JP2004216826A - Molding method of tire and extruder for ribbon shaped rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for molding a tire capable of controlling a rubber material in a ribbon shaped rubber extruded at respective parts of the same in a high precision, in the method for molding a tire comprising mixing a plurality of rubber compositions under changing a mixing ratio of the compositions according to a pattern previously defined, extruding a continuous ribbon shaped rubber with a definite cross section in which the rubber material changes at least at a part, and assembling the rubber material with the definite cross section by directly rounding like a screw on a rotating support. <P>SOLUTION: Each of the pellet shaped rubber composition is plasticized by continuously feeding at a respective charging rate based on a changing pattern of the mixing ratio previously determined. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tire molding method for spirally winding a ribbon-shaped rubber extruded from an extruder around a rotating support and assembling a rubber member having a predetermined cross section, and in particular, a tire molding in which the rubber material of the ribbon-shaped rubber is changed. About the method.
[0002]
[Prior art]
Conventionally, when molding tires, ribbon-shaped rubber extruded from a small extruder has been used for the purpose of miniaturizing extrusion equipment, improving tire uniformity, or flexibly responding to small lot multi-size production. A method is known in which a spirally wound directly on a rotating support is laminated and laminated to form a rubber member having a predetermined cross section.Furthermore, when extruding this ribbon-like rubber, a mixing ratio of a plurality of rubber compositions is determined in advance. A method has been proposed in which these are mixed in a given pattern to change the rubber material of the ribbon-shaped rubber, and rubber members made of different rubber materials are formed in at least two regions. (For example, Patent Document 1).
[0003]
In this method, when extruding a ribbon-shaped rubber, by changing the rubber material in a stepwise manner, what has been conventionally formed by overlapping a plurality of rubber members separately is formed by a continuous spiral winding operation. Since it is possible to assemble these multiple rubber members using only a small equipment, for example, only one extruder, and further, when extruding the ribbon-like rubber, by gradually changing the rubber material In addition, it is possible to eliminate a boundary existing between a plurality of rubber members and to prevent the occurrence of peeling or the like under a stress action which may occur at the boundary.
[0004]
In this known method, in order to change the mixing ratio in a predetermined pattern, each of the rubber compositions composed of a continuum having a uniform cross section was supplied to the extruder while changing the feed rate determined by the mixing ratio. Thereafter, it is customary to combine these rubber compositions into one screw portion and to mix them while plasticizing them together in the screw portion. FIG. 3 is a perspective view of an input port of an extruder showing a conventional method of supplying a rubber composition. For example, when extruding a ribbon-shaped rubber in which a rubber material changes from two types of rubber compositions A and B. Then, the respective rubber compositions are put into the hopper 91 as continuous bodies A and B having a rectangular cross section, and the feeding speed at that time is adjusted by the feed rollers 92A and 92B which feed the respective continuous bodies A and B therebetween. By controlling the rotation speed, these mixing ratios are changed.
[0005]
However, this method of controlling the mixing ratio of the rubber composition makes it difficult to make the shape of the cross section of each continuous body uniform over its length direction, and also causes unstable slip between the feed roller and the continuous body. It is difficult to control the mixing ratio of these rubber compositions with high precision due to the occurrence of the rubber composition. As a result, the rubber material in a part of the rubber member formed by laminating the ribbon-shaped rubber is required to have a predetermined rubber material. There was a problem that was difficult.
[0006]
[Patent Document 1]
JP 2000-79643 A
[Problems to be solved by the invention]
The present invention has been made in view of such a problem, and a mixing ratio of a plurality of rubber compositions is changed in a predetermined pattern to mix them, and a rubber material changes at least in part. In a tire molding method in which a ribbon-shaped rubber having a continuous cross section is extruded, and this rubber is spirally wound directly on a rotating support to assemble a rubber member having a predetermined cross-section, the rubber material of the ribbon-shaped rubber to be extruded is applied to each part. It is an object of the present invention to provide a tire molding method that can be controlled with high precision.
[0008]
[Means for Solving the Problems]
To achieve the above object, the present invention has been made, and its gist configuration and operation will be described below.
[0009]
The tire molding method according to claim 1, wherein the mixing ratio of the plurality of rubber compositions is changed in a predetermined pattern to mix them, and the rubber material is changed at least partially in a continuous ribbon shape having a constant cross section. In a tire molding method of extruding rubber, directly spirally winding the rubber on a rotating support and assembling a rubber member having a predetermined cross section,
The rubber compositions in the form of pellets are continuously supplied at respective supply rates based on the change pattern of the mixing ratio to plasticize these rubber compositions.
