JP4104993B2 - Tire molding method and ribbon-like rubber extruder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a tire molding method in which a ribbon-shaped rubber extruded from an extruder is spirally wound around a rotating support and a rubber member having a predetermined cross section is assembled, and in particular, a tire molding in which the rubber material of the ribbon-shaped rubber is changed. Regarding the method.
[0002]
[Prior art]
Conventionally, ribbon-shaped rubber extruded from a small extruder has been used to form tires for the purpose of downsizing extrusion equipment, improving tire uniformity, or flexibly responding to small lot multi-size production. A method is known in which a rubber member having a predetermined cross section is formed by directly spirally winding on a rotating support and molding a rubber member having a predetermined cross section. Further, 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 a rubber member made of a different rubber material is formed in at least two regions by changing the rubber material of a ribbon-like rubber by changing the pattern in a given pattern. (For example, Patent Document 1).
[0003]
In this method, when extruding a ribbon-shaped rubber, the rubber material is changed stepwise so that a conventional method in which a plurality of rubber members are separately stacked is molded by a continuous spiral winding operation. These rubber members can be assembled using only a small equipment, for example, a single extruder, and the rubber material is gradually changed when extruding the ribbon-like rubber. Thus, it is possible to eliminate the boundary existing between the plurality of rubber members and prevent the occurrence of peeling or the like under the stress action that may occur at the boundary.
[0004]
In this known method, in order to change the mixing ratio in a predetermined pattern, each rubber composition composed of a continuous body having a uniform cross section was supplied to the extruder while changing the supply speed determined by the mixing ratio. Thereafter, these rubber compositions are usually merged into one screw part, and these are mixed in the screw part while being plasticized together. FIG. 3 is a perspective view of an inlet of an extruder showing a conventional method for supplying a rubber composition. For example, in the case of extruding a ribbon-like rubber whose rubber material changes from two types of rubber compositions A and B Each of the rubber compositions is fed into the hopper 91 as a continuum A and B having a rectangular cross section, and the feed speed at that time is determined by the feed rollers 92A and 92B feeding the continuums A and B. These mixing ratios are changed by controlling the rotation speed.
[0005]
However, this method of controlling the mixing ratio of the rubber composition makes it difficult to make the cross-sectional shape of each continuous body uniform in the length direction, and also causes unstable slip between the feed roller and the continuous body. As a result, it is difficult to control the mixing ratio of these rubber compositions with high accuracy. As a result, the rubber material in the portion of the rubber member formed by laminating the ribbon-like rubber is made predetermined. 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 problems, and the mixing ratio of a plurality of rubber compositions is changed in a predetermined pattern to mix them, and the rubber material changes at least partially. In the method of molding a tire in which a ribbon-shaped rubber having a continuous cross section is extruded, and the rubber member having a predetermined cross section is assembled by directly spirally winding the rubber on a rotating support, the rubber material of the ribbon-shaped rubber to be extruded at each portion. An object of the present invention is to provide a tire molding method that can be controlled with high accuracy.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has been made, and the gist configuration and operation thereof will be described below.
[0009]
According to a method for molding a tire according to claim 1, the mixing ratio of a plurality of rubber compositions is changed in a predetermined pattern, and these are mixed, and based on the change in the pattern, at least in a part in the length direction. In a molding method of a tire in which a continuous ribbon-shaped rubber having a constant cross section with a change in the mixing ratio is extruded, and the rubber member having a predetermined cross section is assembled by spirally winding the rubber on a rotating support.
Each rubber composition in the form of pellets is continuously supplied at respective supply speeds based on the change pattern of the mixing ratio to plasticize these rubber compositions.
[0010]
According to the method for molding a tire according to the present invention, since a plurality of rubber compositions are pelletized and these are continuously supplied, the supply speed, that is, the supply amount per hour can be accurately measured. 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 ribbon-like rubber to be extruded can be controlled with high accuracy.
