JP2007301830A - Method for producing pneumatic radial tire for heavy load and pneumatic radial tire for heavy load - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a pneumatic radial tire for heavy loads which is excellent in bead part durability without causing problems such as air entrainment and a defective shape and the pneumatic radial tire for heavy loads. <P>SOLUTION: The method for producing the pneumatic radial tire for heavy loads which has a bead filler 3 and a soft rubber member 4 between the main part 2A and folding part 2B of a carcass ply 2 and in which the inner end part 4a of the soft rubber member is contacted with the folding part 2B includes a process in which the bead filler 3 is divided into a first bead filler 3A and a second bead filler 3B, a process in which the second bead filler is stuck to a bead core, and the first bead filler 3A is stuck to the main part 2A, a process in which the first bead filler 3A is coated in a joint by making the soft rubber member 4 adjoin the main part 2A and the first bead filler 3A, and a process in which the folding part 2B is folded back around the bead core. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a heavy-duty pneumatic radial tire and a heavy-duty pneumatic radial tire (hereinafter also simply referred to as “manufacturing method” and “tire”, respectively). The present invention relates to a method for manufacturing a heavy duty pneumatic radial tire, and a heavy duty pneumatic radial tire obtained thereby.

  Generally, in a pneumatic radial tire, a carcass ply constituting the skeleton is extended in a toroidal shape from a tread portion to a bead portion through a sidewall portion, and then folded from the inside to the outside around a bead core embedded in each bead portion. And has a locked structure.

  As shown in FIG. 7 (a), in order to ensure rigidity, the bead portion 20 is located outward in the tire radial direction of the bead core 1 and between the carcass ply main body portion 2A and the folded portion 2B. A bead filler 103 made of hard rubber is disposed. Further, a soft rubber member 104 is disposed outside the bead filler 103 in the tire radial direction for the purpose of reducing shear strain between the main body portion 2A and the folded portion 2B of the carcass ply.

A heavy-duty pneumatic radial tire having a configuration in which two types of rubber members made of hard rubber and soft rubber are disposed between a main body portion and a folded portion of a carcass ply in a bead portion is disclosed in, for example, Patent Document 1. Yes.
JP2003-11622A (Claims, [FIG. 1], etc.)

  The arrangement structure of the plurality of rubber members between the main body portion and the folded portion of the carcass ply can be variously configured, but as shown in FIG. In the structure where the cross-section is tapered along the folded-back portion 2B of the ply, the soft rubber member 104 is disposed in a state where the inner end portion 104a in the tire radial direction is in contact with the main body portion 2A of the carcass ply. It becomes.

  Here, at the time of vulcanization, the carcass ply cord shows a movement that is pulled out radially outward in the main body portion 2A and radially inward in the folded portion 2B (see FIG. 7B). Arrow). Accordingly, when the inner end portion 104a in the tire radial direction of the soft rubber member 104 is disposed on the main body portion 2A side, the inner end portion 104a is opposed to the movement of the ply cord, and as illustrated in the manufacturing process. This causes a phenomenon that the tip is bent and the inner end 104a of the product tire is indented into the ply coating rubber. In such a state, due to the difference in rigidity between the ply coating rubber and the soft rubber member 104, the strain concentrates on the part during running, and if the running is continued as it is, there is a large difference in hardness between the two rubbers due to the blending or between the rubbers. If the adhesion of the rubber is not sufficient, cracks occur at the rubber interface. For this reason, there is a problem that this may become a core and eventually progress to a separation failure, and the durability of the product tire may be significantly impaired. This problem is particularly noticeable in a heavy-duty pneumatic radial tire with a large load.

  The above problem can be solved by disposing the inner end portion 104a of the soft rubber member in contact with the folded portion 2B rather than the main body portion 2A of the carcass ply. Is produced by so-called single stage molding, in which a series of green tire assembly processes are performed on one molding drum. That is, in this case, the soft rubber member 104 is attached on the carcass ply to the folded portion 2B side with respect to the fixed position of the bead core, and then the folded portion 2B is folded. The property of the part 2B is likely to be defective.

  As described above, there is not enough technology for manufacturing tires with excellent durability without causing other problems such as air entry and shape defects, and such technology has been established. It was sought to do.

