JP2003226114A - Pneumatic tire and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire having both of WET draining performance and rolling resistance performance, and to provide a manufacturing method thereof. <P>SOLUTION: When a line separated from the tire equator line CL outward in the tire cross section at a distance L of 10-50% of a distance W between the equator line CL and the tread grounding end (k) is set as a central boundary 1, tanδ of a tread rubber 20A forming a central range CE from the tire equator line CL to the central boundary 1 at a temperature of 0° is set at 0.6 or more, and tanδ of a tread rubber 20B forming a shoulder range SE outside in the tire cross direction from the tread grounding end (k) at a temperature of 60° is set at 0.2 or less. With this structure, WET draining performance of the tread 22 in the central range CE on a central side in the tire cross direction is improved, and RR performance of the tread 22 in the shoulder range SE on a right side in the tire cross direction is improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pneumatic tire capable of achieving both WET drainage performance and RR performance (rolling resistance performance) and a method for manufacturing the pneumatic tire.

[0002]

2. Description of the Related Art In conventional pneumatic tires, WET
In order to improve drainage performance, there was a pattern / rubber correspondence method. That is, as a pattern correspondence method,
By increasing the negative ratio, forming multiple sipes on the tread surface, narrowing the tread width, etc., WE
The drainage performance was improved. However, there is a problem in that wearability and steering stability are reduced.

On the other hand, as a method for dealing with rubber, tan δ has been improved to improve WET drainage performance. However, wear resistance and rolling resistance performance (hereinafter referred to as "RR performance" as appropriate)
Called. ) Was worse.

The rolling resistance performance (hereinafter referred to as "RR
Performance ”. ) To improve the pattern
There was a rubber handling method. That is, as a method for dealing with patterns, RR performance is improved by eliminating sipes to be formed on the tread surface. However,
There was a problem that the WET drainage performance and riding comfort deteriorate.

On the other hand, as a method of dealing with rubber, the RR performance has been improved by decreasing tan δ. However, there is a problem that the WET drainage performance deteriorates.

In this way, when the WET drainage performance is improved, the rolling resistance performance tends to be inferior, and conversely,
When the rolling resistance performance is improved, the WET drainage performance tends to be inferior, and it is difficult to achieve both performances at the same time.

Further, conventionally, when the tread rubber is reduced due to abrasion or the like, there is a problem that the rolling resistance performance is reduced by the reduced volume.

[0008]

Therefore, in consideration of the above facts, the present invention changes the physical properties of the tread rubber composing the tread depending on the area of the tread.
An object of the present invention is to provide a pneumatic tire capable of achieving both ET drainage performance and rolling resistance performance and a manufacturing method thereof.

[0009]

A pneumatic tire according to claim 1, wherein the pneumatic tire has a tread made of tread rubber, the tire equatorial line extending from the tire equatorial line toward the outer side in the tire width direction. 0 ° C of the tread rubber forming the central region from the tire equator line to the central boundary line, when a line including a distance of 10% or more and 50% or less of the distance from the tire to the tread contact end is defined as the central boundary line.
Tan δ at 60 ° C. of the tread rubber forming the shoulder region outside the tread ground contact end is 0.2 or less.

Next, the function and effect of the pneumatic tire according to claim 1 will be described.

According to the experiments conducted by the inventors, it has been found that, in general, in the tread rubber, the larger the value of tan δ at 0 ° C., the better the WET drainage property. Also, 60
It was found that the smaller the value of tan δ at ° C, the better the rolling resistance performance (so-called RR performance). Further, when a tread rubber having a large tan δ value at 0 ° C. is arranged inside the tire width direction and a tread rubber having a small tan δ value at 60 ° C. is arranged outside the tire width direction, the WET drainage performance and the RR performance are It turns out that both can be achieved.

Therefore, in the pneumatic tire of the present invention, a line extending from the tire equator line toward the outer side in the tire width direction by a distance of 10% or more and 50% or less of the distance from the tire equator line to the tread ground contact end is the central boundary. When a line is used, the tan δ at 0 ° C. of the tread rubber that constitutes the central region from the tire equator line to the central boundary line is 0.6 or more, and the tread that constitutes the shoulder region on the outer side in the tire width direction from the tread grounding end. By setting the tan δ at 60 ° C. of the rubber to be 0.2 or less, both the WET drainage performance and the RR performance can be achieved. In particular, the fuel economy of the vehicle can be improved by improving the RR performance.

