JP2009061690A - Method of manufacturing annular rubber member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an annular rubber member, in which the partial increase in thickness of a joint part is prevented and a shape in the peripheral direction is made uniform when the end parts of belt-like rubbers are laminated and pasted in the thickness direction. <P>SOLUTION: In the method of manufacturing the annular rubber member provided with a step for extruding a rubber through a mouth ring belt-like by an extruder 30 and laminating and pasting the end parts of the belt-like rubbers to each other, the thickness of an opening 21 of the mouth ring 20 is reduced in the starting period and the finishing period of the extrusion of the belt-like rubber to make thickness of the starting end part and the finishing end part of the belt-like rubber thin, and the starting end part and the finishing end part which are made thin are laminated and pasted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an annular rubber member typified by a bead filler as a tire constituent member.

  As shown in FIG. 7, the tire is configured by combining various rubber members such as a sidewall rubber 2, a tread rubber 3, a carcass ply 4, and an inner liner rubber 5. The bead member 10 is disposed in each of the pair of bead portions 1, and the width direction end portion of the carcass ply 4 is wound back so as to sandwich the bead portion 10. As shown in FIG. 8, the bead member 10 includes an annular bead filler 1 b made of hard rubber having a triangular cross section and a bead core 1 a made of a convergent body such as a rubber-coated steel wire.

  The annular bead filler 1b has a length corresponding to the peripheral length of the bead core 1a by extruding a bead filler 1b having a predetermined cross-sectional shape into a belt shape by an extruder as disclosed in Patent Document 1 below, for example. After cutting, it is molded by pasting the ends together. However, if the end portions are laminated in the thickness direction and bonded together, the thickness of the joint portion is locally increased and the shape becomes nonuniform, which may deteriorate the tire uniformity. Moreover, although it can also be considered that the end portions are not laminated, the positioning of the end portions and the crimping process tend to be difficult.

Patent Document 2 listed below describes a method in which a rubber is directly extruded onto a molding plate that is rotatably supported to form an annular shape, thereby forming a seamless bead filler. However, this method uses a molded plate that contacts in a direction orthogonal to the die of the extruder and a guide member having a shape corresponding to the cross-sectional shape of the bead filler, and requires a special device to implement. Become.
JP-A-6-297603 JP 2005-335244 A

  The present invention has been made in view of the above circumstances, and the purpose thereof is that the thickness of the joint portion is not locally increased when the ends of the belt-like rubber are laminated and bonded together in the thickness direction, and the circumferential direction Is to provide a method for producing an annular rubber member capable of making the shape uniform.

  The above object can be achieved by the present invention as described below. That is, the manufacturing method of the annular rubber member according to the present invention includes a step of extruding rubber in a band shape through a die by an extruder, and laminating and bonding the ends of the band rubber to form an annular shape. In the manufacturing method of the annular rubber member comprising, at the start and end of extruding the belt-shaped rubber, the thickness of the opening of the base is reduced, and the start and end portions of the belt-shaped rubber are thinned, and the thinned start end And the end portion are laminated and bonded together.

  According to the present invention, the thickness of the joint portion is prevented from being locally increased by thinning the start and end portions of the belt-like rubber and laminating and bonding the thinned start and end portions. Thus, the shape of the annular rubber member can be made uniform in the circumferential direction.

  In the above, it is preferable to reduce the thickness of the opening so that the thickness of the start end portion and the end end portion of the belt-like rubber gradually decreases toward the tip end. According to such a configuration, it is relatively easy to extrude the start end portion and the end end portion of the belt-like rubber, and the molding accuracy of both end portions can be increased, so that the shape of the annular rubber member can be made more uniform.

  In the above, it is preferable that the direction in which the thickness of the opening is reduced at the beginning of extruding the belt-like rubber and the direction in which the thickness of the opening is reduced at the end of extruding the belt-like rubber are different from each other. These end portions are laminated in the thickness direction and are easily bonded together. Further, the shape of the annular rubber member can be made more uniform by accurately molding the cross section of the joint portion where the start end portion and the end end portion are laminated.

  The present invention is applicable to the manufacture of a bead filler having a triangular cross-section with a tapered outer peripheral portion. In this case, a bead filler as an annular rubber member is formed by extruding a bead filler into a band shape through a die by an extruder, and laminating and bonding the end portions of the bead filler as the band-shaped rubber.

  In the above, the thickness of the opening is reduced by rotating the side surface forming portion forming the side surface of the bead filler around the apex position of the bead filler at the beginning and the end of extruding the bead filler as the belt-like rubber. It is preferable to make it.

