JP2009051158A - Tire vulcanizing mold and method of manufacturing pneumatic tire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire vulcanizing mold which inhibits a lowering of tread physical properties in a tire which keeps a plurality of kinds of rubber compositions having different vulcanizing speeds arranged in a width direction of a tread part, and to provide a method of manufacturing a pneumatic tire using the same. <P>SOLUTION: The method of manufacturing a pneumatic tire 10 is configured as follows. A tread molding surface 2 in a vulcanizing mold 1 is made to correspond to vulcanizing speed of a plurality of kinds of rubber compositions 11a, 11b arranged at a tread part 11. The plurality of kinds of rubber compositions 11a, 11b having different vulcanizing speeds are arranged in the vulcanizing mold 1 composed of a plurality of kinds of metals 2a, 2b having different heat conductivities, and in the tread part 11 to mold an unvulcanized tire. The unvulcanized tire is vulcanized and molded by the vulcanizing mold 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tire vulcanization mold and a method for manufacturing a pneumatic tire using the same, and more specifically, the tread physical properties of a tire in which a plurality of types of rubber compositions having different vulcanization speeds are arranged in the width direction of the tread portion. The present invention relates to a tire vulcanization mold in which a decrease is suppressed and a method for manufacturing a pneumatic tire using the same.

  With the increasing performance of vehicles in recent years, the required characteristics of tires are becoming more diverse, and two types of rubber with different physical properties with treads arranged in the tire width direction on the premise of specifying the mounting position on the vehicle Tires whose tire performance is improved by adopting a so-called dual tread structure composed of a composition have come to appear widely (for example, see Patent Document 1).

Generally, rubber compositions having different physical properties have different vulcanization speeds. Therefore, tires having rubber compositions having different physical properties arranged in the tread portion have vulcanization times set based on rubber compositions having a low vulcanization speed. Yes. For this reason, a rubber composition having a high vulcanization rate must be overvulcanized, and accordingly, there is a problem that it is difficult to obtain desired tread physical properties.
JP 2003-326917 A

  An object of the present invention is to eliminate the above-mentioned conventional problems, and to suppress a decrease in tread physical properties in a tire in which a plurality of types of rubber compositions having different vulcanization speeds are arranged in the width direction of the tread portion. The object is to provide a tire vulcanization mold and a method for producing a pneumatic tire using the same.

  In order to achieve the above object, a tire vulcanization mold of the present invention is a mold for vulcanizing a pneumatic tire in which a plurality of types of rubber compositions having different vulcanization speeds are arranged in the tire width direction of the tread portion. The tread molding surface of the mold is composed of a plurality of types of metals having different thermal conductivities corresponding to the vulcanization rate of the rubber composition, and these metals are used for a rubber composition having a high vulcanization rate. The metal having a low thermal conductivity is in contact with the rubber composition having a low vulcanization speed, and the metal having a high thermal conductivity is in contact with the rubber composition.

Furthermore, in the above-described configuration, it is preferable to configure as described in (1) and / or (2) below.
(1) The tread molding surface is constituted by a plurality of molding surfaces having different thermal conductivities, and these molding surfaces are configured to be fitted to the inner peripheral surface of the mold.
(2) The thermal conductivity of the metal constituting the tread molding surface is set to 1 to 500 W / m · K.

  Further, in the method for producing a pneumatic tire according to the present invention, a plurality of types of rubber compositions having different vulcanization speeds are arranged in the tire width direction of the tread portion to form an unvulcanized tire, Vulcanization molding is performed by the tire vulcanization mold described above.

  According to the present invention, in a mold for vulcanizing a pneumatic tire in which a plurality of types of rubber compositions are disposed in the tire width direction of the tread portion, the rubber composition in which the tread molding surface of the mold is disposed in the tread portion. The metal is composed of a plurality of types of metals having different thermal conductivities in accordance with the vulcanization speed of the rubber. The rubber composition with a low vulcanization rate is placed so that a metal with high thermal conductivity is in contact with it, so that a rubber composition with a high vulcanization rate and a rubber composition with a low vulcanization rate are molded to approximately the same degree of vulcanization. Therefore, a pneumatic tire having desired tread physical properties can be obtained.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a part of a tire vulcanization mold according to an embodiment of the present invention and a pneumatic tire corresponding thereto. In FIG. 1, a tire vulcanizing mold 1 includes an upper mold 1a and a lower mold 1b, and a tread molding surface 2 that forms a tread portion 11 of a pneumatic tire 10 is fitted on the inner peripheral surface thereof. In the present embodiment, the tread molding surface 2 is constituted by an upper molding surface and a lower molding surface made of two kinds of metals 2a and 2b having different thermal conductivities.