The tread rubber forming the intermediate region between the central region and the shoulder region is a normal tread rubber, for example, tan δ at 0 ° C. is 0.45 and tan δ at 60 ° C. is 0.25. Tread rubber is used.

Here, in the non-resonant forced vibration method in which the sinusoidal stress generated in a steady state is measured without giving the test piece of tread rubber a steady sinusoidal strain and causing the test piece to resonate, "tan δ" means , The tangent of the loss angle (δ). Further, the “loss angle (δ)” means a phase angle between strain and stress.

That is, when the dynamic storage elastic modulus is E'and the dynamic loss elastic modulus is E ", tan δ = E" / E 'is displayed.

Here, the dynamic storage elastic modulus E'is the real part of the complex elastic modulus, and means the magnitude of the in-phase stress component when a unit sinusoidal distortion is applied.

The dynamic loss elastic modulus is "E", which is the imaginary part of the complex elastic modulus and means the magnitude of a stress component whose phase advances by π / 2 from the distortion when a unit sinusoidal distortion is applied. To do.

Further, the pneumatic tire is used by being mounted on a rim defined by a standard issued by JATMA (Japan) or the like according to each size.

In the present specification, the "tread ground contact end" means a tread when the tire is assembled to the "standard rim", the "standard internal pressure" is filled, and the "standard load" is statically applied. Section refers to the outer end in the tire width direction (tire axial direction) that is in contact with the road surface.

Here, the standard load is the maximum load (maximum load capacity) of a single wheel in the applicable size described in the standard below, and the standard internal pressure is the unit load in the applicable size described in the standard below. It is the air pressure corresponding to the maximum load (maximum load capacity) of the wheel, and the rim is a standard rim in the applicable size described in the following standards.

The standard is defined by an industrial standard effective in the region where the tire is produced or used. For example, in Japan, "JATMA" of the Japan Automobile Tire Manufacturers Association
"Year Book".

The pneumatic tire manufacturing method according to claim 2 is the pneumatic tire manufacturing method according to claim 1, in which an unvulcanized rubber is wound around a molding drum to mold an inner liner. Inner liner molding process,
An unvulcanized rubber containing cord is attached from above the inner liner, a carcass layer forming step of forming a carcass layer, and an unvulcanized rubber is attached from above the carcass layer, a bead portion and a side portion. A tire outer contour molding step of molding, a belt layer molding step of pasting a belt from above the carcass layer, and molding a belt layer, from the tire equatorial line to the tire width direction outer side from the tire equatorial line to the tread ground end. When a line including a distance of 10% or more and 50% or less is defined as a central boundary line, a central region from the tire equator line to the central boundary line is formed, and t at 0 ° C. after vulcanization is set.
An unvulcanized first rubber having an δ of 0.6 or more and a vulcanized tan δ at 60 ° C. of 0.2 or less after vulcanization, which constitutes a shoulder region outside the tread ground contact end in the tire width direction. Stick the one that is integrated with the second rubber of sulfur,
And a tread forming step of forming a tread.

Next, the function and effect of the pneumatic tire manufacturing method according to the second aspect will be described.

The pneumatic tire according to claim 1 is manufactured as follows.

First, in the inner liner molding step, unvulcanized rubber is wound around the molding drum to mold the inner liner.

Next, in the carcass layer molding step, unvulcanized rubber containing the cord is attached from above the inner liner to mold the carcass layer.

Next, in the tire contour molding step, unvulcanized rubber is attached from above the carcass layer to mold the bead portion and the side portion.

Next, in the belt layer forming step, the belt is attached from above the carcass layer to form the belt layer.

Next, in the tread molding step, a line which is located at a distance of 10% or more and 50% or less of the distance from the tire equator line to the tread ground contact end outward from the tire equator line in the tire width direction is defined as the central boundary line. In the case of forming a central region from the tire equator line to the central boundary line and vulcanizing it at 0 ° C.
An unvulcanized first rubber having a tan δ of 0.6 or more,
The one in which the shoulder region located on the outer side in the tire width direction from the tread ground contact end is integrated and an unvulcanized second rubber having a tan δ at 60 ° C. of 0.2 or less after vulcanization is attached, and the tread is attached. Molded.

The unvulcanized third rubber forming the intermediate region between the central region and the shoulder region has, for example, a tan δ at 0 ° C. of 0.45 and a tan δ at 60 ° C. after vulcanization.
Is used, and these three types of rubber are integrated.

A raw tire is manufactured by the above steps.

