Glass-ceramic component and method for producing a glass-ceramic component - Patents.com

Abstract

To provide a glass-ceramic constituent member (30) according to the present invention.SOLUTION: A glass-ceramic constituent member (30) comprises a bent part for coupling two sheet type leg parts (31, 32) at an angle to each other along a bent section (35) extending in a direction of a constituent member height (h1), wherein the bent part has a convex bending region (36) in a region on a constituent member outer side (34), the convex bending region (36) has an outer bending radius (Ra). and a bending section (35) has rise parts (38) in both long-side end regions (E1, E2) thereof. In order to improve attractiveness of the outside appearance and also enhance the strength of the constituent member, the present invention is characterized in that maximum extension lengths of the bead-shaped rise parts (38) in the long-side end regions (E1, E2) viewed in a radial direction of the convex bending region (36) is larger than 0 mm and smaller than 0.7 mm than a vertex of the outer bending radius (Ra) at an interval of 15 mm from the long-side end parts (E1, E2) arranged correspondingly.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to a glass ceramic component having a bend that connects two planar legs at an angle to one another along a bend section extending in the direction of the component height, the bend having a convex bend region in the region on the outer side of the component, the convex bend region having an outer bend radius in the middle of the component height, and the bend section having a ridge in the region of both long sides. [Background technology]

[0002] Glass ceramics are special materials that are produced by temperature-controlled, precise crystallization, so-called ceramization, from glass, so-called green glass, which has previously been melted in a melting tank and generally formed into sheets. The characteristic properties of glass ceramics are their high resistance to temperature changes and their very low thermal expansion. Glass ceramics are used, for example, as cooktops in the case of hotplates, oven linings, covering plates for radiant heaters, sight glasses in stoves used for heating, and sight glasses in general in combustion units.

[0003] It is known that curved sight glasses for fireplaces or stoves are generally produced with extremely small radii of about 10 mm on gas-operated bending machines, where green glass sheets in the non-ceramicized state are curved in an additional process before the actual ceramization.

[0004] To produce such bent glass ceramics, a green glass sheet with the required outer dimensions is generally provided. This green glass sheet is preheated to a temperature between 350° C. and 750° C. and positioned on a vacuum table in a bending apparatus. The bending zone is then locally heated by gas-operated line burners to a temperature that allows the green glass sheet to be plastically deformed in the bending zone. The bending process is then carried out, during which the free leg of the green glass sheet is bent to the desired angle. The bending area is then cooled to a temperature at which the bending area solidifies and whereby plastic deformation is no longer possible. The resulting formed body is then stress-relieved for less than 500 seconds at a temperature in the range of 650° C. to 750° C. Finally, a cooling step is carried out, during which the bent green glass body is cooled to room temperature.

[0005] Conventional ceramming methods can then be carried out on the bent green glass sheet.

[0006] In the bending method known from WO 2005042420, an oscillating gas line burner heats the glass sheet to the softening point of the glass. The glass sheet is then deformed along the bending edge and thereafter cooled.

[0007] DE 10 2009012018 A1 describes a method by which curved glass-ceramic sheets can be produced, which can have bending radii in the range of 30 mm to 200 mm. In this case, the green glass sheet is deformed in a forced and controlled manner in a deformation tool. In this case, the deformation process is integrated into the ceramming process, which allows a time optimization of the production. In this case, the heating of the glass sheet in the green glass state, which is required for ceramming, is used to deform the glass sheet once it has reached a sufficiently viscous state.

[0008] DE 10 2018 102 932 A1 describes a method for deforming a glass sheet in the green glass state. A sufficiently wide strip-shaped deformation area is heated by a controlled heating process. The deformation of the glass sheet is then carried out with the aid of a deformation tool. In this case, two legs connected to each other via a bend are bent toward each other. In this case, the bend is formed in such a way that a radius transition occurs between the legs.

[0009] All of these methods can be used to produce a flat glass sheet that has a uniaxial bend between two planar legs, the bend forming a convex bend area in the outer region of the component. Summary of the Invention [Problem to be solved by the invention]

[0010] It is an object of the present invention to provide a glass-ceramic component which is distinguished by improved appearance and component strength. [Means for solving the problem]

[0011] The object of the present invention is achieved in that the maximum extension length of the ridges in the long side end region of the bending section, as viewed in the radial direction of the convex bending region, is greater than 0 mm and smaller than 0.7 mm relative to the apexes of the outer bending radii spaced 15 mm from the correspondingly arranged long side end.

[0012] During the manufacturing process, ridges are inevitable and unavoidable. These ridges are often also called "bead-like ridges". The inventors have realized that when the ridges extend less than 0.7 mm in the radial direction, and particularly preferably less than 0.5 mm, the ridges are barely visible, which greatly improves the visual appearance.

[0013] Furthermore, these glass ceramic components can also be more easily integrated into frame structures, since in this case the reduced height ridges hardly impair the integration.

[0014] A further important advantage is the increased fracture strength and deformability of the glass ceramic component compared to known glass ceramic plates. In bending tests in which the legs of the glass ceramic component are bent against one another, it has been found that a higher degree of elastic deformation is possible than in components known from the prior art. This is an important advantage when the glass ceramic component according to the invention is used in high-temperature areas, for example in oven doors. In this case, the glass ceramic component is generally integrated into a frame. If the frame expands or contracts during oven operation due to temperature changes, the glass ceramic component does not have to follow said deformations due to its small thermal expansion. However, such temperature interactions can be compensated for without problems by the fact that the legs can be bent against one another with a higher degree of deformation.

