VARIABLE PROFILE ROLLS FOR ROLLING MILLS

Abstract: The roll comprises a roll core (1a) on which a sleeve (2) is shrink-fitted to define an annular space (5) at each end of the roll between the roll core and the sleeve. Two annular pistons (45,46) are accommodated within the annular space and hydraulic fluid lines which extend through the roll core communicate with hydraulic fluid chambers (50,51,52) at each end of the pistons. Valves (66,67,66′,67′) are provided in the hydraulic fluid lines and one or more position sensors (61,62) is arrranged to produce a signal indicative of the axial position of each piston. A control unit (69) is connected to the position sensors and arranged to control the valves in response to the said signal and thus to control of the positions of the pistons.

Description: The present invention relates to variable profile rolls for rolling mills and is concerned with such rolls of the type which comprise a roll core on which a sleeve is shrink-fitted, an annular space being defined between the roll core and the sleeve at each end of the roll, at least one annular piston within the annular space and a hydraulic fluid supply including hydraulic fluid lines which extend through the roll core and communicate with hydraulic fluid chambers at each end of the or each piston and, in use, with a hydraulic fluid source through a rotary joint at one end of the roll. In order to ensure satisfactory rolling operation for workpieces of differing width, various types of rolling means have been proposed and used (cf. for example JP-A 61-7004, JP-A 61-7013 and JP-A 59 104 205). A typical example is a rolling mill with rolling rolls having a variable profile. The rolling rolls comprise a roll core on which a sleeve is fitted to define a liquid-tight chamber between an end of the sleeve and a corresponding end of the roll core. Fitted between the opposing surfaces of the ends of the sleeves and the roll core, one of which is a tapered surface, is an annular piston or pistons having a tapered surface complementary to or in intimate contact with the first tapered surface. With such an arrangement, axial shifting of the annular piston or pistons will cause radial expansion or compression of the end of the sleeve so that the roll profile may be varied as desired. With a rolling mill of the type having rolling rolls which are each fitted with an annular piston or pistons as described above, control of the roll profile into a described shape is assured by detecting and controlling the axial position of the annular piston or pistons with a high degree of accuracy. As mentioned above, the roll end is provided with one annular piston or a plurality of such pistons. In the former case, the construction is relatively simple, but control of the roll into a complicated shape is not possible. In the latter case, the construction is relatively complicated but it is possible to control the roll into a complicated shape by adjusting the positions of the pistons independently of one another. Figures 1 and 2 are a partial front elevation, partly in section, and a scrap sectional elevation, respectively of a variable profile roll equipped with three annular pistons at each end as is known from JP-A 61-7004 and JP-A 61-7013. The roll 1 comprises a roll core 1a on which a sleeve 2 is shrink-fitted to define a barrel shape. A portion of the roll core 1a corresponding to the end 3 of the sleeve constitutes a stepped portion 4 having a diameter smaller than that of the sleeve 2 on the roll core 1a and the inner surface of the sleeve end 3 is tapered, that is to say divergent, towards the end of the sleeve. Thus, a cylindrical annular space 5 is defined by the outer periphery of the stepped portion 4 and the tapered inner periphery of the sleeve end 3. A plurality, and in this case three, annular pistons 6,7 and 8 are fitted in the space 5 to be movable in the axial direction. The outer surfaces of the pistons 6,7 and 8 are so tapered to be complementary and in intimate contact with the tapered inner surface of the sleeve end 3. The outer surfaces of the pistons 6,7 and 8 on the side adjacent to the end of the sleeve are formed with annular grooves 12,13 and 14 into which respective O rings 18,19 and 20 are fitted. A portion of the sleeve end 3 extending beyond the stepped portion 4 towards a journal box 21 has an inner diameter greater than that of the tapered inner periphery of the sleeve end 3 and has a screw thread 22. A neck portion 24 of smaller diameter than the stepped portion 4 extends from the latter and is contiguous with a shaft 23. A seal ring 25 is fitted over the neck portion 24 and one side surface thereof abuts a stepped surface between the neck portion 24 and the stepped portion 4. An O ring 26 is inserted between the seal ring 25 and the neck portion 24 while another O ring 27 is inserted between the seal ring 25 and the sleeve end 3. A ring nut 28 is threadably engaged with the thread 22 and securely holds the seal ring 25 in position. The space defined by the sleeve end 3, the stepped portion 4 and the seal ring 25 can be therefore maintained in a sealed, liquid-tight state. First to fourth oil chambers 29,30,31 and 32 are defined respectively at the end of the annular piston 6 remote from the journal box 21, between the annular pistons 6 and 7, between the annular pistons 7 and 8 and between the annular piston 8 and the