[0010]
According to the method of molding a tire according to the present invention, a plurality of rubber compositions are pelletized and continuously supplied, so that the supply speed, that is, the supply amount per time can be accurately measured, and The mixing ratio of the rubber composition can be accurately controlled so as to change in a predetermined pattern, and the rubber material of each portion of the extruded ribbon rubber can be controlled with high accuracy.
[0011]
Here, in the present specification, "mixing" a plurality of rubber compositions includes a case where a mixing ratio at the time of mixing is 100% of one kind of rubber composition, and therefore, "mixing" This also includes the case where the process is shifted to the next process without using a kind of rubber composition. Further, the "pattern" when changing the mixture ratio is a function of the mixture ratio as a function of the time from the start of extrusion when forming one rubber member, and the "support" The term includes a tire building drum, a tire being formed, a rubber member forming drum, a rubber member being formed, a base tire in a retreaded tire, and the like. In addition, "spirally winding" means that the ribbon-shaped rubber is wound while being moved in the axial direction of the support, that is, the ribbon-shaped rubber is wound in the axial direction of the support. It also includes simply spirally winding and laminating radially outward without moving.
[0012]
The method of molding a tire according to claim 2 is the method according to claim 1, wherein the rubber compositions supplied in a continuous amount are continuously mixed prior to plasticizing the rubber composition in a pellet form. It is.
[0013]
According to this tire molding method, since the respective rubber compositions continuously measured in the state of pellets are continuously mixed in a state of pellets prior to plasticization, excellent mixing with excellent dispersion can be performed. By controlling the rubber material of the ribbon-shaped rubber with higher precision, and by reducing the sharing of the function of mixing a plurality of rubber compositions together with the screw portion having the function of plasticizing the rubber composition, the The length can be shortened.
[0014]
The ribbon-shaped rubber extruder according to claim 3 is a ribbon-shaped rubber extruder used in the tire molding method according to claim 1 or 2,
It comprises a continuous measuring device for continuously measuring a plurality of pellet-shaped rubber compositions, and a screw portion for plasticizing the measured rubber compositions.
[0015]
According to this ribbon-shaped rubber extruder, since a continuous measuring device for continuously measuring the pellet-shaped rubber composition is separately provided, the supply amount of each pellet-shaped rubber composition is adjusted to a predetermined mixing ratio. Can be faithfully controlled so that each of the supply speeds is determined based on the change pattern of the ribbon-shaped rubber. As described above, it is possible to control the rubber material of each portion of the extruded ribbon-shaped rubber with high accuracy. it can.
[0016]
The ribbon-shaped rubber extruder according to claim 4 is an extruder used in the tire molding method according to claim 3,
A continuous mixer for continuously mixing the measured pelletized rubber compositions is provided on the upstream side of the screw portion.
[0017]
According to this ribbon-shaped rubber extruder, since the continuous mixer is provided on the upstream side of the screw portion, as described above, the rubber material of the ribbon-shaped rubber can be controlled with higher precision, and the length of the screw portion can be reduced. can do.
[0018]
According to a fifth aspect of the present invention, there is provided a ribbon-shaped rubber extruder according to the third or fourth aspect, further comprising a gear pump for metering the plasticized rubber material.
[0019]
According to this ribbon-shaped rubber extruder, a gear pump for metering and feeding the rubber material is provided, so that the extrusion amount of the ribbon-shaped rubber can be controlled to be constant, thereby forming a ribbon rubber of the rubber material with higher precision. can do.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing a method of laminating a ribbon rubber R using the ribbon rubber extruder 1 of this embodiment, and FIG. 2 is a system diagram showing a configuration of the ribbon rubber extruder 1. When a tire is assembled by assembling a rubber member G constituting a tire, for example, a tread member, the tire is extruded from the extruder 1 while rotating the support 8 while the tire in the process of assembling the rubber member G is used as the support 8. The rubber member G is formed by passing the ribbon-shaped rubber R between a pair of molding rollers 9 for specifying its cross-sectional shape, and spirally winding and laminating it on the support 8.