This green tire is vulcanized by a vulcanizing mold in a subsequent vulcanizing step to manufacture a pneumatic tire.
With this manufacturing method, the pneumatic tire according to claim 1 can be manufactured efficiently and accurately.

The pneumatic tire manufacturing method according to claim 3 is the pneumatic tire manufacturing method according to claim 1, in which unvulcanized rubber is wound around the split core to form an inner liner. Inner liner molding process
An unvulcanized narrow ribbon-shaped rubber containing a cord is wound on the inner liner from one end in the core width direction to the other end, and when reaching one end or the other end, While wrapping the rubber back toward the other end or one end again, the rubber is transitionally moved in the circumferential direction of the core and continuously wound, and a carcass layer molding step of molding a carcass layer, and the carcass layer A belt layer molding process of pasting a belt from above and molding a belt layer,
When a line which is 10% or more and 50% or less of the distance from the tire equatorial line to the tread ground contact end on the belt layer outward from the tire equatorial line in the tire width direction is defined as a central boundary line, After vulcanization, the central region from the equator line to the central boundary line was formed and tan δ at 0 ° C was 0.6.
The unvulcanized narrow ribbon-shaped first rubber as described above is spirally wound in the core width direction, and the tread central region molding step of molding the tread central region, and from the tread contact end to the tire width direction outer side. A tread shoulder region is formed by spirally winding, in the core width direction, an unvulcanized narrow ribbon-shaped second rubber that constitutes a certain shoulder region and has a tan δ at 60 ° C. of 0.2 or less after vulcanization. And a tread shoulder region forming step.

Next, the function and effect of the method for manufacturing a pneumatic tire according to claim 3 will be described.

The pneumatic tire according to claim 1 is manufactured as follows.

In the inner liner molding step, unvulcanized rubber is wound around the split core to mold the inner liner.

Next, in the carcass layer molding step, an unvulcanized narrow ribbon-shaped rubber containing cord is wound from one end of the inner liner to the other end in the core width direction. When it reaches the end or the other end, the rubber is folded back and is wound again toward the other end or the one end, and the rubber is transitionally moved in the circumferential direction of the core and continuously wound to form the carcass layer. Is molded.

Next, in a tire outer shape forming step, unvulcanized rubber in the form of a narrow ribbon is attached from above the carcass layer to mold the bead portion and the side portion.

Next, in the belt layer forming step, the belt is attached from above the carcass layer to form the belt layer.

Next, in the tread center region molding step, a distance of 10% or more and 50% or less of the distance from the tire equator line to the tread ground contact end is provided on the belt layer from the tire equator line toward the outer side in the tire width direction. When the entered line is the central boundary line, it forms the central region from the tire equator line to the central boundary line, and after vulcanization, tan δ at 0 ° C is 0.6 or more. One rubber is spirally wound in the core width direction to mold the tread central region.

Next, in the tread shoulder region molding step, an unvulcanized narrow ribbon having a shoulder region outside the tread ground contact end in the tire width direction and having a tan δ at 60 ° C. of 0.2 or less after vulcanization is formed. -Shaped second rubber is spirally wound in the core width direction to mold the tread shoulder region.

Before the tread shoulder region molding process, in the tread intermediate region molding process, for example, tan δ at 0 ° C. after vulcanization is 0.45, and tan δ at 60 ° C.
An unvulcanized, narrow ribbon-shaped third rubber having a δ of 0.25 is spirally wound in the core width direction to mold the tread intermediate region.

A green tire is manufactured by the above steps.

This green tire is vulcanized by a vulcanization mold in a subsequent vulcanization process to manufacture a pneumatic tire.
The core is divided and removed after vulcanization.

According to this manufacturing method, the pneumatic tire according to claim 1 can be manufactured efficiently and accurately.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION A pneumatic tire according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the pneumatic tire 10 has a pair of left and right bead cores 12. A carcass layer 14 straddles the bead core 12 in a toroidal shape.

An inner liner 16 is arranged inside the carcass layer 14 in the tire radial direction.

A belt layer 18 is arranged on the outer side of the carcass layer 14 in the tire radial direction.

A tread rubber 20 is arranged outside the belt layer 18 in the radial direction of the tire.

Here, 10% or more of the distance W from the tire equator line CL to the tread ground contact end k from the tire equator line CL toward the outer side in the tire width direction (direction of the arrow A in FIG. 1) 5
When a line including a distance L of 0% or less is defined as the central boundary line l, in the central region CE from the tire equator line CL to the central boundary line l, the tread rubber 20A having a tan δ at 0 ° C. of 0.6 or more is It is used.