[0015] The inventors' efforts have led to a significant increase in the fracture strength. In this case, ten pieces of glass-ceramic components bent and cerammed according to the prior art and ten glass-ceramic components according to the invention with the same component dimensions were measured. In both cases, the glass-ceramic components had a decoration in the edge area on the side surrounded by the bending angle (a circumferentially extending frame-like area printed with enamel paint and forming a decorative frame).

[0016] The prior art component had an average breaking load of 150N and broke when deformed a distance of 3.3mm.

[0017] The component according to the invention had an average breaking load of 185N and broke when deformed a distance of 4.2mm.

[0018] The measurement method was developed as follows.

[0019] The long leg of the tested glass ceramic component had a length of 358 mm. The short leg of the glass ceramic component had a length of 200 mm. The height of the glass ceramic component in the direction of the bending axis was 254 mm. The thickness of the glass ceramic component was 4 mm. The outer bending radius was 9.5 mm and a bending angle of 90° was selected. The width of the decorative frame was 2 cm.

[0020] The measurement device used was a TIRAtest28150 manufactured by TIRA GmbH.

[0021] The glass ceramic component was clamped on both sides of the long leg perpendicular to the bending axis, so that the long leg was oriented vertically and the short leg was oriented horizontally facing forward.

[0022] The short leg was inserted on all three sides, except for a region 5 mm away from the bend, into an aluminum profile assembled in the shape of a U. On the upper side of the U-shaped assembled aluminum profile, an additional profile (force transmission strut) was placed parallel to the bending axis, which was used to absorb the forces of the measuring device.

[0023] This design of the aluminum profile with additional support columns for force transmission ensured that the force was distributed uniformly over the entire edge surface of the short leg. The support columns were positioned so that the force was applied to the short leg at a distance of 162.5 mm from the inner surface of the long leg. Due to this force application, the short leg was bent downwards while the bent section was bent upwards. The distance and force at which the glass-ceramic component fractured were recorded.

[0024] Surprisingly, the shock load capacity, such as occurs for example when closing an oven door having such a glass-ceramic component, has also been significantly improved.

[0025] Again, the inventors carried out tests in which several samples of glass-ceramic components according to the invention and of the prior art were tested, the samples according to the prior art had an average fracture energy of 8.6 J, and the glass-ceramic components according to the invention had an average fracture energy of 15.1 J.

[0026] The measurement method was developed as follows.

[0027] The long leg of the tested glass ceramic component had a length of 659 mm. The short leg of the glass ceramic component had a length of 439 mm. The height of the glass ceramic component in the direction of the bending axis was 487 mm. The thickness of the glass ceramic component was 4 mm. The outer bending radius was 9.5 mm and a bending angle of 90° was selected. The width of the decorative frame was 4 cm.

[0028] The components to be tested were installed into a commercially available fireplace door from Spartherm, model Varia2Rh.

[0029] A weight was attached to the door handle via a deflection roller, which was lifted when the door was opened. The wider the door was opened, the higher the weight was lifted. When the door was released, the weight fell again, thus closing the door. From the mass of the weight and the height it fell, the energy required to close the door was calculated.

[0030] The door was first opened so that the weight was raised to a height of 10 cm. The handle was then released, which caused the door to close. In subsequent tests the door was opened stepwise, each time wider, so that the weight was raised 10 cm higher than in the previous step. This was repeated until the plate broke. The energy at the step where the glass-ceramic component broke corresponded to the fracture energy.

[0031] A weight of 2.2 kg was used, which resulted in a measured energy range of approximately 2 J to 26 J, depending on the height from which the weight was dropped.

[0032] Within the scope of the invention, the glass ceramic component can have a single bend between the two surface legs, but it is also conceivable that the glass ceramic component has at least two bends each extending between the surface legs, with all bends preferably being configured in accordance with one of the claims.

[0033] In one preferred embodiment of the invention, it may be provided that the external bending radius is in the range of x mm to less than 15 mm in the middle of the component height, where x corresponds to the dimension of the thickness of the glass ceramic component in the region of one of the legs.

[0034] In one preferred embodiment of the invention, it may be envisaged that the legs each have a predetermined leg height, each of which extends laterally at a distance of 30 mm measured parallel to and perpendicular to a component height extending along the bending section and along the vertex line of the external bending radius, and that the leg height-component height difference of the first leg and / or the leg height-component height difference of the second leg is 0 or more and less than 0.8 mm, preferably less than 0.6 mm, particularly preferably less than 0.5 mm.

[0035] Such glass-ceramic components are particularly dimensionally stable and can be easily and visually attractively integrated into support frames, such as are typical in oven doors.

[0036] The drop in height in the region of the connection to the bend is so slight that it is almost imperceptible, which makes it possible to realize a type of construction in which, in cooperation with the frame structure, a continuous shadow gap is formed in the edge region of the glass ceramic structure, with the slight drop in height hardly impairing the appearance of a straight shadow gap.

[0037] If a difference in dimensions of less than 0.8 mm is selected, then particularly large oven doors can be attractively produced. Differences of less than 0.6 mm, particularly preferably less than 0.5 mm, can be used for demanding architectural configurations.

[0038] One preferred embodiment of the invention is configured such that the linearly extending portions of the convex bending region extend in the direction of the component height and in the middle of the component height through the apex of the outer bending radius, which linearly extending portions merge in each of the two long side end regions into ascending ramp portions of a ridge, which are followed by a convexly curved, in particular partially cylindrical, chamfer which defines the ridge on the radially outer side.

