Method for producing a cast molded part of a vulcanizing mold for vehicle tires
The method addresses the challenge of incorporating snow edges in vulcanizing molds by using selective milling and casting with aluminum-magnesium alloy, ensuring effective snow edge integration and efficient tire mold production.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CONTINENTAL REIFEN DEUTSCHLAND GMBH
- Filing Date
- 2025-12-15
- Publication Date
- 2026-06-25
AI Technical Summary
Existing methods for manufacturing vulcanizing molds for vehicle tires fail to incorporate snow edges effectively, as they are either impossible or require high effort due to material removal processes like plasma coating that destroy these features.
A method involving selective material-removing surface treatment and milling to create a model with excess areas, allowing for the incorporation of snow edges by retaining material during plasma coating, followed by milling to form raised ridges, and subsequent casting with aluminum-magnesium alloy to produce a mold part.
Enables the simple and effective integration of snow edges into the mold, enhancing tire traction by maintaining structural integrity and durability, while allowing for efficient production through segmented manufacturing.
Smart Images
Figure EP2025087062_25062026_PF_FP_ABST
Abstract
Description
[0001] 202406031
[0002] 1
[0003] Description
[0004] Method for manufacturing a cast molded part of a vulcanizing mold for vehicle tires
[0005] The invention relates to a method for producing a cast mold part of a vulcanizing mold for vehicle tires, according to the preamble of claim 1.
[0006] Vulcanizing molds, as components of hot presses, typically consist of several molded parts used in a vulcanization process to form the outer surface of a vehicle tire. The tire is formed by the tread, shoulders, sidewalls, and bead. The unvulcanized green tire blank is thus vulcanized in such a mold during the vulcanization process, thereby achieving its final rubber-elastic state. During this vulcanization, the tire blank acquires its tread pattern, which is determined by the corresponding negative shape of the molded surface, particularly that of a tread pattern mold.
[0007] For tire performance, especially for the snow and ice performance of winter tires, it is advantageous if the mantle-shaped tread surface of the vehicle tire not only has a defined roughness, but also so-called snow edges (snowedges or raised edges) are arranged on tread block edges to provide additionally increased gripping edges.
[0008] EP 3261 830 B1 describes, by way of example, how the molded parts of the vulcanization mold, in particular the profile molded parts, are provided with a defined roughness by means of a corresponding plasma coating in order to transfer this roughness to the mantle-shaped tread surface of the vehicle tire during vulcanization. For this purpose, 202406031
[0009] 2. A rigid model component with a model tread surface is created. A plasma coating is then applied to this model tread surface over its entire area. Subsequently, a profile positive of the desired tread is milled into the mantle-shaped model tread surface of the model component to obtain a so-called master model.
[0010] A flexible impression, preferably made of silicone rubber, is then created from the master model. This impression will have a defined roughness and a negative profile of the desired tread pattern. A rigid plaster cast is then made from this flexible impression, resulting in a casting core that retains the roughness and positive profile of the desired tread pattern. This casting core is then filled with an aluminum-magnesium alloy to create a mold for use in the vulcanization mold. The negative profile of the desired tread pattern, including the defined roughness, is incorporated into this cast part.The manufacturing process is partly segmented, resulting in segmented cast molded parts that also form the vulcanization shape in a segmented manner.
[0011] During the described manufacturing process of the molded parts, the entire tread surface of the molded part is blasted in a first step as part of the plasma coating process. This removes up to 0.3 mm of material from the tread surface. A so-called snow edge, which typically protrudes approximately 0.3–0.5 mm from the surface of the tire tread, could therefore not be incorporated into the mold as a raised ridge, as such a ridge would be destroyed or removed during the blasting process in the first step. Another method for permanently incorporating the snow edge in 202406031
[0012] 3. The model shape after plasma coating is not possible or only possible with very high effort.
[0013] The object of the invention is therefore to provide a method for producing a cast molded part of a vulcanizing mold for vehicle tires that eliminates the described disadvantages.
[0014] This problem is solved by a method according to the independent claim. The dependent claims specify preferred embodiments.