  The tire vulcanization mold 1 according to the present invention includes a pneumatic tire 10 in which a plurality of types (two types in the figure) of rubber compositions 11a and 11b having different vulcanization speeds are arranged in parallel in the tire width direction of the tread portion 11. This is a mold for vulcanization molding, and the tread molding surface 2 of the vulcanization mold 1 for vulcanization molding of the tread portion 11 is made to correspond to the vulcanization speed of the rubber compositions 11a and 11b, and has different thermal conductivity. It consists of two types of metals 2a and 2b. Then, these metals 2a and 2b are in contact with the rubber compositions 11a and 11b having a low vulcanization rate against the rubber compositions 11a and 11b having a low vulcanization rate. The metal 2a and 2b having high thermal conductivity are arranged so as to contact each other.

  By comprising in this way, it becomes possible to shape | mold the rubber composition 11a, 11b with a quick vulcanization | cure speed | rate, and the rubber composition 11a, 11b with a slow vulcanization | curing degree, and had the desired tread physical property. The pneumatic tire 10 can be obtained.

  In the above-described embodiment, the case where the rubber composition disposed in the tread portion 11 is configured by the two types of rubber compositions 11a and 11b has been described. However, the rubber composition disposed in the tread portion 11 has two types. There are cases where three or more types of rubber compositions are arranged without being limited to the types. In such a case, the tread molding surface 2 is constituted by molding surfaces made of three or more kinds of metals according to the types of rubber compositions having different vulcanization rates. Furthermore, depending on the arrangement form of the rubber composition arranged in the tread portion 11, there are cases where each molding surface is configured by combining parts made of a plurality of metals divided in the tire circumferential direction.

  In the above-described embodiment, the tire vulcanization mold 1 is illustrated as a two-part mold composed of the upper mold 1a and the lower mold 1b. However, the mold type is not limited to this. Moreover, the mold of the sectional type divided | segmented into plurality in the tire circumferential direction may be sufficient.

  In the above-described embodiment, the tread molding surface 2 is configured separately from the tire vulcanization mold 1, and the tread molding surface 2 is configured by fitting into the inner peripheral surface of the tire vulcanization mold 1. However, the tread molding surface 2 is not necessarily formed separately from the tire vulcanization mold 1, and the tread molding surface 2 and the tire vulcanization mold 1 are configured integrally, and the upper mold 1 a and the lower mold 1 are formed. The mold 1b itself can be composed of metals 2a and 2b having different thermal conductivities.

  However, the tread molding surface 2 is constituted by a plurality of molding surfaces having different thermal conductivities so as to be able to cope with differences in the vulcanization speeds of various types of rubber compositions arranged in the tread portion 11, and these molding surfaces are tires. It is good to comprise so that it may fit in the internal peripheral surface of the vulcanization metal mold | die 1. FIG. Thereby, according to the kind of rubber composition arrange | positioned at the tread part 11, various tread shaping | molding surfaces with various metals with different heat conductivity beforehand are obtained, without procuring a new vulcanization die 1 each time. By preparing these and using them in combination, it is possible to vulcanize and mold various pneumatic tires.

  In the present invention, the thermal conductivity of the metals 2a and 2b constituting the tread molding surface 2 is preferably set to 1 to 500 W / m · K, preferably 20 to 350 W / m · K. Thereby, each tread physical property can be set appropriately. If the thermal conductivity mentioned above is less than 1 W / m · K, the vulcanization will be insufficient, and if it exceeds 500 W / m · K, it will be overvulcanized, which will adversely affect the physical properties of the tire.

  The pneumatic tire 10 of the present invention is obtained by vulcanization molding using the tire vulcanization mold 1 described above. That is, in the pneumatic tire 10, as illustrated in FIG. 1, a plurality of types of rubber compositions 11a and 11b having different vulcanization speeds are arranged in the tire width direction of the tread portion 11 to form an unvulcanized tire. .