[0039] The chamfer allows the radial extent of the ridge to be significantly reduced. Furthermore, the chamfer has the special advantage that the radially outwardly angular projections, which are typical of bead-like ridges, are cut off. This makes the glass ceramic component significantly less susceptible to mechanical loads acting on the ridge. Such loads are expected in particular when the glass ceramic component is precisely fitted and assembled into a frame.

[0040] In this case, a refinement of the invention may provide that the convexly curved, in particular partially cylindrical, surface formed by the chamfer has an extension in the direction of the component height in the range from 0.1 mm to 4 mm and / or that the arcuate extension of this convexly curved, in particular partially cylindrical surface transversely to the component height is between 1 mm and 15 mm.

[0041] Such a chamfer has proven to be particularly advantageous when glass ceramic components are used which are precisely fitted and integrated into the frame structure of the oven door.

[0042] Furthermore, if the surface formed by the chamfer runs parallel to the linear section with a deviation of ±10°, the frame part of the frame structure can stand directly on the chamfer and be supported there via an elastic intermediate element, which is significantly less susceptible to breakage than known glass ceramic components.

[0043] The invention also relates to a method for producing a glass-ceramic component, comprising heating a glass sheet in the green glass state from one edge of the glass sheet to the opposite edge by means of a heating device until a heating zone is created in which the temperature level is sufficient to deform the glass sheet, then deforming the glass sheet under the action of a deformation tool, thereby producing a uniaxially bent curvature in the heating zone, thereby forming a bend with a bending section followed on both sides by two planar glass legs, the bending section forming a convex bending area in the area outside the component, which in the area of ​​both long side ends in its opposite edge areas has a ridge that projects radially outward compared to the remaining area of ​​the convex bending area, then cooling the deformed glass sheet until a temperature level is reached at which plastic deformation in the heating zone is no longer possible, and then placing the deformed glass sheet in a ceramming mould for ceramming.

[0044] It is an object of the present invention to provide a method for producing a glass-ceramic component which is distinguished by improved appearance and component strength.

[0045] This problem is solved in that after ceramming a glass ceramic component is formed, in which the maximum extension length of the ridges in the long edge region, seen in the radial direction of the convex bending region, is less than 0.7 mm to the apex of the outer bending radius spaced 15 mm from the correspondingly located long edge.

[0046] For the production of the glass-ceramic component according to the invention or for use in the method according to the invention, green glass sheets of the LAS type, that is to say lithium-aluminum-silicate type, can be used, for example, having the following composition:

[0047] [Table 1]

[0048] In one particularly preferred configuration embodiment of the present invention, it may be envisaged that the glass foot is supported with its foot outer surface on a support surface of a support of a ceramming mold, the deformed glass sheet stands with its raised portion on a recess in the area between the support surfaces of the ceramming mold under the action of the gravity of the deformed glass sheet, and then the deformed glass sheet together with the ceramming mold is placed in a ceramming furnace, in which the deformed glass sheet is cerammed into a glass-ceramic component.

[0049] In this case, the gravity of the deformed glass sheet is utilized to push the ridges that arise during the deformation process back radially into the convex bend region.

[0050] When the glass plate is placed together with the ceramming mold into the ceramming furnace and then the ceramming process is carried out, the glass plate in the green glass state is heated, which softens the glass material. The weight of the glass plate is applied to the ridges, which also soften together with the glass plate. The ridges are then pushed back due to the resulting paste-like state. This occurs when the plate is at a sufficiently low viscosity level for deformation during the ceramming process, just before crystal formation. This allows for an efficient method operation in a simple manner.

[0051] It has been found that this method makes it possible to effectively push back the protuberances, in particular when it is assumed that the recess of the ceramming mould has a partially cylindrical portion, the longitudinal extension of which runs in the axial direction of the uniaxial curvature of the deformed glass sheet, and the radius of the partially cylindrical portion corresponds to the average radius of the bent section with a difference of + / - 1 mm.

[0052] The inventors have realized that it is particularly advantageous if the deformation process of the glass sheet is already configured so that minimal bulges are generated. Thus, in one embodiment of the invention, it is envisaged that the glass sheet in the green glass state is heated by a heating device with a line gas burner to form a heating zone, then when the glass sheet reaches a sufficient temperature level for deformation, the line gas burner is switched off, the heating zone is lightly cooled, for example by compressed air, to a temperature level at which plastic deformation is still possible, and then the plastic deformation of the glass sheet is carried out by a deformation tool, which is forced to guide the glass sheet to a uniaxially bent curve.

[0053] Cooling of the heating zone results in an equalization of the temperature difference between the bending line and the bending edge, whereby cooling can only take place to the extent that subsequent deformation is still possible.

[0054] Heating with a gas flame (or CO2 laser) primarily heats the surface, which is then transported slowly to the sheet center due to thermal conduction, i.e. overheating of the surface. This results in a higher temperature at the surface than would be necessary for bending, whereas in the sheet center (with respect to the glass thickness) the bending temperature has not yet been reached. By cooling it is therefore desirable to equalize the temperature difference between the surface and the sheet center, and also to cool the bend edge, which during heating is overheated due to the additional energy input over the grinding edge, more strongly, again to achieve a temperature equalization over the bend line.

[0055] In particular, the method utilizes the knowledge that a line burner cannot achieve an exactly uniform heating of the heating zone. The flame of the gas burner hits the glass sheet around the edge area, especially in the edge area of ​​the heating zone. This results in more energy being input into the glass sheet there than in other sheet areas. As a result, the viscosity of the edge area is significantly reduced, which unfavorably promotes bead formation. The proposed cooling, in particular compressed air cooling, results in a uniform temperature level in the bending zone, which has a positive effect on the ridges, which are smaller and extend radially outward than in conventional bending methods.

