JP2008030519A - Pneumatic tire and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To preclude ride comfort in a vehicle from worsening and decrease the hazard of low internal pressure CBU. <P>SOLUTION: At the inside surface of an inner liner 19, a heat insulating layer 23 is formed, which has a number of independent bubbles 21 and consists chiefly of a high molecular material M, and the independent bubbles 21 are formed inside the hollow glass beads 25 dispersed in the high molecular material M. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic tire having an inner liner side subjected to heat insulation, and a method for manufacturing the pneumatic tire from a vulcanized tire (a method for manufacturing a pneumatic tire).

A pneumatic tire used in a vehicle such as a passenger car exhibits a load bearing ability by an internal pressure of filled air, and includes a pair of bead portions, a carcass, a tread portion, a belt, a pair of sidewall portions, and the like as tire constituent members. As prepared. Here, the carcass is configured by rubber coating a plurality of carcass cords made of organic fibers, for example, and the belt is formed by rubber coating a plurality of steel cords made of steel fibers, for example ( (See Patent Document 1 and Patent Document 2).
JP-A-7-304308 Japanese Patent Laid-Open No. 11-20418

  By the way, if the carcass, tread portion, belt, etc. are repeatedly deformed by rolling while the pneumatic tire is running, heat will be generated from the carcass, tread portion, belt, etc., and the temperature of the filled air of the pneumatic tire will be increased. As a result, the internal pressure of the pneumatic tire also increases. Therefore, as the running speed of pneumatic tires increases, the amount of heat generated from the carcass, tread portion, belt, etc. increases as the number of repeated deformations of the carcass, tread portion, belt, etc. increases. The internal pressure of the entering tire increases rapidly, and the ride comfort of the vehicle deteriorates. On the other hand, considering the ride comfort of the vehicle, if the initial internal pressure of the pneumatic tire is set low, when the traveling speed of the pneumatic tire is low, the amount of deformation such as the carcass cord becomes large, There is a risk of low internal pressure CBU (cord break). In particular, the above-mentioned problem is remarkable in pneumatic tires used for passenger cars and racing vehicles that travel at high speed.

  Therefore, an object of the present invention is to provide a novel pneumatic tire and a method for manufacturing the same, which are mainly intended to solve the above-described problems.

  A first feature of the present invention (a feature of the invention described in claim 1) is a pair of bead portions each having a bead core, a toroidal carcass provided so as to straddle between the pair of bead cores, A tread portion provided at a crown portion on the outer surface of the carcass, a belt provided between the tread portion and the carcass, and sidewall portions provided at a pair of side portions on the outer surface of the carcass. And an inner liner provided on the inner surface of the carcass, wherein a heat insulating layer having a number of closed cells is formed on the inner surface of the inner liner, and the heat insulating layer is made of a polymer material. It is constituted as a main material, and the closed cells are formed inside hollow glass beads dispersed in the polymer material.

  According to the 1st characteristic, since the said heat insulation layer which has many said closed cells is formed in the inner surface of the said inner liner, the heat insulation effect outstanding in the said inner liner side can be exhibited. As a result, as the running speed of the pneumatic tire increases, even if the amount of heat generated from the carcass, the tread portion, the belt, etc. increases, the temperature of the filling air of the pneumatic tire increases. This can be suppressed as much as possible, and as a result, an increase in the internal pressure of the pneumatic tire can be suppressed as much as possible.

  Further, since the heat insulating layer is composed mainly of a polymer material, and the closed cells are formed inside the hollow glass beads dispersed in the polymer material, the pneumatic tire is running. Even if the heat insulation layer is repeatedly deformed by rolling, it is possible to prevent the heat insulation layer from being cracked or peeled off and to maintain the shape of the closed cells.

  The second feature of the present invention (the feature of the invention described in claim 2) is that, in addition to the first feature, the thermal conductivity of the heat insulation layer is 0.1 to 0.3 W / m · K. Is the gist.

  A third feature of the present invention (a feature of the invention described in claim 3) is that, in addition to the first feature or the second feature, the thickness of the heat insulating layer is 0.5 to 1.0 mm. Is the gist.

  According to a fourth feature of the present invention (a feature of the invention described in claim 4), in addition to the first feature to the third feature, the tread portion side portion and the sidewall portion side portion of the heat insulating layer are provided. The gist is that the thickness is thicker than the thickness of the bead portion side portion of the heat insulating layer.

  According to a fifth feature (feature of the invention described in claim 5) of the present invention, in addition to the first feature to the fourth feature, the thickness of both end regions of the tread portion side portion in the heat insulating layer is The gist is that it is thicker than the thickness of the central region of the tread portion side portion of the heat insulating layer.