  Accordingly, an object of the present invention is to provide a heavy-duty pneumatic radial tire manufacturing method capable of producing a heavy-duty pneumatic radial tire excellent in bead portion durability without causing problems such as pneumatic entry and shape defects, and An object of the present invention is to provide a heavy-duty pneumatic radial tire obtained thereby.

  As a result of intensive studies, the present inventor has eliminated the rubber member attached to the folded portion of the carcass ply or reduced the size thereof as much as possible to prevent the occurrence of air entry and shape defects when folding the folded portion. It has been found that it can be suppressed, and the present invention has been completed.

That is, according to the method of manufacturing a heavy-duty pneumatic radial tire of the present invention, the bead cores embedded in the pair of bead portions are respectively folded back and locked from the inside to the outside of the tire, and extend in a toroidal shape between the bead cores. A carcass ply comprising at least one layer of a main body part and a folded part continuously provided on the main body part and folded around the bead core, between the main body part and the folded part of the carcass ply, A bead filler disposed in contact with the bead core; and a soft rubber member disposed on an outer side of the bead filler in a tire radial direction, and an inner end portion in the tire radial direction of the soft rubber member includes the carcass In the method for manufacturing a heavy-duty pneumatic radial tire in contact with the folded portion of the ply,
A bead filler dividing step for dividing the bead filler into a first bead filler and a second bead filler; and the second bead filler is affixed to the bead core, and the first bead filler is attached to the body portion of the carcass ply. Adhering step of adhering the bead filler, and soft rubber for adhering the soft rubber member to the main body of the carcass ply adjacent to the first bead filler so as to cover the first bead filler at the joint It includes a member sticking step and a folding step of folding the folded portion of the carcass ply around the bead core.

In another method of manufacturing a pneumatic radial tire for heavy loads according to the present invention, the bead cores embedded in the pair of bead portions are respectively folded back and engaged from the inside to the outside of the tire and extended in a toroidal shape between the bead cores. A carcass ply comprising at least one layer of a carcass ply comprising: a main body portion that is present; and a folded portion that is provided continuously from the main body portion and is folded around the bead core; and between the main body portion and the folded portion of the carcass ply. A bead filler disposed in contact with the bead core, and a soft rubber member disposed on an outer side of the bead filler in the tire radial direction, and an inner end portion in the tire radial direction of the soft rubber member, In the method of manufacturing a heavy-duty pneumatic radial tire in contact with the folded portion of the carcass ply,
A bead filler dividing step of dividing the bead filler into a first bead filler and a second bead filler; a soft rubber member dividing step of dividing the soft rubber member into a first soft rubber member and a second soft rubber member; The second bead filler is attached to the bead core and the first bead filler is attached to the carcass ply main body, and the first soft rubber member is attached to the main body of the carcass ply. And adhering the first bead filler adjacent to the first bead filler so as to cover the first bead filler, and adhering the second soft rubber member to the folded portion of the carcass ply. A wrapping step, and a wrapping step of wrapping the folded portion of the carcass ply around the bead core;
It is characterized by including.

Furthermore, another heavy-duty pneumatic radial tire manufacturing method according to the present invention includes a bead core embedded in a pair of bead portions, and is folded back and locked from the inside to the outside of the tire in a toroidal shape between the bead cores. A carcass ply including at least one layer of an extending main body part and a folded part continuously provided around the main body part and folded around the bead core. A bead filler disposed in contact with the bead core, an intermediate rubber and a soft rubber member disposed on the outer side of the bead filler in the tire radial direction, and the tire diameter of the intermediate rubber and the soft rubber member In the method for manufacturing a heavy-duty pneumatic radial tire in which the inner end in the direction is in contact with the folded portion of the carcass ply,
A bead filler dividing step of dividing the bead filler into a first bead filler and a second bead filler; an intermediate rubber dividing step of dividing the intermediate rubber into a first intermediate rubber and a second intermediate rubber; and the second bead. A bead filler attaching step for attaching the filler to the bead core and the first bead filler to the main body of the carcass ply; and the first intermediate rubber to the main body of the carcass ply; An intermediate rubber adhering step for adhering the first bead filler adjacent to the bead filler so as to cover the first bead filler, and adhering the second intermediate rubber to the folded portion of the carcass ply, and the soft rubber Adhering the member to the main body of the carcass ply adjacent to the first intermediate rubber so as to cover the first intermediate rubber at the joint And quality rubber member attaching step, the folded portion of the carcass ply and is characterized in that it comprises a folding step of folding around the bead cores.