[0056] In this case, it can be particularly advantageously provided that after the line gas burner is switched off, the burner nozzle of the line gas burner is cleaned with compressed air, which is also used to cool the heating zone, thereby reducing the expenditure on the device, since the burner nozzle is also used for cooling.

[0057] In this case in particular it may be provided that compressed air is used to extinguish the flames formed in the individual burner nozzles.

[0058] The generally mentioned effect of uneven heating in the edge regions of the bending zone is positively influenced by the fact that, according to one aspect of the invention, it is provided that the end regions of the heating zone, which are arranged in correspondence with the opposite edges of the glass sheet, are cooled more intensively than the remaining regions of the heating zone or that only these end regions are cooled exclusively.

[0059] In one further embodiment of the invention, compressed air-operated cooling devices are provided in the region of the edges located on opposite sides of the glass sheet, which cooling devices have compressed air nozzles directed at the edges of the glass sheet, and compressed air can be blown via the compressed air nozzles onto the edges during and / or after the operation of the line gas burners. This arrangement allows a deliberate influence on the edge region. If the compressed air nozzles are used during the operation of the heating device, they prevent or reduce the effect of the heating device being wrapped around the free edge of the heating zone. This results in a more uniform temperature level throughout the bending zone. If the compressed air-operated compressed air nozzles are used after the operation of the heating device, the cooling of the edge region can be precisely performed.

[0060] Another aspect of the invention may be characterized in that the heating device inputs energy in a distributed manner into the heating zone, forming areas with lower energy input and areas with higher energy input in comparison. In this way, a temperature as uniform as possible can be achieved precisely over the entire bending zone. For this purpose, a laser source can be preferably used as the heating device. With the laser source, a very precise energy input into the glass sheet can be controlled. It is particularly preferably provided that a CO2 laser with a galvanometer scanner for radiation deflection is used as the heating device. With such a device, the energy input can be precisely varied over the bending line length and width.

[0061] It has been found that the correct adjustment of the temperature difference between the upper and lower surfaces of the glass sheet in the bent edge region also has a positive effect on bead formation. Thus, in one embodiment of the invention, it is envisaged that the heating device has an upper heating element and a lower heating element, the upper heating element being arranged in the region of the upper surface of the glass sheet and the lower heating element being arranged in the region of the lower surface of the glass sheet, the upper heating element and the lower heating element respectively causing different energy inputs into the glass sheet.

[0062] In one embodiment of the invention, the bead formation is also positively influenced if it is provided that during the heating process the glass sheet is preferably supported by grippers, so that deformation in the heating zone is initially prevented, and deformation only takes place after the heating process and optionally a subsequent cooling process for homogenizing the temperature distribution along the bending line have been completed.

[0063] The present invention will be described in more detail below based on the illustrated embodiments. [Brief description of the drawings]

[0064] [Figure 1] FIG. 1 is a schematic diagram showing a fireplace. [Diagram 2] 2 is a perspective view showing the fireplace door shown in FIG. 1 as seen from the front. FIG. [Diagram 3] 5 is a diagram showing a cross section taken along the cutting line shown in FIG. 4. [Figure 4] FIG. 4 shows the glass-ceramic component shown in FIG. 3. [Diagram 5] 5 is a view of the glass ceramic component shown in FIG. 3 from a different perspective than in FIG. 4. [Figure 6] FIG. 2 shows a partial perspective front view of a curved glass ceramic component with a decorative coating. [Figure 7] FIG. 2 is a partial perspective front view of a bent glass ceramic component. [Figure 8] FIG. 2 is a partial perspective view showing a glass component in a green glass state before ceramization. [Figure 9] FIG. 9 is a partial perspective view of a glass-ceramic component manufactured from the glass component shown in FIG. 8. [Figure 10] FIG. 2 is a schematic diagram showing a deformation device. [Figure 11] FIG. 2 is a perspective front view of a ceramizing mold receiving a glass component therein. [Figure 12]12A-12C show schematic views of details of the unit shown in FIG. 11 in different perspective views. [Figure 13] FIG. 2 shows different measurement curves of a glass ceramic component. [Figure 14] FIG. 2 shows different measurement curves of a glass ceramic component. [Figure 15] FIG. 2 shows different measurement curves of a glass ceramic component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] In FIG. 1, a fireplace 10 is shown, as is typically used in residential buildings. The fireplace 10 has a body 11 with a built-in niche 13, in which a heating unit 20, for example a furnace insert, can be built. The heating unit 20 has a door 21, which has a bent glass ceramic component 30, which allows the flame burning in the fireplace 10 to be viewed. The glass ceramic component 30 has two legs 31, 32 which are located at an angle to one another. The two legs 31, 32 are connected together via a bend in the area of ​​a bend section 35. The bend section 35 continues to the body edge 12 of the fireplace 10.

[0066] FIG. 2 shows the door 21 from FIG. 1 in an individual part view. As can be seen in this figure, the glass ceramic component 30 has two legs 31, 32 arranged at an angle of 90° relative to each other. The door profile 22 is attached to two oppositely located horizontal edges of the glass ceramic component 30. In the present embodiment, the two vertical edges of the glass ceramic component 30 arranged in the region of the leg ends 31.3, 32.3 are not surrounded by the door profile 22. This is due to the special design of the present construction. Of course, it is also possible to design a door 21 in which the glass ceramic component 30 is surrounded by the door profile 22 in an annular shape. In this case, the door profile 22 generally forms a frame in which the glass ceramic component 30 can be stably attached.

