WO1999003662A1 - Method for moulding a tyre - Google Patents

Method for moulding a tyre Download PDF

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Publication number
WO1999003662A1
WO1999003662A1 PCT/EP1998/004279 EP9804279W WO9903662A1 WO 1999003662 A1 WO1999003662 A1 WO 1999003662A1 EP 9804279 W EP9804279 W EP 9804279W WO 9903662 A1 WO9903662 A1 WO 9903662A1
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WO
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Application
Patent type
Prior art keywords
mold
surface
molding
tire
model
Prior art date
Application number
PCT/EP1998/004279
Other languages
French (fr)
Inventor
Antoine Paturle
Original Assignee
Compagnie Generale Des Etablissements Michelin - Michelin & Cie
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00Moulds or cores; Details thereof or accessories therefor
    • B29C33/42Moulds or cores; Details thereof or accessories therefor characterised by the shape of the moulding surface, e.g. ribs or grooves
    • B29C33/424Moulding surfaces provided with means for marking or patterning
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00Moulds or cores; Details thereof or accessories therefor
    • B29C33/38Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
    • B29C33/3842Manufacturing moulds, e.g. shaping the mould surface by machining
    • B29C33/3857Manufacturing moulds, e.g. shaping the mould surface by machining by making impressions of one or more parts of models, e.g. shaped articles and including possible subsequent assembly of the parts
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C39/00Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2030/00Pneumatic or solid tyres or parts thereof

Abstract

The invention concerns a method for moulding a tyre enabling to reproduce, over at least part of said tyre external surface, a texture formed of a plurality of recesses and designs of feeble height and reproducing very accurately the texture of a predetermined material.

Description

MOLDING METHOD OF A TIRE.

The invention relates to a tire molding process, and more particularly to a molding process to reproduce a texture on at least a portion of the surface of a tire.

For molding a tire using a mold is generally composed of several parts which, when they are assembled to form said mold define a mold space for molding said tire. Part is more specifically intended to mold the tire region constituting the tread, said tread being provided with a tread molded by raised elements carried by said mold part; the other parts constituting the mold is intended for molding the outside surfaces of the sidewalls and beads of said tire. Each portion to mold a side is referred to as shell.

To make the different parts of a tire mold, it is known:

- for carrying out the part molding the tread, to use the molding technique by casting an aluminum alloy against a mold whose molding surface reproduces the said strip the tread elements (blocks , ribs);

- carry the shells by turning in a solid piece of metal.

The thus produced metal shells are then subjected to a work of engraving to engrave accurately the various desired patterns on the tire, for example, tire size, indications relating to conditions of use of the symbols the recommended use of the tire, and possibly any ground on an aesthetic effect on the tire surface (note the growing demand for the latter).

To achieve this it is necessary to machine the metal shell by a milling high accuracy, even more difficult to realize that the surfaces on which it is practiced are curved surfaces; these precision machining operations require complex equipment and require a relatively long machining time. In addition, the used machining technique imposes a limit on the size of the patterns that can be obtained; indeed, below a given size pattern, the same milling controlled by a computer does not allow to achieve extremely fine pattern. In particular, achieving textures formed of a plurality of hollows and reliefs can be low amplitude (that is to say between 5 microns and 0.5 mm) disposed in one or more units selected beforehand, is impossible to achieve by this method. To achieve such grounds, there are other known techniques (etching or laser) that are particularly expensive and time consuming to implement.

In addition, the realization of indentation patterns on the sidewall of the tire requires making the impression of the same patterns but in relief on the shell (i.e. projecting from the molding surface of the shell); it is industrially very difficult and very expensive to want to try to get these reliefs on a shell by machining or by adding material.

To produce a large number of tires having on their outer surfaces inscriptions or patterns of high graphic quality, it is necessary to have a plurality of identical molds made and engraved one by one, which further amplifies the costs of making since each shell shall be subject to a particular etching and yet identical to prints of other shells for the molding of similar tires.

It should be added that a defective mold piece due to a machining error during the etching operation, causes the waste of said workpiece to avoid producing tires having appearance defects after molding.

The finding that has been made reveals that there is no method to both industrial and economic embodiment tires provided with patterns forming a texture reproducing a given texture and this on at least a portion of their outer surface by means of a part of a tire mold having on at least part of its molding surface, a plurality of compounds of the parts in relief patterns and low parts by hollow and / or height with respect to the molding surface, said plurality of units being arranged to form a texture reproducing for example the texture of a fabric or other structure. By low height, a pattern height ranging from 5 microns to 0.5 mm and height means a height is defined between 0.5 mm and 5 mm.