  In the present invention, the width of the second soft rubber member or the second intermediate rubber along the turned-up portion of the carcass ply is in a no-load state when the tire is mounted on an applied rim and filled with a specified air pressure. The height from the bottom of the bead core to the end of the folded portion of the carcass ply is preferably in the range of 25 to 60%. In the present invention, the applicable rim means a rim defined in the following standard, and the prescribed air pressure means an air pressure defined in accordance with the maximum load capacity in the following standard. The standard is defined by an industrial standard effective in the region where the tire is produced or used. For example, “The Tire and Rim Association Inc. Year Book” in the United States, and “The European Tire and Land” in Europe. It is “Standards Manual” of Rim Technical Organization, and “JATMA Year Book” of Japan Automobile Tire Association in Japan.

  The heavy-duty pneumatic radial tire of the present invention is manufactured by the above-described method for manufacturing a heavy-duty pneumatic radial tire of the present invention.

  In the tire of the present invention, when the JIS-A hardness of the coating rubber of the carcass ply is 100, the JIS-A hardness of the soft rubber member is in the range of 70 to 90, and the JIS of the bead filler is JIS. It is preferable that -A hardness exists in the range of 110-130.

  According to the present invention, the above configuration makes it possible to produce a heavy-duty pneumatic radial tire that can provide a heavy-duty pneumatic radial tire with excellent bead durability without causing problems such as air entry and shape defects. It has become possible to realize a method and a heavy-duty pneumatic radial tire.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
FIG. 1 shows a schematic cross-sectional view of an example of a heavy-duty pneumatic radial tire of the present invention. As shown in FIG. 1, the heavy-duty pneumatic radial tire of the present invention is folded and locked around the bead cores 1 respectively embedded in a pair of bead portions 20 from the inside to the outside of the bead core 1. The main body 2A is extended to the main body 2A, and the folded portion 2B is provided around the bead core 1 so as to be continuous with the main body 2A. Further, between the body portion 2A and the folded portion 2B of the carcass ply, there is a bead filler 3 disposed in contact with the bead core 1, and a soft rubber member 4 disposed on the outer side in the tire radial direction, and The inner end 4a in the tire radial direction of the soft rubber member 4 is in contact with the folded portion 2B of the carcass ply.

  In the present invention, when manufacturing such a tire, the bead filler 3 is divided into a first bead filler 3A and a second bead filler 3B (bead filler splitting step), and the first of the two in contact with the bead core 1 is divided. While adhering the two bead fillers 3B to the bead core 1, the first bead filler 3A is attached to the main body 2A of the carcass ply (bead filler attaching step) (see FIG. 2A).

  Next, as shown in the figure, the soft rubber member 4 is attached to the main body portion 2A of the carcass ply adjacent to the first bead filler 3A so as to cover the first bead filler 3A at the joint (soft rubber member). (Attaching step) ((a) in the figure), the folded portion 2B of the carcass ply is folded around the bead core 1 (folding step) ((b) in the figure), and the tire is molded.

  In the present invention, since the tire is formed by so-called single stage molding including the above-described series of steps, a rubber member can be attached to the carcass ply folded portion 2B side with respect to the fixed position of the bead core 1. Therefore, as shown in FIG. 1, a tire in which the inner end portion 4a in the tire radial direction of the soft rubber member 4 is in contact with the folded portion 2B of the carcass ply is inflated or has poor properties at the folded portion. It becomes possible to manufacture without causing a problem.

  Moreover, in the manufacturing method of this invention, in addition to the bead filler 3, the soft rubber member 4 can also be divided | segmented. In this case, first, the bead filler 3 is divided into the first bead filler 3A and the second bead filler 3B (bead filler dividing step), and the soft rubber member 4 is divided into the first soft rubber member 4A and the second soft rubber member 4B. (Soft rubber member dividing step).

