Method for producing a vulcanization mold and vulcanization mold produced according to the method

Abstract

The invention relates to a method for producing a vulcanization mold (1) for vehicle tires (4), wherein the radially inner side of the vulcanization mold (1) has a cast molding surface (3) made of a molding material (30), which has molding protrusions (5) for forming incisions in the tread profile of a vehicle tire (4) to be manufactured. The molding protrusions (5) are formed by first providing a core (50) made of a metal having a higher strength than the molding material (30) and subsequently at least partially coating the core (50) with the molding material (30) during casting of the molding surface (3). A corresponding vulcanization mold is also defined.

Description

Technical Field

[0001] The present invention relates to a method for producing a vulcanizing mold for vehicle tires, the vulcanizing mold having a molding surface made of casting molding material on its radially inner side, the molding surface having molding protrusions for forming cuts in the tread profile of the vehicle tire to be manufactured.

[0002] The present invention also relates to a vulcanizing mold for manufacturing vehicle tires produced according to this method. Background Technology

[0003] A vulcanizing mold for vehicle tires consists of mold sections, the molded surfaces of which together form the radial outer surface of the tire to be manufactured, such as the tread, shoulder area, sidewall, and bead area.

[0004] The mold sections of a vulcanizing mold are made of metal, typically steel or aluminum. Mold surfaces made of steel are usually machined from solid materials, while mold surfaces made of aluminum are typically produced through a casting process. Those skilled in the art are well aware of center-split vulcanizing molds and segmented vulcanizing molds.

[0005] Uncured green tire blanks are hot-pressed in a vulcanizing mold and transformed into their final rubber elastic state through a rubber crosslinking reaction. The tread profile and sidewall design of a vehicle tire are achieved by giving the molded surface with corresponding molded protrusions for forming cuts in the tread profile a corresponding negative profile.

[0006] These cuts in the tread profile can, for example, define individual tread blocks. In particular, winter tires also feature fine cuts or sipes in the tread profile elements, which give the tire advantageous properties on winter road surfaces. These cuts may sometimes have complex three-dimensional shapes, making the production of corresponding molding protrusions in the molding surface of the vulcanizing mold also relatively complex.

[0007] Conventional casting molds (e.g., made of aluminum with casting molded protrusions) have material-related strength limitations, which restrict the production-related realization of functional molded structures (especially fine molded protrusions).

[0008] It is also known in the prior art that these molded protrusions are produced separately using other molding surfaces of a vulcanizing mold. For example, to manufacture fragile structures (such as grooving patterns) suitable for use in casting molds for tire production, these fragile structures are produced from other materials with different mechanical properties (such as sheet steel) and cast into a molding surface with shaped anchors underneath. The casting creates an interlocking engagement rather than material bonding. Furthermore, the production of such grooving blades is very difficult, especially in the case of 3D grooving patterns. Compared to directly cast structures, these separately cast molded protrusions are more susceptible to tolerances in terms of manufacturing technology.

[0009] The problem this creates is that (especially when the molded protrusions that reach the full depth of the tread profile are very narrow and high), the cast structure is within the allowable height tolerance but has only low durability, while separately formed steel inserts used to form the molded protrusions have good durability but are usually outside the height tolerance range.

[0010] DE 10 2012 102 322 A1 also proposed producing molded protrusions using rapid prototyping processes (such as 3D printing or laser sintering), and then introducing these molded protrusions into the casting molded surface. However, both the production of the molded protrusions and their subsequent introduction into the casting molded surface are complex and seem to require improvement. Summary of the Invention

[0011] Therefore, the object of the present invention is to provide a method for producing vulcanizing molds and a corresponding vulcanizing mold that overcomes the shortcomings of the prior art.

[0012] To address the aforementioned problem, the present invention proposes a method design based on the features of claim 1.

[0013] Furthermore, a corresponding vulcanizing mold according to the features of claim 7 is proposed to solve the aforementioned problem.

[0014] Advantageous configurations and developments of the present invention are the subject of the dependent claims.

[0015] The method for producing vulcanizing molds proposed in the context of this invention provides that, in order to form a molded protrusion, firstly, a core made of a metal with a strength higher than that of the molding material is provided, and then the core is at least partially coated with the molding material during the casting of the molding surface, thereby forming a molded protrusion with an inner core by the casting molding material while the molding surface is being formed.

