JP2012035499A - Method of manufacturing tire, tread member and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing the tire which enhances adhesiveness between a tread member and a tire frame member while reducing rolling resistance in the tire having the tire frame member formed by using a resin material, and the tire.SOLUTION: A vent 18 penetrated to the side opposite to a grounding surface 12 is formed on the bottom part 16A of a lateral main groove 16 (groove) of the tread member 10, so that when the tread member 10 and the tire frame member 24 are adhered to each other, air between the tread member 10 and the tire frame member 24 can be smoothly discharged through the vent 18 to the inside of the lateral main groove 16 (groove). This is particularly effective when a gauge G of the bottom part 16A of the lateral main groove 16 (groove) is set thin in order to reduce the volume of the tread member 10.

Description

  The present invention relates to a tire manufacturing method, a tread member, and a tire.

  A tire mounted on a rim includes one bead in which a bead core is embedded, a sidewall connected to the bead, and a protruding piece connected to the sidewall. The tire is integrally formed of a polymer material and the protruding pieces are joined to each other. A reinforcing cord is continuously wound in the tire circumferential direction on the outer surface in the tire radial direction of the tread bottom portion of the tire body in a spiral manner on a tire body made of a pair of semi-annular tire pieces that can form a tread bottom portion A structure is disclosed in which at least one reinforcing layer and a tread rubber attached to the outside of the reinforcing layer are integrated by vulcanization in a vulcanization mold (see Patent Document 1).

JP-A-3-143701

  When the gauge at the bottom of the groove in the tread member is relatively thick as in the conventional example described above, the bottom of the groove is highly rigid, so when the tread member is integrated with the tire body, The air between the tire body could be pushed out.

  However, if the gauge at the bottom of the groove in the tread member is thickened, the volume of the tread member increases, which is disadvantageous in terms of rolling resistance. In addition, when the gauge at the bottom of the groove of the tread member is thin, the rigidity of the bottom of the groove is low and easily deformed. Therefore, when the tread member is bonded to the tire frame member, the gap between the tread member and the tire frame member is It is considered that a part of the air tends to remain at the bottom of the groove.

  In view of the above facts, an object of the present invention is to increase the adhesion between the tread member and the tire frame member while reducing the rolling resistance by reducing the volume of the tread member.

  According to the first aspect of the present invention (tire manufacturing method), a tire frame member is formed using a resin material, a groove is formed on the grounding surface side, and a ventilation hole is formed through the bottom of the groove on the opposite side to the grounding surface. The tread member formed with the tire frame member is disposed outside the tire frame member in the tire diameter direction, an adhesive member is disposed between the outer peripheral surface of the tire frame member and the tread member, and the tread member is disposed on the tire frame member. Adhere to.

  In the method for manufacturing a tire according to claim 1, since a vent hole penetrating on the side opposite to the ground contact surface is formed at the bottom of the groove of the tread member, when the tread member is bonded to the tire frame member, Air between the tread member and the tire frame member can be smoothly discharged into the groove through the vent hole. This is particularly effective when the gauge at the bottom of the groove is thin in order to reduce the volume of the tread member. For this reason, the adhesiveness between a tread member and a tire frame member can be enhanced while reducing the rolling resistance by reducing the volume of the tread member.

  According to a second aspect of the present invention (tire manufacturing method), in the tire manufacturing method according to the first aspect, the vent is formed when the tread member is formed.

  In the tire manufacturing method according to the second aspect, since the vent hole at the bottom of the groove is formed when the tread member is formed, an increase in the number of steps can be suppressed.

  A third aspect of the present invention (a method for manufacturing a tire) is the method for manufacturing a tire according to the first or second aspect, wherein the air hole is formed after the tread member is formed and before the adhesion to the tire frame member. Perforated.

  In the method for manufacturing a tire according to claim 3, since the ventilation holes in the groove wall are perforated after molding the tread member and before bonding to the tire frame member, the position, number, size, etc. of the ventilation holes are determined. It can be set arbitrarily. For this reason, the tread member which has various ventilation holes at low cost can be manufactured.