[0021]
The ribbon-shaped rubber extruder 1 shown in FIG. 2 shows an example in which three types of rubber compositions are supplied. The extruder 1 has a tank 4A for receiving a rubber composition A in the form of a pellet transported by a pipe. , A continuous measuring device 5A for continuously measuring the rubber composition A from the tank 4A, and similarly, corresponding to the tank 4B, the continuous measuring device 5B, and the rubber composition C corresponding to the rubber composition B. A continuous mixer 6 which comprises a tank 4C and a continuous measuring device 5C, continuously receives the continuously measured rubber compositions in the form of pellets and continuously mixes them, a mixed pellet-like rubber material And a gear pump 3 for metering the plasticized rubber material.
[0022]
The continuous measuring devices 4A, 4B, and 4C used here receive the respective rubber compositions in the form of pellets and discharge them in the form of pellets. For example, the number of revolutions is controlled using a twin screw to accurately supply the rubber compositions. The amount can be measured. As a specific example of this apparatus, there is a "two-axis screw type cassette weighing feeder" manufactured by Kubota Corporation.
[0023]
Further, the continuous mixer used here is to improve mixing and dispersion of the rubber composition received in the form of pellets, and to discharge a rubber material in a state in which a plurality of types of pellets are mixed. An example is "Continuous KM type mixer" manufactured by Reedige AG (Germany).
[0024]
The method of molding a tire using the extruder 1 is as follows. Each of the pellet-shaped rubber compositions is continuously weighed by the continuous measuring devices 4A, 4B, and 4C at a feed rate determined from a predetermined change pattern of the mixing ratio, and the continuously weighed pellet-shaped rubber compositions are continuously mixed by a continuous mixer. 6, the pelletized rubber material thus mixed is continuously plasticized by the screw portion 2, and this is metered and supplied by the gear pump 3 to extrude the ribbon-like rubber R from the extruder. After the rubber R has been molded by the molding roller 9 and its cross-sectional shape has been specified, the rotating support is rotated based on a predetermined laminating method, that is, a laminating position and a laminating order of the ribbon-shaped rubber R which are predetermined every time. 8 is spirally wound to form a rubber member G.
[0025]
Here, in order to set a predetermined change pattern of the mixing ratio, the rubber material distribution in the length direction of the ribbon-like rubber is set from the rubber material distribution for each region of the rubber member G to be molded and the lamination method. From the rubber material distribution in the length direction, a change pattern of the mixing ratio can be obtained using the ribbon cross-sectional area and the extrusion speed.
[0026]
【The invention's effect】
As is apparent from the above description, according to the present invention, each of the rubber compositions in the form of pellets is continuously supplied at a respective supply rate based on a predetermined change pattern of the mixing ratio, and these rubber compositions are formed. Since the composition is plasticized, the rubber material at each portion of the extruded ribbon rubber can be controlled with high precision. In addition, since the rubber composition as the raw material is handled in the form of pellets, a means such as pipe transfer can be used to transport the rubber composition from the raw material tank to the extruder. Can be saved.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a method of laminating a ribbon rubber using a ribbon rubber extruder according to an embodiment of the present invention.
FIG. 2 is a system diagram showing a ribbon-shaped rubber extruder according to an embodiment of the present invention.
FIG. 3 is a perspective view of an input port of an extruder showing a conventional method for supplying a rubber composition.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ribbon rubber extruder 2 Screw part 3 Gear pump 4A, 4B, 4C Tank 5A, 5B, 5C Continuous measuring device 6 Continuous mixer 8 Support 9 Molding roller R Ribbon rubber G Rubber member

Claims (5)

The mixing ratio of a plurality of rubber compositions is changed in a predetermined pattern to mix them, extrude a continuous ribbon-like rubber having a constant cross section in which the rubber material changes at least in part, and rotate the rubber on a rotating support. In a tire molding method of directly spirally winding a rubber member having a predetermined cross section,
A method of molding a tire, wherein each rubber composition in the form of a pellet is continuously supplied at a respective supply speed based on the pattern of change in the mixing ratio, and the rubber composition is plasticized. The method for molding a tire according to claim 1, wherein each of the continuously measured rubber compositions is continuously mixed prior to plasticizing the rubber composition in a pellet form. A ribbon-shaped rubber extruder used in the method for molding a tire according to claim 1 or 2,
A ribbon-shaped rubber extruder comprising: a continuous measuring device for continuously measuring a plurality of pellet-shaped rubber compositions; and a screw portion for plasticizing the measured rubber compositions. The ribbon-shaped rubber extruder according to claim 3, wherein a continuous mixer for continuously mixing the weighed respective pellet-shaped rubber compositions is provided upstream of the screw portion. 5. The ribbon-shaped rubber extruder according to claim 3, further comprising a gear pump for metering the plasticized rubber material.

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