Roller table roll, particularly for conveying furnace-heated metallic strip material

Abstract

The invention relates to a roller table roll used, in particular, for conveying furnace-heated metallic strip material, cast billets made of steel and the like. The roller table roll comprises a roll shaft (4) and a roll casing (1) that is mounted on the roll shaft (4) at least at the roll ends (2; 3). The aim of the invention is to prevent damages caused by electric currents and by sparking on the product surface. To this end, the roll casing (1) is mounted on the roll shaft (4) while being electrically and/or thermally insulated at least at the roll ends (2; 3).

Description

[0001] 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] journaled on the roller shaft at least at the roller ends.

[0002] 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.

[0003] It is known (DE 24 26 135 C2) to provide a roller conveyor roll for the transport of rolled products [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.

[0004] 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 journaled 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.

[0005] 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 there between.

[0006] 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.

[0007] A further advantage arises when the profile bars are axially secured with respect to the roller shaft and the roller casing together with bearing rings.

[0008] 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 bearing.

[0009] 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 bearing and a fixed bearing 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.

[0010] 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.

[0011] 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 for torque transmission. 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.

[0012] According to a further alternative, the insulating body is configured as a conical bearing whose cone shaped inner ring and/or whose cone shaped outer ring and/or their conical rollers respectively form 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 bearing and fixed bearing units are required. In this manner electrical currents in the axial direction are especially suppressed.

[0013] 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.

[0014] The inclination of the cone [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.

[0015] 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.

[0016] Another configuration provides that a roller shell segment is journaled at the respective roller ends in respective conical bearings and generally centrally by means of insulating bodies distributed over the periphery.

[0017] In the drawing embodiments of the invention are shown and are described in greater detail in the following.

[0018] The drawing shows:

[0019] FIG. 1 an axial longitudinal section through a first embodiment of the roller conveyor roll,

[0020] FIG. 2 an axial longitudinal section through a second embodiment of a roller-conveyor roll with roller casing or shell segments,

[0021] FIG. 2 a the associated side view,

[0022] FIG. 3 an axial longitudinal section through a third embodiment of the roller conveyor roll,

[0023] FIG. 3 a the associated side view, and

[0024] FIG. 4 an axial longitudinal section through a fourth embodiment of the roller conveyor roll.

[0025] 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 journaled at least at the roll ends 2 and 3 in respective electrical and/or thermal insulators on the roller shaft 4 (FIGS. 1 and la as a first embodiment).

[0026] 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 (FIG. 1, 1A, FIG. 2, 2A and FIG. 3, 3A). Alternatively, a one-piece annular insulating body 6 (FIG. 4) can be provided.

[0027] 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.

[0028] 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 bars 7 are secured together with bearing rings 11 and 12 on shaft steps 13. The axial retaining is effected by sheet metal rings 17 welded onto the ends 14 and 15 and which are respectively applied together with the bearing 16 formed by the profiled rods 7. These bearings 16 can be formed as a loose bearing 16a and a fixed bearing 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.

[0029] In a second embodiment (FIGS. 2, 2A) the roller shell or casing 1 is subdivided into a plurality of spaced apart roller shell segments 1a, 1b, 1c, 1d, etc. arranged upon the roller shaft 4 and which are centered on the roller shaft 4 with respect to the insulating bodies 5 and transfer the drive torque.

[0030] According to a third embodiment (FIGS. 3 and 3A) the insulating body 5 is configured as a conical bearing 18 of which either the conical inner ring 18a or the conical outer ring 18b and or the conical rollers 18c respectively form the insulating bodies 5.

[0031] In the fourth embodiment (FIG. 4) the conically shaped inner ring 18a is axially shiftable and is adjustable against the spring force upon the roller shaft 4. The conical inner ring 18a is braced on the roller shaft 4 axially by means of dish-disk springs 19 which are seated against a shaft step 20. The ring 18a is shiftable relative to the hollow conical outer ring 18b fixedly connected with the roll shell or casing 1. The torque in this configuration is transferred by frictional connection to the conical outer ring 18b. The insulating material is the ceramic from which the conical outer ring is composed.

[0032] Instead of ceramic, glass fiber textiles can be used in a corresponding thickness or layering.