  Next, in the same manner as described above, the second bead filler 3B is attached to the bead core 1, the first bead filler 3A is attached to the main body 2A of the carcass ply (bead filler attaching step), and further, the first soft The rubber member 4A is attached to the main body portion 2A of the carcass ply so as to be adjacent to the first bead filler 3A so that the first bead filler 3A is covered at the joint portion, and the second soft rubber member 4B is folded back of the carcass ply. It sticks to the part 2B (soft rubber member sticking process) (refer Fig.3 (a)). Thereafter, the folded portion 2B of the carcass ply is folded around the bead core 1 (folding step) ((b) in the figure), whereby the tire can be molded.

Also in this case, since the rubber member adhered to the carcass ply turn-up portion 2B side with respect to the fixed position of the bead core 1 can be reduced, the inner end portion 4a in the tire radial direction of the soft rubber member 4 shown in FIG. However, it is possible to manufacture a tire having a structure in contact with the turn-up portion 2B of the carcass ply without causing problems such as air entry at the time of turn-up and defective properties of the turn-up portion.

  4 and 5 show a bead portion sectional structure when only the bead filler 3 is divided, and a bead portion sectional structure when both the bead filler 3 and the soft rubber member 4 are divided. As shown in the figure, when the latter method is used, the second soft rubber member 4B can be extended to the outer side in the tire axial direction of the second bead filler 3B. There is also an advantage that the area for relaxing the strain can be expanded.

  In this case, the size of the second soft rubber member 4B to be adhered to the folded portion 2B is such that the width w along the folded portion 2B of the carcass ply is fitted with the tire to the applicable rim and filled with the prescribed air pressure. It is preferable that the height hc from the bottom of the bead core 1 to the end of the folded portion 2B of the carcass ply is in the range of 25 to 60%, particularly 35 to 40% in an unloaded state. (See FIGS. 1 and 3). If the width w of the second soft rubber member 4B is larger than 60% of the carcass folded portion height hc, the above-described air-filling and the poor quality of the carcass ply folded portion 2B are likely to occur.

  Further, the present invention is not limited to the case where only the bead filler and the soft rubber member are disposed between the main body portion and the folded portion of the carcass ply, and as shown in FIG. 6A, the main body portion 12A of the carcass ply. The bead filler 13, the intermediate rubber 15 and the soft rubber member 14 are sequentially disposed between the intermediate rubber 15 and the folded portion 12B, and the inner ends of the intermediate rubber 15 and the soft rubber member 14 in the tire radial direction are carcass plies. The present invention can also be applied to a tire that is in contact with the folded portion 12B.

  In this case, first, the bead filler 13 is divided into the first bead filler 13A and the second bead filler 13B (bead filler dividing step), and the intermediate rubber 15 is divided into the first intermediate rubber 15A and the second intermediate rubber 15B. Dividing (intermediate rubber dividing step), the second bead filler 13B is attached to the bead core 11, and the first bead filler 13A is attached to the main body 2A of the carcass ply (bead filler attaching step) (FIG. 6 ( b)).

  Next, as shown in the drawing, the first intermediate rubber 15A is attached to the main body portion 12A of the carcass ply so as to be adjacent to the first bead filler 13A so as to cover the first bead filler 13A at the joint portion. The intermediate rubber 15B is adhered to the folded portion 12B of the carcass ply (intermediate rubber adhering step), and the soft rubber member 14 is adjacent to the main portion 12A of the carcass ply and adjacent to the first intermediate rubber 15A. Then, the first intermediate rubber 15A is pasted so as to be covered (soft rubber member pasting step), and the folded portion 2B of the carcass ply is folded back around the bead core 1 (folding step), thereby molding the tire.

Also in this case, since the rubber member adhered to the carcass ply turn-up portion 12B side with respect to the fixed position of the bead core 11 can be reduced, either the intermediate rubber 15 or the inner end portion in the tire radial direction of the soft rubber member 14 can be used. It is possible to manufacture a tire having a structure in contact with the turn-up portion 12B of the carcass ply without causing problems such as air entry at the time of turn-up and defective properties of the turn-up portion. Incidentally, in this case, also the width w ₁ along the turnup portion 2B of the carcass ply of the second intermediate rubber 15B of attaching the folded portion 12B side, similarly to the case of the width w of the second soft rubber member 4B, 25-60% of the height hc from the bottom of the bead core 1 to the end of the turn-up portion 12B of the carcass ply in an unloaded state when the tire is mounted on the applicable rim and filled with the prescribed air pressure, in particular 35- It is preferable to determine to be within the range of 40% (see FIG. 6B). If the width w ₁ of the second intermediate rubber 15B is larger than 60% of the carcass folded-back portion height hc, air is likely to enter and the carcass ply folded-back portion 12B has poor quality.

