JP5743464B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire in which a tire frame member is formed of a resin material.

  In recent years, a so-called resin tire has been proposed in which a tire frame member is formed of a resin material and a rubber tread is provided on the outer periphery of the tire frame member.

JP 05-116504 A

However, in the conventional resin tire, the tire outer portion such as the side portion and the bead portion is a tire skeleton member (sometimes called a tire case, a pressure vessel or the like) itself, and the resin material is exposed on the surface of the tire outer portion. It has a configuration.
Pneumatic tires have different properties such as flexibility (spring), fatigue resistance, trauma resistance, weather resistance, wear resistance, heat resistance, etc. for absorbing impacts from the road surface. A plurality of types of rubber members are used in these rubber pneumatic tires.
Various materials are commercially available or proposed as resin materials, but the performance required for the outer part of the tire, such as trauma resistance and weather resistance, is not comparable to the rubber materials used in current pneumatic tires. However, the resin tire is required to improve the durability of the outer portion of the tire.

  In view of the above fact, an object of the present invention is to improve durability of a tire outer portion in a pneumatic tire in which a tire frame member is formed of a resin material.

The pneumatic tire according to claim 1, Rutotomoni provided a tire frame member made of resin material formed into a toroidal shape so as to extend between the pair of bead portions, the outer peripheral surface of the tire frame member, the end portion A cushion rubber formed in a tapered shape that gradually decreases in thickness, a tread layer provided on the cushion rubber, and an end on the inner side in the tire radial direction of the tread layer so as to cover an outer portion of the tire frame member the outer surface of the sidewall portion from the parts, and provided continuously to the inner surface of the bead portion, the tread layer side of the tapered shape formed end, and the end portion which is tapered the cushion rubber is bonded And a covering layer formed to be continuous with the cushion rubber .

Next, the operation of the pneumatic tire according to claim 1 will be described.
In the pneumatic tire according to claim 1, since the coating layer is provided on the outer side portion of the tire skeleton member made of a resin material, it is possible to suppress trauma of the tire outer side portion of the tire skeleton member caused by contact with the curbstone or the like. I can do it.
In addition, since the resin material of the tire frame member is covered with the coating layer and not exposed to the outside, deterioration of the resin material due to sunlight, water, etc. from the outside of the tire is suppressed, and the weather resistance of the tire outer portion of the tire frame member is suppressed. Improves.
In addition, by continuously extending the coating layer from the outer surface to the inner surface of the bead portion, the coating layer can be brought into contact with the rim, and the sealing property between the bead portion and the rim is a conventional general rubber. It can be secured in the same manner as a pneumatic tire made of steel.

  The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the coating layer is vulcanized rubber.

Next, the operation of the pneumatic tire according to claim 2 will be described.
By using a vulcanized rubber as the coating layer, it is possible to obtain the same damage resistance and weather resistance at the tire outer side as those of a conventional general rubber pneumatic tire.
In addition, it is preferable to use the rubber | gum similar to the rubber | gum currently used for the sidewall of the conventional general rubber-made pneumatic tire and the outer surface of a bead part as a rubber | gum used for a coating layer.

The invention according to claim 3 is the pneumatic tire according to claim 2, wherein the tread layer is vulcanized rubber .

Next, the operation of the pneumatic tire according to claim 3 will be described.
In the pneumatic tire according to claim 3, the outer peripheral surface of the tire frame member is covered with a tread layer made of vulcanized rubber, and the outer side surface (tire side) of the tire frame member is covered with a cover layer made of vulcanized rubber. Therefore, the entire tire outer surface of the tire frame member is covered with the vulcanized rubber, and the deterioration of the resin material due to sunlight, water, etc. from the outside of the tire can be suppressed. For this reason, in the pneumatic tire of claim 3, weather resistance equivalent to that of a conventional general rubber pneumatic tire can be obtained on the outer surface (outer peripheral surface and outer surface) of the tire frame member.
In addition, the rubber | gum used for a tread layer uses the thing excellent in abrasion resistance at least compared with the resin material used for a tire frame member.

  According to a fourth aspect of the present invention, in the pneumatic tire according to the third aspect, the tread layer and the covering layer are integrally formed.

Next, the operation of the pneumatic tire according to claim 4 will be described.
In the pneumatic tire according to claim 4, since the vulcanized rubber coating layer and the vulcanized rubber tread layer are integrally formed, there is no seam between the coating layer and the tire frame member, and the The problem such as peeling of the seam is not fundamentally caused by the use or the like, and the durability can be improved. In addition, since the entire outer surface of the pneumatic tire is covered with vulcanized rubber, the appearance quality similar to that of a conventional general rubber pneumatic tire can be obtained.