[0015] According to the invention, a method for producing a cast mold part of a vulcanizing mold for vehicle tires, the surface of which forms at least a portion of a tread surface of a tread of a vehicle tire to be vulcanized, is provided comprising at least the following steps:
[0016] - Creating a rigid model molded part with a model tread surface;
[0017] - Performing a material-removing surface treatment of the model mold part, in which the entire model running strip surface is treated in such a way that a portion of the material of the model mold part is removed or abraded, for example by between 0.1mm and 0.5mm, preferably by at least 0.3mm;
[0018] - selective milling of a profile positive of the tread of the vehicle tire to be vulcanized into the model tread surface of the model molded part to obtain a master model;
[0019] - Creating a flexible impression (Flexible) from the obtained master model, preferably made of silicone rubber, so that the flexible impression has a negative design of the profile positive of the tread of the vehicle tire to be vulcanized;
[0020] - Creating a rigid cast from the flexible impression, preferably from plaster, so that a rigid casting core mold part is produced which has the profile positive of the tread of the vehicle tire to be vulcanized; 202406031
[0021] 4
[0022] - Casting or pouring the core mold part, preferably with an aluminum-magnesium alloy, to obtain the cast mold part for the vulcanization mold, wherein
[0023] - the model molded part is created with a model tread surface that has at least one base area and at least one excess area raised in relation to it, wherein the respective excess area is raised or projected from the base area by an allowance, and
[0024] - The selective milling of the profile positive of the tread of the vehicle tire to be vulcanized involves milling a groove structure into the excess area of the model tread surface in such a way that a raised ridge is left between the groove structure and the respective base area, which is associated with a snow edge protruding from the tread surface of the tread of the vehicle tire to be vulcanized.
[0025] The method according to the invention thus provides a simple way in which a structure forming the raised snow edge can be incorporated into the (profile) mold for forming the tread of the vehicle tire, even when the model mold is subjected to a material-removing surface treatment. This is made possible precisely by providing the excess area from which the profile design is milled out while retaining the raised rib. The material-removing surface treatment essentially preserves this excess, so that the raised rib can be retained by selective milling.
[0026] Material-removing surface treatment is understood to mean that in
[0027] As part of the surface treatment of the entire model-
[0028] A portion of the material is removed from the tread surface in any way. 202406031
[0029] 5
[0030] Furthermore, any number of plaster casts can be made from the flexible impression to preserve the casting core mold. Thus, only one application of the appropriate material-removing surface treatment and selective milling, while retaining the webs, etc., is necessary.
[0031] Preferably, the molded part is further designed such that radii are arranged in the tread surface of the model between the base area and the oversize area, particularly with a radius of between 0.2 mm and 1.2 mm, preferably 1 mm. In this way, corresponding radii can also be incorporated between the respective snow edge and the tread block, which simplifies the stability of the snow edges in the vulcanized tire, the durability of the snow edges in the vulcanized tire, and the demolding of the tire after vulcanization.
[0032] Preferably, the allowance by which the excess material protrudes from the base area is between 0.5 mm and 1.0 mm, preferably between 0.8 mm and 1 mm. This provides a sufficient excess of material from which the raised web of the desired height can then remain after selective milling.
[0033] Preferably, the selective milling of the profile positive of the tread of the vehicle tire to be vulcanized further includes milling off the raised rib between the groove structure and the respective base area, in particular such that the allowance during selective milling is reduced to between 0.2 mm and 0.8 mm, preferably between 0.3 mm and 0.5 mm. Consequently, the full allowance of the raised rib is not necessarily retained, and a corresponding buffer is planned, which is then removed during selective milling. 202406031
[0034] 6
[0035] Preferably, it is further provided that, during the selective milling of the profile positive of the tread of the vehicle tire to be vulcanized, the groove structure is milled into the excess area of the model tread surface in such a way that a raised ridge with a width of between 0.1 mm and 1.0 mm, preferably between 0.3 mm and 0.5 mm, remains. The model component is thus aligned with corresponding precision in the milling machine in order to create appropriately wide and high, and therefore stable, ridges during the formation of the groove structure.
