CN-117545608-B - Mold for forming tire and tire production method

CN117545608BCN 117545608 BCN117545608 BCN 117545608BCN-117545608-B

Abstract

A tire building mold (1) is provided, which includes a tread forming portion (20), the tread forming portion (20) being configured such that a plurality of segments (21) are opened and closed by moving in a radial direction. The tire molding die (1) is characterized in that each segment (21) includes a holder (22), a plurality of design surface dividing die parts (23) arranged in parallel in the circumferential direction on the inner side in the radial direction of the holder (22), and a plate spring member (25), the plurality of design surface dividing die parts (23) are fixed to the plate spring member (25), and the plate spring member (25) is fixed to the holder (22) at both ends in the circumferential direction. The tire molding die (1) is further characterized in that the plurality of design surface dividing die parts (23) rotate while being moved away from the holder (22) due to elastic deformation of the plate spring member (25) when the tread molding part (20) is opened. A method of producing a tyre is also provided, said method using said tyre building mould (1).

Inventors

ISHIHARA YASUYUKI

Assignees

株式会社普利司通

Dates

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

Claims (4)

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 retainer that is driven toward a radially outer side when the tread forming portion is opened; a plurality of design face dividing mold portions each including a tread design face for forming a tread of the tire and arranged in a circumferentially aligned manner on a radially inner side of the holder, and A plate spring member disposed between the holder and the plurality of design face dividing mold portions, the plurality of design face dividing mold portions being fixed to the plate spring member, and both circumferential ends of the plate spring member being fixed to the holder, and When the tread forming portion is opened after vulcanization forming of the tire, the plurality of design face dividing mold portions move in a direction away from the holder with the plurality of design face dividing mold portions rotating about an axis parallel to the axis of the tread forming portion by elastic deformation of the plate spring member toward the radial inner side.
2. The mold for forming a tire as in claim 1, wherein, One circumferential end of the plate spring member is fixed to an end face of one circumferential side of the holder, and the other circumferential end of the plate spring member is fixed to an end face of the other circumferential side of the holder.
3. The mold for forming a tire according to claim 1 or 2, the mold comprising: a plurality of the leaf spring members arranged in a spaced-apart manner in a direction parallel to an axis of the tread forming portion.
4. 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, The tread molding portion is provided with a plurality of design surface dividing mold portions each of which is fixed to the plate spring member and which are arranged in a circumferential arrangement, and When each of the segments moves toward the radially outer side to open the tread forming portion, the tire is demolded from the tread forming portion with the leaf spring member elastically deformed toward the radially inner side and the plurality of design face dividing mold portions rotated about an axis parallel to the 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 the above-described 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, for example, by grooves and sipes on the tread of the formed tire. 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 configured in such a manner that the mold for forming a tire for vulcanization molding an unvulcanized green tire includes an annular tread molding portion that is 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 includes a holder that is driven toward a radial outside when the tread molding portion is opened, a plurality of design face dividing mold portions that each include a tread design face for forming a tread of the tire and are arranged in a circumferential arrangement on a radial inside of the holder, and a leaf spring member that is arranged between the holder and the plurality of design face dividing mold portions, the plurality of design face dividing mold portions being fixed to the leaf spring member, and both circumferential ends of the leaf spring member being fixed to the holder, and moving in a direction parallel to the plurality of design face dividing mold portions in a radial direction around the rotation axis of the plurality of the leaf spring member when the tread molding portion is opened after the 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 one circumferential end of the plate spring member is fixed to an end face of one circumferential side of the holder, and the other circumferential end of the plate spring member is fixed to an end face of the other circumferential side of the holder. In an embodiment, the mold for forming a tire of the present disclosure may be configured to include a plurality of the leaf spring members arranged in a spaced-apart manner in a direction parallel to an axis of the tread forming portion. The tire production method of the present disclosure is a tire production method for vulcanizing and molding an unvulcanized green tire to produce a tire by using a mold for forming a tire, the mold including 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 the tread molding portion is provided with a plurality of design face dividing mold portions, each of the design face dividing mold portions is fixed to a plate spring member and the plurality of design face dividing mold portions are arranged in a circumferential arrangement, and when each of the segments is moved toward a radial outside to open the tread molding portion, the tire is demolded from the tread molding portion w