the outer side in the tread width direction in the first wire chafer 11. The portion is indicated as “first width direction outer end portion (P2)”, and the end portion of the second wire chafer 13 that is located at the outermost position in the tire radial direction is indicated as “second radial direction outer end portion (P3)”. The position of the outer surface of the tire that is in contact with the rim flange F of the rim wheel R at the tire normal internal pressure is indicated as “surface position (P4)” (see FIG. 2).

  The angle at which the cord (metal) is inclined with respect to the tire radial direction in the first wire chafer 11 is referred to as a “first inclination angle”, and the cord 13 a ( The angle at which the metal is inclined is denoted as “second inclination angle (α)”, and the angle at which the cord (metal) is inclined with respect to the tire radial direction in the third wire chafer 15 is denoted as “third inclination angle”. The angle at which the cord (metal) is inclined with respect to the tire radial direction in the fourth wire chafer 17 is referred to as a “fourth inclination angle”. That is, the first tilt angle, the second tilt angle (α), the third tilt angle, and the fourth tilt angle are in the range of 0 to 90 degrees.

  As shown in FIG. 2, the first width direction inner end portion (P1) is located on the outer side in the tire radial direction than the first width direction outer end portion (P2). That is, the first width direction inner end portion (P1) protrudes a distance D toward the tire radial direction outer side from the first width direction outer end portion (P2).

  Further, the second radially outer end (P3) passes through the surface position (P4) and extends radially inward from the vertical line (L1) extending from the surface position (P4) to the tire inner surface vertically. Is located.

  If the second radially outer end (P3) is located on the outer side in the tire radial direction than the vertical line (L1), the effect of alleviating the shear strain around the carcass layer 5 due to the collapse phenomenon is increased. Accordingly, the effect of suppressing deformation in the tire circumferential direction becomes too great, and the rubber around the carcass layer 5 that cannot be deformed in the tire circumferential direction is deformed in the tire width direction.

  As a result, although the shear strain around the carcass layer 5 due to the collapse phenomenon can be alleviated, a failure that occurs along the carcass layer 5 (for example, the carcass layer 5 and the first wire chafer 11 or the second wire chaser). It becomes difficult to suppress separation due to shear strain between the fur 13 and the durability of the bead portion 3 is deteriorated.

  As shown in FIG. 3, the second inclination angle (α) is preferably 85 to 90 degrees. If the second inclination angle (α) is smaller than 85 degrees, it is not sufficient to suppress the temperature rise of the bead part 3 during traveling of the vehicle, and the durability of the bead part 3 cannot be improved. There is.

  Moreover, it is preferable that the first tilt angle, the second tilt angle (α), the third tilt angle, and the fourth tilt angle are different from each other in order to suppress deformation in the tire circumferential direction by 20% or more. That is, the cord of the first wire chafer 11, the cord 13 a of the second wire chafer 13, the cord of the third wire chafer 15, and the cord of the fourth wire chafer 17 cross each other. Is preferred.

  In addition, the 3rd wire chafer 15 has covered the 2nd radial direction outer side edge part (P3) toward the tread width direction outer side. Moreover, the 4th wire chafer 17 has covered the 3rd wire chafer 15 toward the tread width direction outer side.

(Operations and effects according to the first embodiment)
According to the pneumatic tire 1 which concerns on 1st Embodiment demonstrated above, the 1st wire chafer 11 and the 2nd wire chafer 13 which are arrange | positioned inside the tread width direction of the carcass layer 5 in the bead part 3 are provided. Thus, deformation of the bead portion 3 that contacts the rim flange F of the rim wheel R is suppressed (it can be made less susceptible to tire deformation), and a failure that occurs along the carcass layer 5 (for example, the carcass layer 5). ) And the first wire chafer 11 or the second wire chafer 13 can be suppressed, and the durability of the bead portion 3 can be improved.

  Specifically, the carcass layer which becomes the skeleton of the pneumatic tire 1 by the first width direction inner end portion (P1) being positioned on the outer side in the tire radial direction than the first width direction outer end portion (P2). 5 can be reinforced and deformation in the tire circumferential direction can be suppressed.