[0036] Preferably, a plasma coating is applied to the model tread surface as a material-removing surface treatment. During the application of the plasma coating, the entire model tread surface, both in the base area and in the excess area, is ablated by a corresponding plasma treatment, and a thermal spray layer is applied to the entire model tread surface. This spray layer comprises a matrix and statistically distributed spray additives, such as grains. In this way, the roughness of the model tread surface can be increased, which then also results in increased roughness of the tread surface in the vulcanized tread.
[0037] The roughness can advantageously be adjusted by appropriately selecting the spray layer or spray additives. Since the groove structure is milled in after such plasma coating application, the roughness is not present in the groove structure itself, so that the transverse grooves subsequently formed in the vulcanized vehicle tire also do not exhibit such increased roughness.
[0038] The advantage here is that the master model exhibits this roughness, which is transferred to the final cast part through the steps mentioned above. The roughness of the vulcanized vehicle tire is 202406031.
[0039] 7. A roughness between 5 mm and 50 mm, preferably between 7.5 mm and 25 mm, and particularly preferably between 10 mm and 15 mm, is advantageous. It should be taken into account that the roughness is slightly reduced by the impression and casting steps. This must be taken into account when adjusting the plasma coating in order to obtain the correct final roughness on the vulcanized vehicle tire.
[0040] Preferably, the base area of the model tread surface, after selective milling, forms a shape block that corresponds to a profile block on the tread surface of the vehicle tire to be vulcanized. Furthermore, it is preferably provided that the groove structure milled into the excess area of the model tread surface corresponds to a transverse groove on the tread surface of the vehicle tire to be vulcanized. The correspondingly surface-treated base area can thus be easily used to define the shape of a profile block in the finished vehicle tire, while the correspondingly milled excess area defines the shape of the groove and the transition between the profile block and the groove.
[0041] Preferably, several manufactured core mold parts are assembled segmentally, and the assembled core mold parts are cast together with an aluminum-magnesium alloy and preferably subsequently separated again into individual cast parts. This simplifies production, since not all steps of the manufacturing process are carried out with a single large mold, but rather the segments are produced individually in most steps.
[0042] The drawings show: 202406031
[0043] 8
[0044] Fig. 1 shows a section through a transverse groove with snow edges;
[0045] Fig. 2 shows a section through a chamfered transverse groove with snow edges;
[0046] Fig. 3 shows a schematic view of a heating press with a vulcanization mold; and
[0047] Fig. 4 shows an exemplary sequence of a process for producing a cast mold part for the vulcanization mold according to Fig. 3.
[0048] Figure 1 shows an example of a cross-section through a profiled vehicle tire 1 in the area of a transverse groove 2, which is formed between two tread blocks 3 in a tread 1a. Accordingly, the transverse groove 2 extends from a groove base 2a across sidewalls 2b to a tread surface 2c of the vehicle tire 1. At the transition between the respective sidewall 2b and the tread surface 2c, a snow edge 4 is provided, which, as a raised ridge, has a height H above the tread surface 2c of the respective tread block 3 of between 0.2 mm and 1.0 mm, preferably between 0.3 mm and 0.5 mm, and a width B of between 0.1 mm and 1.0 mm, preferably between 0.3 mm and 0.5 mm. The snow edge 4 transitions into the tread surface 2c of the respective profile block 3 in a rounded manner, for example with a radius R of 1 mm. However, the radius R can also be chosen differently.
[0049] Additionally, as shown in Fig. 2, a chamfer 5 can be provided between at least one of the side flanks 2b and the respective snow edge 4, in particular the side flank 2b or snow edge 4 trailing in the direction of travel.
[0050] Such snow edges 4 can improve traction by forming additional gripping edges that can also penetrate the snow 202406031
[0051] 9. In order to incorporate such snow edges 4 with or without chamfer 5 into the tread 1a, molded parts 10 must be manufactured accordingly as components of a vulcanization mold 20. A highly schematic representation of such a vulcanization mold 20 as a component of a heating press 30 is shown in Fig. 3.
[0052] Accordingly, the vulcanization mold 20 is arranged in a sealable container 21 and has several mold parts 10 which together form the outer surface of the vehicle tire 1 in a vulcanization process. The unvulcanized green tire blank is vulcanized after being placed in the container 21 and during the contact of the mold parts 10 with the tire blank by the application of pressure and heat, thereby bringing it into its final rubber-elastic state to form the vehicle tire 1.