The object of the invention is to provide an economical method of molding a tire provided on at least one outer surface portion of a texture formed by a plurality of hollows and reliefs of low and / or medium arranged height with each other in a determined manner and reproducing the surface condition of a predetermined material. Another object of the invention is to provide inexpensively at least a portion of a tire mold having, on at least part of its molding surface, a plurality of average height terrain grounds for molding intaglio patterns on at least a portion of the surface of a tire.

According to the invention, the method of molding a tire provided on at least one outer surface portion of a texture comprises the following steps: a - making a basic model by machining, said model reproducing the outer geometry the part of the tire to be molded; b - on at least a portion of the outer surface of the base model, establishment of a body having a surface for forming a portion of the surface of the base model, said body being provided on said surface of the plurality motifs in hollow and relief (in addition to the fastening means may be provided to maintain said body on the model); c- on this basic model, molding an imprint in a castable material, and solidifying said material being characterized in the solid state by a suitable deformation of elasticity to allow the release of said footprint, without having to destroy the base model; d- production by molding on the imprint of a mold-in against and solidifiable flowable material, said material resistant to temperatures above 200 ° C; e molding of the corresponding mold piece by casting a metal alloy against the mold; f- releasing the mold part, possibly against destruction of the mold; g- assembly of the mold part to form a tire mold; h- establishment of a tire blank uncured and molded in the mold; i molding and vulcanization of the tire blank.

The method according to the invention offers the advantage of allowing the realization of an almost limitless number of strictly identical tires from a single mold; Furthermore, it is also easy to manufacture a large number of counter-molds and thus to mold parts strictly identical from a single basic model.

It is of course possible to provide in addition etching to achieve the usual inscriptions (the tire size, brand or other logo) directly on the base model is the tire mold portion obtained. It is also possible to arrange, on the basic model, metal chips or any other material, said wafers carrying appropriate markings.

Advantageously, the step b of the method according to the invention can be carried out as follows: the plurality of patterns formed on the outer surface of the base model is obtained by the partial or total covering said surface with at least one body having in particular the form of a plurality of grains, of a leaf of a plant, tissue or any other shape so as to form on said surface a large number of hollows and reliefs to be reproduced by molding over at least a portion of the surface of the tire. This approach offers the advantage of allowing the faithful reproduction of a given texture pattern; Furthermore, it is easy to make a change in the surface of the tire mold by simply conducting the removal or covering materials monitoring the installation of a new cover material contained another reason. Thus, the same basic model allows a plurality of molds of the same tire size having different textures.

Another alternative embodiment of the process step b according to the invention consists in carrying out at least part of the basic model in a material that is to be etched by chemical etching or by either a laser (e.g. resin material) for reproducing a predetermined pattern formed of a large number of hollow and low reliefs height per unit area.

Another advantage of the process according to the invention lies in the significant reduction in the cost of obtaining each tire mold part.

In the case of patterns having against undercuts formed on the base model, then it is judicious to employ a sufficiently deformable and resilient material to effect the molding and demolding of the impression without destroying the basic model.

Advantageously, this process also permits the molding of tires comprising on their outer surface a large number of elements in relief so as to impart thereto an aesthetic effect such as achieve enhanced brightness (thus meeting expectations Builders cars and drivers) using preferably pitch patterns of the order of 0.5 mm or less (which may even down to a few microns).

The tire molding process according to the invention also has the advantage of allowing easy and cost refurbishment of such basic model by replacing the coating material when it is worn or damaged after use. To further increase the decorative effect and enhance certain predetermined regions of a tire, it is possible to use several types of body or cover materials and arrange them in different places on the same basic model.

The invention will be better understood using the single figure attached to this description and is not limited in anything possibilities of the invention.

- Figure 1 shows a partial view of the surface of a part of a basic model, said portion locally having a plurality of elements in relief forming a texture having a visible aesthetic effect.

1 schematically shows part of a basic model 1 made of resin and for molding a shell part itself intended for molding a tire sidewall.

This basic model part was conducted by direct machining a block of material and reproduces the geometry of a part of the surface of a tire sidewall.

On part 3 of the surface 2 of the base model 1 on which it is intended to mold a fingerprint, there are a textile fabric 4 forming a partial overlap of said body model. The frame 5 and son chain 6 of this fabric forming on said surface a plurality of embossed patterns; the mean diameter of said son is close to 0.4 mm. The maximum amplitude between the depressions formed in the zones 7 where there is no warp nor weft son son and reliefs 8 of maximum height (corresponding to overlapping regions of the warp and weft son son) is substantially equal 0.5 mm.

In this case, the fabric strip has been precoated with a coating on its face intended to come into contact with the basic model in order to prevent penetration of the material forming the cavity for molding said impression under the son of warp and weft (which would result in a tearing of said material during demolding of the impression and a lower quality reproduction 1 -

texture). Then this tape was placed in the right position and glued on the basic model by changing the elasticity of the fabric to follow closely the outer geometry of said model.

