JP2006346999A - Pneumatic tire and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To almost dispense with a stockyard or the like for intermediate members while extremely simplifying process, control, etc. by sufficiently reducing the kinds of the intermediate members to further enable the constitution of a bead filler material having an expected shape, a dimension and the like. <P>SOLUTION: In manufacturing a pneumatic tire equipped with not only a tread part, and side wall parts and bead parts, both of which form a pair, but also the bead cores arranged to the respective bead parts and the bead fillers arranged outward in their radial directions from the outer peripheral sides of the bead cores and characterized in that at least one of the height and volume in the radial direction of either one of the bead fillers becomes larger than that of the other head filler, the respective bead filler materials 6a and 6b arranged on the outer peripheral sides of the respective bead cores 4 are constituted by winding and laminating ribbon like rubber strips 7 to mold a green tire. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire having improved exercise performance and the like, and more particularly, a method for manufacturing a pneumatic tire in which a pair of bead fillers are disposed asymmetrically in a cross section in the width direction of the tire, and a pneumatic tire manufactured by the method It is about.

  In a conventional pneumatic tire, a pair of bead fillers are generally arranged symmetrically with respect to each other in the cross section of the tire in the width direction.

  In recent years, however, a pair of bead fillers are arranged symmetrically, and the conventional tires in which both the bead fillers have the same radial height and volume are intended to improve the performance of pneumatic tires. Thus, it has been proposed to adopt an asymmetric arrangement in which the radial height of one bead filler is higher than that of the other bead filler.

  However, conventionally, when manufacturing a pneumatic tire, a green tire is molded using a rubber material having a predetermined predetermined cross-sectional shape and dimensions, which is formed by extrusion using an extruder, as each bead filler material. Therefore, in order to realize each bead filler having different shape, dimensions, etc. by using this conventional technology, as in the proposed technology, it becomes asymmetrical arrangement in the product tire. Therefore, it is necessary to make the shape and size of the integrated rubber material relatively different from each other. Therefore, in order to form a green tire, each of the plurality of types of the integrated rubber material is previously set. An intermediate part where it is unavoidable to mold and manage and to feed a predetermined rubber material to the molding process in a predetermined order Involving the type of increase itself, and it was a problem in the production and management.

  An object of the present invention is to solve such problems of the prior art, and the object of the present invention is to reduce the types of intermediate members sufficiently and still achieve the expected result. By making it possible to construct a bead filler material having shape, dimensions, etc., while sufficiently improving the motion performance of the product tire, etc., almost no stock yards etc. are required for intermediate members, and production, management, etc. It is in providing the manufacturing method of the pneumatic tire which can be made very simple, and the pneumatic tire manufactured by the method.

  The method for manufacturing a pneumatic tire according to the present invention includes a tread portion, sidewall portions extending radially inward continuously to the side portions of the tread portion, and the inner peripheral side of each sidewall portion. A bead filler, an annular bead core disposed on each bead portion, and a bead filler disposed radially outward from the outer peripheral side of each bead core, the radius of one of the bead fillers When manufacturing a pneumatic tire in which at least one of the height and volume in the direction is larger than that of the other bead filler, each bead filler material disposed on the outer peripheral side of each bead core is made into a ribbon-like rubber strip. The green tire is formed by winding and laminating.

  Here, preferably, the width of the ribbon-shaped rubber strip is in the range of 4 to 15 mm, and the thickness is in the range of 0.3 to 1.2 mm.

  The pneumatic tire according to the present invention is manufactured according to any one of the above methods.

  In each bead filler configured to be asymmetrically arranged in the cross section in the width direction of the tire, the height and volume of the bead filler that is the outer side of the mounting, for example, in the mounting posture of the pneumatic tire on the vehicle, When it is made larger than those of the bead fillers, it is possible to achieve a high level of both improvement in riding comfort when the vehicle is traveling straight ahead and steering stability when the vehicle is turning.

  On the other hand, contrary to the above, when the height and volume of the bead filler on the inner side of the mounting are made larger than those of the bead filler on the outer side of the mounting, the rigidity of the portion on the inner side of the mounting is increased. Therefore, it is possible to achieve both steering stability and straight-line stability.