  Along with the suppression of deformation in the tire circumferential direction, an increase in temperature of the bead portion 3 during vehicle travel can be suppressed, so that the durability of the bead portion 3 can be improved.

  In addition, the second radially outer end (P3) is located on the inner side in the tire radial direction from the vertical line (L1) extending vertically from the surface position (P4) toward the tire inner surface, and the second inclination angle. Is 85 to 90 degrees, the shear strain around the carcass layer 5 due to the collapse phenomenon can be alleviated, and failures such as separation can be suppressed.

  In particular, when the second inclination angle (α) is 85 to 90 degrees, deformation in the tire circumferential direction can be suppressed, and deformation of the bead portion 3 (deformation around the bead core 3a) can be suppressed. . Therefore, since the shear strain around the carcass layer 5 due to the collapse phenomenon can be alleviated, it is possible to suppress a failure such as a separation and to suppress an increase in the temperature of the bead portion 3 during traveling of the vehicle. Therefore, the durability of the bead part 3 can be improved.

[Second Embodiment]
Next, a pneumatic tire according to a second embodiment will be described with reference to FIG. FIG. 4 is an enlarged sectional view in the tread width direction of a bead portion constituting the pneumatic tire according to the second embodiment. The difference from the pneumatic tire according to the first embodiment described above will be mainly described.

  As shown in FIG. 4, a nylon chafer 19 formed of nylon and rubber is disposed between the third wire chafer 15 and the fourth wire chafer 17. The nylon chafer 19 covers the third radial outer end (P5), which is the end most positioned on the outer side in the tire radial direction of the third wire chafer 15, facing the outer side in the tread width direction.

(Operations and effects according to the second embodiment)
According to the pneumatic tire 1 according to the second embodiment, in addition to the operations and effects of the first embodiment, the nylon chafer 19 has the third radially outer end (P5) at the outer side in the tread width direction. By covering the surface, the failure that occurs along the carcass layer 5 (for example, separation due to shear strain between the second wire chafer 13 adjacent to the carcass layer 5 and the carcass layer 5) is suppressed. And the durability of the bead portion 3 can be further improved.

[Third Embodiment]
Next, a pneumatic tire according to a third embodiment will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view in the tread width direction of a bead portion constituting a pneumatic tire according to a third embodiment. In addition, the part which is different from the pneumatic tire which concerns on 1st Embodiment and 2nd Embodiment mentioned above is mainly demonstrated.

  As shown in FIG. 5, taper toward the outer side in the tire radial direction between the carcass layer 5 and the fourth wire chafer 17 and on the outer side in the tire radial direction from the third radial outer end (P5). A rubber member 21 formed of rubber having a Shore A hardness of 70 degrees or more is disposed.

  The Shore A hardness was measured by using a Shore hardness meter (hardness tester) to hit a test piece (rubber piece) placed on a table with a hammer and bounce the hammer back. Indicates hardness.

(Operations and effects according to the third embodiment)
According to the pneumatic tire 1 according to the third embodiment, in addition to the functions and effects of the first embodiment, the rubber member 21 is located on the outer side in the tire radial direction from the third radial outer end (P5). To suppress a failure that occurs along the carcass layer 5 (for example, separation due to shear strain between the second wire chafer 13 adjacent to the carcass layer 5 and the carcass layer 5). And the durability of the bead portion 3 can be further improved.

[Other embodiments]
As described above, the contents of the present invention have been disclosed through the embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention.

  Specifically, the pneumatic tire 1 has been described as a heavy-duty pneumatic tire that is mounted on a heavy-duty vehicle having a large load capacity or body weight such as a truck or a bus. However, the pneumatic tire 1 is not limited thereto. Of course, it may be a pneumatic tire mounted on a general passenger car.

  Moreover, in the pneumatic tire which concerns on embodiment mentioned above, although demonstrated as what has the 3rd wire chafer 15 and the 4th wire chafer 17, it is not limited to this, 3rd The wire chafer 15 and the fourth wire chafer 17 may not be provided.

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  Next, in order to further clarify the effect of the present invention, the results of tests performed using pneumatic tires according to the following Comparative Examples 1 and 2 and Examples 1 to 3 will be described. In addition, the data regarding the pneumatic tire which concerns on Comparative Examples 1 and 2 and Examples 1-3 were measured on the conditions shown below.

