Abstract
A method for producing a vulcanizing mold for vehicle tires, in which the vulcanizing mold has radially on the inside cast mold surfaces of a mold material with mold projections for forming cuts in the tread profile of the vehicle tire to be manufactured. The mold projections are formed by in each case first providing a core of a metal of higher strength than the mold material and then coating the core at least partially with the mold material during the casting of the mold surfaces. A corresponding vulcanizing mold is also specified.
Claims
1. A method for producing a vulcanizing mold for vehicle tires, wherein the vulcanizing mold has radially on the inside cast mold surfaces of a mold material with mold projections for forming cuts in the tread profile of the vehicle tire to be manufactured, wherein, for forming the mold projections, a core of a metal of higher strength than the mold material is provided and is at least partially coated with the mold material during the casting of the mold surfaces.
2. The method as claimed in claim 1, wherein the core is completely coated with and encased by the mold material.
3. The method as claimed in claim 1, wherein at least one sipe blade, at least a region of which is not coated with the mold material, is attached to the core.
4. The method as claimed in claim 1, wherein the mold material is used on the basis of aluminum and the core is formed from steel.
5. The method as claimed in claim 1, wherein the core has a multiplicity of apertures, which are penetrated by the mold material.
6. The method as claimed in claim 5, wherein the apertures are formed in the form of bores in the core or the core has a grid-like structure containing the apertures.
7. The method as claimed in claim 1, wherein the core is produced from a sheet metal blank or in an additive process.
8. A vulcanizing mold for the manufacture of vehicle tires, which has radially on the inside mold surfaces with mold projections of a cast mold material, the mold projections being configured for forming cuts in the tread profile of the vehicle tire to be manufactured, wherein the mold projections each have a core of a metal of higher strength than the mold material which is at least partially coated with the mold material.
9. The vulcanizing mold as claimed in claim 8, wherein the core is completely coated with and encased by the mold material.
10. The device as claimed in claim 9, wherein at least one sipe blade protruding from the mold material is attached to the core.
11. The vulcanizing mold as claimed in claim 8, wherein the core has a multiplicity of apertures, which are filled by the mold material.
12. The vulcanizing mold as claimed in claim 11, wherein the apertures are formed by bores in the core or the core has a grid-like structure, which forms the apertures.
13. The vulcanizing mold as claimed in claim 8, wherein the core has externally formed-on stiffening ribs.
14. A method of forming a vehicle tire, comprising: providing the vulcanizing mold according to claim 1, and manufacturing the vehicle tire using the vulcanizing mold.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Further configurations and details of the invention are explained below in exemplary embodiments with reference to the drawing, in which:
[0031] FIG. 1 shows a vulcanizing mold for vehicle tires according to the invention in a schematic representation;
[0032] FIG. 2 a shows the cross section through a mold projection in a first embodiment of the invention;
[0033] FIG. 2 b shows the longitudinal section through the mold projection according to FIG. 2 a;
[0034] FIG. 3 a shows the cross section through a mold projection in a second embodiment of the invention;
[0035] FIG. 3 b shows the longitudinal section through the mold projection according to FIG. 3 a;
[0036] FIG. 4 a shows the cross section through a mold projection in a third embodiment of the invention;
[0037] FIG. 4 b shows the longitudinal section through the mold projection according to FIG. 4 a;
[0038] FIG. 5 shows the cross section through a mold projection in a fourth embodiment of the invention;
[0039] FIG. 6 a shows the plan view of a sixth embodiment of the invention;
[0040] FIG. 6 b shows a section through the embodiment according to FIG. 6 a;
[0041] FIG. 7 a shows the plan view of a seventh embodiment of the invention;
[0042] FIG. 7 b shows a section through the embodiment according to FIG. 7 a.
DETAILED DESCRIPTION
[0043] FIG. 1 illustrates in a greatly simplified schematic representation a vulcanizing mold 1 for the production of an indicated vehicle tire 4, which is inserted into the vulcanizing mold 1 as a green, unvulcanized tire blank and is hot-pressed in the vulcanizing mold 1 in a manner known per se, it being transformed into its final rubber-elastic state by means of rubber cross-linking reactions. For this purpose, the vulcanizing mold 1 consists of a multiplicity of openable and closable mold segments 2, which have on their radial inner side facing the vehicle tire 4 cast mold surfaces 3 of a mold material 30, for example aluminum. These mold surfaces have a surface profiling not reproduced in detail in the representation according to FIG. 1 with protruding mold projections 5, which represent the negative shape of the positive shape desired in the vehicle tire 4 to be produced, with tread bars, sipes, inscriptions, etc. In particular, in the case of mold projections 5 that are very fine and reach to the full tread-profile depth, which are shown in various embodiments of the representations according to FIGS. 2 a to 5, the strength and dimensional accuracy of the same have to meet the highest requirements.