According to a fifth aspect of the present invention, in the pneumatic tire according to the third or fourth aspect, the tread layer and the covering layer are made of different types of rubber.

Next, the operation of the pneumatic tire according to claim 5 will be described.
By configuring the tread layer and the coating layer with different types of rubber, rubber suitable for the tread layer can be used for the tread layer, and rubber suitable for the outer portion of the tire can be used for the coating layer.
For example, the rubber of the tread layer can use at least a rubber having higher abrasion resistance than the rubber of the coating layer, and the rubber of the coating layer is more resistant to damage (not easily cracked than the rubber of the tread layer). It is preferable that even if cracks occur, it is difficult for cracks to develop.), And rubber having excellent weather resistance can be used.

The invention according to claim 6 is the pneumatic tire according to any one of claims 1 to 5 , wherein the coating layer includes a cord layer or a fiber layer.

Next, the operation of the pneumatic tire according to claim 6 will be described.
Since the cord layer or the fiber layer is included in the coating layer, the damage resistance of the outer portion of the tire can be further improved.

As described above, since the pneumatic tire according to claim 1 has the above-described configuration, the durability of the outer portion of the tire can be improved.
Since the pneumatic tire according to claim 2 has the above-described configuration, it is possible to obtain external damage and weather resistance equivalent to those of a conventional general rubber pneumatic tire.
Since the pneumatic tire according to claim 3 has the above-described configuration, it is possible to obtain the weather resistance of the tire outer surface (outer surface and outer peripheral surface) equivalent to a conventional general rubber pneumatic tire.
Since the pneumatic tire according to claim 4 has a configuration described above, high durability can be obtained, also, it is possible to obtain the same quality of appearance and the pneumatic tire of the conventional general rubber.
Since the pneumatic tire according to claim 5 has the above-described configuration, the tread layer and the tire outer portion can sufficiently exhibit the characteristics of the rubber material at each portion, and the tread layer and the tire outer portion. Thus, performance similar to that of a conventional rubber pneumatic tire can be obtained.
Since the pneumatic tire according to claim 6 has the above-described configuration, it is possible to further improve the damage resistance of the outer portion of the tire.

It is the perspective view which made the section which shows the whole structure of a pneumatic tire the cross section. It is a disassembled perspective view of a pneumatic tire. It is a perspective view which shows the temporary assembly covered with the envelope. It is sectional drawing which shows an example of a temporary assembly. It is sectional drawing which shows typically the example which has arrange | positioned the temporary assembly supported by the supporting member on a trolley in the container for vulcanization | cure. It is sectional drawing which shows another example of a temporary assembly.

A structure of a pneumatic tire 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, the pneumatic tire 10 includes a tire skeleton member 12 that is formed using a resin material and straddles one bead portion 28 and the other bead portion 28 in a toroidal shape. A tread layer 16 is disposed on the outer peripheral surface, and a side coating layer 36 is disposed on the outer surface of the tire frame member 12.

(Tire frame member)
The tire frame member 12 of the present embodiment uses a thermoplastic material, for example, a shape corresponding to the crown portion 24 of the pneumatic tire 10, and a side continuous from the both sides in the tire axial direction of the crown portion 24 to the inside in the tire radial direction. For example, it is molded by injection molding or the like so as to have a shape corresponding to the wall portion 26 and a shape corresponding to the bead portion 28 connected to the inside of the sidewall portion 26 in the tire radial direction.

  A bead core 30 is embedded in the bead portion 28. As the material of the bead core 30, for example, metal, organic fiber, organic fiber coated with resin, hard resin, or the like can be used. The bead core 30 may be omitted if the rigidity of the bead portion 28 is ensured and there is no problem in fitting with the rim (not shown).

  As the resin material constituting the tire frame member 12, rubber-like elastic thermoplastic resin, thermoplastic elastomer (TPE), thermosetting resin, or the like can be used. Considering the properties, it is desirable to use a thermoplastic elastomer.

Examples of the thermoplastic elastomer include amide-based thermoplastic elastomer (TPA), ester-based thermoplastic elastomer (TPC), olefin-based thermoplastic elastomer (TPO), styrene-based thermoplastic elastomer (TPS) specified in JIS K6418, Examples thereof include urethane-based thermoplastic elastomer (TPU), crosslinked thermoplastic rubber (TPV), and other thermoplastic elastomers (TPZ).
Examples of the thermoplastic resin include urethane resin, olefin resin, vinyl chloride resin, polyamide resin, and the like.