[0067] The door 21 has a number of hinges 23 that define vertical hinge axes. The hinges 23 are attached to the door profile 22. The hinges 23 allow the door 21 to be connected to the heating unit 20 and to be pivotable about the vertical axis from a closed position shown in Figure 1 to an open position.

[0068] 3-5 show the construction of the glass-ceramic component 30 in more detail, however, it should be understood that these figures are schematic and do not faithfully reflect the details of the glass-ceramic component 30. The glass-ceramic component 30 has a first leg 31 and a second leg 32 disposed at an angle thereto.

[0069] Within the scope of the present invention, it is to be understood that in particular all angles formed between the two legs 31 and 32 are less than 150°, preferably less than 120°, particularly preferably less than 100°.

[0070] Within the scope of the present invention, it may be assumed that the minimum angle formed between the two legs 31 and 32 is at least 45°, preferably at least 60°, particularly preferably at least 80°.

[0071] In a particular embodiment envisaged within the scope of the invention, where an angle of 60° is formed, the glass-ceramic component has two legs 31, 32 of equal length (with a difference of 5%), which then form two of the three sides of an equilateral triangle.

[0072] The first leg 31 has an inner leg surface 31.1 facing the component inner side 33. On the opposite side, the first leg 31 has an outer leg surface 31.2. Similarly, the second leg 32 has an inner leg surface 32.1 and an outer leg surface 32.2. The above-mentioned angle is formed between the two inner leg surfaces 31.1, 32.1. The two legs 31, 32 are connected to each other via an integral bend forming a bent section 35. On the side opposite the bent section 35, the legs 31, 32 each have a leg end 31.3, 32.3, which form a free end at this point of the glass-ceramic component 30.

[0073] The bending section 35 forms, in the region of the component outer side 34, a convex bending region 36. In the region of the component inner side 33, a concave bending region 37 is provided. The convex bending region 36 forms an outer radius Ra, the concave bending region 37 forms an inner radius Ri.

[0074] The glass-ceramic component 30 preferably has a thickness d of at least 2.7 mm and at most 6.3 mm, particularly preferably at least 3.7 mm and at most 5.3 mm.

[0075] 3 shows a side view of the glass-ceramic component 30 along the section line III-III in FIG. 4, whereas FIG. 4 shows the view shown in FIG. 3 from the left. FIG. 5 shows a plan view from above of the view shown in FIG. 3. As can be seen in FIGS. 4 and 5, the bending section 35 has ridges 38 (see FIG. 8) in its two long end regions E1, E2. As can also be seen in these figures, the legs 31, 32 have leg heights h2, h3. In this case, the leg heights h2 and h3 are measured along a line parallel to the component height h1 extending along the bending section, the distance a2, a3 of the lines h2, h3 relative to the line h1 being 30 mm. The line h1 represents the component height measured along the apex that bisects the angle of the convex bending section 36.

[0076] In the present invention, the difference between h2-h1 or h3-h1 is less than 0.8 mm, preferably less than 0.6 mm, and particularly preferably less than 0.5 mm.

[0077] The glass-ceramic component 30 shown in Figure 6 is substantially constructed according to the design of the glass-ceramic component 30 shown in Figures 3 to 5. In addition, in the edge region of the glass-ceramic component 30, a circumferentially extending coating 40 is provided. The coating 40 is applied to the inner side 33 of the component and is formed by a ceramic pigment which is fired during the ceramification process of the glass ceramic. In this case, a fired ceramic pigment means a coating which comprises a solid mixture of glass as dispersion medium and at least one pigment as dispersed phase.

[0078] The construction of the glass-ceramic component 30 shown in FIG. 7 corresponds to the glass-ceramic component 30 shown in FIG.

[0079] Figure 8 shows an enlarged detail of the glass-ceramic component 30, for example as shown in Figures 3 to 7. In this case, the end region E1 at the end of the bending section 35 is shown enlarged. As can be seen in this figure, a ridge 38 is arranged in the end regions E1, E2 of the bending section 35. This ridge 38 projects in the radial direction beyond the remaining region of the bending section 35. The ridge 38 has a ramp section 38.1 which rises continuously towards the free edge of the convex bending region 36.

[0080] Another detail of the glass-ceramic component 30 is shown in Figure 9. As can be seen in this figure, the raised portion 38 is followed by a ramp portion 38.1 and is then followed by a partially cylindrical chamfer 38.2. The cylindrical chamfer 38.2 forms a surface which extends in the direction of the component height h1 within a range of 0.1 mm to 4 mm. The chamfer has an arcuate surface which extends transversely to the component height h1 with an arcuate dimension in the range of 1 to 15 mm.

[0081] The glass-ceramic components shown in the figures are produced using a combination of advantageous deformation methods and advantageous ceramming methods.

[0082] The deformation method is now explained in more detail below with reference to Fig. 10. In this embodiment, the glass sheet 50 in the green glass state is placed with its glass foot 51 on a flat support surface 90 and fixed there, for example by means of a vacuum device. On the side opposite to the support surface 90, the glass sheet 50 is held on a second glass foot 52 by a deformation tool 80. In this case, the deformation tool 80 has two grippers 81 which engage on opposite edges 53, 54 of the glass sheet 50.