[0053] During vulcanization, the tire blank receives its tread pattern, which is determined by the corresponding negative shaping of the molded surface 11 of the molded parts 10 that are brought into contact with the tire blank during vulcanization. Different molded parts 10 with different molded surface 11 must be provided for the respective area of the vehicle tire 1, e.g., the tread 1a, sidewall 1b, and bead areas 1c.
[0054] The molded part 10 for forming the tread 1a can, for example, be referred to as a profile molded part, wherein the corresponding negative shape of the desired profiled tread 1a is formed on the molded part surface 11 of the (profile) molded part 10. Accordingly, corresponding structures for forming the transverse groove 2, which separates the profile blocks 3, for forming the snow edges 4, and optionally the chamfer 5, and for forming any further profile elements, are present on the molded part surface 11 of the molded part 10.
[0055] 10. This is done according to the invention by the following method, which is illustrated by way of example in Fig. 4:
[0056] In a first step ST1, a rigid model part M10 with a model running surface M11 is provided. The model running surface M11 is divided into a base area M11a and an excess area M11b, which is not present in conventional model parts M10. The excess area M11b has an excess relative to the base area M11a, i.e., it rises by an excess A of between 0.5 mm and 1.0 mm, preferably between 0.8 mm and 1 mm, from the base area M11a. The raised excess area M11b transitions into the base area M11a via a radius M11c with a radius R of preferably 1 mm. Depending on the dimensions of the model part M10, several base areas M11a and / or several excess areas M11b can alternate in this way on the model running surface M11.
[0057] In a second step ST2, a material-removing surface treatment is then carried out, in which the entire model tread surface M1 1, i.e., both in the base area M11 a and in the oversize area M1 1 b, is treated. Material removal means that, as part of the surface treatment, a portion of the material is removed from the entire model tread surface M11.
[0058] Such a material-removing surface treatment can, for example, involve applying a plasma coating 12 to the entire model tread surface M11, i.e., both in the base area M11a and in the oversize area M11b. This plasma coating 12 increases the surface roughness of the model mold M10, so that a surface roughness also develops in the cast mold 10, which is transferred to the tread surface 2c of the finished vehicle tire 1 during the vulcanization of the tire blank. 202406031
[0059] 11
[0060] During the application of the plasma coating 12, the entire model tread surface M11 of the model part M10 is uniformly ablated by a surface treatment in a plasma, i.e., preferably up to 0.3 mm of material is removed from the surface of the model tread surface M11. Since this material removal ideally occurs uniformly in the base area M11a, the oversize area M11b, and the radius area M11c, the allowance A of between 0.5 mm and 1.0 mm, preferably between 0.8 mm and 1 mm, is essentially retained.
[0061] Simultaneously, during this material-removing surface treatment, a thermal spray coating is applied to the entire treated model tread surface M11. This spray coating consists of a matrix and statistically distributed spray additives. The spray additives can be, for example, grains selected according to the desired roughness and properties of the plasma coating 12.
[0062] Instead of or in addition to this plasma coating 12, other material-removing surface treatments can also be used.
[0063] After completion of the material-removing surface treatment, in a third step ST3, a profile positive of the desired tread 1a is selectively milled into the excess area M11b of the model tread surface M11 of the model part M10 to obtain a so-called master model U. This means that, as shown in Fig. 4 in the third step ST3, for example, a groove structure M12 is selectively milled into the excess area M11b, the groove structure M12 being based on the shape of the transverse groove 2 in the desired tread 1a.
[0064] Simultaneously, this process separates or creates form blocks M13 in the model mold M10, which correspond to the later profile blocks 3 in the tread 1a. 202406031
[0065] 12
[0066] The groove structure M12 is milled into the excess area M11b of the model tread surface M11 in such a way that raised ridges M14 remain, which correspond to the later snow edges 4 in the tread 1a. This is made possible precisely because the excess area M11b, with the allowance A, protrudes from the base area M11a of the model tread surface M11. The model component M10 must be aligned accordingly on the milling machine to form the raised ridges M14 as symmetrically as possible and with correct dimensions.