・ Tire size: 46 / 90R87
・ Applicable rim: 29.00 / 6.00
・ Internal pressure condition: 700 kpa
First, the structure of the pneumatic tire according to Comparative Examples 1 to 3 and Examples 1 to 4 will be described with reference to Table 1.

The pneumatic tire according to Comparative Example 1, as shown in Table 1 and Figure 6, a nylon chafer 19 a plurality of (in FIG. 6 4 layers) disposed in the tread width direction in the side of the first wire chafer 11 Have. In the pneumatic tire according to Comparative Example 1, the first inclination angle is 40 degrees.

The pneumatic tire according to Comparative Example 2, as shown in Table 1 and Figure 6, a second wire chafer 13 disposed in the tread width direction in the side of the first wire chafer 11, the second wire chafer And a third wire chafer 15 that covers the entire 13 toward the outer side in the tread width direction. In the pneumatic tire according to Comparative Example 2, the first inclination angle is 40 degrees, the second inclination angle (α) is 40 degrees, and the third inclination angle is 40 degrees.

  The pneumatic tire according to Example 1 is the one described in the first embodiment (see FIGS. 1 and 2). Further, as shown in Table 1, in the pneumatic tire according to Example 1, the first inclination angle is 40 degrees, the second inclination angle (α) is 90 degrees, and the third inclination angle is 40 degrees. Yes, the fourth tilt angle is 40 degrees. That is, the cord 13a of the second wire chafer 13 is disposed along the tire circumferential direction (see FIG. 3).

  The pneumatic tire according to Example 2 has been described in the second embodiment described above (see FIG. 4). In the pneumatic tire according to Example 2, as shown in Table 1, the first inclination angle is 40 degrees, the second inclination angle (α) is 90 degrees, and the third inclination angle is 40 degrees. Yes, the fourth tilt angle is 40 degrees.

  The pneumatic tire according to Example 3 has been described in the third embodiment described above (see FIG. 5). In the pneumatic tire according to Example 3, as shown in Table 1, the first inclination angle is 40 degrees, the second inclination angle (α) is 90 degrees, and the third inclination angle is 40 degrees. Yes, the fourth tilt angle is 40 degrees.

The tire circumferential direction deformation amount, bead temperature and drum travel distance of the pneumatic tires according to Comparative Examples 1 and 2 and Examples 1 to 3 will be described with reference to Table 2.

<Tire circumferential deformation>
The pneumatic tire according to Comparative Example 1 is mounted on a test drum, and the pneumatic tire is statically loaded with a maximum load capacity of “about 588 kN”, and the tread portion tread position is from the tire rotation center during drum running. Deformation amount of deformation of the outer surface of the bead portion with respect to the tire radial direction until and deformation amount of deformation of the outer surface of the bead portion with respect to the tire radial direction from the tire rotation center to the tread portion treading position of the tread portion; The amount of deformation in the tire circumferential direction measured on the basis of “100” was set to “100”, and the amount of deformation in the tire circumferential direction of each pneumatic tire was similarly displayed as an index. Note that the smaller the numerical value, the smaller the amount of deformation in the tire circumferential direction.

  As a result, the pneumatic tires according to Examples 1 to 4 have a smaller deformation amount in the circumferential direction of the tire than the pneumatic tires according to Comparative Examples 1 and 2 (suppressed), so that the durability of the bead portion is improved. I found out that

<Bead temperature>
The pneumatic tire according to Comparative Example 1 is attached to a test drum, and the maximum temperature of the outer surface of the bead portion that contacts the rim flange when the drum is running measured by an infrared thermometer (hereinafter, bead portion temperature) is set to “100”. Similarly, the bead temperature of each pneumatic tire was displayed as an index. In addition, bead part temperature is so low that a numerical value is small.

  As a result, since the pneumatic tire according to Examples 1 to 4 has a lower bead portion temperature than the pneumatic tire according to Comparative Example 1, it was found that the durability of the bead portion can be improved.