[0083] One or more heating devices 70 can heat a strip extending from one edge 53 to the opposite edge 54 of the glass sheet 50 until the strip forms a heating zone 57 and softens.

[0084] In this embodiment, the heating device 70 comprises an upper heating element 71 acting on the upper surface 55 of the glass sheet and a lower heating element 72 acting on the opposite lower surface 56 of the glass sheet. In this way, fast and efficient heating is possible. In addition, this gives rise to the possibility that energy input means with different strengths can be formed for the upper surface 55 and the lower surface 56 of the glass sheet, which advantageously influences the deformation method.

[0085] Once the glass sheet 50 has been heated until it is in a sufficiently softened state, it is bent in the region of the heating zone 57. For this purpose, the glass sheet 50 is moved by the gripper 81 in the region of the glass foot 52 towards the glass foot 51, which is restrained on the support surface 90. In this way, a bend is produced in the heating zone 57, which is bent once or uniaxially to form the bend section 35.

[0086] By the above-mentioned method, for example, a glass plate having a thickness of 4 mm can be formed, in which the glass legs 51, 52 are positioned at an angle of 90° relative to each other and the bending section 35 has a bending radius of 9.5 mm in the convex bending region 36. The deformation speed was set to 5 seconds.

[0087] Line gas burners may be used as the heating elements 71 and 72. These line gas burners have a heat output of at least 10 W / cm 2 The effective area output is preferably 20 W / cm2, where the effective area output represents the heat energy actually deposited in the glass per unit time. 2 ~1000W / cm 2 In the case of a gas burner, the available power is rather higher than when using a laser, e.g. a CO2 laser. However, it is preferable to use both of the heat sources to achieve a power of 20 W / cm2. 2 ~1000W / cm 2 Set within the range.

[0088] After carrying out the deformation of the glass sheet 50, the glass sheet 50 is cerammed, again using the ceramming method according to the invention, which is explained in more detail below with reference to Figures 11 and 12.

[0089] In Fig. 11, a ceramming mould 60 is shown diagrammatically. The ceramming mould 60 has two supports 61, 62 which are arranged at an angle of 90° to one another. A joint 63 is further integrated into the ceramming mould 60, which joint 63 forms a recess 64. The support 62 has inner support faces 61.2, 62.2 which preferably merge continuously into a recess 64. The radius of the recess 64 corresponds to the average bending radius of the convex bending region 36 of the glass pane 50.

[0090] During the bending process, the aforementioned protruding ridges 38 appear at the ends E1, E2 of the long sides of the bent section 35, protruding in the radial direction beyond the apex of the convex bending region 36 in the middle part (1 / 2*h1). The protrusion of the ridges 38 can be clearly seen in FIG.

[0091] The glass sheet 50 is placed in the ceramming mold 60 such that the glass legs 51, 52 are supported, preferably planar, against the support surfaces 61.2, 62.2. Furthermore, the ridges 38 are raised in the recesses 64. As can be seen in Fig. 12, this results in the remaining areas of the convex bending region 36 being spaced above the bottom of the recesses 64 of the ceramming mold 60. The glass sheet 50 thus stands, under its gravity G, essentially on the ridges 38 at the ends of the long sides of the bending section 35.

[0092] The combination of the ceramming mold 60 and the glass sheet 50 is then placed in a ceramming furnace. There, a ceramming program of known type is carried out, and the glass sheet 50 in the green glass state is transformed into the glass-ceramic component 30. In the process, the glass sheet 50 is heated and brought to a temperature state in which the glass sheet 50 softens. During the heating of the glass sheet 50, ceramming starts at a certain temperature level. In the process, crystals grow in the crystal nuclei. Within a short time window until the crystal nuclei have a certain size, the bead-like ridges 38 can be pushed back under the action of the gravity G of the glass sheet 50, so that the protrusion of the ridges is reduced. Once the crystal nuclei have reached a certain critical size, deformation is no longer possible. The advantage of the method according to the invention is that within a short time window, a significant reduction in the height of the ridges 38 can be achieved solely under the gravity G of the glass sheet 50. In this case, the above-mentioned cylindrical chamfer 38.2 is also formed in the contact area of ​​the ridges 38 against the recesses 64.

[0093] 13 to 15, the advantageous influence of the ridges 38 using the method according to the invention will now be further explained.

[0094] In each of these figures, a reference contour N is marked. The reference contour N represents a line extending in the direction of the longitudinal extension of the convex bending region 36 in the region of the component outer side 34, i.e. in the direction of the component height h1. This line intersects with the apex of the external bending radius (Ra) of the convex bending region 36 at a distance of 15 mm from each of the long side ends E1, E2 (measured in the direction of the component height h1). This distance is indicated by the reference A in FIG. 15.

[0095] Two curves are superimposed on the reference contour N in each figure. Curve 2, which is drawn in all three figures, represents the measurement curve formed by guiding the feeler over the apex line of the external bending radius Ra and measuring the end regions E1, E2. Correspondingly, in this measurement protocol, the last 16 mm of the outer edge measured inwards in the region of the ridge 38 are measured.

[0096] Curve 2 represents a glass-ceramic component 30 bent in the standard manner according to the prior art (SG) and cerammed in the standard manner, ie without the aid of a bead area (SK).

[0097] As this figure makes clear, the ridge 38 extends in the radial direction over 1 mm beyond the reference contour N. Furthermore, it can be seen that the ramp portion 38.1 of this ridge 38 starts at about 7 mm and has a relatively steep gradient angle.