  According to a fourth aspect of the present invention (tread member), a groove is formed on the grounding surface side, and a vent hole penetrating on the opposite side of the grounding surface is formed at the bottom of the groove.

  In the tread member according to claim 4, with such a configuration, when the tread member is bonded to the outer peripheral surface of the tire frame member, the air between the tread member and the tire frame member is allowed to pass through the ventilation hole at the bottom of the groove. It can be smoothly discharged into the groove.

  According to a fifth aspect of the present invention (tire), a tire frame member formed using a resin material, a groove is formed on the ground contact surface side, a vent hole is formed at the bottom of the groove, and the tire diameter of the tire frame member A tread member disposed on the outer side in the direction, and disposed between an outer peripheral surface of the tire frame member and the tread member to bond the tread member and the tire frame member and close the vent hole of the tread. And an adhesive member.

  In the tire according to claim 5, the tread member in which the air hole is formed in the bottom of the groove is bonded to the outer peripheral surface of the tire frame member by the adhesive member, and the air hole is closed by the adhesive member. Therefore, air does not remain between the tread member and the tire frame member at the position of the bottom of the groove. The same applies when the volume of the tread member is small and the gauge at the bottom of the groove is thin. For this reason, the adhesiveness between a tread member and a tire frame member can be enhanced while reducing the rolling resistance of the tire by reducing the volume of the tread member.

  As described above, according to the tire manufacturing method of the first aspect of the present invention, the adhesiveness between the tread member and the tire frame member is reduced while reducing the rolling resistance by reducing the volume of the tread member. An excellent effect that it can be increased is obtained.

  According to the tire manufacturing method of the second aspect, an excellent effect is obtained that an increase in the number of man-hours can be suppressed.

  According to the tire manufacturing method of the third aspect, it is possible to obtain an excellent effect that a tread member having various ventilation holes can be manufactured at low cost.

  According to the tread member of claim 4, when the tire tread member is bonded to the outer peripheral surface of the tire frame member, the air between the tread member and the tire frame member is introduced into the groove through the vent hole at the bottom of the groove. The excellent effect that it can discharge | emit smoothly is acquired.

  According to the tire of the fifth aspect, an excellent effect is obtained that the adhesion between the tread member and the tire frame member can be improved while reducing the rolling resistance of the tire by reducing the volume of the tread member. It is done.

It is a top view which shows a tread member. It is sectional drawing which shows the temporary assembly at the time of tire manufacture. It is an expanded sectional view equivalent to the 3-3 arrow in Drawing 1 showing the state where the tread member is vulcanized and bonded to the tire frame member. It is sectional drawing which shows the state by which the ventilation hole was block | closed with the adhesive member.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(Tread material)
In FIG. 1, a tread member 10 according to the present embodiment is a PCT (Pre-Cured Tread) configured using rubber, for example. For example, SBR (styrene-butadiene rubber) is used as the rubber.

  A tread pattern having a circumferential main groove 14 and a lateral main groove 16 as an example of a groove is formed on the grounding surface 12 side of the tread member 10. In order to form this tread pattern, the tread member 10 may be molded by vulcanizing an unvulcanized rubber in a PCT mold.

  When the tread member 10 is disposed on the outer periphery of the tire frame member 24, the belt-like tread member 10 may be wound in an annular shape, or the tread member 10 previously formed in an annular shape may be temporarily expanded. The diameter may be fitted to the outer peripheral surface 24 </ b> A of the tire frame member 24.

  A vent hole 18 is formed in the bottom 16A of the horizontal main groove 16 so as to penetrate to the side opposite to the ground contact surface 12 (inner peripheral surface 13 in FIG. 3). For example, two circumferential main grooves 14 are formed on each side of the tire equatorial plane CL in the tire width direction. A center land portion row 20 is formed between the two circumferential main grooves 14. In addition, shoulder land portion rows 22 are formed on the outer sides in the tire width direction of the respective circumferential main grooves 14. The horizontal main groove 16 is formed in the shoulder land portion row 22, for example.

