The invention pertains to a bearing block for holding a bearing for a roller, in particular a strand-guiding roller in a strand-guiding device of a strand-casting machine. The invention also pertains to a strand-casting device with at least one corresponding bearing block.
In strand-casting machines for casting slabs, rotationally supported rollers are used, which have the job of guiding the cast metal strand after it has left the mold along a defined path; these rollers also cool and support the strand. The rollers are supported by their necks by means of bearings in bearing blocks and, to carry away heat, they are cooled by feeding a coolant (especially water) under pressure to the interior of the roller and of the bearing block, this feed being realized through rotary unions, for example.
The support and/or guidance of the metal strand can, depending on the casting format and position, be accomplished on all sides of the strand, from opposite sides of the strand, or only from the bottom surface of the strand. Accordingly, the rollers are used in various arrangements, such as roller rings, offset double rollers, multiply supported longitudinal rollers, or single rollers.
The rollers, especially the roller jackets, the bearing blocks, and the bearings, are exposed to extreme thermal loads as a result of direct/indirect contact with the glowing metal strand and above all as a result of radiant heat. This is true in particular for the rollers in the turning zone. To this must be added the effects of the aggressive environment caused by water contaminated with casting powder residues and also by steam, scale, etc.
In many cases, it is necessary for the rollers to be close together and thus to have small diameters in order that the strand can be supported effectively, which additionally increases the stress on the rollers. The sizes of the bearings therefore also become smaller.
Narrow gaps between adjacent strands and other components of the casting machine such as cooling elements, steel structures, foundations, or pipelines demand that the roller guides be designed to be as compact as possible. Nevertheless, the rollers which are used and their arrangement must also be extremely reliable, have a long service life, and require only modest maintenance.
Bearings which meet these stringent requirements are known in principle from the prior art, e.g., from DE 23 47 892 or WO 2011/065882 A1. These two documents each disclose bearing blocks manufactured as solid castings of martensitic steel. Each has an integrated cooling channel for a coolant with an inlet and an outlet.
Although these bearing blocks are already easy to maintain simply because they are manufactured as solid castings, they nevertheless suffer from the disadvantage that neither their cooling action nor their support function is monitored.
JP 2009269040 A discloses the monitoring of the rotational speed of a strand guide roller.
US 2011/0158571 A1 discloses a sealed rolling bearing.
The invention is based on the goal of elaborating a known bearing block in such a way that the product quality of the cast slabs can be improved.
This goal is achieved by the bearing block according to claim 1.
The claimed detection of the rotational speed makes it possible to monitor the rotational functionality of the bearing. This is especially important with respect to the improvement of product quality, because stationary rollers will cause striations to be formed on the cast slabs as they are guided along the strand-guiding system. The formation of so-called “black stones”, i.e., scale deposits, is thus also avoided, which would otherwise damage the produced slabs during the further course of processing.
In addition to the provision of a rotational speed sensor, it is also advantageous to provide at least one temperature sensor to detect the temperature of the coolant in the coolant channel.
The provision of this temperature sensor makes it possible advantageously to monitor the functionality and thus the overall support function of the rollers. In particular, the claimed temperature measurement makes it possible to achieve automatic control of the quantity of coolant being supplied to the bearing block and thus to optimize coolant consumption.
According to an exemplary embodiment, two temperature sensors are provided, each of which is configured as a thermocouple. A first thermocouple is provided in the inlet of the coolant channel to detect the coolant inlet temperature there. A second thermocouple is provided in the outlet of the coolant channel to detect the coolant outlet temperature there. The detection of the inlet temperature and outlet temperature of the coolant makes possible an especially precise monitoring of the action of the cooling system and thus, in association with that, an optimal automatic control of the coolant feed and/or coolant consumption.
According to a first exemplary embodiment, the rotational speed sensors can be designed as Hall sensors cooperating with magnets on the roller neck. The rotational speed sensor is preferably mounted in a blind hole introduced into the bearing from the outside.
The thermocouples are preferably configured as screw-in thermocouples, one of which is screwed into a bore in the inlet, the other into a bore in the outlet of the coolant channel.
In the coolant channel there are preferably several stabilizing ribs. These are required for technical manufacturing reasons, when the bearing block, as claimed, is designed as a solid casting. In addition, they have the job of supporting and stabilizing the coolant channel.
The goal of the invention described above is also achieved by a strand-guiding device of a strand-casting machine, wherein at least one neck of one of the strand-guiding rollers of the strand-guiding device is supported in a bearing block according to the invention. The advantages of this solution correspond to the advantages cited above in reference to the claimed bearing block.
Additional advantageous embodiments of the bearing block according to the invention and of the strand-guiding device according to the invention are the object of the dependent claims.
Four figures are attached to the description, wherein:
The invention is described in detail below in the form of exemplary embodiments with reference to the cited figures. In all the figures, technical elements which are the same are designated by the same reference numbers.
To detect the rotational speed of the roller and thus to monitor the rotational functionality of the bearing, the bearing block 1 comprises a Hall sensor 13, as shown in
Number | Date | Country | Kind |
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10 2015 225 024.5 | Dec 2015 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/080702 | 12/12/2016 | WO | 00 |