[0098] Curve 2 is contrasted with curve 1, which represents a glass-ceramic component 30 formed by the modified method (WG) as described with reference to FIG. 10. The standard ceramming method (SK) was used. As this figure illustrates, in comparison with curve 2, bead heights of less than 0.8 mm can be formed. The slope angle of the ramp portion 38.1 of this ridge 38 is significantly less steep than that of curve 2. Furthermore, the start of the ramp portion 38.1 has been shifted and now begins at approximately 9.5 mm.

[0099] In Fig. 14, curve 3 is plotted. This curve 3 represents a glass-ceramic component 30 formed by the deformation method (WG) as described with reference to Fig. 10. In addition, the ceramming method (WK) as described with reference to Figs. 11 and 12 was used.

[0100] In this figure, the advantageous effect of both methods according to the invention on the formation of the bead-like ridge 38 can be clearly seen. Figure 14 makes it clear that the bead-like ridge 38 protrudes only very slightly, in particular by less than 0.5 mm. Furthermore, the slope of the ramp section 38.1 is significantly less steep. The ramp section starts at approximately 9 mm.

[0101] In FIG. 15, curve 2 from FIGS. 13 and 14 is plotted again. In addition, curve 4 is plotted in FIG. 15, which represents a glass-ceramic component 30, for which the standard bending method (SG) as known from the prior art was used. For ceramization, the ceramization method according to the invention (WK) was used, as explained with reference to FIGS. 11 and 12. This figure concretely demonstrates the positive effects of the ceramization method according to the invention. Correspondingly, the height of the bead-like ridge 38 can be significantly reduced. The gradient of the ramp section 38.1 is also significantly reduced. The start of the ramp section 38.1 has not shifted compared to the case of curve 2.

[0102] A comparison of curves 1, 3 and 4 in figures 13 to 15 further reveals that by combining the bending method (WG) with the ceramming method (WK) a greater reduction in the height of the ridges can be achieved than would have been possible from the individual method steps, i.e. a particularly advantageous synergistic effect results from the combination of both method steps.

[0103] It should be noted here that the chamfer 38.2 of the bead-like protuberance 38 could not be measured accurately in curves 3 and 4, based on the measurement method used.

Claims

1. A glass ceramic component (30) comprising a bent portion which connects two planar legs (31, 32) at an angle to one another along a bent section (35) which extends in the direction of the component height (h1), the bend has a convex bend region (36) in the region of the component exterior (34), the convex bend region (36) having an external bend radius (Ra); The bent section (35) has a ridge (38) in both long edge regions (E1, E2) of said glass ceramic component (30), a maximum extension length of the protuberances (38) in the long edge regions (E1, E2) in the radial direction of the convex bend region (36) is greater than 0 mm and smaller than 0.7 mm with respect to a vertex of the outer bend radius (Ra) spaced 15 mm from the corresponding long edge (E1, E2), A glass-ceramic component (30).

2. a maximum extension length of the protuberances (38) in the long edge regions (E1, E2) in the radial direction of the convex bend region (36) is less than 0.5 mm from the apex of the outer bend radius (Ra) spaced 15 mm from the correspondingly located long edge (E1, E2), 2. The glass-ceramic component according to claim 1.

3. the external bending radius (Ra) is in the range of x mm to less than 15 mm in the middle of the component height (h1), where x corresponds to the thickness dimension of the glass ceramic component in the region of one of the two legs; 3. The glass-ceramic component according to claim 1 or 2.

4. said legs (31, 32) each having a predetermined leg height (h2, h3) each extending a distance of 30 mm laterally measured parallel to and perpendicular to said component height (h1) which extends along said bending section (35) and along the apex line of said external bending radius (Ra); the difference between the leg height (h2) and the component height (h1) of the first leg (31) and / or the difference between the leg height (h3) and the component height (h1) of the second leg (32) is 0 or more and less than 0.8 mm, preferably less than 0.6 mm, particularly preferably less than 0.5 mm; 4. The glass-ceramic component according to claim 1.

5. the thickness of the glass ceramic component in the region of at least one of the two legs is in the range of 2.7 mm to 6.3 mm, preferably in the range of 3.7 mm to 5.3 mm; 5. The glass-ceramic component according to claim 1.

6. a linearly extending portion (36.1) of the convex bending region extends in the direction of the component height (h1) and in the middle of the component height (h1) through the apex of the external bending radius (Ra), said linearly extending portion (36.1) merging in each of the two long edge regions (E1, E2) into an ascending ramp portion (38.1) of the ridge (38), which is followed by a convexly curved, in particular partially cylindrical, chamfer (38.2) which defines the ridge (38) on the radially outer side, 6. The glass-ceramic component according to claim 1.

7. the convexly curved, in particular partially cylindrical, surface formed by the chamfer (38.2) has an extension in the direction of the component height (h1) in the range of 0.1 mm to 4 mm and / or the arcuate extension of the convexly curved, in particular partially cylindrical, surface transversely to the component height (h1) is in the range of 1 mm to 15 mm; 7. The glass-ceramic component of claim 6.

8. the surface formed by the chamfer (38.2) extends parallel to the linearly extending portion (36.1) with a deviation of ±10°; 8. The glass-ceramic component according to claim 6 or 7.

9. the legs (31, 32) each have a predetermined leg height (h2, h3), which, measured parallel to and perpendicular to the component height (h1) which extends along the bending section (35) and along the apex line of the external bending radius (Ra), respectively, extend at a distance of 30 mm laterally to said apex line, said leg heights (h2, h3) being selected in the range of 150 mm to 1500 mm, preferably in the range of 200 mm to 1000 mm or particularly preferably in the range of 225 mm to 850 mm; 9. The glass-ceramic component according to claim 1.