  Further, as these thermoplastic materials, for example, the deflection temperature under load (0.45 MPa load) specified in ISO75-2 or ASTM D648 is 78 ° C or higher, and the tensile yield strength specified in JIS K7113 is 10 MPa or higher. Also, the tensile yield point elongation specified in JIS K7113 is 10% or more, the tensile fracture elongation specified in JIS K7113 is 50% or more, and the Vicat softening temperature (Method A) specified in JIS K7206 is 130 ° C or more. Can be used.

  The tire skeleton member 12 of the present embodiment is first molded into a halved shape centered around the center of the pneumatic tire 10 in the tire width direction, that is, the tire equatorial plane CL, or the vicinity thereof. It is comprised by joining edge parts. For this joining, for example, a welding method using the same or different thermoplastic material or molten resin, or a hot plate is sandwiched between the ends, and the hot plates are removed while pressing the ends closer together. Then, joining may be performed by a hot plate welding method for welding a half-shaped product in a molten state at the end portion. Furthermore, a joint member 34 such as an adhesive may be used in combination with these.

  A reinforcing cord 32 is wound around the crown portion 24 of the tire frame member 12 in a spiral shape, for example. As the cord 32, for example, a steel cord, a monofilament (single wire) such as a metal fiber or an organic fiber, or a multifilament (twisted wire) obtained by twisting these fibers may be used. When a steel cord is used as the cord 32, for example, a sheet (not shown) made of a thermoplastic material is attached to the outer side of the crown portion 24 in the tire diameter direction, and the cord 32 is heated while the cord 32 is heated. It can be buried by spiral winding in the circumferential direction. At this time, both the cord 32 and the sheet may be heated.

  As described above, the reinforcing cord 32 is spirally wound around the crown portion 24 in the tire circumferential direction, whereby the rigidity of the crown portion 24 in the tire circumferential direction is improved and the fracture resistance of the crown portion 24 is improved. Can be improved. Moreover, the puncture resistance in the crown part 24 of the pneumatic tire 10 can thereby be improved. When reinforcing the crown portion 24, it is preferable to wind the cord 32 spirally in the tire circumferential direction because it is easy to manufacture, but the cord 32 may be discontinuous in the tire width direction. Further, a further reinforcing material (polymer material, metal fiber, cord, nonwoven fabric, woven fabric) is embedded in the tire frame member 12 (for example, the bead portion 28, the sidewall portion 26, the crown portion 24, etc.). The tire frame member 12 may be reinforced.

(Tread layer)
A tread layer 16 is disposed on the outer peripheral surface of the tire frame member 12 via a cushion rubber 14.
The tread layer 16 of the present embodiment uses a rubber similar to a conventional tread rubber of a rubber pneumatic tire or a tread rubber for a retread tire.
The cushion rubber 14 can be the same as the cushion rubber used when manufacturing a precure (cold) retread tire in which a vulcanized rubber having a tread surface molded in advance is pasted.
A drain groove 16A is formed on the tread layer 16 in the same manner as a conventional rubber pneumatic tire. Moreover, a well-known thing is used as a tread pattern.

(Side coating layer)
A side coating layer 36 is disposed on the outer surface of the tire frame member 12. For the side coating layer 36 of the present embodiment, the same rubber as that used for the sidewalls of conventional conventional rubber pneumatic tires and bead portions is used.
The side coating layer 36 of the present embodiment continuously extends from the end portion of the tread layer 16 to the inner surface of the bead portion 28 through the outer surface of the sidewall portion 26, the outer surface of the bead portion 28, and the inner end of the bead portion 28. ing.

  In the present embodiment, the thickness of the cushion rubber 14 and the thickness of the side coating layer 36 are set to be substantially the same. Moreover, the end part formed in the taper shape of the side coating layer 36 and the end part formed in the taper shape of the cushion rubber 14 are joined so that the side coating layer 36 and the cushion rubber 14 may be continuous.

  Thus, in the pneumatic tire 10 of the present embodiment, the entire outer surface of the tire frame member 12 is completely covered with the vulcanized rubber.