  The vent hole 18 is, for example, circular from the viewpoint of suppressing the vent hole 18 from becoming a starting point of cracking. The diameter of the air hole 18 is 20 to 300% of the gauge G (FIG. 3) of the bottom portion 16 </ b> A of the horizontal main groove 16. Here, when the lower limit of the numerical range is set to 20%, if the lower limit is not reached, when the tread member 10 is bonded to the outer peripheral surface 24A of the tire frame member 24 (FIG. 3), the tire frame member 24 and the tread member 10 are bonded. This is because it becomes difficult for the air between the two to be discharged through the vent hole 18. The reason why the upper limit of the numerical range is set to 300% is that if the upper limit is exceeded, there is a possibility that a crack starting from the vent hole 18 may occur. As an example, when the gauge G of the bottom portion 16A of the horizontal main groove 16 is 1 mm, the diameter of the vent hole 18 is preferably about 1 mm.

  The vent hole 18 is formed when the tread member 10 is molded, or is drilled after the tread member 10 is molded and before bonding to the tire frame member 24 (FIGS. 2 and 3). When the vent hole 18 is formed when the tread member 10 is formed, an increase in man-hours can be suppressed. Further, when the vent hole 18 is drilled after molding the tread member 10 and before bonding to the tire frame member 24, the position, number, size, etc. of the vent hole 18 can be arbitrarily set, and the cost can be reduced. Thus, the tread member 10 having various vent holes 18 can be manufactured.

  The shape of the air hole 18 may be any shape as long as it does not easily become a crack starting point, and may be other than a circle. The number and position of the air holes 18 are arbitrary, and the air holes 18 may be formed in the circumferential main groove 14.

(Tire manufacturing method)
2 and 3, in the tire manufacturing method according to the present embodiment, the tire frame member 24 is formed using a resin material, and the circumferential main groove 14 and the lateral main groove, which are examples of grooves, are formed on the ground contact surface 12 side. The tread member 10 is formed on the bottom 16A of the horizontal main groove 16 and has a vent hole 18 penetrating to the opposite side of the ground contact surface 12. The tread member 10 is disposed outside the tire skeleton member 24 in the tire diameter direction. In this method, an adhesive member 26 is disposed between the outer peripheral surface 24 </ b> A of the member 24 and the tread member 10, and the tread member 10 is bonded to the tire frame member 24.

  The vent hole 18 is formed when the tread member 10 is molded, or is drilled after the tread member 10 is molded and before bonding to the tire frame member 24 (FIG. 2). In addition, after forming a certain amount of air holes 18 when the tread member 10 is formed, the additional air holes 18 may be drilled before bonding to the tire frame member 24 (FIG. 2).

  In FIG. 3, a tire frame member 24 is made of a thermoplastic material, which is an example of a resin material, and has, for example, a shape corresponding to the crown portion 32 of the tire 30 and an inner side in the tire radial direction from both sides in the tire axial direction of the crown portion 32. And a shape corresponding to the bead portion 36 connected to the inner side in the tire radial direction of the side portion 34. A bead core 38 is embedded in the bead portion 36. As the material of the bead core 38, for example, metal, organic fiber, organic fiber coated with resin, or hard resin is used. The bead core 38 may be omitted if the rigidity of the bead portion 36 is ensured and there is no problem in fitting with the rim (not shown).

  As the thermoplastic material, a thermoplastic resin having a rubber-like elasticity, a thermoplastic elastomer (TPE), or the like can be used. However, considering the elasticity at the time of travel and the moldability at the time of manufacture, the thermoplastic elastomer is It is desirable to use it.

  Examples of the thermoplastic elastomer include an amide thermoplastic elastomer (TPA), an ester thermoplastic elastomer (TPC), an olefin thermoplastic elastomer (TPO), a styrene thermoplastic elastomer (TPS) defined 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.

  Furthermore, as these thermoplastic materials, for example, the deflection temperature under load specified at ISO 75-2 or ASTM D648 (at the time of 0.45 MPa load) is 78 ° C. or higher, the tensile yield strength specified by JIS K7113 is 10 MPa or higher, Similarly, 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. Things can be used.