[0016] The outstanding feature of this molded protrusion, made of casting molding material and having an inner core of a higher-strength metal, formed in a vulcanizing mold according to the present invention, is that the molded protrusion exhibits exceptionally high mechanical durability and reliably meets the required height tolerances, even in cases of very narrow and / or complex cross-sectional designs. Simultaneously, it significantly simplifies the production of vulcanizing molds.

[0017] It goes without saying that, by the method according to the invention, at least one molded protrusion, particularly having a complex or narrow and tall shape, is produced. However, the molded protrusion produced in the molded surface by the method according to the invention can also be combined with conventionally designed molded protrusions.

[0018] According to the present invention, the inner molding surface of the vulcanizing mold is made entirely of casting molding material, the inner molding surface including existing molding protrusions for forming cuts in the tread profile of the vehicle tire to be manufactured, but these molding protrusions are reinforced with a reinforcing core made of metal, and the molding protrusions are at least partially surrounded by casting molding material and integrated into the casting molding surface.

[0019] According to the proposal of the present invention, the core is completely coated and encased in the molding material, so that the core is no longer visible when the molding surface is viewed.

[0020] According to another proposal of the invention, the core has multiple orifices through which the molding material penetrates during the casting process. In this way, a tight interlocking connection is formed between the molding material that forms the contour of the molding protrusions and the inner core, because it is not possible to produce material adhesion between the core, which is made of a stronger metal, and the molding material in every case.

[0021] According to the proposal of the present invention, these orifices can be produced by forming a plurality of holes in the core, into which molding material can penetrate during the coating of the core.

[0022] Alternatively, the core can also have a mesh-like structure, or any other open structure or geometry containing orifices. This configuration is particularly advantageous when the wall thickness of the molding material coated around the core is very small. Otherwise, there are risks that the molten molding material will solidify prematurely on the core during casting, and that the core's structure will not be completely penetrated by the molten material. However, when the core is formed with a mesh-like structure, the presence of multiple orifices ensures that the molten casting molding material completely fills the core. This also improves the adhesion between the core and the surrounding molding material.

[0023] Steel is considered particularly suitable as a core material, and casting molding materials are preferably selected in a known manner based on aluminum or corresponding alloys.

[0024] According to another proposal of the invention, the core can be produced, for example, from a bent sheet metal blank, or by an additive manufacturing process (e.g., from a laser-sintered material or a material formed by a 3D printer). In any case, the core design must allow for the anticipated loads and, where necessary, provide a corresponding structural design including a mathematical topology optimization model.

[0025] In particular, the laser sintering materials used to produce the core are metals (such as steel, aluminum, and titanium) and their alloys that can be processed by laser sintering, as well as other sintered metals and sintered materials (such as ceramics and alumina).

[0026] Where necessary, a core partially or completely encased in molding material may be attached (e.g., welded) with grooved blades, at least a portion of which is also not covered by molding material, in order to replicate the finest structure positioned with high precision in the molding protrusion.

[0027] In particular, when the core is manufactured using additive manufacturing processes, simulated and optimized structures with complex geometries can be directly produced with the highest precision using data calculated from the model.

[0028] Additionally, if necessary, additional features (such as shaped reinforcing ribs) can be provided to each individual core along its extension axis to improve the stiffness of the connection. Attached Figure Description

[0029] Further configurations and details of the invention will now be explained with reference to the accompanying drawings through exemplary embodiments, in which:

[0030] Figure 1 A vulcanizing mold for a vehicle tire according to the present invention is shown schematically.

[0031] Figure 2a A cross-section through a molded protrusion of a first embodiment of the invention is shown;

[0032] Figure 2b It shows crossing according to Figure 2a The longitudinal section of the molded protrusion;

[0033] Figure 3a A cross-section through a molded protrusion of a second embodiment of the invention is shown;

[0034] Figure 3b It shows crossing according to Figure 3a The longitudinal section of the molded protrusion;

[0035] Figure 4a A cross-section through a molded protrusion of a third embodiment of the invention is shown;

[0036] Figure 4b It shows crossing according to Figure 4a The longitudinal section of the molded protrusion;

[0037] Figure 5 A cross-section through a molded protrusion of a fourth embodiment of the invention is shown;

[0038] Figure 6a A plan view of the sixth embodiment of the present invention is shown;

[0039] Figure 6b It shows crossing according to Figure 6a A cross-section of an embodiment;

[0040] Figure 7a A plan view of the seventh embodiment of the present invention is shown;

[0041] Figure 7b It shows crossing according to Figure 7a A cross section of an embodiment.