(Pneumatic tire manufacturing method)
Next, the manufacturing method of the pneumatic tire 10 of this embodiment is demonstrated.
(1) First, the tire frame member 12 made of a resin material, the vulcanized or semi-vulcanized tread layer 16, and the vulcanized or semi-vulcanized side coating layer 36 are formed in advance.
In addition, it is preferable to shape | mold the side coating layer 36 in the shape along the sticking site | part of the tire frame member 12. As shown in FIG.

(2) As shown in FIG. 2, a cushion rubber 14, which is an example of an unvulcanized rubber, is disposed on the outer peripheral surface 12 </ b> A of the tire frame member 12, and vulcanized or A semi-vulcanized tread layer 16 is disposed. When the tread layer 16 is disposed on the outer periphery of the cushion rubber 14, for example, the belt-like tread layer 16 may be wound around the outer periphery of the cushion rubber 14 in an annular shape, or a tread formed in advance in an annular shape. Layer 16 may be used. A tread pattern is engraved on the surface of the tread layer 16.

  When disposing the unvulcanized cushion rubber 14 on the outer peripheral surface 12A of the tire frame member 12, it is preferable to apply, for example, one or two layers of adhesive 40 to the outer peripheral surface 12A. The adhesive 40 is preferably applied in an atmosphere with a humidity of 70% or less. The adhesive 40 is not limited to a specific type, but for example, a triazine thiol-based adhesive can be used. Other examples include a chlorinated rubber adhesive, a phenol resin adhesive, an isocyanate adhesive, and a halogen. A rubberized adhesive or the like can also be used.

  In addition, before applying the adhesive 40 to the outer peripheral surface 12A, it is preferable to buff the outer peripheral surface 12A with sandpaper, a grinder, or the like. This is because the adhesive 40 is easily attached to the outer peripheral surface 12A. Furthermore, it is preferable to degrease the outer peripheral surface 12A after buffing with alcohol or the like. Further, it is preferable to perform corona treatment or ultraviolet irradiation treatment on the outer peripheral surface 12A after buffing.

  When the vulcanized or semi-cured tread layer 16 is disposed on the outer side in the tire diameter direction of the cushion rubber 14, a member having adhesiveness on the back surface side of the tread layer 16 or the outer peripheral surface side of the cushion rubber 14. For example, it is preferable to apply the rubber cement composition 42 in advance. This is because the tread layer 16 is temporarily attached to the cushion rubber 14 to improve the workability.

  When SBR (styrene-butadiene rubber) is used as the material of the tread layer 16, it is preferable to use, for example, SBR splice cement as the rubber cement composition 42. Further, when an SBR rubber having a high NR (natural rubber) blending ratio is used as the material of the tread layer 16, it is preferable to use a blend of BR (butadiene rubber) with an SBR splice cement. In addition, as the rubber cement composition 42, it is possible to use a solventless cement containing a liquid elastomer such as liquid BR or a cement mainly composed of a blend of IR (isoprene rubber) -SBR.

(3) Next, the vulcanized or semi-cured side coating layer 36 is disposed on the outer surface 12B of the tire frame member 12.
When the side coating layer 36 is disposed on the outer surface 12B of the tire frame member 12, the adhesive 40 or the rubber cement composition 42 is applied to the outer surface 12B. Before applying the adhesive 40 or the rubber cement composition 42 to the outer surface 12B, the outer surface 12B may be buffed with sandpaper or a grinder, and the outer surface 12B after buffing is washed with alcohol or the like. Degreasing may be performed, and corona treatment or ultraviolet irradiation treatment may be performed on the outer surface 12B after buffing. In addition, a display (not shown) such as a manufacturer name, a product name, and a tire size is formed on the outer surface of the side covering layer 36.

(4) As shown in FIG. 3 and FIG. 4, a pair of annular support members having a structure close to the rim, covering the entire outer surface of the tire frame member 12 on which the tread layer 16 and the side covering layer 36 are arranged with an envelope 18. 66. An end edge (not shown) of the envelope 18 in the tire radial direction is sandwiched between the bead portion 28 and the flange portion 66F. Further, a pressing member 90 formed of an elastic body such as rubber is temporarily disposed in the groove 16A so as to fill the groove 16A (the pressing member 90 is removed after vulcanization).
The envelope 18 is a covering member made of, for example, rubber having airtightness and stretchability, moderately stable thermally and chemically, and having appropriate strength. The envelope 18 is provided with a valve 64 for evacuating the region covered with the envelope 18 to press the tread layer 16 and the side coating layer 36 against the tire frame member 12 side. The valve 64 preferably has a valve mechanism (not shown) for preventing the inflow of air from the outside into the envelope 18 after evacuation.