  When the annular rubber member is a bead filler as described above, the opening of the base has a triangular shape. Therefore, if the thickness of the opening is simply reduced, the height of the opening is not maintained, and the bead filler starts and ends. The cross-sectional shape of the film tends to be distorted, making lamination difficult. On the other hand, according to the above-described configuration of the present invention, the start end portion and the end end portion of the bead filler are reduced by changing the thickness of the opening without changing the height of the opening and maintaining the opening in a triangular shape. Can be thinned. As a result, the start end portion and the end end portion can be easily and accurately stacked, and the both end portions can be appropriately bonded together.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, an example in which the annular rubber member is a bead filler 1b having a triangular cross-section with a tapered outer peripheral portion as shown in FIGS. FIG. 1 is a schematic configuration diagram showing an example of a manufacturing apparatus used in the present invention. FIG. 2 is a front view of the base. FIG. 3 is an enlarged view of a main part showing the opening of the base, with the cover plates 58 and 68 removed from the base 20.

  As shown in FIG. 1, the manufacturing apparatus includes a base 20, an extruder 30 that extrudes rubber in a band shape via the base 20, and a control device 40 that controls the operation thereof. The extruder 30 includes a hopper 31 into which a rubber material is charged, a screw 32 that feeds the rubber material forward, a cylindrical barrel 33 that incorporates the screw 32, and a drive device 34 that drives the screw 32. Is provided.

  The base 20 is connected to the distal end side of the barrel 33 of the extruder 30, and a belt-shaped bead filler is extruded from an opening 21 formed on the front surface thereof. A rubber channel through which rubber supplied from the extruder 30 passes is provided inside the base 20, and the opening 21 is formed on the downstream side of the rubber channel. As will be described later in detail, the base 20 is configured to be able to reduce the thickness of the opening 21. A turntable (not shown) is horizontally disposed in front of the base 20 (left side in FIG. 1).

  As shown in FIGS. 2 and 3, the opening 21 is formed in a triangular shape corresponding to the cross-sectional shape of the bead filler 1b. The side surface of the bead filler is formed by the pair of side surface forming portions 50 and 60, and the reference symbol P is the apex position of the bead filler. In the present embodiment, the side molding parts 50 and 60 are constituted by plate-like members having a quadrilateral view.

  The side surface forming portion 50 is fixedly supported on the lower surface of the support plate 51, and the support plate 51 is rotatably supported on the lower ends of the pair of guide bars 52 and 53. The cylinder 54 is fixed with the output rod 55 facing downward, and a plate 56 is attached to the tip of the output rod 55. The upper end of the guide bar 52 is fixed to the plate 56, but the upper end of the guide bar 53 passes through a hole formed in the plate 56.

  When the output rod 55 is advanced, the guide bar 52 moves down together with the plate 56, but the height of the guide bar 53 does not change. Therefore, as shown in FIG. 4, the side molding 50 can be rotated counterclockwise around the apex position P of the bead filler, and the thickness of the opening 21 can be reduced from above. In the process of reducing the thickness, the height of the opening 21 (corresponding to the height H of the bead filler 1b shown in FIG. 6) does not change, and the opening 21 is maintained in a triangular shape.

  The mechanism that operates the side surface forming portion 60 is a configuration in which the mechanism that operates the side surface forming portion 50 is turned upside down, a support plate 61, a pair of guide bars 62 and 63, a cylinder 64 having an output rod 65, Plate 66. When the output rod 65 is advanced, as shown in FIG. 5, the side molding 60 can be rotated clockwise around the apex position P of the bead filler, and the thickness of the opening 21 can be reduced from below.

  The control device 40 has a function of controlling the driving and braking of the screw 32, the operation of retracting the output rods 55 and 65, and the rotation operation of the turntable.

  Hereinafter, a method for manufacturing the bead filler 1b as the annular rubber member will be described. First, a rubber material is put into the hopper 31, fed forward while being kneaded by the screw 32, and supplied to the base 20. The rubber supplied to the base 20 is pushed out from the opening 21 as a belt-shaped bead filler having a triangular cross section, and is placed on the turntable. The bead filler is curved with the rotation of the turntable, cut to a predetermined length, and then formed into an annular shape by stacking and bonding the end portions. In addition, the bead core previously formed in the annular shape can be placed on the turntable, and the bead filler can be molded into the annular shape while being bonded to the bead core.

  At this time, in the present invention, at the beginning and the end of extruding the bead filler, the thickness of the opening 21 of the base 20 is reduced, and the beginning and end portions of the bead filler are thinned. Laminate and paste together. Thereby, it can prevent that the thickness of a joint part becomes large locally, and can make the shape of the bead filler 1b uniform in the circumferential direction.