<Drum mileage>
The pneumatic tire according to Comparative Example 1 is mounted on a test drum, and the pneumatic tire is loaded with a load of “1000 kN” which is about 1.7 times the maximum load capacity, and the drum is run at a speed of 10 km per hour. The drum travel distance, which is the distance until destruction, was set to “100”, and the drum travel distance of each pneumatic tire was similarly displayed as an index. The larger the numerical value, the longer the drum travel distance.

  As a result, the pneumatic tires according to Examples 1 to 4 have a longer drum travel distance than the pneumatic tires according to Comparative Examples 1 and 2, and thus the durability of the bead portion can be improved.

It is a tread width direction sectional view of the pneumatic tire concerning a 1st embodiment. It is a tread width direction expanded sectional view of a bead part which constitutes a pneumatic tire concerning a 1st embodiment. It is a figure (A arrow figure of FIG. 2) which shows only the chafer which comprises the pneumatic tire which concerns on 1st Embodiment. It is a tread width direction expanded sectional view of a bead part which constitutes a pneumatic tire concerning a 2nd embodiment. It is a tread width direction expanded sectional view of a bead part which constitutes a pneumatic tire concerning a 3rd embodiment. It is a tread width direction expanded sectional view of a bead part which constitutes a pneumatic tire concerning comparative example 1. It is a tread width direction expanded sectional view of the bead part which constitutes the pneumatic tire concerning comparative example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 3 ... Bead part, 3a ... Bead core, 3b ... Bead filler, 5 ... Carcass layer, 5 ... Bead part, 7 ... Belt layer, 9 ... Tread part, 11 ... 1st wire chafer, 13 ... Second wire chafer, 13a ... cord, 15 ... third wire chafer, 17 ... fourth wire chafer, 19 ... nylon chafer, 21 ... rubber member, R ... rim wheel, F ... rim flange

Claims (6)

A pair of bead portions including at least a bead core;
A carcass layer that is folded between the bead cores and around the bead cores;
A first wire chafer that is folded around the carcass layer in the bead portion and formed of metal and rubber;
The carcass layer in the bead portion and the first wire chafer are arranged on the inner side in the tread width direction, and include a second wire chafer formed of metal and rubber,
A first width direction inner end portion (P1) that is an end portion located on the inner side in the tread width direction of the first wire chafer is a first end portion located on the outer side in the tread width direction of the first wire chafer. Located in the tire radial direction outer side than the width direction outer side end (P2),
The second radial outer end (P3), which is the end most positioned on the outer side in the tire radial direction of the second wire chafer, is a surface that is the position of the outer surface of the tire in contact with the rim flange of the rim wheel at the normal tire pressure. It is located on the inner side in the tire radial direction than the vertical line (L1) that passes through the position (P4) and extends vertically from the surface position (P4) toward the tire inner surface,
A heavy duty pneumatic tire characterized in that a second inclination angle (α), which is an angle at which the metal is inclined with respect to a tire radial direction in the second wire chafer, is 85 to 90 degrees. Disposed in the tread width direction in the side of the second wire chafer and the and second radially outer end portion (P3) covers outward tread width direction, the is formed by the metal and rubber The heavy duty pneumatic tire according to claim 1, further comprising a three-wire chafer. The third is located in the tread width direction in the side of the wire chafer and the and the third wire chafer covering outward tread width direction, the fourth wire chafer formed by the metal and rubber The heavy duty pneumatic tire according to claim 2, further comprising: A third radially outer end (P5) which is disposed on the inner side in the tread width direction of the third wire chafer and is located at the outermost position in the tire radial direction of the third wire chafer is a tread width direction. The heavy-duty pneumatic tire according to claim 2 or 3, further comprising a nylon chafer that covers the outer side and is formed of nylon and rubber. The third wire chafer is formed of rubber having a Shore A hardness of 70 degrees or more, which is disposed on the outer side in the tire radial direction from the third outer radial end (P5) which is the end most positioned on the outer side in the tire radial direction. The heavy-duty pneumatic tire according to claim 2, further comprising a rubber member.   The heavy load according to any one of claims 1 to 5, wherein an end portion of the second wire chafer located closest to the inner side in the tire radial direction is positioned further to the inner side in the tire radial direction than the bead core. Pneumatic tire.

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