  In the production method of the present invention, the bead filler and the soft rubber member, or the bead filler, the intermediate rubber and the soft rubber member are arranged between the main body portion and the folded portion of the carcass ply by the single stage molding. Only the point of formation is important, and the details of the other production steps are not particularly limited, and can be appropriately carried out according to a conventional method.

  The heavy-duty pneumatic radial tire of the present invention is manufactured by the manufacturing method of the present invention described above, and the inner end 4a in the tire radial direction of the soft rubber member 4 as shown in FIG. 6B, or a structure in which the inner end portions in the tire radial direction of the intermediate rubber 15 and the soft rubber member 14 are in contact with the folded portion 12B of the carcass ply as shown in FIG. . That is, in the tire of the present invention, the inner end portion of the soft rubber member (intermediate rubber) is disposed in a direction that matches the movement of the carcass cord during vulcanization. As a result, it is possible to prevent a decrease in durability due to the occurrence of separation.

  As described above, in the present invention, the bead filler is disposed for the purpose of ensuring the rigidity of the bead portion and is made of hard rubber, and the soft rubber member has a shear strain between the carcass ply body and the folded ply. It is arranged for the purpose of reducing and is made of soft rubber. Further, the intermediate rubber is arranged between the bead filler and the soft rubber member for the purpose of alleviating the difference in hardness between these rubber members, and is made of rubber having an intermediate hardness between the bead filler and the soft rubber member. . The hardness of each rubber member can be determined according to the purpose of use of the tire. Preferably, when the JIS-A hardness of the coating rubber of the carcass ply 2 is 100, the soft rubber member 4 Is set in a range of JIS-A hardness 70 to 90, and the bead filler 3 is set in a range of JIS-A hardness 110 to 130. Preferably, when the JIS-A hardness of the coating rubber of the carcass ply 12 is 100, the soft rubber member 14 has a JIS-A hardness of 70 to 85, and the bead filler 13 has a JIS-A hardness of 110. The intermediate rubber 15 is set so as to be harder than the soft rubber member 14 within the range of JIS-A hardness 75 to 90. If each hardness exceeds the upper limit, the crack growth property decreases, and if it is less than the lower limit, the case rigidity may not be ensured.

  The tire of the present invention is only required to be manufactured by the above-described manufacturing method of the present invention, whereby the desired effect of the present invention can be obtained. Is not particularly limited, and can be appropriately selected according to a conventional method. For example, as shown in FIG. 1, the tire of the present invention includes a pair of bead portions 20, a pair of sidewall portions 21 that are continuous with the bead portions 20, and a tread portion 22 that is continuous in a toroid shape between the sidewall portions 21. Although not shown, one or more belt layers made of a rubberized layer of a reinforcing cord are disposed on the outer periphery of the crown portion of the carcass ply. In addition, a tread pattern is appropriately formed on the surface of the tread portion 22, and an inner liner is formed in the innermost layer.

Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
A heavy-duty pneumatic radial tire having a bead portion cross-sectional structure shown in FIG. 4 at a tire size ORR59 / 80R63 was manufactured using a single-stage molding method schematically shown in FIG.

  First, the bead filler 3 is divided into a first bead filler 3A and a second bead filler 3B, the second bead filler 3B is attached to the bead core 1, and the first bead filler 3A is attached to the main body 2A of the carcass ply. Sticked. Here, when the JIS-A hardness of the coating rubber of the carcass ply 2 is 100, the JIS-A hardness of the bead filler 3 is 119, and the JIS-A hardness of the soft rubber member 4 is 78. Next, after adhering the soft rubber member 4 to the main body portion 2A of the carcass ply adjacent to the first bead filler 3A and covering the first bead filler 3A at the joint portion, the folded portion 2B is placed around the bead core 1. Then, the tire was molded and the tire of Example 1 was obtained.