[0067] The selective milling in the third step ST3 is carried out such that the allowance A on the webs M14 of the model part M10 remains constant or is reduced, particularly depending on the desired height H of the respective snow edges 4 in the finished vehicle tire. The allowance A thus remains constant or is reduced during milling to between 0.2 mm and 1.0 mm, preferably between 0.3 mm and 0.5 mm. The allowance A in the rigid model part M10 provided in the first step ST1 must also be designed accordingly.
[0068] Since in this third step ST3 only material is milled from the excess area M11b of the model tread surface M11, the previously applied plasma coating 12 remains in the base areas M11a. Depending on the material removal on the webs M14 or the reduction of the excess A, the plasma coating 12 is either retained or not. At the same time, the radius R of the curves M11c, which corresponds to the radius R of the snow edges 4, is also retained.
[0069] In a fourth step ST4, a flexible impression F (flexible) made preferably of silicone rubber is then created from the master model U, which then corresponds to the negative of the master model U or the negative design of the desired tread 1a, i.e. a negative of the plasma coating 12, a negative of the webs M14 (or the snow edges 4), a negative of the groove structure 202406031
[0070] 13
[0071] M12 (or the transverse groove 2) and thus the form blocks M13 (or the profile blocks 3) and possibly other structural elements.
[0072] In a fifth step, ST5, a rigid plaster cast is then created from the flexible impression F, resulting in a casting core G that retains the roughness and profile positive of the desired running track 1a, i.e., like the original model U, it has a roughened surface, webs M14, the mold blocks M13, the groove structure M12, and possibly other structural elements. A series of such casting cores G can be produced successively from the flexible impression F.
[0073] Finally, in a sixth step ST6, the respective casting core part G is cast with an aluminum-magnesium alloy, so that a casting mold or a cast part 10 is produced for use in the vulcanization mold 20. The negative design of the desired tread 1a, including the defined roughness, as well as the negatives of the snow edges 4, the profile blocks 3, and the transverse groove 2, are then incorporated into the respective cast part 10.
[0074] The production of a molded part 10 of the vulcanization mold 20 can also be carried out in segments; that is, in the sixth step ST6, for example, individually manufactured casting core mold parts G are joined together in segments, for example in a ring-shaped arrangement, and all joined casting core mold parts G are cast with an aluminum-magnesium alloy. In this way, the upstream manufacturing process can be carried out in smaller units, and only the final mold or the final molded part 10 is cast in a larger unit, for example in a ring mold, which simplifies the manufacturing process. 202406031
[0075] 14
[0076] Reference symbol list
[0077] 1 vehicle tire
[0078] 1a Running strip
[0079] 1b Side wall
[0080] 1c bead area
[0081] 2 transverse grooves
[0082] 2a Grooved base
[0083] 2b Side flank
[0084] 2c Tread surface
[0085] 3 Profile block
[0086] 4 Snow edge
[0087] 5th phase
[0088] 10 molded part
[0089] 11 Molded part surface
[0090] 12 Plasma coating
[0091] 20 Vulcanization forms
[0092] 21 containers
[0093] 30 Heating press
[0094] A measurement
[0095] B Width of the snow edge 4
[0096] F flexible imprint
[0097] G Casting core mold part
[0098] H Height of the snow edge 4
[0099] M10 model part
[0100] M11 model tread surface
[0101] M11a Basic area
[0102] M11 b Oversize range
[0103] M11c rounding
[0104] M12 groove structure 202406031
[0105] 15
[0106] M13 Formblock
[0107] M14 Bridge
[0108] R radius
[0109] U Original model
[0110] ST 1 - ST6 Steps of the procedure
Claims
202406031 16 Patent claims 1. Method for producing a cast molded part (10) of a vulcanizing mold (20) for vehicle tires (1), the molded part surface (11) of which forms at least a portion of a tread surface (2c) of a tread (1a) of a vehicle tire (1) to be vulcanized, comprising at least the following steps: - Creating a rigid model molded part (M10) with a model tread surface (M11) (ST 1); - Performing a material-removing surface treatment of the model part (M10) in which the entire model running strip surface (M11) is treated in such a way that part of the material of the model part (M10) is removed from the surface (ST2); - selective milling of a profile positive of the tread (1a) of the vehicle tire (1) to be vulcanized