Bead apex rubber-forming method, and bead apex rubber-forming device

Patent metadata

Field	Value
Publication number	US-9944035-B2
Application number	US-201314395769-A
Country	US
Kind code	B2
Filing date	Apr 8, 2013
Priority date	May 16, 2012
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

The present invention forms bead apex rubber with good precision on the outer circumferential surface of the bead core. A molding process, in which unvulcanized rubber is made to flow into a bead apex molding chamber that is surrounded by surfaces that include the outer circumferential surface of a circular bead core and the bead apex rubber is formed directly on the outer circumferential surface of the bead core that is rotating around the core axis, is provided. The molding process comprises: a tip forming step that forms the leading end of the bead apex rubber; a middle section forming step that sequentially forms the bead apex rubber to be continuous with the leading end; and a joining step to join the back end and the leading end of the bead apex rubber by inflowing the unvulcanized rubber therebetween.

First claim

The invention claimed is:

1. A bead apex rubber forming method to form the bead apex rubber continuously in a full circle on an outer circumferential surface of an annular bead core having a core axis, wherein
the method comprises a molding process to form the bead apex rubber integrally on the outer circumferential surface of the bead core while it rotates around the core axis by flowing unvulcanized rubber from a rubber inflow port positioned in a first inner wall surface of a molding head into a bead apex molding chamber,
the bead apex molding chamber is surrounded by the outer circumferential surface of the bead core, the first inner wall surface of the molding head on one side of the core axis direction, and a second inner wall surface of the molding head on the other side of the core axis direction, and wherein the bead apex molding chamber extends in the circumferential direction of the circumferential surface, and the bead apex molding chamber is openable and closable in the circumferential direction by front and rear shutters on a front portion and a rear portion respectively of the bead apex molding chamber in the bead core rotating direction in relation to the rubber inflow port,

wherein the molding process comprises
a tip forming step to form a tip portion of the bead apex rubber between the front and rear shutters by flowing the unvulcanized rubber into the bead apex molding chamber, in a closed state in which the bead apex molding chamber is closed by the front and rear shutters, and in a state in which the rotation of the bead core is prevented,
a middle section forming step progressively forming the bead apex rubber to be continuous with the tip portion by taking away the front shutter from the bead apex molding chamber and flowing the unvulcanized rubber while rotating the bead core,
a joining step to joint integrally a rear end of the bead apex rubber positioned at the bead apex molding chamber and the tip portion by a rubber connecting portion, and
a cut-off step to cut the bead apex rubber off from the rubber in a rubber flow channel which feeds rubber to the rubber inflow port by moving a cutter across the rubber inflow port along the first inner wall surface,
wherein
the rear shutter is positioned between a rear end of the bead apex molding chamber corresponding to an upstream side of the chamber with respect to the bead core rotating direction and the rubber inflow port, so that a space in the chamber for the tip of the bead apex rubber to enter into is formed in the bead apex molding chamber and between the rear end of the bead apex molding chamber and the rear shutter, and
in the joining step,
the bead core is stopped when the tip portion returns into said space of the bead apex molding chamber between the rear end of the bead apex molding chamber and the rear shutter,
the rear shutter is taken away from the bead apex molding chamber to form a connecting space between the rear end of the bead apex rubber and the tip portion of the bead apex rubber, and
the unvulcanized rubber is flowed into the connecting space to form the rubber connecting portion,

wherein,
the cutter is slidable along a cutter-guiding groove formed on the first inner wall surface,
the rear shutter is slidable along a shutter-guiding groove of the molding head,
the rubber inflow port and the shutter-guiding groove open in a bottom-surface of the cutter-guiding groove that is opposite to the bead apex molding chamber in a thickness direction of the cutter-guiding groove, and
the opening of the rubber inflow port and the opening of the shutter-guiding groove are arranged side by side in the circumferential direction.

2. The bead apex rubber forming method as set forth in claim 1 , wherein the shutter-guiding groove is inclined at an angle toward a front end of the bead apex molding chamber in the bead core rotating direction.

3. The bead apex rubber forming method as set forth in claim 1 , wherein a distance along the first inner wall surface between the opening of the shutter-guiding groove and the opening of the rubber inflow port is not more than 1 mm.

4. The bead apex rubber forming method as set forth in claim 1 , wherein an angle of the shutter-guiding groove with respect to the circumferential direction is smaller than an angle of the rubber flow channel with respect to the circumferential direction.

5. The bead apex rubber forming method as set forth in claim 1 , wherein, in the joining step, the unvulcanized rubber is flowed into the connecting space in a state where the cutter closes the opening of the shutter-guiding groove.

6. The bead apex rubber forming method as set forth in claim 1 , wherein, in the joining step, the unvulcanized rubber is flowed into the connecting space in a state where the anterior end surface of the rear shutter is flush with the bottom-surface of the cutter-guiding groove.

Assignees

• Sumitomo Rubber Ind
• Nakata Eng Co Ltd
• Nakata Eng Co Ltd

Inventors

• Onimatsu Hiroyuki
• Nakao Naoyasu
• Takahashi Hiroyuki

Classifications

• B29K2021/00

  Use of unspecified rubbers as moulding material · CPC title

• B29D2030/482

  Applying fillers or apexes to bead cores · CPC title

• B29D30/48 Primary

  Bead-rings or bead-cores (from wire B21F37/00); Treatment thereof prior to building the tyre · CPC title

• B29K2105/246

  Uncured, e.g. green · CPC title

• B29C48/37

  Gear pumps · CPC title