  The tire skeleton member 24 is first molded into a half-shape centered on, for example, the tire width direction center of the tire 30, that is, the tire equatorial plane CL or its vicinity, and the ends of the crown portion 32 are joined to each other. It is constituted by doing. For this joining, for example, a joining member 42 such as the same or different thermoplastic material or adhesive is used.

  A reinforcing cord 44 is wound around the crown portion 32, for example, spirally. As the cord 44, 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 44, for example, a sheet (not shown) made of a thermoplastic material is attached to the outer side of the crown portion 32 in the tire diameter direction, and the cord 44 is heated while the cord 44 is heated. It can be buried by spiral winding in the circumferential direction. At this time, both the cord 44 and the sheet may be heated.

  As described above, the reinforcing cord 44 is spirally wound around the crown portion 32 in the tire circumferential direction to improve the rigidity of the crown portion 32 in the tire circumferential direction and to prevent the crown portion 32 from breaking. Can be improved. Moreover, the puncture resistance in the crown part 32 of the tire 30 can be enhanced thereby. When reinforcing the crown portion 32, it is preferable to wind the cord 44 spirally in the tire circumferential direction because it is easy to manufacture, but the cord 44 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 24 (for example, the bead portion 36, the side portion 34, the crown portion 32, etc.) The tire frame member 24 may be reinforced with a reinforcing material.

  The bonding member 26 is, for example, unvulcanized rubber, and the tread member 10 can be bonded to the outer peripheral surface 24A of the tire frame member 24 by vulcanization bonding. Prior to the bonding of the tread member 10, the bonding member 26 is disposed on at least one of the outer peripheral surface 24 </ b> A of the tire frame member 24 and the inner peripheral surface 13 (surface opposite to the ground contact surface 12) of the tread member 10. An uneven portion (not shown) is provided in advance on the outer peripheral surface 24A of the tire frame member 24 so that the adhesive member 26 fits with the uneven portion when the outer peripheral surface 24A and the tread member 10 are bonded. It is preferable to make it.

  When the adhesive member 26 is disposed on the outer peripheral surface 24A of the tire frame member 24, it is preferable to apply, for example, one or two layers of another adhesive (not shown) to the outer peripheral surface 24A. Similarly, when the adhesive member 26 is disposed on the inner peripheral surface 13 of the tread member 10, for example, one or two layers of another adhesive (not shown) are preferably applied to the inner peripheral surface 13. . The adhesive is preferably applied in an atmosphere with a humidity of 70% or less. Although this adhesive is not limited to a specific kind, for example, a triazine thiol-based adhesive can be used, and a chlorinated rubber adhesive, a phenol resin adhesive, an isocyanate adhesive, a halogen A rubberized adhesive or the like can also be used.

  Moreover, it is preferable that the surface to which the adhesive is applied (the outer peripheral surface 24A of the tire frame member 24 and the inner peripheral surface 13 of the tread member 10) is roughened by shot blasting in advance. This is because the adhesive is more easily attached. Furthermore, it is preferable to degrease the surface after buffing by washing with alcohol or the like. Further, it is preferable to perform corona treatment or ultraviolet irradiation treatment on the surface after the roughening treatment.

  When the tread member 10 is disposed on the outer side in the tire diameter direction of the adhesive member 26 after the adhesive member 26 is disposed on the outer peripheral surface 24A of the tire frame member 24, the inner peripheral surface 13 side of the tread member 10 or the adhesive For example, a rubber cement composition (not shown) having adhesiveness is preferably applied to the outer peripheral surface side of the member 26. This is because when the tread member 10 is attached to the adhesive member 26, the tread member 10 is temporarily fixed and the workability is improved.

  When SBR (styrene-butadiene rubber) is used as the material of the tread member 10, it is preferable to use, for example, SBR splice cement as the rubber cement composition. Further, when an SBR rubber having a high NR (natural rubber) compounding ratio is used as the material of the tread member 10, it is preferable to use a material in which BR (butadiene rubber) is blended with an SBR splice cement. In addition, as the rubber cement composition, 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.