  A sixth feature of the present invention (a feature of the invention described in claim 6) is a method of manufacturing a pneumatic tire having a heat treatment on the inner liner side from a vulcanized tire, and a plurality of hollow tires. The gist is to form a heat insulating layer having a large number of closed cells by applying a polymer solution in which glass beads are dispersed to the inner surface of the inner liner of the vulcanized tire.

  According to the sixth feature, since the heat insulating layer having a large number of the closed cells is formed on the inner surface of the inner liner, an excellent heat insulating action can be exhibited on the inner liner side. As a result, as the running speed of the pneumatic tire increases, even if the amount of heat generated from the carcass, the tread portion, the belt, etc. increases, the temperature of the filling air of the pneumatic tire increases. This can be suppressed as much as possible, and as a result, an increase in the internal pressure of the pneumatic tire can be suppressed as much as possible.

  Further, since the polymer solution in which a large number of the hollow glass beads are dispersed is applied to the inner surface of the inner liner of the vulcanized tire, the heat insulation is caused by rolling while the pneumatic tire is running. Even if deformation occurs repeatedly in the layer, it is possible to suppress the occurrence of cracking or peeling in the heat insulating layer and to maintain the shape of the closed cells.

  According to the invention of any one of claims 1 to 6, it is generated from the carcass, the tread portion, the belt and the like as the traveling speed of the pneumatic tire increases. Even if the amount of heat increases, the increase in internal pressure of the pneumatic tire can be suppressed as much as possible, so that the ride comfort of the vehicle is not deteriorated and the initial internal pressure of the pneumatic tire is set low. This eliminates the need to reduce the risk of low internal pressure CBU (cord destruction).

  In addition, even when the heat insulation layer is repeatedly deformed by rolling while the pneumatic tire is running, the heat insulation layer can be prevented from being cracked or peeled, and the shape of the closed cells is maintained. Therefore, an excellent heat insulating effect can be stably exhibited over a long period on the inner liner side.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  Here, FIG. 1 is a partial cross-sectional view of a pneumatic tire according to an embodiment of the present invention, FIG. 2 is a schematic view showing a heat insulating layer in the pneumatic tire according to the embodiment of the present invention, and FIG. It is explanatory drawing of the manufacturing method of the pneumatic tire which concerns on this embodiment.

  As shown in FIG. 1, a pneumatic tire 1 according to an embodiment of the present invention exhibits a load bearing ability by the internal pressure of the filled air A and has a pair of annular bead portions that can be fitted to the rim 3. 5 is provided. Each bead portion 5 includes a bead core 7 and a bead filler 9 disposed outside the bead core 7 in the tire radial direction R. The bead portion 5 refers to a portion from the bead toe (bead tip) to 1/3 of the tire cross-sectional height.

  A pair of bead cores 7 are provided so as to straddle a toroidal carcass 11. Specifically, one bead core 7 is moored so that one end portion of the carcass 11 is folded back, and the other bead core. 7, the other end of the carcass 11 is moored so as to be folded back. The carcass 11 is configured by rubber coating a plurality of carcass cords (not shown) made of organic fibers, and the carcass cords extend in parallel in the radial direction.

  A tread portion 13 is provided at a crown portion on the outer peripheral surface of the carcass 11. A plurality of circumferential main grooves (not shown) extending in the tire circumferential direction C may be formed in the tread portion 13. Further, between the carcass 11 and the tread portion 13, a belt 15 of at least two layers (in the embodiment of the present invention, two layers) is provided, and this belt 15 is a plurality of steel fibers. The belt cord (not shown) is covered with rubber.

  Side wall portions 17 are respectively provided on the pair of side portions on the outer surface of the carcass 11. Furthermore, an inner liner 19 is provided on the inner surface of the carcass 11 to prevent air leakage.

  Then, the characteristic part of the pneumatic tire 1 which concerns on embodiment of this invention is demonstrated.

  As shown in FIGS. 1 and 2, a heat insulating layer 23 having a large number of closed cells 21 is formed on the entire inner surface of the inner liner 19, and the heat insulating layer 23 is made of silicone resin M (polymer material). 1) as a main material. The closed cells 21 are formed inside spherical hollow glass beads 25 dispersed in the silicone resin M.

  And the heat conductivity of the heat insulation layer 23 is 0.1-0.3 W / m * K. Here, the heat conductivity of the heat insulation layer 23 is set to 0.1 W / m · K or more. If the heat conductivity of the heat insulation layer 23 is less than 0.1 W / m · K, heat is applied to the heat insulation layer 23. It is because it becomes easy to collect. On the other hand, the heat conductivity of the heat insulation layer 23 is set to 0.3 W / m · K or less because when the heat conductivity of the heat insulation layer 23 exceeds 0.3 W / m · K, the heat insulation layer 23 has an excellent heat insulation effect. It is because it becomes difficult to exhibit.

