The invention relates to a roller-conveyor roller, especially for the transport of furnace-heated metallic strip material, continuous castings of steel or the like, with a roller shaft and a roller shell casing secured to the roller shaft at least at the roller ends.
Because of a general difference in the electrical potentials between a metallic product and a roller-conveyor roll, electrical currents and spark formation can result in surface defects in the manufactured material.
It is known (DE 24 26 135 C2) to provide a roller conveyor roll for the transport of rolled products such as rolling mill products which can resist impact with the rolled product. It has not been noted therein that such roller conveyor rolls also contribute to electrical currents and spark formation which can degrade the rolled product.
The invention has therefore as its object to suppress such electrical currents and spark formation so that the mentioned damage no longer can arise.
The object set forth is achieved according to the invention in that the roller shell or casing is electrically and/or thermally insulated at the respective roller ends, at least, where it is mounted on the roller shaft. Such a roller conveyor roll is suitable for roller conveyors or roller conveyor segments in regions of inductive heating and induced electrical fields as well as wherever general differences in electrical potentials between a rolled product or continuously-cast product and a roller conveyor roll can arise and wherever electrical currents and spark formation can contribute to surface defects. Advantageously, such a roller-conveyor roll can also be used to largely suppress the heat transfer by conduction between the roller casing or shell heated by a product and the roller shaft or roller axle which as a rule is cooled.
A further feature of the invention is that between the roller casing at the roller ends and the roller shaft, individual insulating bodies are distributed around the respective peripheries or a one-piece annular insulating body is provided. The insulating bodies can thus serve to center the roller casing on the roller shaft and/or for torque transmission therebetween.
In a feature of the invention the individual insulating bodies distributed around the periphery are comprised of profile rods. The profile can be round rods, flat or rectangular cross sections or can be composed of other cross sectional shapes. The material for such profiled bars can be of ceramic or other insulating materials of corresponding strength.
A further advantage arises when the profile bars are axially secured with respect to the roller shaft and the roller casing together with mounting rings.
To restrict axial shifting it is, for example, advantageous for the axial securing to be achieved with sheet metal rings welded onto the ends of the mounting rings.
While the roller casing and the roller shaft are basically separate from one another and are connected together exclusively by means of the insulated bodies, by means of the axial retainers, a loose mount and a fixed mount can be formed between the roller casing and the roller shaft. As a result, thermal stresses can be compensated and thermal expansion and contraction can be accommodated.
Basically a further advantage is achieved in that the insulating bodies can center the roller shell on the roller shaft and simultaneously form a torque transmitting medium. In this manner a compact unit which is advantageous for any requisite force transmission in a roller conveyor roll is obtained.
In an alternative embodiment, the roller shell or casing is subdivided into roller shell segments arranged in the roller shaft and mounted on the roller shaft by insulated bodies which serve to center them on the roller shaft and transmit torque between the roller shaft and the roller-shell segments. The insulating bodies are distributed around the periphery of the roller shaft. In this manner the roller shell or casing segments are separated from the roller shaft and are exclusively connected through the described insulating bodies.
According to a further alternative, the insulating body is a cone-shaped inner ring and/or a cone-shaped outer ring and/or conical rollers that form the insulating bodies. Because of the short roller casing segments the longitudinal expansion and contraction and the expansion and contraction resulting from heating in the axial direction has play which is negligible so that no arrangement of loose mount and fixed mount is required. In this manner electrical currents in the axial direction are especially suppressed.
A further feature of the invention is that any increased play in the mutual fitting of the insulating bodies and their retaining portions resulting from heating of the roller casing can be compensated by the fact that the conically shaped inner ring is axially shiftable and is adjustable against a spring force on the roller shaft.
The inclination of the cone angle is then so selected that because of the longitudinal expansion of the roller casing or shell the outer cone assumes a different position upon the inner cone and thereby largely compensates for the expansion of the diameter.
In a practical embodiment the conically shaped inner ring is biased on the roller shaft by means of dished-disk springs which can be seated against a step or shoulder on the stuff and against the hollow conical outer ring which is fixedly connected to the roll casing or shell and which is shiftable axially with respect to the roller shaft. The play is continuously eliminated by the spring force.
Another configuration provides that a roller shell segment is mounted at the respective roller ends in respective conical mounts and generally centrally by means of insulating bodies distributed over the periphery.
In the drawing embodiments of the invention are shown and are described in greater detail in the following. In the drawing:
a is the associated side view,
a is the associated side view; and
The roller conveyor rolls serve for example for transport of strip material which passes out of a treatment furnace or for the transport of continuous-casting strands, for example. The basic structure encompasses a roller shell or casing 1. The latter is mounted at least at the roll ends 2 and 3 in respective electrical and/or thermal insulators on the roller shaft 4 (
The insulation is comprised of individual insulating bodies distributed around the periphery of the roller shaft 4 between the roller shell or casing 1 and the roller shaft 4 at the roll ends 2 and 3 (
The individual insulating bodies 5 distributed around the periphery are comprised of profile rods 7 which have a round, flat, rectangular or polygonal cross section. The profile bars 2 are comprised of ceramic or some other material having an insulating effect.
The roller shaft 4 is equipped with bearing stubs 8 and 9 and is cooled by means of a cooling medium which flows through a core channel 10. The profile rods 7 are secured between outer and inner mounting rings 11 and 12 at shaft steps 13. The rods are axially retained by sheet metal end rings 17 welded onto ends 14 and 15 of the mounting rings 11 and 12 and installed together with the mount 16 formed by the profiled rods 7. These mounts 16 can be formed as a loose mount 16a and a fixed mount 16b to allow thermal expansion. The insulating bodies 5 center the roll shell 1 on the roller shaft 4 and form simultaneously by form locking and/or force locking a torque transmitting means.
In a second embodiment (
According to a third embodiment (
In the fourth embodiment (
Instead of ceramic, glass fiber textiles can be used in a corresponding thickness or layering.
A roller shell or casing segment 1a, 1b, etc. can at each of the roller ends 2 and/or 3 be mounted in the conical mount 18 somewhat centrally by means of insulating bodies 5 distributed over the periphery.
To limit creep currents over the surface of the insulating body 5a dried ambient atmosphere is applied. Such an atmosphere can be obtained for example in the region of a treatment furnace.
Number | Date | Country | Kind |
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101 28 999 | Jun 2001 | DE | national |
This application is a continuation of application Ser. No. 10/480,717 filed 11 Dec. 2003 (now abandoned) as a national stage of PCT/EP02/05954 filed 31 May 2002 and based upon German national application 10128999.5 of 15 Jun. 2001 under the International Convention.
Number | Name | Date | Kind |
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3900913 | Drumm | Aug 1975 | A |
4181217 | Huls et al. | Jan 1980 | A |
4235002 | Pav et al. | Nov 1980 | A |
4299018 | Bickerstaff et al. | Nov 1981 | A |
5151737 | Johnson et al. | Sep 1992 | A |
5362230 | Facco | Nov 1994 | A |
5421724 | Facco | Jun 1995 | A |
Number | Date | Country | |
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20060275728 A1 | Dec 2006 | US |
Number | Date | Country | |
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Parent | 10480717 | US | |
Child | 11505227 | US |