  6A and 6B show bead fillers formed into an annular shape according to the present invention, in which (a) a plan view, (b) a bb cross-sectional view, (c) a cc cross-sectional view, and (d) a dd cross-sectional view, respectively. (E) ee sectional drawing. Reference sign Es is the start end of the bead filler, and reference sign Ee is the end of the bead filler.

  In this embodiment, as shown in FIG.6 (b), the thickness of the start end part Es and the termination | terminus part Ee is gradually reduced toward the front-end | tip. Thereby, since the extrusion of the start end portion Es and the end end portion Ee becomes relatively easy and the molding accuracy of the both end portions Es and Ee can be increased, the shape of the bead filler 1b can be made more uniform. Such shapes of the start end portion Es and the end portion Ee can be obtained by gradually changing the degree of decrease in the thickness of the opening 21 at the start and end of extrusion.

  Moreover, in this embodiment, when extruding a bead filler in a strip shape, the direction in which the thickness of the opening 21 is reduced at the beginning and the direction in which the thickness of the opening 21 is reduced at the end are different from each other. Specifically, as can be seen from FIGS. 6B to 6E, the thickness of the opening 21 is decreased from above at the beginning of extrusion (see FIG. 4), and the thickness of the opening 21 is decreased at the end of extrusion. The thickness is decreased from below (see FIG. 5), and the thicknesses of the starting end portion Es and the terminating end portion Ee are decreased from different directions.

  Thereby, it becomes easy to laminate | stack the starting edge part Es and the terminal part Ee in the thickness direction, and to bond. Moreover, since the cross section of the joint part which laminated | stacked the start part Es and the termination | terminus part Ee can be shape | molded accurately, the shape of the bead filler 1b can be made more uniform. The forming of the start end portion Es and the end end portion Ee can be easily performed by controlling the operation of the side surface forming portions 50 and 60 via the cylinders 54 and 64 by the control device 40.

[Another embodiment]
(1) In the above-described embodiment, an example in which the bead filler as the belt-shaped rubber is formed in an annular shape by making one round is shown, but in the present invention, it may be formed in an annular shape by making two or more rounds. Even in such a case, the starting end portion and the terminating end portion of the belt-like rubber are thinned, and they are laminated and bonded together. Thereby, the dispersion | variation in the thickness of strip | belt-shaped rubber | gum can be suppressed, and the shape of an annular | circular shaped rubber member can be equalized suitably in the circumferential direction.

  (2) In the above-described embodiment, the example in which the bead filler is manufactured as the annular rubber member has been described. However, the present invention is not limited to this, and can be applied to other annular rubber members such as sidewall rubber. . Further, a gear pump may be provided continuously at the front end side of the extruder, and a fixed amount of rubber may be supplied to the die based on the function of the gear pump.

Schematic configuration diagram showing an example of a manufacturing apparatus used in the present invention Front view of the base Enlarged view of the main part showing the opening of the base Enlarged view of the main part showing a state where the thickness of the opening of the base is reduced. Enlarged view of the main part showing a state where the thickness of the opening of the base is reduced. Figure of a bead filler formed into an annular shape according to the present invention Sectional view showing an example of a pneumatic tire Perspective view showing a partially broken bead member

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Bead core 1b Bead filler 10 Bead member 20 Base 21 Opening 30 Extruder 40 Controller 50 Side surface molding part 60 Side surface molding part Es Start end part Ee End part

Claims (5)

In the method for producing an annular rubber member comprising a step of forming an annular shape by extruding rubber through a base by an extruder and laminating and bonding the ends of the belt-shaped rubber,
At the beginning and the end of extruding the belt-shaped rubber, the thickness of the opening of the base is reduced to thin the start and end portions of the belt-shaped rubber, and the thinned start and end portions are laminated and bonded together. A method for producing an annular rubber member, comprising:   The manufacturing method of the annular rubber member according to claim 1, wherein the thickness of the opening is reduced so that the thickness of the start end portion and the end end portion of the belt-like rubber gradually decreases toward the tip end.   The annular rubber according to claim 1 or 2, wherein a direction in which the thickness of the opening is reduced at the beginning of extruding the belt-like rubber is different from a direction in which the thickness of the opening is reduced at the final stage of extruding the belt-like rubber. Manufacturing method of member.   The method for manufacturing an annular rubber member according to any one of claims 1 to 3, wherein the annular rubber member is a bead filler having a triangular cross-section with a tapered outer peripheral portion.   The thickness of the opening is reduced by rotating a side surface forming portion that forms a side surface of the bead filler around an apex position of the bead filler at the start and end of extruding the bead filler as the belt-shaped rubber. The manufacturing method of the annular | circular shaped rubber member of 4.

Images