[0011]
Here, in this specification, “mixing” a plurality of rubber compositions includes a case where the mixing ratio at the time of mixing is 100% of one kind of rubber composition, and therefore “mixing” means In addition, a case where the process proceeds to the next treatment without any kind of rubber composition is included. The “pattern” when changing the mixing ratio is a function of the mixing 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 molding drum, a tire in the middle of molding, a rubber member molding drum, a rubber member in the middle of molding, or a base tire in a retread tire. “Spiral winding” means that the ribbon-shaped rubber is wound in the axial direction of the support in addition to winding the ribbon-shaped rubber in the axial direction of the support, that is, spirally wound. It includes simply winding and laminating the layers radially outward without moving them.
[0012]
The method for 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 pellet-shaped rubber composition. It is.
[0013]
According to this tire molding method, each rubber composition continuously metered before plasticization is continuously mixed in the form of pellets, so that mixing with excellent dispersion can be performed. The rubber material of the ribbon-like rubber can be controlled with higher accuracy, and by reducing the sharing of the function of mixing a plurality of rubber compositions that the screw part responsible for plasticizing the rubber composition has combined, The length can be shortened.
[0014]
The ribbon-like rubber extruder according to claim 3 is a ribbon-like rubber extruder used in the tire molding method according to claim 1 or 2,
Each continuous meter for continuously weighing a plurality of pellet rubber compositions and a screw portion for plasticizing the measured rubber composition are provided.
[0015]
According to this ribbon-like rubber extruder, since the continuous metering device for continuously weighing the pellet-like rubber composition is individually provided, the supply amount of each pellet-like rubber composition is set to a predetermined mixing ratio. It is possible to faithfully control the respective supply speeds determined based on the change pattern, and as described above, it is possible to control the rubber material of each portion of the extruded ribbon-like rubber with high accuracy. it can.
[0016]
The ribbon-like rubber extruder according to claim 4 is an extruder used for the tire molding method according to claim 3,
A continuous mixer for continuously mixing each measured pellet-like rubber composition is provided on the upstream side of the screw portion.
[0017]
According to this ribbon-like rubber extruder, the continuous mixer is provided on the upstream side of the screw part. As described above, the rubber material of the ribbon-like rubber can be controlled with higher accuracy, and the length of the screw part can be shortened. can do.
[0018]
According to a fifth aspect of the present invention, there is provided a ribbon-like rubber extruder according to the third or fourth aspect, further comprising a gear pump for metering a plasticized rubber material.
[0019]
This ribbon-like rubber extruder has a gear pump that meteres and feeds rubber material, so the extrusion amount of ribbon-like rubber can be controlled to a constant level, and more accurate ribbon-like rubber material can be formed. can do.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view showing a method of laminating a ribbon-like rubber R using the ribbon-like rubber extruder 1 of this embodiment, and FIG. 2 is a system diagram showing the configuration of the ribbon-like rubber extruder 1. When a tire was molded by assembling a rubber member G constituting the tire, for example, a tread member, the tire in the middle of assembling the rubber member G was used as a support 8 and was extruded from the extruder 1 while rotating the support 8. The ribbon-shaped rubber R is passed between a pair of molding rollers 9 that specify the cross-sectional shape, and is spirally wound on the support 8 to form a rubber member G.
[0021]
A ribbon-like rubber extruder 1 shown in FIG. 2 shows an example in the case of supplying three kinds of rubber compositions. This extruder 1 is a tank 4A for receiving a pipe-shaped pellet-like rubber composition A. And a continuous meter 5A for continuously metering the rubber composition A from the tank 4A, and similarly corresponding to the tank 4B corresponding to the rubber composition B, the continuous meter 5B, and the rubber composition C. The tank 4C and the continuous meter 5C are provided, and the continuously metered rubber composition is continuously received in the form of pellets, and the continuous mixer 6 for continuously mixing them, and the mixed pellet rubber material And a gear pump 3 for metering the plasticized rubber material.