The center region CE has a trapezoidal shape in which the surface of the tread 22 is short and the side of the belt layer 18 is long when viewed from the cross section cut in the tire width direction.

On the other hand, in the shoulder region SE which is in the tire width direction outside from the tread ground contact end k by a distance S of 10% or more and 30% or less of the distance W from the tire equator line CL to the tread ground contact end k, at 60 ° C. A tread rubber 20B having a tan δ of 0.2 or less is used.

Further, the central area CE and the shoulder area SE
In the intermediate region ME located between the two, the tread rubber 20C having a tan δ at 0 ° C. of 0.45 and a tan δ at 60 ° C. of 0.25 is used.

A plurality of circumferential grooves 24 extending in the tire circumferential direction are formed on the surface of the tread 22.

As described above, in the pneumatic tire 10 of the present embodiment, the tread rubber 20A in the central region CE is the most excellent in terms of WET drainage performance, the tread rubber 20C in the middle region ME is next, and the last Further, the tread rubber 20B in the shoulder area SE is excellent. Therefore, the WET drainage performance is as follows: central area CE> middle area ME>
The order of the shoulder area SE is excellent.

On the other hand, regarding the RR performance, the tread rubber 20B in the shoulder region SE is the most excellent, the tread rubber 20C in the intermediate region ME is next excellent, and finally the tread rubber 20A in the central region CE is excellent. Therefore, the RR performance is as follows: shoulder area SE> intermediate area ME
> The order of the central area CE is excellent.

Next, a method of manufacturing the pneumatic tire 10 will be described.

The pneumatic tire 10 of the present invention has the following 2
It is manufactured by the same manufacturing method.

First, the first manufacturing method will be described.

In the inner liner molding step, unvulcanized rubber is wound around a molding drum (not shown),
The inner liner 16 is molded.

Next, in the carcass molding step, an unvulcanized rubber having a carcass cord coated with rubber is pressure-bonded onto the inner liner 16. As a result, the carcass layer 14 is molded.

Next, in the tire contour molding step, unvulcanized rubber is attached from above the carcass layer 14 to mold the bead portion 26 and the side portion 28.

Next, in the belt layer forming step, a plurality of belts are attached from above the carcass layer 14 to form the belt layer 18.

Next, in the tread molding step, a line extending from the tire equatorial line CL toward the outer side in the tire width direction by a distance L of 10% or more and 50% or less of the distance W from the tire equatorial line CL to the tread ground contact end k. Is the central boundary line l, an unvulcanized first rubber that constitutes the central region CE from the tire equator line CL to the central boundary line l and has a tan δ at 0 ° C. of 0.6 or more after vulcanization, An unvulcanized second part that forms a shoulder region SE on the tire width direction outer side from the tread ground contact end k and has a tan δ at 60 ° C. of 0.2 or less after vulcanization
The rubber and the intermediate region ME between the central region CE and the shoulder region SE are formed to have a tan δ at 0 ° C. of 0.4 after vulcanization.
Unvulcanized No. 3 with tan δ of 0.25 at 5 and 60 ° C
The rubber and the rubber are extruded from separate extruders (not shown).

The various rubbers that have been extruded are integrated by a conventionally known multi-head tuber (not shown), and the integrated one is pasted on the belt layer 18.

A raw tire is manufactured through the above steps.

After that, the green tire is vulcanized in the vulcanizing step by the vulcanizing mold to manufacture the pneumatic tire 10. By such a manufacturing method, the pneumatic tire 1 of the present invention
0 can be manufactured efficiently and accurately.

Next, the second manufacturing method will be described.

First, in the inner liner molding step, unvulcanized rubber is wound around a split core (not shown) to mold the inner liner 16.

Although not shown, this split core is
The split type non-deformable high-rigidity core, which has been known from the past and has an outer surface contour that is approximately similar to the inner surface shape of a product tire.

Next, in the carcass layer forming step, one or more carcass cords are bundled in parallel from above the inner liner 16 and the rubber-coated unvulcanized narrow ribbon-shaped rubber is applied in the core width direction. It is wound from one end to the other end, and when it reaches one end or the other end, the rubber is folded back and wound again toward the other end or one end, and the rubber is cored. Carcass layer 1 with transitional movement in the circumferential direction and continuous winding
4 is molded.

The small ribbon-shaped rubber is supplied from a conventionally known device (not shown) and is wound on the inner liner 16 by this device.

Next, in the tire outer contour molding step, unvulcanized small ribbon-shaped rubber is attached from above the carcass layer 14 to mold the bead portion 26 and the side portion 28.