  Moreover, the thickness of the heat insulation layer 23 is 0.5-1.0 mm. Here, the thickness of the heat insulating layer 23 is set to 0.5 mm or more, because if the thickness of the heat insulating layer 23 is 0.5 mm, it is difficult to exert an excellent heat insulating action by the heat insulating layer 23. It is. On the other hand, the thickness of the heat insulating layer 23 is set to 1.0 mm or less. If the thickness of the heat insulating layer 23 exceeds 1.0 mm, the steering stability may be adversely affected due to the weight increase of the pneumatic tire 1. Because it occurs.

  Furthermore, the thickness of the tread portion side portion 23a (in other words, the back side portion of the tread portion 13) and the sidewall portion side portion 23b (in other words, the back side portion of the sidewall portion 17) in the heat insulating layer 23 is determined by the heat insulating layer. It is thicker than the thickness of the bead portion side portion 23 (in other words, the back side portion of the bead portion 5). In addition, the thickness of both end regions 23ae of the tread portion side portion 23a in the heat insulating layer 23 is thicker than the thickness of the central region 23ac of the tread portion side portion 23a in the heat insulating layer 23.

  Next, the manufacturing method of the pneumatic tire which concerns on embodiment of this invention is demonstrated.

  As shown in FIG. 3, the method for manufacturing a pneumatic tire according to the embodiment of the present invention includes a tire 1 ′ in which a pneumatic tire 1 (see FIG. 1) that has been heat-insulated on the inner liner 19 side has been vulcanized and molded. The specific contents of the method for manufacturing a pneumatic tire according to the embodiment of the present invention are as follows.

  That is, first, a spray 27 containing a silicone resin solution L (one of polymer solutions), a number of hollow glass beads 25 (see FIG. 2), and silica powder (not shown) is prepared. Next, the hollow glass beads 25 and the silica powder are dispersed in the silicone resin solution L by shaking the spray 27 well. Then, by spraying with the spray 27, the silicone resin solution L in which a large number of hollow glass beads 25 and silica powder are dispersed is applied over the entire inner surface of the inner liner 19 in the vulcanized tire 1 ′. Then, a heat insulating layer 23 having a large number of closed cells 21 is formed. As described above, the pneumatic tire 1 that has been heat-insulated on the inner liner 19 side can be manufactured from the vulcanized tire 1 ′.

  In addition, after forming the heat insulation layer 23, it is desirable to heat-process the heat insulation layer 23 and to harden the heat insulation layer 23. Further, instead of applying the silicone resin solution L to the inner surface of the inner liner 19 by spraying with the spray 27, the silicone resin solution L may be applied to the inner surface of the inner liner 19 by brushing.

  Then, the effect | action and effect of the pneumatic tire 1 which concerns on embodiment of this invention, and its manufacturing method are demonstrated.

  Since the heat insulating layer 23 having a large number of closed cells 21 is formed over the entire inner surface of the inner liner 19 (in the method for manufacturing a pneumatic tire according to the embodiment of the present invention, the inner surface of the inner liner 19 In order to form the heat insulating layer 23 having a large number of closed cells 21 over the entire region), an excellent heat insulating action can be exhibited on the inner liner 19 side. As a result, as the running speed of the pneumatic tire 1 increases, the temperature of the filling air A of the pneumatic tire 1 increases even if the amount of heat generated from the carcass 11, the tread portion 13, the belt 15 and the like increases. As a result, it is possible to suppress the increase in the internal pressure of the pneumatic tire 1 as much as possible.

  Further, since the heat insulating layer 23 is composed of the silicone resin M as a main material and the closed cells 21 are formed inside the hollow glass beads 25 dispersed in the silicone resin M (air according to the embodiment of the present invention). In the method of manufacturing a tire, since the silicone resin solution L in which a large number of hollow glass beads 25 are dispersed is applied to the inner surface of the inner liner 19 in the vulcanized tire 1 ′) Even if the heat insulating layer 23 is repeatedly deformed by rolling while the tire 1 is running, it is possible to prevent the heat insulating layer 23 from being cracked or peeled, and the shape of the closed cells 21 can be maintained.