[0042] List of reference numerals

[0043] 1: Vulcanizing mold

[0044] 2: Mold Section

[0045] 3: Molded surface

[0046] 4: Vehicle tires

[0047] 5: Molded protrusions

[0048] 30: Molding materials

[0049] 50: Core

[0050] 51: Orifice

[0051] 52: Reinforcing ribs

[0052] 502: Grooved blade

[0053] 503: Support Leg Detailed Implementation

[0054] Figure 1 A vulcanizing mold 1 for producing the indicated vehicle tire 4 is shown in a very simplified schematic representation. The vehicle tire, as an unvulcanized green tire blank, is inserted into the vulcanizing mold 1 and hot-pressed within it in a manner known per se, transforming into its final rubber-elastic state through a rubber crosslinking reaction. For this purpose, the vulcanizing mold 1 consists of a plurality of openable and closable mold sections 2, which have cast molding surfaces 3 made of molding material 30 (e.g., aluminum) on their radially inward sides facing the vehicle tire 4. These molding surfaces have surface profiles (in accordance with...) Figure 1(Not detailed in the representation), the surface profile has prominent molded protrusions 5, which present a negative shape corresponding to the desired positive shape of the vehicle tire 4 to be produced, which has tread blocks, sipes, markings, etc. In particular, when the molded protrusions 5 are very fine and reach the full depth of the tread profile (according to...), Figures 2a to 5 (As shown in various embodiments), the strength and dimensional accuracy of the molded protrusions must meet the highest requirements.

[0055] The basis for the following explanation Figures 2a to 5 The representation of the molded protrusion 5 should first be noted that, for the sake of simplicity, these figures are only schematic illustrations of the structure by way of example, and do not represent the real, and sometimes complex, three-dimensional design.

[0056] If can be based on Figure 2a and Figure 2b As shown in the first embodiment of the molded protrusion 5, a core 50 made of a metal with a strength higher than that of the molding material 30 is first provided to form the protrusion, such as a steel sheet blank. Subsequently, during the production of the molded surface 3 made of the molding material 30 (particularly aluminum) by a casting process, the core 50 is completely coated and enclosed by the casting molding material 30, so that the molding material 30 forms the outer contour and thus forms the desired geometry of the molded protrusion 5, and the core 50 is arranged internally in a reinforcing manner. Therefore, the molded protrusion 5 integrally protrudes from the casting molded surface 3, and due to the coating of the casting molding material 30 on the core 50, the molded protrusion has the highest form and dimensional tolerances, while the steel core 50 arranged internally ensures that the molded protrusion 5 has particularly high strength and mechanical load-bearing capacity.

[0057] according to Figure 3a and Figure 3b The core 50 may also have a plurality of apertures 51, which can be formed, for example, by introducing holes into the core 50. Although according to Figure 3a and Figure 3b Although not explicitly shown in the representation, when the coating of the core 50 is formed with the molding material 30, these orifices 51 are completely filled with this material, thereby establishing a tight interlocking engagement between the core 50 and the molding material 30 that encloses and coats the core 50.

[0058] according to Figure 4a and Figure 4bIn an exemplary embodiment, a similar effect can be achieved by giving the core 50 a mesh structure or a more open structure, wherein the core 50 is produced, for example, from a steel mesh. This mesh structure also defines a plurality of orifices 51, which are filled with a molding material 30 molten in liquid form during the casting molding surface 3. Furthermore, when the wall thickness of the molding material 30 coated on the core 50 is very small, this configuration has the effect of preventing the molten molding material 30 from solidifying prematurely on the core 50 and preventing the core 50 from being incompletely filled with the molding material 30.

[0059] according to Figure 5 In an exemplary embodiment, to improve the rigidity of its connection, the core 50 may also have additional protruding reinforcing elements formed along its extension axis, such as reinforcing ribs 52 formed on the outside.