  According to the present invention, a bead filler material used for molding a green tire is specified in advance in width and thickness, for example, one type of ribbon, so as to achieve such an improvement in exercise performance of a pneumatic tire. To form a difference in shape and size between a pair of bead filler materials according to requirements by changing the number of times the rubber strip is wound, etc. Therefore, the required asymmetry of both bead fillers in the product tire can be brought about simply by changing the winding manner of the rubber strip.

  Therefore, there is no need to produce, store, or manage intermediate members such as a plurality of types of rubber materials in advance at the required timing, making production and management simple and easy. In addition, the occupied space for storing the intermediate member can be greatly reduced.

  In addition, here, the conventional technology for integrally molding rubber materials of various shapes and dimensions by configuring asymmetric bead filler material having a required shape and the like by winding and laminating ribbon-shaped rubber strips of predetermined dimensions. In comparison, the base and other jigs and tools can be greatly reduced, and the number of man-hours for exchanging them can also be greatly reduced.

  The configuration of the bead filler material here can be performed directly by supplying a ribbon-shaped rubber strip to a tire molding machine online and winding and laminating it on the tire molding machine, or a bead filler separate from the tire molding machine. It can also be done indirectly by off-line winding lamination to the required shape, etc. by the molding machine. In this latter case, each configured different bead filler material is supplied to the tire molding machine as a pair. They can be used for green tire molding.

  By the way, in the configuration of each pair of bead filler materials, the shape, dimensions, etc. of both of them are changed according to the tire molding machine, regardless of whether the bead filler molding machine is used. By selecting the winding coordinates for the stacking, it can be performed easily and freely.

  Here, in the bead filler material configured as described above, and in the pair of bead fillers of the product tire, when the rubber volume is constant and only the radial height is made different, the increase in the tire weight is suppressed, The operational effect of being able to achieve both steering stability and riding comfort performance can be brought about. On the other hand, when only the rubber volume is made different with the radial height of each bead filler being constant, It is possible to bring about an effect that the straight running stability can be improved while suppressing the longitudinal rigidity of the tire and maintaining the riding comfort performance.

Here, the width and thickness of the ribbon-like rubber strip are preferably in the range of 4 to 15 mm and 0.3 to 1.2 mm, respectively.
According to this, the bead filler of the tire for a passenger car can be formed more easily, quickly, and always properly by winding and laminating the rubber strip.

  And according to the pneumatic tire concerning this invention, because of the asymmetry according to the requirement of a bead filler, the exercise performance etc. of a pneumatic tire can be improved as expected.

  FIG. 1 is a cross-sectional view in the width direction showing the main part of a green tire molded in accordance with the present invention. In the figure, 1 is a tread portion constituting portion, and 2 is a tread portion constituting portion 1 continuously to each side portion. A pair of sidewall portion constituting portions extending inward in the radial direction, and 3 denotes a bead portion constituting portion continuous to the inner peripheral side of each sidewall portion constituting portion 2.

  Here, an annular bead core 4 is disposed in each bead portion constituting portion 3, and each side portion of the carcass 5 formed of one or more carcass plies is wound up radially outward around the bead core 4. Then, on the outer peripheral side of the bead core 4, a pair of left and right bead filler materials 6a and 6b are tapered into a mountain shape between the main body portion 5a of the carcass 5 and the rolled-up portion 5b thereof. Arrange.

  These bead filler materials 6a and 6b shown in the figure have a width of 4 to 15 mm, more preferably 5 to 9 mm, and a thickness of 0.3 to 1.2 mm, preferably 0.5 to 0.7 mm. A ribbon-shaped rubber strip 7 in a range is wound and laminated, for example, in a spiral shape, and here, of these bead filler materials 6a and 6b, the product tire is positioned on the outside of the vehicle in a device posture toward the vehicle. become. Both the height in the radial direction and the rubber volume of the bead filler material 6a on the left side of the figure are both larger than those of the bead filler material 6b on the right side.

  Such a pair of bead filler materials 6a and 6b is, for example, fed online to a tire molding machine with a rigon-like rubber strip 7 molded by an extruder die or the like, and different predetermined ones on a molding machine. It can comprise by winding and laminating directly so that it may become the shape and dimension.