In this case, the average number of recesses on the base model i.e. the number of embossed patterns on the unit area per tire mold is at least equal to 2. 10 per square meter. This value is used to measure how the method according to the invention is efficient and economically advantageous compared to conventional methods.

A shell for molding a tire sidewall may be formed of several concentric annular parts, the clearances between said annular parts being suitable to allow a good evacuation of the air entrapped during molding of a tire and at least one of said parts being obtained by the method of the invention. Thus, it is possible to replace only part of a shell by another of the same size but having a different decorative pattern on its molding surface.

Preferably, the relief patterns on the mold have a maximum height at most equal to 0.5 mm so as to facilitate the venting of entrapped air between the mold and a tire being molded against the occurrence of defects of aspect.

The method described allows the reproduction on the surface of a tire of any textures and particularly formed of textures patterns whose reliefs and recesses have very small heights, up to a few microns and a very high density, by example greater than 1. 10 grooves or other deformations per square meter (the reproduction of such textures on tire mold is virtually impossible with the conventional methods of manufacturing said molds). Implementation of this method allows for various surface states of a tire, such as various particular aesthetic reasons or reasons giving to said surface a particular touch (for example: a velvety velvet fabric).

Description of the process steps for molding the texture of a fabric on the outer surface of a tire sidewall: Having constructed the basic model reproducing the geometry of said flank and after covering said pattern with a fabric according to Figure 1, is performed for molding a casting mold piece on the base model and a solidifiable flowable material and can optionally remain elastic after solidification. A material that can be used in this application is for example of silastene.

After removal of the impression is made by molding on the footprint, against a mold in a solidifying material and characterized in that after said solidifying material is substantially non-deformable. The outer surface of said reproduced against mold identically the surface of the resin base model in every detail. A very good material is for example plaster particle size chosen for its particularly well suited to the reproduction of the finest motifs in relief.

After demoulding the plaster against mold, the mold part is molded by casting on the mold against a pourable and solidifiable material, such as an aluminum alloy or steel.

After completion of the tire mold part according to the method described, it can be realized a perfect finish to the assembly of the various elements constituting said mold. This finishing operation of a mold part is of considerably simplified remains over current operations since there is no marking to be performed on said part.

The various constituent parts of a tire mold are then assembled prior to molding a tire.

The method according to the invention also provides mold parts for molding the tread surface of a tread of a tire a plurality of recessed patterns, forming a texture, so as to impart to said band when new improved characteristics in wet grip.

Claims

1 - A method of molding a tire provided on at least a portion of its outer surface with a plurality of patterns, said patterns being comprised of hollow and / or reliefs, said method comprising the steps of:
a - making a base model (1), the outer surface (2) of said model reproducing the outer geometry of the part of the tire to be molded; b - on at least one portion (3) of the external surface (2) of the base model (1), setting up a body (4) having a surface for forming a part of the surface model base, said body being provided on said surface a plurality of recessed patterns (7) and raised portion (8); c- on this basic model (1), molding an imprint in a castable material, and solidifying said material being characterized in the solid state by a suitable deformation of elasticity to allow the release of said footprint, without to destroy the basic model; d- production by molding on the imprint of a mold-in against and solidifiable flowable material, said material resistant to temperatures above 200 ° C; e molding of the corresponding mold piece by casting a metal alloy against the mold; f- releasing the mold part, possibly by destroying the counter mold. g- assembly of the mold part to form a tire mold; h- establishment of a tire blank uncured and molded in the mold; i molding and vulcanization of the tire blank.
2 - Process according to claim 1 characterized in that at least part of the recessed and raised patterns is obtained by etching at least one of the materials forming the surface of the base model.
3 - Method according to claim 1 or claim 2 characterized in that at least one of the materials forming the base model covering body is made of resin and in that at least part of the recessed and raised patterns is obtained by laser engraving on the surface of said material.
4 - A method of molding a tire provided on at least a portion of its outer surface with a plurality of patterns, said patterns being comprised of hollow and / or reliefs, said method comprising the steps of:
a - making a base model (1), the outer surface (2) of said model reproducing the outer geometry of the part of the tire to be molded; b - on at least one portion (3) of the external surface (2) of the base model (1), put in place by partial or total of said surface with at least one material in particular in the form of a sheet provided with a surface texture, a fabric or any other form so as to form on said surface a large number of recesses (7) and projections (8) to be reproduced identically by molding on at least a portion of the molding surface of the tire mold. c- on this basic model (1), molding an imprint in a castable material, and solidifying said material being characterized in the solid state by a suitable deformation of elasticity to allow the release of said footprint, without to destroy the basic model; d- production by molding on the imprint of a mold-in against and solidifiable flowable material, said material resistant to temperatures above 200 ° C; e molding of the corresponding mold piece by casting a metal alloy against the mold; f- releasing the mold part, possibly by destroying the counter-mold; g- assembly of the mold part to form a tire mold; h- establishment of a tire blank uncured and molded in the mold; i molding and vulcanization of the tire blank.
5 - A method according to claim 4 characterized in that the material at least partially covering the surface of the base model is coated on its surface wall intended to come into contact with said model to facilitate demolding of the intended impression under step c.
6 - Method according to one of claims 1 to 5 characterized in that the pattern density, i.e. the number of patterns in recessed and raised per unit area is at least 1. 10 units per square meter.
7 - Method according to one of claims 1 to 6 characterized in that the against-mold is made by casting a plaster of particle size adapted to reproduce in detail the state of initial surface of the base model.
PCT/EP1998/004279 1997-07-18 1998-07-10 Method for moulding a tyre WO1999003662A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
FR97/09243 1997-07-18
FR9709243 1997-07-18