  As shown in FIG. 2, when the tread member 10 is bonded to the outer peripheral surface 24A of the tire frame member 24, at least the adhesive member 26 is disposed between the tire frame member 24 and the tread member 10. A temporary assembly 48 is formed by covering the ground contact surface 12 side of the tread member 10 with an envelope 46. The envelope 46 is a covering member made of, for example, rubber having airtightness and stretchability, moderately stable thermally and chemically, and having appropriate strength. The envelope 46 is provided with a valve 50 for enabling the inside of the region covered with the envelope 46 to be maintained in a pressurized state or a vacuumed state.

  In the example shown in FIG. 2, the tire frame member 24 is assembled to an annular support member 40 having a structure close to a rim, and the bead portion 36 is in close contact with the flange portion 40 </ b> F of the support member 40. The envelope 46 covers the outer surfaces of the side portions 34 on both sides of the tire frame member 24 and the tread member 10, and an edge (not shown) on the inner side in the tire diameter direction is between the bead portion 36 and the flange portion 40F. It is sandwiched. A through hole 52 is provided on the inner peripheral surface of the support member 40.

  In the temporary assembly 48, the inside of the envelope 46 is pressurized to a predetermined pressure (for example, 500 kPa) through the valve 50. This pressure is lower than the pressure at the time of vulcanization in a container (not shown) described later, and the tread member 10 is pressed against the tire frame member 24 side by the pressure difference.

  On the other hand, by evacuating from the valve 50 in the state of the temporary assembly 48, the envelope 46 is brought into close contact with the tread member 10 and the tire frame member 24, and the tread member 10 is pressed against the tire frame member 24 side. May be.

  When the tire frame member 24 has sufficient rigidity not to be deformed when the envelope 46 is evacuated, the tread member 10 and the outer surface side of the tire frame member 24 are used without using the support member 40. In addition to the inner surface side, the envelope 46 may be covered.

  Then, the temporary assembly 48 is accommodated in a predetermined container (not shown), and vulcanization is performed by heating and pressurizing the container. This container is a so-called vulcanization can, but any container can be used as long as it has a capacity to accommodate the temporary assembly 48 and can withstand the heating and pressurization during vulcanization. In FIG. 3, vulcanization conditions are, for example, a temperature of 120 ° C., a pressure p of 600 kPa, and a time of 1 hour. The pressure p acts on the tread member 10 from the envelope 46 side, and also acts on the inner surface side of the tire frame member 24 through the through hole 52 of the support member 40 as shown in FIG. Since the inside of the temporary assembly 48 is pressurized to 500 kPa, the tread member 10 is pressed against the tire frame member 24 side by the difference of 100 kPa.

  Here, sulfur or peroxide can be used as the vulcanization accelerator. Carbon black or silica can be used for the reinforcing agent of the adhesive member 26, and silica is more preferable. Further, aminosilane or polysulfide can be used as the coupling agent.

  When the resin material used for the tire frame member 24 is a thermoplastic material, the vulcanization temperature is preferably 100 ° C. or higher and lower than 160 ° C. This is because if the temperature is 160 ° C. or higher, the crown portion 32 reinforced by the cord 44 may buckle due to thermal contraction of the thermoplastic material. Moreover, it is because the vulcanization degree of the adhesive member 26 may become inadequate that it is less than 100 degreeC.

  Thus, the temperature in the container is set, the pressure in the container is set to a pressure suitable for vulcanization, and vulcanization is performed for a predetermined time, whereby the adhesive member 26 is vulcanized, and the tread member 10 is The tire 30 is vulcanized and bonded to the outer peripheral surface 24 </ b> A of the member 24. When the semi-vulcanized tread member 10 is used, the tread member 10 is further vulcanized to reach the degree of vulcanization of the final product.

  At this time, in this embodiment, since the vent hole 18 penetrating on the opposite side (inner peripheral surface 13) to the ground surface 12 is formed in the bottom portion 16A of the horizontal main groove 16 in the tread member 10, Air between the tire frame member 24 and the tire frame member 24 is smoothly discharged in the direction of arrow A through the vent hole 18 into the horizontal main groove 16. Specifically, the air between the tread member 10 and the tire frame member 24 is discharged into the air hole 18 through the air hole 18 in the process in which the adhesive member 26 is vulcanized and cured. The air discharge path is not limited to the vent hole 18 and is also discharged from between the end of the tread member 10 and the tire frame member 24 in the tire width method.