[0033] A roller shell or casing segment 1a, 1b, etc. can at each of the roller ends 2 and/or 3 be journaled in the conical bearing 18 somewhat centrally by means of insulating bodies 5 distributed over the periphery.

[0034] To limit creep currents over the surface of the insulating body 5a dryed ambient atmosphere is applied. Such an atmosphere can be obtained for example in the region of a treatment furnace.

[0035] Reference List

[0036] 1 Roller shell or casing

[0037] la Roller casing segment

[0038] 1 b Roller casing segment

[0039] 1 c Roller casing segment

[0040] 1 d Roller casing segment

[0041] 2 Roller end

[0042] 3 Roller end

[0043] 4 Roller shaft

[0044] 5 Individual insulating Body

[0045] 6 One piece insulating body

[0046] 7 Profiled bar

[0047] 8 Bearing step

[0048] 9 Bearing step

[0049] 10 Core passage

[0050] 11 Bearing ring

[0051] 12 Bearing ring

[0052] 13 Shaft step

[0053] 14 End

[0054] 15 End

[0055] 16 Bearing formed from profiled bars

[0056] 16 a Loose bearing

[0057] 16 b Fixed bearing

[0058] 17 Shell metal ring

[0059] 18 Conical bearing

[0060] 18 a Inner cone-shaped ring

[0061] 18 b Outer cone-shaped ring

[0062] 18 c Conical rollers

[0063] 19 Dished disk spring

[0064] 20 Shaft step

Claims

1. A roller conveyor roll, especially for the transport of furnace-heated metallic strip, continuously cast stands of steel or the like with a roller shaft and a roller shell or casing journaled at least at the roller ends on the roller shaft, characterized in that the roller shell (1) is journaled on the roller shaft (4) at least at the roller ends (2, 3) respectively with electrical and/or thermal insulation.

2. The roller conveyor roll according to claim 1 characterized in that between the roller casing or shell (1) at the roller ends (2, 3) and the roller shaft (4), respective individual insulating bodies (5) distributed over the periphery or annular insulating body (6) are provided.

3. The roller conveyor roll according to claim 2 characterized in that individual insulating bodies (5) or profiled rods (7) are distributed over the periphery.

4. The roller conveyor roll according to one of claims 1 to 3 characterized in that the profiled bars (7) together with bearing rings (11, 12) are axially secured relative to the roller shaft (4) and the roller shell (1).

5. The roller conveyor roll according to claim 4 characterized in that the axial retention is comprised of a sheet metal ring (17) welded on the ends (14, 15) of the bearing (16).

6. The roller conveyor roll according to one of claims 4 or 5 characterized in that by means of the axial retention, a loose bearing (16a) and a fixed bearing (16b) are formed between the roller shell (1) and the roller shaft (4).

7. The roller conveyor roll according to one of the claims 1 to 6 characterized in that the insulating body (5) centers the roller shell or casing (1) on the roller shaft (4) and simultaneously forms the torque transmitting means.

8. The roller conveyor roll according to one of the claims 1 to 7 characterized in that the roller shell (1) is subdivided into a plurality of spaced apart roller shell segments (1a, 1b, 1c, 1d) arranged on the roller shaft 4 and centered with a plurality of insulating bodies (5) distributed around the periphery respectively and serving as drive torque transferring members.

9. The roller conveyor roll according to claim 1 characterized in that the insulating body (5) is configured as a conical bearing (18) whose conical inner ring (18a) and/or whose conical outer ring (18b) and/or whose conical rollers (18c) form respective insulating bodies (5).

10. The roller conveyor roll according to claim 9 characterized in that the conical inner ring (18a) is axially shiftable and adjustable under spring force on the roller shaft (4).

11. The roller conveyor roll according to claim 10 characterized in that the conical inner ring (18a) is axially shiftable on the roller shaft (4) by means of dished disk springs (19) which are braced against a shaft step (20) relative to the hollow conical outer ring 18b fixed with the roller shell (1).

12. The roller conveyor roll according to one of claims 8 to 11 characterized in that a roller shell segment (1a, 1b, etc.) is respectively journaled at a roller end (2, 3) in a conical bearing (18) and substantially midway by means of insulating bodies (5) distributed around the periphery.