CN-117529396-B - Mold for forming tire and tire production method

CN117529396BCN 117529396 BCN117529396 BCN 117529396BCN-117529396-B

Abstract

The present invention provides a tire molding die (1) and a tire production method using the same, the tire molding die (1) is equipped with an annular tread molding portion (20), the tread molding portion (20) is configured to open and close when a plurality of segments (21) are moved in a radial direction, and has a plurality of design face dividing die portions (23, 24), each of the plurality of design face dividing die portions (23, 24) is equipped with a tread design face (20 c) for molding a tread (2 c) of a tire (2), is arranged side by side in a circumferential direction of the segments (21), and is configured to rotate about a rotatable shaft (26) parallel to an axis of the tread molding portion (20) when the tread molding portion (20) is opened after the tire (2) has undergone vulcanization molding.

Inventors

ISHIHARA YASUYUKI

Assignees

株式会社普利司通

Dates

Publication Date: 20260508
Application Date: 20211124
Priority Date: 20210622

Claims (6)

1. A mold for forming a tire for vulcanization molding an unvulcanized green tire into a tire, the mold comprising: an annular tread molding portion divided into a plurality of segments arranged in a circumferential direction and configured to be opened and closed by moving each of the segments in a radial direction, wherein, Each of the segments comprises: A plurality of design face dividing mold portions each including a tread design face for forming a tread of the tire, the plurality of design face dividing mold portions being arranged in a circumferential direction of the segment, and configured to rotate about a rotatable shaft parallel to an axis of the tread forming portion when the tread forming portion is opened after vulcanization forming of the tire.
2. The mold for forming a tire as in claim 1, wherein, Each of the segments comprises: a retainer driven radially outward by the container when the tread forming portion is opened, and Each of the plurality of design face-dividing mold portions is rotatably supported by the rotatable shaft with respect to the holder.
3. The mold for forming a tire of claim 2, the mold comprising: The two pieces of said design face divide the mould part, wherein, A rotatable shaft corresponding to one of the design face dividing mold portions is arranged on one circumferential end side of the holder, and a rotatable shaft corresponding to the other of the design face dividing mold portions is arranged on the other circumferential end side of the holder.
4. A mold for forming a tire as in claim 3, wherein, The design surface dividing mold portion includes a back plate portion and a pair of side plate portions extending radially inward from both ends of the back plate portion in the axial direction and supported by the rotatable shaft at the back plate portion.
5. The mold for forming a tire as in any one of claims 2 to 4, wherein, A spring member is attached between the design face dividing mold portion corresponding to the spring member and the holder to hold the design face dividing mold portion corresponding to the spring member at a predetermined position, and when the tread forming portion is opened, the spring member is elastically deformed to allow the design face dividing mold portion to rotate relative to the holder.
6. A tire production method for producing a tire by vulcanization molding an unvulcanized green tire using a mold for forming a tire, the mold comprising an annular tread molding portion which is divided into a plurality of segments arranged in a circumferential direction and is configured to be opened and closed by moving each of the segments in a radial direction, wherein, When the tread forming portion is opened by moving each of the segments radially outward, the tire is demolded from the tread forming portion with each of a plurality of design face dividing mold portions provided in the segments in a circumferentially aligned manner rotated about a rotatable shaft parallel to an axis of the tread forming portion.

Description

Mold for forming tire and tire production method Technical Field The present disclosure relates to a mold for forming a tire and a tire production method. Background In a known conventional mold for forming a tire used in vulcanization molding of an unvulcanized green tire to produce the tire, it is known that an annular tread molding portion (tread mold) for forming a tread of the tire is divided into a plurality of segments arranged in a circumferential direction and is configured to be opened and closed by moving each of the segments in a radial direction (for example, see patent documents 1 to 3). Prior art literature Patent literature Patent document 1 Japanese patent laid-open No. 2000-326332 Patent document 2 Japanese patent laid-open No. 2000-334740 Patent document 3 Japanese patent laid-open No. 2009-149979 Disclosure of Invention Problems to be solved by the invention In the above-described conventional mold for forming a tire, the tread design surface oriented toward the radially inner side of each segment is generally provided with protrusions such as ribs or vanes protruding from the tread design surface toward the radially inner side so as to form a tread pattern having irregularities constituted by grooves and sipes on the tread of the formed tire, for example. However, in a configuration in which the tread design surface is provided with the projections, when the tire is demolded from the tread forming portion by moving the segments toward the radially outer side after vulcanization forming, high undercut resistance of the tread is caused by the projections, particularly, the projections on both circumferential end sides of the segments. Thus, in the case of forming a tire having a complicated tread pattern, for example, the above-described excessively high undercut resistance may cause defects such as permanent deformation and protrusion breakage in the tread of the tire after demolding. The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to provide a mold for forming a tire and a tire production method, which can reduce undercut resistance of a tread caused by a protrusion at the time of tire demolding. Solution for solving the problem The mold for forming a tire of the present disclosure is a mold for forming a tire for vulcanization molding an unvulcanized green tire into a tire, the mold comprising an annular tread molding portion divided into a plurality of segments arranged in a circumferential direction and configured to be opened and closed by radially moving each of the segments, wherein each of the segments comprises a plurality of design face dividing mold portions each including a tread design face for forming a tread of the tire, the plurality of design face dividing mold portions being arranged in the circumferential direction of the segments, and the plurality of design face dividing mold portions being configured to rotate about a rotatable shaft parallel to an axis of the tread molding portion when the tread molding portion is opened after vulcanization molding of the tire. In an embodiment, the mold for forming a tire of the present disclosure may be configured in such a manner that each of the segments includes a holder that is driven radially outward by a container when the tread forming portion is opened, and each of the plurality of design face-dividing mold portions is rotatably supported by the rotatable shaft with respect to the holder. In an embodiment, the mold for forming a tire of the present disclosure may be configured such that the mold includes two pieces of the design face dividing mold portions, wherein a rotatable shaft corresponding to one of the design face dividing mold portions is arranged at one circumferential end side of the holder, and a rotatable shaft corresponding to the other of the design face dividing mold portions is arranged at the other circumferential end side of the holder. In an embodiment, the mold for forming a tire of the present disclosure may be configured in such a manner that the design surface dividing mold portion includes a back plate portion and a pair of side plate portions extending from both ends in the axial direction of the back plate portion toward the radial inside and is supported by the rotatable shaft at the back plate portion. In an embodiment, a mold for forming a tire of the present disclosure may be configured such that a spring member is attached between the design face dividing mold portion corresponding to the spring member and the holder to hold the design face dividing mold portion corresponding to the spring member at a predetermined position, and the spring member is elastically deformed to allow the design face dividing mold portion to rotate relative to the holder when the tread forming portion is opened. The tire production method of the present disclosure is a tire production method of vulcanizing and molding an unvulcanized green t