[0022]
Continuous meter 4A, 4B, 4C used here accepts and discharges each rubber composition in the form of pellets in the form of pellets. For example, the rotational speed is controlled accurately using a twin screw. The amount can be measured. As an example of this specific apparatus, there is a “biaxial screw type cassette weighing feeder” manufactured by Kubota Corporation.
[0023]
Further, the continuous mixer used here is a mixture of the rubber composition dispersed in the pellet state, and discharging the rubber material in a state where a plurality of types of pellets are mixed. As an example, there is a “continuous KM mixer” manufactured by Redige (Germany).
[0024]
A method of molding a tire using the extruder 1 is as follows. Each pellet rubber composition is continuously weighed by continuous metering devices 4A, 4B, and 4C at a feed rate determined from a predetermined change ratio of the mixing ratio, and the continuously metered pellet rubber compositions are continuously mixed. 6 is continuously mixed, and then the pelletized rubber material is continuously plasticized by the screw part 2 and is metered by the gear pump 3 to extrude the ribbon-shaped rubber R from the extruder. After the rubber R is molded by the molding roller 9 and its cross-sectional shape is specified, the support is rotated on the basis of a predetermined laminating method, that is, a laminating position and a laminating order of the ribbon-shaped rubber R predetermined for each time. A rubber member G is formed by spirally winding the material 8.
[0025]
Here, in order to set a predetermined change ratio of the mixing ratio, the rubber material distribution in the length direction of the ribbon-shaped rubber is set from the rubber material distribution for each region of the rubber member G to be molded and the lamination method. Then, a change pattern of the mixing ratio can be obtained from the rubber material distribution in the length direction 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 rubber composition in the form of pellets is continuously supplied at respective supply speeds based on a predetermined change pattern of the mixing ratio, and these rubbers are supplied. Since the composition is plasticized, the rubber material in each portion of the extruded ribbon-like rubber can be controlled with high accuracy. In addition, since the rubber composition used as a raw material is handled in the form of pellets, means such as pipe conveyance can be used to convey 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 for laminating ribbon-like rubber using a ribbon-like rubber extruder according to an embodiment of the present invention.
FIG. 2 is a system diagram showing a ribbon-like rubber extruder according to an embodiment of the present invention.
FIG. 3 is a perspective view of an inlet of an extruder showing a conventional method for supplying a rubber composition.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ribbon-shaped rubber extruder 2 Screw part 3 Gear pump 4A, 4B, 4C Tank 5A, 5B, 5C Continuous meter 6 Continuous mixer 8 Support body 9 Molding roller R Ribbon-shaped rubber G Rubber member

Claims (5)

A ribbon having a constant cross section in which the mixing ratio of a plurality of rubber compositions is changed in a predetermined pattern and mixed, and the mixing ratio changes at least in a part of the length direction based on the change in the pattern. In a method of molding a tire in which a rubber member having a predetermined cross section is assembled by extruding a rubber-like rubber and spirally wound directly on a rotating support body.
A method of molding a tire in which each rubber composition in the form of pellets is continuously supplied at respective supply speeds based on the change pattern of the mixing ratio to plasticize these rubber compositions.   The method for molding a tire according to claim 1, wherein the rubber compositions continuously metered are continuously mixed prior to plasticizing the pellet-shaped rubber composition. A ribbon-like rubber extruder used in the tire molding method according to claim 1 or 2,
A ribbon-like rubber extruder comprising a continuous meter for continuously weighing a plurality of pellet-like rubber compositions and a screw portion for plasticizing the measured rubber composition.   The ribbon-like rubber extruder according to claim 3, wherein a continuous mixer for continuously mixing the measured pellet-like rubber compositions is provided on the upstream side of the screw portion.   The ribbon-shaped rubber extruder according to claim 3 or 4, further comprising a gear pump for metering and feeding the plasticized rubber material.

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