Rolling mill

Abstract: A rolling mill comprises working rolls (5, 8), backup rolls (2, 12), beams (18, 19, 30, 31) disposed parallel to the rolls for supporting the working rolls, an supports (141, 142, 231, 232) mounted on the housing (131-134) of the rolling mill for slidably supporting the beams. The beams have roll benders (29) engaging with metal chocks (6, 7, 4, 10) of the working rolls and are moved axially by actuators (25) that are disposed separately, so as to control the shape of the material being rolled. Each support has central projection (153) extending beyond the position of the roll benders (29) and supporting symmetrically the bending force without perrnitting movements to develop about the axis of the beam thereon. The beams further, are provided with internal conduits (21) for cooling means.

Description: This invention relates to a four-high rolling mill according to the first portion of claim 1. It is known that a four-high rolling mill in which upper and lower working rolls are displaceable in the axial direction so as to cross one another is effective in correcting the shape or improving the sectional profile of a rolled sheet. In order to improve the shape of the rolled sheet or improve its sectional profile in the abovementioned rolling mill, it is required to secure proper axial movement of the upper and lower working rolls and to apply a force to bend a roll axis, or so-called "roll bender" force, to the roll chocks. The working roll bender also has the role of pushing the working rolls against the backup rolls to transmit the driving turning force to the backup rolls when rolling is not effected such as during a rolling pass. This roll bender force is applied by exerting a force between the working roll system and another system. A hydraulic cylinder is generally used as the roll bender. A four-high rolling mill similar to the above is descirbed in Japanese Patent Publication No. 51-7635. When the roll bender force is between two systems as described above, moving the working rolls risks damage to the hydraulic cylinder serving as the roll benders and in practice the working rolls can be moved only when the roll bender force is not applied, that is, when the hydraulic cylinders are released. Unless the roll bender force is applied, however, the driving force during the rotation of the working rolls is not transmitted to the backup rolls so that the speed of rotation of the backup rolls drops considerably or they stop completely. For these reasons, movement of the working rolls is effected only when the rotation of the rolls is stopped, thus limiting the rolling efficiency. Also known, from EP-A1-26-903, is a rolling mill in which an opposed pair of intermediate rolls are supported at their ends by chocks that are vertically adjustable on elongate blocks extending parallel to the rolls. The blocks bridge small gaps between the chocks and the main frames of the roll housing at opposite ends of the rolls to be supported by the housing, and a hydraulic drive can displace the blocks, chocks and rolls as a unit in the axial direction of the rolls for control of the shape of the rolled material. In this earlier disclosure, the roll bending forces produce substantial moments about the longitudinal axes of the blocks which can result in unwanted deflections and displacements. The chocks may also be subject to high pressures from resisting horizontal movement of the blocks towards them due to the loading of the blocks, so that frictional forces can develop that will make precise adjustments of the rolls more difficult. From JP-A-50-12385 there is known - as closest prior art - a four-high rolling mill, comprising a roll housing in which are mounted a pair of working rolls and a pair of backup rolls therefor. Said working rolls are supported in roll chocks at their opposite ends and are provided with drive means, with roll bending means and with means for relative axial displacement disposed on the driving side of the rolling mill. Supports are fixed in the roll housing for slidably supporting a plurality of beams extending parallel to the working rolls and having vertical flat faces for vertical guiding the working roll chocks. Said supports comprise central projections extending horizontally towards the working rolls and having vertical flat endfaces, and also upper and lower projections equally spaced vertically from said central projections. The upper and the central projections are provided with downward extensions for laterally restricting movements of the beams when the working rolls are removed. The roll bending means of the working rolls are disposed in said beams to engage the working roll chocks and are located symmetrically with respect to the axis of the central projection of the support. Each working roll is coupled by a pin as a coupling member with a driving spindle, which also is used for the relative axial displacement of the working rolls. For avoiding any disturbance of the coupling members between the working rolls and the driving spindle the shifting forces are limited so that in practice the working rolls will not be shifted during the rolling operation. When the working rolls have been removed, all of the beams are free shiftable in the length direction so that the leading in and the adjusting of the new working rolls will be difficult. The object of the invention is to provide a rolling mill in which the working rolls can move smoothly in the vertical direction and which can be operated in an efficient manner with idle times kept to a minimum. Said object will be solved by the features of claim 1. Preferably, the beams each have passages within them forming liquid-carrying conduits, a liquid for cooling or lubricating the working rolls being pressure-fed to the conduits to be sprayed onto the working rolls from a series of outlet nozzles in each said conduit. This liquid distribution arrangement