(Example 2)
A heavy-duty pneumatic radial tire having a bead portion cross-sectional structure shown in FIG. 5 at a tire size ORR59 / 80R63 was manufactured using a single-stage molding method schematically shown in FIG.

  First, the bead filler 3 was divided into the first bead filler 3A and the second bead filler 3B, and the soft rubber member 4 was divided into the first soft rubber member 4A and the second soft rubber member 4B. Here, the width w along the carcass ply turn-up portion 2B of the second soft rubber member 4B is the turn-up portion from the bottom portion of the bead core 1 in a no-load state when the tire is mounted on the applicable rim and filled with the prescribed air pressure. The height up to the end of 2B was set to 35%. When the JIS-A hardness of the coating rubber of the carcass ply 2 was 100, the JIS-A hardness of the bead filler 3 was 119 and the JIS-A hardness of the soft rubber member 4 was 78.

  Next, the second bead filler 3B is adhered to the bead core 1, the first bead filler 3A is adhered to the main body portion 2A of the carcass ply, and the first soft rubber member 4A is attached to the main body portion 2A of the carcass ply. Adjacent to one bead filler 3A, it was stuck so as to cover the first bead filler 3A at the joint, and the second soft rubber member 4B was stuck to the folded portion 2B of the carcass ply. Thereafter, the folded portion 2B was folded around the bead core 1 to form a tire, whereby the tire of Example 2 was obtained.

(Comparative example)
With a tire size ORR59 / 80R63, a heavy-duty pneumatic radial tire having a bead portion cross-sectional structure shown in FIG. 7A was manufactured by ordinary single-stage molding.

  The test tires obtained in each of the examples and comparative examples were filled with an internal pressure of 600 kPa, loaded with a load of 94.5 tons, and subjected to a straight drum test at a traveling speed of 8 km / h. The crack generation state was confirmed. The results are shown in Table 1 below.

  As shown in Table 1 above, in the tire of each example manufactured by applying the manufacturing method of the present invention, it is possible to prevent the inner end portion of the soft rubber member from sinking into the ply coating rubber. It was confirmed that the separation failure caused by this could be prevented.

1 is a schematic cross-sectional view showing an example of a heavy-duty pneumatic radial tire of the present invention. It is explanatory drawing which concerns on the manufacturing method of the pneumatic radial tire for heavy loads of this invention. It is explanatory drawing which concerns on the manufacturing method of the other pneumatic radial tire for heavy loads of this invention. It is a schematic sectional drawing which shows the bead part cross-section of an example of the pneumatic radial tire for heavy loads of this invention. It is a schematic sectional drawing which shows the bead part sectional structure of an example of the pneumatic radial tire for other heavy loads of this invention. (A) is a schematic sectional drawing which shows the bead part cross-section of an example of the further another heavy-duty pneumatic radial tire of this invention, (b) is description which concerns on the manufacturing method of this pneumatic radial tire for heavy loads FIG. (A) is schematic sectional drawing which shows the bead part cross-section of an example of the conventional heavy-duty pneumatic radial tire, (b) is explanatory drawing which shows the state which the soft rubber member sunk into the coating rubber of the carcass ply. It is.

Explanation of symbols

1,11 Bead core 2,12 Carcass ply (2A, 12A body part, 2B, 12B folded part)
3,13 Bead filler (3A, 13A first bead filler, 3B, 13B second bead filler)
4,14 Soft rubber member (4A first soft rubber member, 4B second soft rubber member)
4a Inner end 15 of a soft rubber member Intermediate rubber (15A first intermediate rubber, 15B second intermediate rubber)
20 Bead part 21 Side wall part 22 Tread part

Claims (7)