As shown in FIG. 4, an expandable / contractable annular bladder 70 is disposed on the inner surface side of the tire frame member 12. By inflating the bladder 70, the inner surface side of the tire frame member 12 can be pressed by the outer surface of the bladder 70. Thereby, the vicinity of the end portion in the tire radial direction of the side coating layer 36 can be pressed against the inner surface of the bead portion 28, and the shape of the tire frame member 12 can be maintained. The bladder 70 is provided with a valve (not shown) for allowing air to enter and exit the inside.
In this way, the tire frame member 12 on which the tread layer 16 and the side covering layer 36 are disposed is covered with the envelope 18, and the bladder 70 is disposed on the inner side and assembled to the support member 66 to form the temporary assembly 20.

(5) And as shown in FIG. 5, this temporary assembly 20 is accommodated in the container 22, and the inside of the container 22 is heated and pressurized to perform vulcanization. The container 22 is a so-called vulcanization can, but may be any container as long as it has a capacity for accommodating the temporary assembly 20 and can withstand heating and pressurization during vulcanization.
Since the tire frame member 12 is a thermoplastic resin, the temperature at the time of vulcanization is set to be lower than the melting point of the thermoplastic resin so that the tire frame member 12 is not melted or softened and deformed.
Of course, the vulcanization time is set to a time required for the cushion rubber 14 to be completely vulcanized. When the tread layer 16 and the side coating layer 36 are semi-vulcanized products, the vulcanization time is of course set to a time necessary for the tread layer 16 and the side coating layer 36 to be completely vulcanized. . The vulcanization time and vulcanization temperature are appropriately set to optimum values depending on the rubber used.

  In this embodiment, the unvulcanized rubber is only the thin sheet-like cushion rubber 14 before vulcanization, and the other rubbers, that is, the tread layer 16 and the side coating layer 36 are semi-vulcanized or completely vulcanized. Therefore, the vulcanization time can be greatly shortened as compared with the case where the tread layer 16 and the side coating layer 36 are made of unvulcanized rubber.

  When a thermoplastic resin is used as a member constituting the tire as in the pneumatic tire 10 of the present embodiment, in order to prevent deformation of the member (tire frame member 12) formed of the thermoplastic resin, There is a limitation that the vulcanization temperature cannot be raised satisfactorily (compared to the vulcanization temperature of a conventional rubber pneumatic tire not using a thermoplastic resin). Therefore, in order to completely vulcanize the rubber, the vulcanization time must be extended (compared with the vulcanization time of a conventional rubber pneumatic tire not using a thermoplastic resin).

  In the pneumatic tire 10 of the present embodiment, the tread layer 16 and the side covering layer 36 are semi-cured or completely vulcanized, and the unvulcanized rubber is only the thin sheet-like cushion rubber 14. Therefore, as described above, compared with the case where the tread layer 16 and the side coating layer 36 are made of unvulcanized rubber, the vulcanization time can be greatly shortened, and the deterioration of the cycle time can be suppressed. it can.

In the pneumatic tire 10 of the present embodiment, since the outer surface of the tire frame member 12 formed of a thermoplastic resin is covered with the side coating layer 36, when the thermoplastic resin is exposed to the tire outer portion. In comparison, for example, the damage resistance of the outer side of the tire due to contact with a curb or the like and the weather resistance due to sunlight, water, or the like can be greatly improved.
Further, since the side coating layer 36 covers the portion that comes into contact with the rim, that is, the outer surface and the inner end portion of the bead portion 28, a conventional rubber pneumatic tire is provided between the rim and the bead portion 28. The same high sealing performance can be obtained.

Thus, in the present embodiment, the tread layer 16 and the side coating layer 36 are joined to the tire frame member 12 using a thermoplastic material without using a vulcanization mold that requires a large vulcanizing device. Therefore, the manufacturing cost of the pneumatic tire 10 using the thermoplastic material for the tire frame member 12 can be reduced.

  The pressurization in the container 22 is not necessarily essential, and vulcanization can be performed only by heating. However, by applying pressure in the container 22, the adhesion of the tread layer 16 to the tire frame member 12 can be further increased.

[Other Embodiments]
In the above embodiment, only the adhesive 40 or the rubber cement composition 42 is interposed between the side coating layer 36 and the tire frame member 12, but as between the tread layer 16 and the tire frame member 12. A thin sheet-like unvulcanized rubber sheet may be interposed.