10. the maximum leg length of the legs (31, 32), extending perpendicular to the apex line, is selected within the range of 200 mm to 1000 mm, the leg length of the first leg (31) corresponding to the leg length of the second leg (32) with a difference of 5%; or the maximum leg length of the first leg (31), extending perpendicularly to the apex line, is different from the maximum leg length of the second leg (32), extending perpendicularly to the apex line, the maximum leg length of the longer leg (31 or 32) being selected within the range of 200 mm to 1500 mm, preferably within the range of 250 mm to 1000 mm, particularly preferably within the range of 300 mm to 800 mm, and the maximum leg length of the shorter leg (31 or 32) being selected within the range of 100 mm to 1000 mm, preferably within the range of 150 mm to 800 mm, particularly preferably within the range of 200 mm to 600 mm; 10. The glass-ceramic component according to claim 4 or 9.

11. A method for producing a glass-ceramic component (30), comprising the steps of: Heating the glass sheet (50) in a green glass state from one edge (53) of the glass sheet (50) to the opposite edge (54) by a heating device (70) having a line gas burner until a heating zone (57) is created whose temperature level is sufficient to deform the glass sheet (50); Then, when the glass sheet (50) has reached a temperature level sufficient for deformation, the line gas burners are turned off and the heating zone (57) is cooled to a temperature level at which plastic deformation is still possible; Then, the glass sheet (50) is plastically deformed under the action of a deformation tool (80), thereby producing a uniaxially bent curve in the heating zone (57), thereby forming a bent section (35) flanked on either side by two planar glass legs (51, 52); The bent section (35) forms a convex bent area (36) in the region of the outer side (34) of the component, the convex bending region (36) has, in both long side end regions (E1, E2) in the region of the opposite edges (53, 54), ridges (38) which protrude radially outwardly compared to the remaining regions of the convex bending region (36); The deformed glass sheet (50) is then cooled in the heating zone (57) until it reaches a temperature level at which plastic deformation is no longer possible, The deformed glass sheet (50) is then placed in a ceramming mould (60) and cerammed, forming the glass-ceramic component (30) after ceramming in such a way that the maximum extension of the ridges (38) in the long edge regions (E1, E2), seen in the radial direction of the convex bending region (36), is greater than 0 mm and smaller than 0.7 mm with respect to the apex of the outer bending radius (Ra) spaced 15 mm from the correspondingly located long edge (E1, E2), method.

12. A method for producing a glass-ceramic component (30), comprising the steps of: heating the glass sheet (50) in a green glass state from one edge (53) to the opposite edge (54) of said glass sheet (50) by a heating device (70) until a heating zone (57) is created whose temperature level is sufficient to deform said glass sheet (50); Then, the glass sheet (50) is deformed under the action of a deformation tool (80), thereby producing a uniaxially bent curve in the heating zone (57), thereby forming a bent section (35) flanked on either side by two planar glass legs (51, 52); The bent section (35) forms a convex bent area (36) in the region of the outer side (34) of the component, the convex bending region (36) has, in both long side end regions (E1, E2) in the region of the opposite edges (53, 54), ridges (38) which protrude radially outwardly compared to the remaining regions of the convex bending region (36); The deformed glass sheet (50) is then cooled in the heating zone (57) until it reaches a temperature level at which plastic deformation is no longer possible, The deformed glass sheet (50) is then placed in a ceramming mould (60) and cerammed, forming the glass-ceramic component (30) after ceramming in such a way that the maximum extension of the ridges (38) in the long edge regions (E1, E2), seen in the radial direction of the convex bending region (36), is greater than 0 mm and less than 0.7 mm with respect to the apex of the outer bending radius (Ra) spaced 15 mm from the correspondingly located long edge (E1, E2), characterised in that the edge regions (E1, E1) of the heating zone (57), which are arranged corresponding to the opposite edges (53, 54) of the glass sheet (50), are cooled more intensively than the remaining regions of the heating zone (57) or only the edge regions (E1, E1) are cooled exclusively. method.

13. The glass legs (51, 52) are supported with their outer legs surfaces on the support surface (61.2) of the support (61) of the ceramizing mold (60), the deformed glass sheet (50) stands with its raised portion (38) on a recess (64) in the area between the support faces (61.2) of the ceramizing mold (60) under the action of gravity of the deformed glass sheet (50), then the deformed glass sheet (50) together with the ceramizing mold (60) is placed in a ceramizing furnace, in which the deformed glass sheet (50) is ceramized into a glass-ceramic component (30).

13. The method according to claim 11 or 12.

14. the recess (64) of the ceramming mold (60) has a partially cylindrical portion, the longitudinal extension of the partially cylindrical portion extending in the axial direction of the uniaxial curvature of the deformed glass sheet (50); the radius of the partially cylindrical portion corresponds to the average radius of the bent section by a difference of −1 mm to +1 mm; 14. The method of claim 13.

15. The heating device (70) distributes energy input into the heating zone to form areas with lower energy input and other areas with higher energy input in comparison.

15. The method according to any one of claims 11 to 14.

16. The heating device may be a laser light source, preferably a CO ２ Lasers, particularly preferably CO2 lasers equipped with galvanometer scanners for redirecting radiation. ２ A laser is used, 16. The method of claim 15.

17. During the heating process, the glass sheet (50) is preferably supported by a gripper (81) so that deformation in the heating zone (57) is prevented during heating.

17. The method according to any one of claims 11 to 16.

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