[0060] The core 50 enclosed by the molding material 30 in the exemplary embodiments described above can be formed, for example, from a sheet metal blank (which is cut and bent into the desired shape if necessary), or produced by additive manufacturing processes (e.g., by laser sintering or 3D printing) according to the calculated design.

[0061] Figure 6a and Figure 6b Another embodiment of the vulcanization mold is shown. In the molded protrusion 5, cast in a ribbed manner from the molding material 30, a plurality of cores 50 are completely cast therein, i.e., these cores are completely enclosed by the molding material 30 during the casting process. Furthermore, grooving blades 502 are attached to each core 50 in a generally T-shaped manner, for example, by welding. This attachment occurs before the cores 50 are cast into the molding material. A region of the grooving blades 502, which are attached in some way to the cast cores 50, extends out from the formed ribs 503 after the molding material 30 is cast, and in this extended region is not enclosed by the molding material 30. As part of the molded protrusion 5, the grooving blade replicates the finest grooving structure in a precisely positioned manner.

[0062] exist Figure 7a and Figure 7b Another embodiment of the vulcanizing mold is shown in the figure. In this case, the core 50 is arranged within a molded protrusion 5 cast from the molding material 30, but has multiple angled legs 503, the free ends of which protrude from the molding material 30, such that the core 50 is not covered by the molding material 30 in this local area of ​​its legs 503. These free ends of the legs 503 are attached (e.g., welded) with grooving blades 502 that are not covered by the molding material 30, so as to replicate the finest structure as part of the molded protrusion 5.

[0063] The above method and the vulcanizing mold produced by the method can, in particular, produce molded protrusions with narrow transverse gaps and chamfers, which have high precision and improved durability.

[0064] Needless to say, the above methods can also be used in other applications in mold making.

Claims

1. A method for producing a vulcanizing mold (1) for vehicle tires (4), wherein, The vulcanizing mold (1) has a casting molded surface (3) made of molding material (30) on its radially inner side. These casting molded surfaces have molding protrusions (5) for forming cuts in the tread profile of the vehicle tire (4) to be manufactured. The molded surface (3) is characterized in that, in order to form the molding protrusions (5), a core (50) made of a metal with a strength higher than that of the molding material (30) is provided, and during the casting of these molding surfaces (3), the core is at least partially coated with the molding material (30), wherein at least one sipe (502) is attached to the core (50), at least a certain area of ​​the at least one sipe is not coated with the molding material (30).

2. The method as described in claim 1, characterized in that, The core (50) is completely coated and enclosed with the molding material (30).

3. The method as described in any one of claims 1 to 2, characterized in that, The molding material (30) is based on aluminum, and the core (50) is formed of steel.

4. The method according to any one of claims 1 to 3, characterized in that, The core (50) has multiple orifices (51) through which the molding material (30) penetrates.

5. The method as described in claim 4, characterized in that, These openings (51) are formed in the core (50) in the form of holes, or the core (50) has a mesh-like structure containing these openings (51).

6. The method according to any one of claims 1 to 5, characterized in that, The core (50) is produced from sheet metal blanks or by additive manufacturing processes.

7. A vulcanizing mold (1) for manufacturing a vehicle tire (4), the vulcanizing mold having a molding surface (3) made of a casting molding material (30) on its radially inner side, the molding surface having molding protrusions (5) and for forming cuts in the tread profile of the vehicle tire (4) to be manufactured, characterized in that, Each of these molded protrusions (5) has a core (50) made of a metal with a strength higher than that of the molding material (30), the core being at least partially coated with the molding material, wherein at least one grooved blade (502) protruding from the molding material (30) is attached to the core (50).

8. The vulcanizing mold (1) as described in claim 7, characterized in that, The core (50) is completely coated and encased by the molding material (30).

9. The vulcanizing mold as described in claim 7, characterized in that, The core (50) has a plurality of orifices (51) which are filled by the molding material (30).

10. The vulcanizing mold as described in claim 9, characterized in that, These openings (51) are formed as holes in the core (50), or the core (50) has a mesh-like structure that forms these openings (51).

11. The vulcanizing mold as described in any one of claims 7 to 10, characterized in that, The core (50) has reinforcing ribs (52) formed on the outside.

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