  Then, the unvulcanized tire is brought into contact with the tread molding surface 2 of the metal 2a, 2b having a low thermal conductivity with the rubber composition 11a, 11b having a high vulcanization speed on the tire vulcanization mold 1 described above. The rubber compositions 11a and 11b having a low vulcanization speed are inserted so as to come into contact with the tread molding surface 2 of the metal 2a and 2b having a high thermal conductivity, and then the unvulcanized tire is vulcanized.

  In the pneumatic tire 10 obtained in this way, the rubber compositions 11a and 11b having a high vulcanization speed and the slow rubber compositions 11a and 11b disposed in the tread portion 11 are formed to have substantially the same vulcanization degree. Therefore, the fall of the tread physical property accompanying the excessive and insufficient vulcanization time is suppressed, and a desired tread physical property can be obtained.

  As described above, the present invention relates to a mold for vulcanizing and molding a tire in which a plurality of types of rubber compositions having different vulcanization speeds are arranged in the width direction of the tread portion, and a method for manufacturing a pneumatic tire using the same. The tread molding surface of the vulcanization mold is made up of multiple types of metals with different thermal conductivities corresponding to the vulcanization speed of the rubber composition placed in the tread part. A pneumatic tire having desired tread physical properties is obtained by molding and vulcanizing the tire. Various tread molding surfaces are prepared in advance using various metals having different thermal conductivities. By combining the two, it is possible to vulcanize various pneumatic tires without procuring new vulcanizing molds. It can be widely applied to.

  A conventional mold in which the entire vulcanization mold 1 including the tread molding surface 2 is made of the same metal (aluminum, thermal conductivity: 220 W / m · K) and a tread molding surface 2 as shown in FIG. Using an inventive mold composed of an upper molding surface made of aluminum 2a (thermal conductivity: 220 W / m · K) and a lower molding surface made of stainless steel 2b (thermal conductivity: 30 W / m · K) As shown in FIG. 1, a rubber composition 11a (T95: 18 minutes @ 160 ° C.) having a low vulcanization speed is arranged on the upper half of the tread rubber 11, and a rubber having a high vulcanization speed is placed on the lower half of the tread rubber 11. Composition 11b (T95: 10 minutes @ 160 ° C.) was placed and each unvulcanized tire was molded. Each of these unvulcanized tires was vulcanized at 160 ° C. for 15 minutes to obtain a pneumatic tire 10 (size: 225 / 40R18).

  When the vulcanization degree of the tread rubber 11 in the pneumatic tire 10 after vulcanization was measured, the lower half 11b of the tread rubber 11 was in an overvulcanized state in a tire that was vulcanized using a conventional mold. On the other hand, in the tire vulcanized using the inventive mold, the upper half 11a and the lower half 11b showed substantially the same degree of vulcanization.

1 is a cross-sectional view showing a part of a tire vulcanization mold and a pneumatic tire corresponding thereto according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire vulcanization die 2 Tread molding surface 2a, 2b Metal 10 Pneumatic tire 11 Tread part 11a, 11b Rubber composition

Claims (4)

  A mold for vulcanizing a pneumatic tire in which a plurality of types of rubber compositions having different vulcanization speeds are arranged in the tire width direction of the tread portion, and the tread molding surface of the mold is vulcanized with the rubber composition It is composed of multiple types of metals with different thermal conductivity corresponding to the speed, and these metals are in contact with a rubber composition with a high vulcanization speed, with a metal with low thermal conductivity, and a rubber with a low vulcanization speed. A tire vulcanization mold arranged so that a metal having high thermal conductivity comes into contact with the composition.   The tire vulcanization mold according to claim 1, wherein the tread molding surface is constituted by a plurality of molding surfaces having different thermal conductivities, and the molding surfaces are fitted to the inner peripheral surface of the mold.   The tire vulcanization mold according to claim 1 or 2, wherein the metal constituting the tread molding surface has a thermal conductivity of 1 to 500 W / m · K.   A plurality of types of rubber compositions having different vulcanization speeds are arranged in the tire width direction of the tread portion to form an unvulcanized tire, and the unvulcanized tire is described in any one of claims 1 to 3. A method of manufacturing a pneumatic tire that is vulcanized and molded by a tire vulcanization mold.