The small ribbon-shaped rubber is also supplied from a conventionally known device (not shown) and is wound around the carcass layer 14 by this device.

Next, in the belt layer molding step, the belts are attached from above the carcass layer 14 to form the belt layer 1
8 is molded.

Next, in the tread central region molding step, on the belt layer 18, 10% or more of the distance W from the tire equator line CL to the tread ground contact end k is 50 or more from the tire equator line CL toward the outer side in the tire width direction. If the line containing the distance L of less than or equal to% is the central boundary line l, the tire equator line C
An unvulcanized narrow ribbon-shaped first rubber that constitutes a central region CE from L to the central boundary line l and has a tan δ at 0 ° C. of 0.6 or more after vulcanization is spiraled toward the core width direction. And the central region CE of the tread 22 is molded.

Next, in the tread intermediate region molding step, an unvulcanized narrow ribbon which constitutes the intermediate region ME and has a tan δ at 0 ° C. of 0.45 and a tan δ at 60 ° C. of 0.25 after vulcanization. -Shaped third rubber is spirally wound in the core width direction, and the intermediate region ME of the tread 22 is molded.

Next, in the tread shoulder region molding step, the shoulder region SE located outside the tread ground contact end k in the tire width direction is formed and tan at 60 ° C. after vulcanization.
The unvulcanized small ribbon-shaped second rubber having a δ of 0.2 or less is spirally wound in the core width direction, and the shoulder region SE of the tread 22 is molded.

A green tire is manufactured by the above steps.

This green tire is vulcanized by a vulcanizing mold in a subsequent vulcanizing step to manufacture the pneumatic tire 10. The core is divided and removed after vulcanization.

By the manufacturing method as described above, the pneumatic tire 10 of the present invention can be manufactured efficiently and accurately.

Next, the operation and effect of the pneumatic tire 10 will be described.

Experiments conducted by the inventors have revealed that, in general, the larger the value of tan δ at 0 ° C., the better the WET drainage of the tread rubber. Also, 60
It was found that the smaller the value of tan δ at ° C, the better the rolling resistance performance (so-called RR performance). Further, when a tread rubber having a large tan δ value at 0 ° C. is arranged inside the tire width direction and a tread rubber having a small tan δ value at 60 ° C. is arranged outside the tire width direction, the WET drainage performance and the RR performance are It turns out that both can be achieved.

Therefore, a line including a distance L of 10% or more and 50% or less of the distance W from the tire equator line CL to the tread ground contact end k from the tire equator line CL toward the outer side in the tire width direction is referred to as a central boundary line l. In this case, the tan δ at 0 ° C. of the tread rubber 20A forming the central region CE from the tire equator line CL to the central boundary line 1 is set to 0.6 or more, and the shoulder region SE on the tire width direction outer side from the tread ground contact end k. Of the tread rubber 20B constituting the
By setting nδ to 0.2 or less, the WET drainage performance can be improved in the central region CE of the tread 22 on the tire width direction center side, and the RR performance can be improved in the shoulder region SE on the tire width direction outer side of the tread 22. You can

As a result, the pneumatic tire 10 of the present invention can achieve both WET drainage performance and RR performance. In particular, the fuel economy of the vehicle can be improved by improving the RR performance.

(Test Example) Next, a test using the pneumatic tire of the present invention will be described.

The pneumatic tire of the present invention and the conventional pneumatic tire were tested for WET drainage performance and rolling resistance performance (WETμ test and RR measurement test).

Here, in the example of the pneumatic tire of the present invention which was the subject of this test, the tread rubber in the central region had a tan δ at 0 ° C. of 0.6, and the tread rubber in the shoulder region was 60. Tan δ at 0 ° C is 0.2, and the tan δ at 0 ° C is 0.
And tan δ at 60 ° C. is 0.25.

Further, with respect to the reference tire which is the conventional pneumatic tire which was the subject of this test, it was 0 in all areas.
Tan δ at ℃ is 0.45, tan δ at 60 ℃
Is 0.25.

The tire size of each of the above tires is 185/6.
5R14 and this tire was mounted on the rim of 5-1 / 2JX14. Moreover, the internal pressure of each tire was set to 180 kPa, and the load was set to 465 kg.

As a test method, in the WETμ test, the friction force generated between the WET road surface and the tire when braking and slip angle were applied to the tire under the WET condition via hydraulic pressure using a trailer was measured.