  As described above, according to the pneumatic tire 1 and the manufacturing method thereof according to the embodiment of the present invention, the pneumatic tire 1 is generated from the carcass 11, the tread portion 13, the belt 15 and the like as the traveling speed of the pneumatic tire 1 increases. Even if the amount of heat increases, the increase in the internal pressure of the pneumatic tire 1 can be suppressed as much as possible, so that the ride comfort of the vehicle is not deteriorated and the initial internal pressure of the pneumatic tire 1 is set low. This eliminates the need to reduce the risk of low internal pressure CBU (cord destruction).

  In addition, even when the heat insulation layer 23 is repeatedly deformed by rolling while the pneumatic tire 1 is running, it is possible to prevent the heat insulation layer 23 from being cracked or peeled, and the shape of the closed cells 21 is maintained. Therefore, it is possible to stably exhibit an excellent heat insulating action on the inner liner 19 side over a long period of time.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, In addition, it can implement in a various aspect. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

  Examples of the present invention will be briefly described.

  First, “Heatguard Paint FC-137” of Fine Chemical Japan Co., Ltd. is prepared as a spray, and a thermal insulation layer having a thickness of about 0.5 mm is formed over the entire inner surface of the inner liner by spraying. The inventive product (tire size: PSR / 55R18) is made as a prototype. In addition, the tire before forming the heat insulation layer on the inner surface of the inner liner (in other words, a vulcanized tire) is used as a comparative tire.

  Next, the inventive tire and the comparative tire are respectively assembled to an 8.5J-18 rim equipped with a wireless temperature / internal pressure sensor, and filled with air of 240 kPa (filled air). Furthermore, the invention tire and the comparative tire were pressed against the indoor drum at a camber angle of 1.5 degrees and a slip angle of 0.5 degrees while applying a load of 655 kg, respectively, and were allowed to run at a high speed under predetermined running conditions. A drum test is performed on each of the tire and the comparative tire. Here, the predetermined traveling condition means a condition of traveling at a speed of 150 km / h for 10 minutes, subsequently at a speed of 200 km / h for 10 minutes, and finally at a speed of 300 km / h for 60 minutes.

  Then, the transition of the temperature and internal pressure of the filled air of the inventive tire and the comparative tire during the drum test is summarized as shown in FIGS. That is, it was experimentally confirmed that the inventive tire can suppress the rise in the temperature and internal pressure of the filled air as compared with the comparative tire.

1 is a partial cross-sectional view of a pneumatic tire according to an embodiment of the present invention. It is a mimetic diagram showing the heat insulation layer in the pneumatic tire concerning the embodiment of the present invention. It is explanatory drawing of the manufacturing method of the pneumatic tire which concerns on embodiment of this invention. It is a graph which shows transition of the temperature of the filling air of the invention tire and comparative tire in a drum test. It is a graph which shows transition of the internal pressure of the invention tire and comparative tire during a drum test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 5 Bead part 7 Bead core 11 Carcass 13 Tread part 15 Belt 17 Side wall part 19 Inner liner 21 Independent cell 23 Heat insulation layer 23a Tread part side part 23ac Central area 23ae Both end area 23b Side wall part side part 25 Hollow glass bead 27 Spray L Silicone resin solution M Silicone resin

Claims (6)

A pair of bead portions each having a bead core; a toroidal carcass provided so as to straddle between the pair of bead cores; a tread portion provided at a crown portion on an outer surface of the carcass; and the tread portion; A pneumatic tire comprising a belt provided between the carcass, sidewall portions provided on a pair of side portions on the outer surface of the carcass, and an inner liner provided on an inner surface of the carcass. In
A heat insulating layer having a large number of closed cells is formed on the inner surface of the inner liner, the heat insulating layer is mainly composed of a polymer material, and the inside of the hollow glass beads in which the closed cells are dispersed in the polymer material. A pneumatic tire characterized in that it is formed.   2. The pneumatic tire according to claim 1, wherein the heat insulating layer has a thermal conductivity of 0.1 to 0.3 W / m · K.   The pneumatic tire according to claim 1 or 2, wherein the heat insulating layer has a thickness of 0.5 to 1.0 mm.   The thickness of the said tread part side part in the said heat insulation layer and the said side wall part side part is thicker than the thickness of the said bead part side part in the said heat insulation layer, The Claim 1- Claim 3 characterized by the above-mentioned. The pneumatic tire according to any one of the above. The thickness of both end regions of the tread portion side portion in the heat insulating layer is thicker than the thickness of the central region of the tread portion side portion in the heat insulating layer. The pneumatic tire according to any one of the above. A method of manufacturing a pneumatic tire that has been heat-treated on the inner liner side from a vulcanized tire,
An air characterized in that a heat insulating layer having a large number of closed cells is formed by applying a polymer solution in which a large number of hollow glass beads are dispersed to the inner surface of the inner liner of the vulcanized tire. A method for manufacturing a tire.

Images