can be employed in place of the header or the like that has been conventionally used for cooling the working rolls and the space thus saved can be utilized to accommodate the beams in the housing. The invention will be described in more detail with reference to a preferred embodiment illustrated in the accompaying drawings, in which: - Fig. 1 is a schematic view of a movable working roll form or rolling mill in accordance with the present invention; Figure 2 is a sectional view taken along line II-II of Figure 1; Figure 3 is a sectional view taken along line III-III of Figure 2; and Figure 4 is a sectional view taken along line IV-IV of Figure 2. Figure 1 illustrates a rolling mill with axially movable working rolls. In this rolling mill, an upper working roll 5 supported by metal chocks 4, 6 and a lower working roll 8 supported by metal chocks 7, 10 and the two rolls can be moved in the directions represented by arrows X and Y, or in the opposite directions. It is known that a material to be rolled can be rolled in an improved form if the working rolls are moved and set so that the roll shoulders of the upper and lower working rolls 5, 8 substantially conform with the ends of the sheet width of the material 9 to be rolled. These working rolls are moved while kept in contact respectively with an upper backup roll 2 supported by metal chocks 1, 3 and a lower backup roll 12 supported by the metal chocks 11, 13. The backup rolls support the reaction to rolling during the rolling operation. Though not shown in the drawings, the working rolls are driven by driving apparatus comprising motors or the like and this driving force is transmitted to the material 9 to be rolled and to the backup rolls 2, 12. Figure 2 illustrates an example of the working roll moving mechanism of the invention. In Figure 2, the working roll 5 is supported by the metal chocks 4, 6 and is driven by the driving apparatus, not shown, through a coupling 26. This working roll 5 is supported on both sides by beams 18, 19 that are guided and supported by supports 141, 142 that are secured to stands 131, 134 and by supports 231, 232 that are secured to stands 132, 133, respectively. The working roll 8 also is supported by the stands 131, 134, 132, 133 through beams 30, 31 and the supports 141, 142, 231, 232, in the same way as the working roll 5. The stands 131 to 134 forms a roll housing. As shown in Figure 3, each of the supports 141, 142 has an upper projection 151, a lower projection 152 spaced vertically from the upper projection 151, and a central projection 153 at an equidistant position from the upper and lower projections 151, 152. All the projections extend toward the working rolls 5, 8. Each of the upper and lower projections 151, 152 is formed with a recess 154 facing the central projection 153. The central projection has at its end 155 small upward and downward extension so that a pair of spaces are formed in which the beams 18, 31 are slidably held. The end 155 has a vertical flat face 156 facing the working rolls 5, 8. In each of the beams 18, 31, that are formed a vertical flat face 161 facing the working roll 5, 8 respectively, a recess 162 formed on a bottom face contacting with the central projection 153 and engaging with one extension of the central projection 153, and a small projection 163 inserted in a recess 154 of the upper or lower projection 151, 152 respectively. The vertical flat faces 161 of the beams 18, 31 are aligned with the vertical flat faces 156 of the supports 141, 142 so that guide faces are formed for the metal chocks 6, 7. The supports 141, 142 that guide and support the beams 18, 19, 30, 31 are made in a form which wraps or encloses the beams and restrains them against horizontal and torsional deflections. In the example shown in Figure 3 these supports 141, 142 are formed as a unitary body, but they may of course, be formed separately. Hydraulic cylinders 29 for roll benders which comprise cylinders, pistons 35, covers 38 and so forth are disposed between the metal chocks 6, 7, (4, 10) and the beams 18, 19, 30, 31. All the cylinders are similar to each other; each is disposed in a recess in its beam and the piston 35 is inserted in the cylinder. Each piston 35 has a rod extending through the hole of a cover 28 and engaging a portion of the chock projecting laterally over the beam. These roll benders are arranged symmetrically of the axes of the central projections 153, and within the central projections 153 so that the reactions of roll bending force applied to the working rolls cancel each other and do not produce any moment about the axes of the beams. Therefore, the metal chocks 6, 8 can move smoothly in the vertical direction according to an automatic thickness control apparatus (not shown). Referring back to Figure 2, cylinders 25 serving as axial adjustment actuators are fitted to the beams 18, 19 by covers 27 and are connected by pins 24 to the fixed supports 231, 232 at the side of the roll driving apparatus so that a space enough to accommodate the coupling 26, driving apparatus etc. can be provided therebetween. Therefore, the couplings 26, etc. can be easily connected or disconnected. Further, even if a coupling, for example, is disconnected from its working roll and displaced somewhat from its operative position for some reason, the beams 18, 19, 30, 31 are not damaged by a contact with it. The working roll 5 is connected to the beams 18, 19 by arms 16, which extends from the metal chock 6, clamped and fixed to a slit portion 33 of the beams by means of plates 32 with bolts 15 and washers 17. This arm 16 may of course be movably connected to the cylinder. The working roll 5 can be moved in the axial direction of the roll by axially moving the beams 18, 19 with the cylinders 25 being operated to exert the displacing force. The working roll 8 also can be moved in a similar manner to that of the working roll 5 in the opposite