  On the other hand, each bead filler material 6a, 6b is a drum of a bead filler molding machine 8 in which a ribbon-like rubber strip 7 is provided separately from the tire molding machine as shown in FIGS. 2 (a) and 2 (b), for example. 9, with one end in the axial direction being specified by the bead core 4, it can also be configured by winding and laminating as necessary in each of the drum axial direction and the radial direction.

  In the latter case, when forming the green tire, each of the predetermined bead filler materials 6a and 6b configured in advance is to be assembled together with each bead core 4 at a predetermined position on the tire molding machine. However, this also allows each bead filler material 6a, 6b to be easily provided with the desired radial height and rubber volume by winding each single strip 7, In addition, the bead filler material 6a, 6b on the bead filler molding machine 8 and the tire molding process on the tire molding machine are matched to meet the tact time, so that the configured bead filler materials 6a, 6b are stored and supplied. Can be substantially eliminated.

  By the way, in the place shown in FIG. 1, each of the tread rubber layer 10 of the tread portion constituting portion 1, the side rubber layer 11 extending from the sidewall portion constituting portion 2 to the bead portion constituting portion 3, and the chafer rubber layer 12 of the bead portion constituting portion 3 is provided. In addition, although it is configured to be formed by winding and laminating ribbon-shaped rubber strips, one or more of these rubber layers can also be configured with an extruded rubber sheet having a predetermined cross-sectional shape.

  FIG. 3 is a cross-sectional view showing a cross-section in the tire width direction in a mold posture when a green tire formed as described above is vulcanized and molded with a vulcanization mold to obtain a product tire. For example, in the product tire 21, the height of the bead filler 22 and the rubber volume that are positioned outside the mounting can be increased as expected as compared with the bead filler 23 that is positioned inside the mounting.

  In this case, for example, by setting the relative height of the bead filler 23 to the bead filler 22 within a range of 30 to 90%, the ride comfort during straight traveling is increased by reducing the rigidity of the side portion on the inner side of the mounting, Steering stability during turning can be increased by increasing the side rigidity.

  On the other hand, when the height and volume of the bead filler 23 on the inner side are made larger than those on the bead filler 22 on the outer side, the rigidity of the tire bead portion on the inner side of the mounting is increased, and the steering stability and the straight running stability are increased. And can be balanced well.

  In addition, when only the relative height is made different with the rubber volume of both the bead fillers 22 and 23 being different, an increase in tire weight can be suppressed to achieve both steering stability and riding comfort performance.

  On the other hand, when the relative height is constant and only the rubber volume is made different, it is possible to improve the straight running stability while maintaining the riding comfort performance by suppressing the longitudinal rigidity of the tire.

  In FIG. 3, reference numeral 24 denotes a tread portion, 25 denotes a pair of sidewall portions, and 26 denotes a bead portion continuous on the inner peripheral side of each sidewall portion 25.

1 is a cross-sectional view in the width direction showing a main part of a green tire molded according to the present invention. It is sectional drawing which shows each bead filler material comprised offline. It is width direction sectional drawing which shows a product tire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part component part 2 Side wall part component part 3 Bead part component part 4 Bead core 5 Carcass 5a Main body part 5b Winding part 6a, 6b Bead filler material 7 Ribbon-like rubber strip 8 Bead filler molding machine 9 Drum 10 Tread rubber layer 11 Side rubber layer 12 Chafer rubber layer 21 Product tire 22, 23 Bead filler 24 Tread part 25 Side wall part 26 Bead part

Claims (3)

A tread portion is provided with a side wall portion and a bead portion that are paired with each other, and a bead core disposed in each bead portion and a bead filler disposed radially outward from the outer peripheral side of each bead core. In producing a pneumatic tire in which at least one of the radial height and volume of one bead filler is larger than that of the other bead filler,
A method for manufacturing a pneumatic tire in which a green tire is formed by forming each bead filler material disposed on the outer peripheral side of each bead core by winding and laminating ribbon-like rubber strips.   The method for producing a pneumatic tire and a pneumatic tire according to claim 1, wherein the ribbon-shaped rubber strip has a width of 4 to 15 mm and a thickness of 0.3 to 1.2 mm.   A pneumatic tire produced by the method according to claim 1 or 2.

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