Publications (1)

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WO1999003662A1 true true WO1999003662A1 (en) 1999-01-28

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PCT/EP1998/004279 WO1999003662A1 (en) 1997-07-18 1998-07-10 Method for moulding a tyre

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000058066A1 (en) * 1999-03-31 2000-10-05 Gravutex Eschmann International Limited Rapid texture prototyping
US6558496B1 (en) 1997-11-28 2003-05-06 Eschmann-Stahl Gmbh & Co., Kg Rapid texture prototyping
US6565693B1 (en) 1997-11-28 2003-05-20 Eschmann-Stahl Gmbh & Co. Kg Rapid texture prototyping
DE102007005455B4 (en) * 2007-02-03 2017-03-23 Continental Reifen Deutschland Gmbh And tire vulcanizing method of manufacturing a tire vulcanizing

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB844714A (en) * 1957-05-20 1960-08-17 Firestone Tire & Rubber Co Method of producing molds
GB2085612A (en) * 1980-08-04 1982-04-28 Goodyear Tire & Rubber Method of making a sight model said model its use as a mold part and said mold
JPS62214910A (en) * 1986-03-17 1987-09-21 Keizo Saeki Manufacture of tire
FR2631861A1 (en) * 1988-05-27 1989-12-01 Staphane Sa Process for the manufacture of an injection mould for a thermoplastic
EP0384775A2 (en) * 1989-02-23 1990-08-29 Bridgestone Corporation Split dies for casting small segments of tire mold
EP0400672A2 (en) * 1989-06-02 1990-12-05 American Bank Note Holographics, Inc. Plastic molding of articles including a hologram or other microstructure
DE4324970A1 (en) * 1993-07-24 1995-01-26 Benecke Kaliko Ag Process for producing an embossing roller for continuously embossing the surface of a thermoplastic film with a pattern
EP0668136A1 (en) * 1994-02-04 1995-08-23 THE GOODYEAR TIRE & RUBBER COMPANY Method and apparatus for making a tire mold

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB844714A (en) * 1957-05-20 1960-08-17 Firestone Tire & Rubber Co Method of producing molds
GB2085612A (en) * 1980-08-04 1982-04-28 Goodyear Tire & Rubber Method of making a sight model said model its use as a mold part and said mold
JPS62214910A (en) * 1986-03-17 1987-09-21 Keizo Saeki Manufacture of tire
FR2631861A1 (en) * 1988-05-27 1989-12-01 Staphane Sa Process for the manufacture of an injection mould for a thermoplastic
EP0384775A2 (en) * 1989-02-23 1990-08-29 Bridgestone Corporation Split dies for casting small segments of tire mold
EP0400672A2 (en) * 1989-06-02 1990-12-05 American Bank Note Holographics, Inc. Plastic molding of articles including a hologram or other microstructure
DE4324970A1 (en) * 1993-07-24 1995-01-26 Benecke Kaliko Ag Process for producing an embossing roller for continuously embossing the surface of a thermoplastic film with a pattern
EP0668136A1 (en) * 1994-02-04 1995-08-23 THE GOODYEAR TIRE & RUBBER COMPANY Method and apparatus for making a tire mold

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 012, no. 073 (M - 674) 8 March 1988 (1988-03-08) *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6558496B1 (en) 1997-11-28 2003-05-06 Eschmann-Stahl Gmbh & Co., Kg Rapid texture prototyping
US6565693B1 (en) 1997-11-28 2003-05-20 Eschmann-Stahl Gmbh & Co. Kg Rapid texture prototyping
WO2000058066A1 (en) * 1999-03-31 2000-10-05 Gravutex Eschmann International Limited Rapid texture prototyping
DE102007005455B4 (en) * 2007-02-03 2017-03-23 Continental Reifen Deutschland Gmbh And tire vulcanizing method of manufacturing a tire vulcanizing

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