direction. In the axial displacement of the working rolls 5, 8, an axial force exerted by each cylinder 25 produces a turning moment on its respective beam 18, 19 because there is a distance between the axes of the cylinders 25 and the beam axes. When the axial force is in the direction X, a force compressing the metal chock 4 is produced, and when the axial force is directed in the direction Y, a force compressing the metal chock 6 is produced. These forces, however are not applied to the metal chocks 4, 6, because the supports 141, 142 have configurations which wrap or surround the beams 18, 19 as to restrict the displacement of the beams toward the metal chocks. Therefore, a proper gap is kept between the metal chocks 4, 6 and the guide faces formed by the vertical flat faces 161 and 156 whereby the working rolls 5, 8 can be moved smoothly. Referring now to Figure 4, hollow liquid introduction conduits 21, indicated by dotted lines in Figure 2, are bored through the centers of beams 18, 19, 30, 31 and liquid is pressure-fed into these bores from inlet openings 22. The liquid, such as cooling water, is sprayed on the working rolls 5, 8 during the rolling operation from a large number of nozzles 20 communicating with the bores 21 through narrow passages 36. The nozzles 20 are disposed near the portions of the working rolls contacting the material to be rolled so that heat conducted to the working rolls can be removed effectively, that is, before the heat reaches deep into the working rolls. In the construction described, the working roll 5 supported by beams 18, 19 and the metal chock 6 move together with each other, and so also do the working roll 8 supported by the beams 30, 31, and the metal chock 7 similarly, while the bending force applied to the working rolls is applied by the cylinders 29 incorporated in the beams, Thus, even when the bender force is applied to the working rolls during their movement this will not damage the pistons 35 even though a force is being also applied to the backup rolls 2, 12 from the cylinders 29 through the working rolls 5, 8. According to this construction, preparation can be made for procedures such as the movement of the working rolls and the like until subsequent rolling without reducing the speed of rotation of the backup rolls even when moving the working rolls axially. As shown in Figure 2, the beams 18, 19 can also cool the working rolls 5. Accordingly, the embodiment of the invention illustrated can provide a compact moving working roll form of rolling mill and can provide a significant effect in improving the efficiency of rolling.

Claims: A four-high rolling mill comprising a roll housing (131 to 134) in which are mounted a pair of working rolls (5, 8) and a pair of backup rolls (2, 12) therefor, said working rolls (5, 8) supported in roll chocks (4, 6, 7, 10) at their opposite ends being provided with drive means (26), with roll bending means (29) and with means (25) for relative axial displacement disposed on the driving side of the rolling mill, supports (141, 142, 231, 232) are fixed in the roll housing for slidably supporting a plurality of beams (18, 19, 30, 31) extending parallel to the working rolls (5, 8) and having vertical flat faces (161) for vertical guiding the working roll chocks (4, 6, 7, 10), said supports (141, 142, 231, 232) comprise central projections (153) extending generally horizontally towards the working rolls and having a vertical flat endface (156), and also upper and lower projections (151, 152) equally spaced vertically from said central projections (153), each central projection (153) is provided at its end (155) with a small downward extension for engaging in a recess (162) formed in the face of the respective beam (30 31) contacting the central projection (53) and each upper projection (151) is provided with a recess (154) engaged by a small projection (163) formed on the contacting face of the respective beam (18, 19), said roll bending means (29) are disposed in said beams (18, 19, 30, 31) to engage the working roll chocks (4, 6, 7, 10) and are located symmetrically with respect to the axis of the central projection (53) of the support, characterized in that each central projection (153) is provided at its end (155) also with a small upward extension for engaging in a recess (162) formed in the face of the respective beam (18, 19) contacting the central projection (153) and each lower projection (152) is provided with a recess (154) engaged by a small projection (163) formed on the contacting face of the respective beam (30, 31), so that the supports (141, 142) wrap or surround the beams, the roll bending means (29) are disposed in said beams (18, 19, 30, 31) wholly within the width of the respective central projections (153), the vertical flat faces (161) of the beams (18, 19, 30, 31) are aligned with the vertical flat endfaces (156) of the central projections (153) so that guide faces are formed for both of the roll chocks (6, 7), said means for relative axial displacement of the working rolls (5, 8) comprising a plurality of actuators (25) connected to the roll housing (131 to 134) and to the beams (18, 19, 30, 31) independently of each other for sliding the beams axially, the axis of each actuator (25) being laterally spaced from the axis of the respective beam. A rolling mill according to claim 1, characterized in that each beam has passages (21) within it for coolant communicating with a plurality of nozzles (20) opening towards said working rolls (5, 8). A rolling mill according to claim 2, characterized in that said beams (18, 19, 30, 31) have fluid entries (22) to said passages (21) near the position at which said actuators (25) are mounted.

Inventors: KIMURA TOMOAKI, MIYAKOZAWA KEIJI, KIMURA, TOMOAKI, MIYAKOZAWA, KEIJI
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1982
Main classification: B21B31
IPC codes: B21B29, B21B27, B21B13, B21B31, B21B37