[0044] With regard to the representations of the mold projections 5 according to FIGS. 2 a to 5 explained below, it should first be noted that these figures only illustrate the structure schematically and by way of example, without reverting to the real, sometimes complex, three-dimensional design for reasons of simplification.
[0045] As can be seen from the representation of a first embodiment of a mold projection 5 according to FIGS. 2 a and 2 b, a core 50 of a metal of higher strength than the mold material 30 is initially provided for forming the projection, for example a blank of a steel sheet. Subsequently, during the production of the mold surface 3 produced from the mold material 30, in particular aluminum, by the casting process, the core 50 is completely coated with and encased by the cast mold material 30, so that the mold material 30 forms the outer contour and thus the desired geometry of the mold projection 5, and the core 50 is arranged internally in the manner of a reinforcement. The mold projection 5 therefore rises up integrally out of the cast mold surface 3 and has the highest form tolerance and dimensional tolerance due to the coating of the core 50 of the cast mold material 30, at the same time the internally arranged steel core 50 ensuring particularly high strength and mechanical load-bearing capacity of the mold projection 5.
[0046] According to the representation in FIGS. 3 a and 3 b, the core 50 may also have a multiplicity of apertures 51, which may be formed for example by introducing bores into the core 50. Although not explicitly shown in the representations according to FIGS. 3 a and 3 b, in the formation of the coating of the core 50 with the mold material 30 these apertures 51 are completely filled by this material, whereby an intensive interlocking engagement is established between the core 50 and the mold material 30, which encases and coats the core 50.
[0047] A similar effect can also be produced by the core 50 according to the exemplary embodiment of FIGS. 4 a and 4 b having a grid structure or comparable open structure, in which the core 50 is for example produced from a steel mesh. Such a grid structure also defines a multiplicity of apertures 51, which are filled by the mold material 30 melted in liquid form during the casting of the mold surfaces 3. Moreover, in the case of very low wall thicknesses of the mold material 30 coating the core 50, such a configuration has the effect of avoiding that the molten mold material 30 solidifies prematurely on the core 50 and the core 50 is not completely filled with mold material 30.
[0048] According to the exemplary embodiment in FIG. 5, to increase the stiffness of its connection, the core 50 may also be formed with further protruding stiffening elements, for example externally formed-on stiffening ribs 52, along its axes of extent.
[0049] The cores 50 encased by the mold material 30 in the exemplary embodiments described above may for example be formed from a sheet metal blank, which if necessary is cut and bent into a desired shape, or else produced in an additive process, for example by means of laser sintering or 3D printing in accordance with a calculated design.
[0050] FIGS. 6 a and 6 b show a further embodiment of the vulcanizing mold. In a mold projection 5 cast from the mold material 30 in the manner of a rib, a multiplicity of cores 50 are completely cast in, i.e. they are completely encased by the mold material 30 in the casting process. Furthermore, a sipe blade 502 is attached to each of the cores 50, for example welded on, approximately in a T-shaped manner. The attachment already takes place before the casting in of the core 50 in the mold material. A region of the sipe blade 502 attached in such a way to the cast-in core 50 is led out from the formed rib 503 after the casting of the mold material 30 and is not encased by the mold material 30 in this led-out region. As a part of the mold projection 5, it replicates even the finest sipe structures in a precisely positioned manner.
[0051] In FIGS. 7 a and 7 b, a further embodiment of the vulcanizing mold is shown. In this case, the core 50 is arranged within the mold projection 5 cast from the mold material 30, but has a plurality of legs 503 protruding at an angle, which protrude with their free end from the mold material 30, so that the core 50 is not encased by mold material 30 in this partial region of its legs 503. Attached to these free ends of the legs 503, for example welded on, are sipe blades 502 not covered by the mold material 30, in order as part of the mold projection 5 to replicate finest structures.
[0052] With the method described above and the vulcanizing mold produced by it, in particular mold projections with a narrow transverse void including chamfers can be produced with high precision and increased durability.
[0053] It goes without saying that the method described above can also be used for other applications in mold making.
LIST OF REFERENCE SIGNS
[0054] 1: Vulcanizing mold [0055] 2: Mold segment [0056] 3: Mold surfaces [0057] 4: Vehicle tire [0058] 5: Mold projection [0059] 30: Mold material [0060] 50: Core [0061] 51: Aperture [0062] 52: Stiffening rib [0063] 502: Sipe blade [0064] 503: Leg