As a WET condition, the asphalt road surface with a water depth of 2 mm was used, and the frictional force was 40 km / h, 60 km /
The average value of the frictional force generated at each of h and 80 km / h was used.

On the other hand, in the RR measurement test, the tire was rotated on a uniaxial drum (normal running), and the resistance in the traveling direction generated between the tire and the ground contact surface at that time was measured.

The drum diameter of the uniaxial drum is 1.7 mm.
The resistance was measured at a speed of 200 km / h.

The results of this test are shown in Table 1 below.

The numerical values in Table 1 are index numbers with the reference tire as the reference (100).

Further, the WET drainage performance is shown by WETμ, and the larger the value in Table 1, the better the WET drainage performance. On the other hand, the RR performance is compared by the rolling resistance value, and the smaller the value in Table 1, the better the RR performance.

[0099]

[Table 1] As shown in Table 1 above, in the pneumatic tire of the present invention,
It was found that both the WET drainage performance and the RR performance were improved as compared with the standard tire.

As a result, in the pneumatic tire of the present invention,
It can be said that both WET drainage performance and RR performance could be achieved.

[0101]

EFFECTS OF THE INVENTION According to the pneumatic tire of the present invention and the method for producing the same, both the WET drainage performance and the RR performance can be achieved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a pneumatic tire according to an embodiment of the present invention.

[Explanation of symbols]

10 pneumatic tires 14 carcass layer 16 Inner liner 18 Belt layer 20A tread rubber 20B tread rubber 22 tread 26 Bead 28 Side part

Claims (3)

[Claims] 1. A pneumatic tire having a tread composed of a tread rubber, which is 10% or more and 50% or more of a distance from a tire equator line to a tread ground contact end outward from a tire equator line in a tire width direction.
When the line including only the following distance is taken as the central boundary line, tan δ at 0 ° C. of the tread rubber forming the central region from the tire equator line to the central boundary line is set to 0.6 or more, and the tread grounding end is To ta of the tread rubber composing the shoulder region on the outer side in the tire width direction at 60 ° C.
A pneumatic tire having nδ of 0.2 or less. 2. The method of manufacturing a pneumatic tire according to claim 1, wherein an inner liner molding step of molding an inner liner by winding unvulcanized rubber around a molding drum, and from the top of the inner liner. A carcass layer forming step of forming an unvulcanized rubber containing a cord and forming a carcass layer, and an outer peripheral forming of a tire in which an unvulcanized rubber is attached from above the carcass layer to form a bead portion and a side portion. A belt layer forming step of forming a belt layer by attaching a belt from above the carcass layer, and 10% or more of the distance from the tire equator line to the tread ground contact end from the tire equator line to the tire width direction outer side 50%
When the line including only the following distance is taken as the central boundary line, the central region from the tire equator line to the central boundary line is constituted, and the tan δ at 0 ° C. after vulcanization becomes 0.6 or more. 1 rubber and a shoulder region on the outer side in the tire width direction from the tread ground contact end, and tan at 60 ° C. after vulcanization
A method for manufacturing a pneumatic tire, comprising: a tread molding step of bonding an unvulcanized second rubber having a δ of 0.2 or less to a tread, and molding the tread. 3. The method for manufacturing a pneumatic tire according to claim 1, wherein an unvulcanized rubber is wound around a split core and an inner liner is molded, and an inner liner molding step is performed. Wrap an unvulcanized narrow ribbon-shaped rubber containing a cord from one end to the other end in the core width direction, and when it reaches one end or the other end, the rubber is folded back to the other end. Carcass layer forming step of forming a carcass layer by winding the rubber toward the end portion or one end portion while continuously moving the rubber in the circumferential direction of the core, and pasting the belt from above the carcass layer. And a belt layer forming step of forming a belt layer, and a distance of 10 from the tire equator line to the tread ground contact end on the belt layer from the tire equator line toward the outer side in the tire width direction. Or if only containing lines distance less than 50% and the central border, tan [delta at 0 ℃ to constitute a central region vulcanized from the tire equator line to the central border 0.6
The unvulcanized narrow ribbon-shaped first rubber as described above is spirally wound in the core width direction, and a tread central region molding step of molding a tread central region, and a tire width direction outer side from the tread ground end. After forming a certain shoulder region and vulcanizing, tan δ at 60 ° C is 0.2.
A pneumatic tire, comprising: a tread shoulder region forming step of forming a tread shoulder region by spirally winding an unvulcanized small-width ribbon-shaped second rubber in the core width direction as described below. Manufacturing method.