  Further, since the adhesive member 26 flows by heating, the air between the tread member 10 and the tire frame member 24 is discharged into the air hole 18 and then enters the air hole 18 and is cured. As a result, as shown in FIG. 4, the air hole 18 is closed by the adhesive member 26.

  The tire manufacturing method according to the present embodiment is particularly effective when the gauge G of the bottom portion 16A of the lateral main groove 16 is thin in order to reduce the volume of the tread member 10. For this reason, the adhesiveness between the tread member 10 and the tire frame member 24 can be enhanced while reducing the rolling resistance by reducing the volume of the tread member 10.

(tire)
2, the tire 30 according to the present embodiment has a tire frame member 24 formed using a resin material, and a circumferential main groove 14 and a horizontal main groove 16 that are examples of grooves on the ground contact surface 12 side. A vent 18 is formed in the bottom 16A of the lateral main groove 16, and the tread member 10 disposed on the outer side in the tire diameter direction of the tire frame member 24, and between the outer peripheral surface 24A of the tire frame member 24 and the tread member 10 The tread member 10 and the tire frame member 24 are bonded to each other and have an adhesive member 26 that closes the vent hole 18 of the tread.

  In the tire 30, the tread member 10 in which the vent hole 18 is formed in the bottom portion 16 </ b> A of the lateral main groove 16 is bonded to the outer peripheral surface 24 </ b> A of the tire frame member 24 by the adhesive member 26. 26, the air does not remain between the tread member 10 and the tire frame member 24 at the position of the bottom portion 16 </ b> A of the lateral main groove 16. The same applies to the case where the volume of the tread member 10 is small and the gauge G (FIG. 3) of the bottom portion 16A of the horizontal main groove 16 is thin. For this reason, the adhesiveness between the tread member 10 and the tire frame member 24 can be increased while reducing the rolling resistance of the tire by reducing the volume of the tread member 10.

  In the above-described embodiment, the tread member 10 is configured using rubber. However, the material of the tread member 10 is not limited to rubber, and other materials having characteristics equivalent to rubber may be used. .

  Moreover, although the thermoplastic material was mentioned as a resin material used for the tire frame member 24, it is not restricted to this, For example, you may use a thermosetting material.

  Furthermore, although the tire 30 according to the above embodiment is a tubeless type tire using the tire skeleton member 24 with the bead core 38, the configuration of the tire 30 is not limited to this. Although illustration is omitted, as the tire frame member 24 using a resin material, a hollow tube body that is formed in an annular shape in the tire circumferential direction and disposed on the outer peripheral portion of the rim may be used.

10 tread member 12 ground contact surface 14 circumferential main groove (groove)
16 Horizontal main groove (groove)
16A Bottom 18 Vent 24 Tire frame member 24A Outer peripheral surface 26 Adhesive member 30 Tire

Claims (5)

A tire frame member is formed using a resin material,
A tread member in which a groove is formed on the ground surface side and a vent hole formed on the bottom of the groove on the opposite side to the ground surface is disposed outside the tire frame member in the tire diameter direction,
The tire manufacturing method which arrange | positions an adhesive member between the outer peripheral surface of the said tire frame member, and the said tread member, and adhere | attaches this tread member to the said tire frame member.   The tire manufacturing method according to claim 1, wherein the vent hole is formed when the tread member is molded.   The tire manufacturing method according to claim 1 or 2, wherein the vent hole is drilled after the tread member is molded and before bonding to the tire frame member.   A tread member in which a groove is formed on the ground surface side, and a ventilation hole penetrating to the opposite side of the ground surface is formed at the bottom of the groove. A tire frame member formed using a resin material;
A groove is formed on the ground contact surface side, a vent is formed at the bottom of the groove, and a tread member disposed on the outer side in the tire diameter direction of the tire frame member;
An adhesive member that is disposed between an outer peripheral surface of the tire frame member and the tread member to bond the tread member and the tire frame member, and closes the ventilation hole of the tread;
Tire with.

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