In the above embodiment, the tread layer 16 and the side covering layer 36 to be attached to the tire frame member 12 are formed as separate bodies, but the tread layer 16 and the side covering layer 36 may be formed integrally. .

  In the above embodiment, vulcanization was performed using the support member 66 and the bladder 70, but the tread layer 16 and the side coating layer 36 were not used without using the support member 66 and the bladder 70 as shown in FIG. Further, not only the outer surface side of the tire frame member 12 but also the inner surface side may be covered with the envelope 18.

  In addition, the form which covers the tread layer 16, the side coating layer 36, and the tire frame member 12 with the envelope 18 is not limited to the present embodiment and the illustrated configuration. The order of the steps in the tire manufacturing method according to the present embodiment can be changed as appropriate.

  In the above embodiment, the end portion of the side coating layer 36 wraps around to the inner surface of the bead portion 28. However, it is sufficient that at least the outer surface of the tire frame member 12 is not exposed when attached to the rim. If there is no problem with the sealing performance, the side coating layer 36 may extend from the tread end to a position in contact with the flange portion of the rim.

  In the above embodiment, the material of the side coating layer 36 is vulcanized rubber, but may be a resin material in some cases. When the material of the side coating layer 36 is a resin material, it is made of a resin material different from the thermoplastic resin constituting the tire frame member 12 and is more resistant to external damage than the thermoplastic resin constituting the tire frame member 12. It is necessary to use a resin material having excellent properties and weather resistance.

In the above embodiment, the material of the side coating layer 36 was only vulcanized rubber. However, in some cases, in order to improve the damage resistance, for example, a cord layer made of inorganic fiber, organic fiber or the like, a nonwoven fabric, A reinforcing layer such as a fiber layer of woven fabric or the like may be embedded. Thereby, the progress of cracks and the like can be suppressed.
A reinforcing layer such as a cord layer made of inorganic fiber, organic fiber or the like, or a fiber layer such as nonwoven fabric or woven fabric is attached to the outer surface of the tire frame member 12, and a side coating layer 36 is attached thereon. May be.

  In the above embodiment, the material of the side coating layer 36 is only one type of vulcanized rubber. However, depending on the case, a configuration of two or more layers made of different types of rubber may be used.

  In the above embodiment, the material of the tread layer 16 is vulcanized rubber. However, in some cases, a resin material may be used. When the material of the tread layer 16 is a resin material, it is a resin material different from the thermoplastic resin constituting the tire frame member 12 and is more resistant to abrasion than the thermoplastic resin constituting the tire frame member 12. It is preferable to use a resin material that excels in resistance.

  In the above embodiment, the tread layer 16 made of a material different from that of the tire frame member 12 is provided on the outer peripheral surface of the tire frame member 12, but in some cases, the crown portion 24 of the tire frame member 12 is formed thick, The tread layer 16 may be used instead.

  In addition, it is preferable to set the hardness of the side coating layer 36 and the tire frame member 12 to be equal so that the side coating layer 36 and the tire frame member 12 do not peel due to bending deformation of the pneumatic tire 10 during traveling. .

10 Pneumatic tire 12 Tire frame member 16 Tread rubber (tread layer)
26 Side wall (outer side)
28 Bead part (outer part)
36 Side coating layer (coating layer)

Claims (6)

A tire skeleton member made of a resin material formed in a toroid shape so as to straddle between a pair of bead parts;
A cushion rubber Rutotomoni, the thickness of the end portion formed to gradually thinning tapered provided on the outer circumferential surface of the tire frame member,
A tread layer provided on the cushion rubber;
Provided continuously from the tire radial inner end of the tread layer to the outer surface of the sidewall portion and the inner surface of the bead portion so as to cover the outer portion of the tire frame member, and formed in a tapered shape on the tread layer side and the end is, the an end portion formed in a tapered cushion rubber is bonded, and a coating layer formed so as to be continuous with the cushion rubber,
Pneumatic tire having   The pneumatic tire according to claim 1, wherein the coating layer is vulcanized rubber.   The pneumatic tire according to claim 2, wherein the tread layer is vulcanized rubber.   The pneumatic tire according to claim 3, wherein the tread layer and the covering layer are integrally formed.   The pneumatic tire according to claim 3 or 4, wherein the tread layer and the coating layer are made of different types of rubber.   The pneumatic tire according to any one of claims 1 to 5, wherein the coating layer includes a cord layer or a fiber layer in the coating layer.