A bead core embedded in each of the pair of bead portions is folded and locked from the inside to the outside of the tire, and a main body portion extending in a toroid shape between the bead cores. A bead filler disposed around the bead core between the main body portion and the folded portion of the carcass ply, and a bead filler of the bead filler. Manufacturing a heavy-duty pneumatic radial tire having a soft rubber member disposed on the outer side in the tire radial direction, and an inner end portion in the tire radial direction of the soft rubber member being in contact with the folded portion of the carcass ply In the method
A bead filler dividing step of dividing the bead filler into a first bead filler and a second bead filler;
While adhering the second bead filler to the bead core, the bead filler adhering step of adhering the first bead filler to the main body of the carcass ply;
A soft rubber member adhering step for adhering the soft rubber member to the main body portion of the carcass ply adjacent to the first bead filler so as to cover the first bead filler at a joint; and
A folding step of folding the folded portion of the carcass ply around the bead core;
The manufacturing method of the pneumatic radial tire for heavy loads characterized by including these. A bead core embedded in each of the pair of bead portions is folded and locked from the inside to the outside of the tire, and a main body portion extending in a toroid shape between the bead cores. A bead filler disposed around the bead core between the main body portion and the folded portion of the carcass ply, and a bead filler of the bead filler. Manufacturing a heavy-duty pneumatic radial tire having a soft rubber member disposed on the outer side in the tire radial direction, and an inner end portion in the tire radial direction of the soft rubber member being in contact with the folded portion of the carcass ply In the method
A bead filler dividing step of dividing the bead filler into a first bead filler and a second bead filler;
A soft rubber member dividing step of dividing the soft rubber member into a first soft rubber member and a second soft rubber member;
While adhering the second bead filler to the bead core, the bead filler adhering step of adhering the first bead filler to the main body of the carcass ply;
The first soft rubber member is attached to the main body portion of the carcass ply adjacent to the first bead filler so as to cover the first bead filler at a joint portion, and the second soft rubber member is A soft rubber member sticking step for sticking to the folded portion of the carcass ply;
A folding step of folding the folded portion of the carcass ply around the bead core;
The manufacturing method of the pneumatic radial tire for heavy loads characterized by including these. A bead core embedded in each of the pair of bead portions is folded and locked from the inside to the outside of the tire, and a main body portion extending in a toroid shape between the bead cores. A bead filler disposed around the bead core between the main body portion and the folded portion of the carcass ply, and a bead filler of the bead filler. For heavy load, having an intermediate rubber and a soft rubber member disposed on the outer side in the tire radial direction, and an inner end portion in the tire radial direction of the intermediate rubber and the soft rubber member being in contact with the folded portion of the carcass ply In the manufacturing method of the pneumatic radial tire,
A bead filler dividing step of dividing the bead filler into a first bead filler and a second bead filler;
An intermediate rubber dividing step of dividing the intermediate rubber into a first intermediate rubber and a second intermediate rubber;
While adhering the second bead filler to the bead core, the bead filler adhering step of adhering the first bead filler to the main body of the carcass ply;
The first intermediate rubber is attached to the main body portion of the carcass ply adjacent to the first bead filler so as to cover the first bead filler at a joint portion, and the second intermediate rubber is attached to the carcass ply. Intermediate rubber sticking process to stick to the folded part of
A soft rubber member adhering step of adhering the soft rubber member to the main body portion of the carcass ply adjacent to the first intermediate rubber so as to cover the first intermediate rubber at a joint portion;
A folding step of folding the folded portion of the carcass ply around the bead core;
The manufacturing method of the pneumatic radial tire for heavy loads characterized by including these.   The width of the second soft rubber member along the folded portion of the carcass ply is folded from the bottom of the bead core when the tire is mounted on an applicable rim and filled with a specified air pressure. The method for producing a heavy-duty pneumatic radial tire according to claim 2, wherein the height is within a range of 25 to 60% of the height to the end portion.   The width of the second intermediate rubber along the turn-up portion of the carcass ply when the tire is attached to an applicable rim and filled with a specified air pressure, and the turn-up portion of the carcass ply from the bottom of the bead core in a no-load state. The method for producing a heavy-duty pneumatic radial tire according to claim 3, wherein the height is within a range of 25 to 60% of the height to the end.   A heavy-duty pneumatic radial tire manufactured by the method for producing a heavy-duty pneumatic radial tire according to any one of claims 1 to 5.   When the JIS-A hardness of the coating rubber of the carcass ply is 100, the JIS-A hardness of the soft rubber member is in the range of 70 to 90, and the JIS-A hardness of the bead filler is 110 to 130. The heavy-duty pneumatic radial tire according to claim 6, which is in the range of.

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