into the model tread surface (M11) of the model mold (M10) to obtain a master model (U) (ST3); - Creating a flexible impression (F) from the obtained master model (U) such that the flexible impression (F) has a negative design of the profile positive of the tread (1a) of the vehicle tire (1) to be vulcanized (ST4); - Creating a rigid cast from the flexible impression (F), preferably from plaster, so that a rigid casting core mold part (G) is created which has the profile positive of the tread (1a) of the vehicle tire (1) to be vulcanized (ST5); - Casting the core mold part (G) with an aluminum-magnesium alloy to obtain the cast mold part (10) for the vulcanization mold, characterized in that - the model molded part (M10) is created with a model tread surface (M11) which has at least one base area (M11a) and at least one oversize area (M11b) raised in relation to it, wherein the respective oversize area (M11b) protrudes from the base area (M11a) by an allowance (A), and 202406031 17 - the selective milling of the profile positive of the tread (1a) of the vehicle tire (1) to be vulcanized includes milling a groove structure (M12) into the excess area (M11b) of the model tread surface (M11) in such a way that a raised rib (M14) is left between the groove structure (M12) and the respective base area (M11a), which is associated with a snow edge (4) projecting from the tread surface (2c) of the tread (1a) of the vehicle tire (1) to be vulcanized.
2. Method according to claim 1, characterized in that the model mold part (M10) is produced such that radii (M11 c) are arranged in the model tread surface (M11) between the base area (M11 a) and the oversize area (M11 b), in particular with a radius (R) of between 0.2 mm and 1.2 mm, preferably 1 mm.
3. Method according to claim 1 or 2, characterized in that the allowance (A) with which the excess area (M11 b) stands out from the base area (M11a) is between 0.5mm and 1.0mm, preferably between 0.8mm and 1mm.
4. Method according to one of the preceding claims, characterized in that the selective milling of the profile positive of the tread (1a) of the vehicle tire (1) to be vulcanized further includes milling off the raised web (M14) between the groove structure (M12) and the respective base area (M11a), in particular such that the allowance (A) is reduced to between 0.2 mm and 0.8 mm, preferably between 0.3 mm and 0.5 mm, during selective milling. 202406031 18 5. Method according to one of the preceding claims, characterized in that, during the selective milling of the profile positive of the tread (1a) of the vehicle tire (1) to be vulcanized, the groove structure (M12) is milled into the oversize area (M11b) of the model tread surface (M11) in such a way that a raised rib (M14) with a width of between 0.1 mm and 1.0 mm, preferably between 0.3 mm and 0.5 mm, remains.
6. Method according to one of the preceding claims, characterized in that a plasma coating (12) is applied to the model tread surface (M11) as a material-removing surface treatment, wherein, during the application of the plasma coating (12), the entire model tread surface (M11) is removed in both the base area (M11a) and the excess area (M11b), and a thermal spray layer is applied to the entire model tread surface (M11), wherein the spray layer comprises a matrix and statistically distributed spray additives, for example, grains.
7. Method according to claim 6, characterized in that the plasma coating (12) is designed such that it gives the master model (U) a defined roughness.
8. Method according to one of the preceding claims, characterized in that a flexible impression (F) is made of silicone rubber.
9. Method according to one of the preceding claims, characterized in that 202406031 19 the base area (M11 a) of the model tread surface (M11 ) after selective milling forms a shape block (M13) which is assigned to a profile block (3) on the tread surface (2c) of the tread (1a) of the vehicle tire (1 ) to be vulcanized.
10. Method according to one of the preceding claims, characterized in that the groove structure (M12) milled into the oversize area (M11 b) of the model tread surface (M11 ) is assigned to a transverse groove (2) on the tread surface (2c) of the tread (1a) of the vehicle tire (1 ) to be vulcanized.
11. Method according to one of the preceding claims, characterized in that several produced casting core parts (G) are assembled segmentally and the assembled casting core parts (G) are cast together with an aluminum-magnesium alloy and preferably subsequently divided again into individual cast mold parts (10).