seal ring 25 and are in communication with a working oil source (not shown) through respective oil passages 33,34,35 and 36 defined in the stepped portion 4 and neck portion 24. Spiral grooves 37 and 38 are formed respectively on the inner and outer peripheries as of the annular piston 6. The spiral groove 37 communicates with the second oil chamber 30 while the spiral groove 38 communicates with the first oil chamber 29. In like manner, the inner and outer peripheries of the annular piston 7 are respectively formed with spiral grooves 39 and 40, the spiral groove 39 communicating with the third oil chamber 31 while the spiral groove 40 communicates with the second oil chamber 30. The inner and outer peripheries of the annular piston 8 are respectively formed with spiral grooves 41 and 42, the spiral groove 41 communicating with the fourth oil chamber 32 while the spiral groove 42 communicates with the third oil chamber 31. These spiral grooves are so formed that they do not communicate with the annular grooves 9,10 and 11 and the grooves 15,16 and 17 formed on the ring pistons 6,7 and 8. Reference numeral 43 represents a bearing and 44 a bearing retaining plate. In a rolling roll of the type described above, the working oil is supplied respectively into the oil chambers 29,30,32 and 32 to independently adjust the positions of the annular pistons 6,7 and 8 so that the outer diameter of the end of the variable profile roll 1 can be varied into the desired complicated shape. It follows, therefore, that when a rolling roll of the type described above is used, for instance, as a backup roll, the shape of the roll is deformed into a shape capable of absorbing the thermal crown of the work roll and the rolling operation is carried out with the sharply deformed portion of the backup roll in contact with the sharply deformed end portion of the thermal crown, whereby the pressing surfaces of the work rolls in contact with the workpiece being rolled can be maintained straight so that the finished article is produced with a high degree of surface flatness. The detection of the axial position of the annular pistons is made by detecting the pressure of the working oil in the hydraulic circuits for shifting the annular pistons in the axial direction. However, the frictional forces between the annular pistons, the roll core and the sleeve are considerable and tend to vary in an unstable manner so that, in some cases, the annular pistons cannot be shifted in response to changes in the pressure of the working oil. Especially in the case where a plurality of annular pistons is provided, it is difficult to confirm the actual positions of the inner pistons so that precise roll profile control in response to the control of the positions of the annular pistons has not yet been possible. It is the object of the present invention to solve the above problems encountered in known rolls and, in particular, to provide a roll in which it is readily possible to detect the axial positions of the annular pistons so that satisfactory roll profile control can be achieved. According to the present invention a roll of the type described above is characterised by valves in the hydraulic fluid lines, one or more position sensors arranged to produce a signal indicative of the axial position of the or each piston and a control unit connected to the position sensors and arranged to control the valves in response to the said signal. Thus in the roll in accordance with the present invention the actual position of the or each piston may be accurately determined and this may then be used to adjust the position of the or each piston into the desired position. In one embodiment of the invention a seal ring seals the outer end of the annular space and the sensor or at least one of the sensors is arranged in the seal and comprises a magnetic rod and an associated detector coil, the magnetic rod being urged into engagement with the outer end face of the piston or one of the pistons or a member arranged to move therewith. In this case, the roll may include one or more electrical connections between the or each position sensor and the control unit which extend through the roll core and through a slit ring at the said one end of the roll. In an alternative embodiment, the roll is again provided with a seal ring which seals the outer end of the annular space and the sensor or at least one of the sensors is arranged in the seal and comprises an eddy current type position sensor arranged to detect the position of the outer end face of the piston or one of the pistons or a member arranged to move therewith. In this event, the roll may also include a transmitting antenna disposed on the seal ring and connected to the position sensor and a receiving antenna arranged on a stationary member and coupled to the transmitting antenna and to the control unit. Whilst the invention is applicable to a roll with only one annular piston at each end it is particularly applicable to rolls having two or more pistons at each end which are arranged in the axial direction of the roll and in this event the roll will include one or more position sensors arranged to detect the axial position of each piston independently. In this event, it will be appreciated that the or each sensor associated with the outermost piston may be of the type referred to above and in the preferred embodiment the position sensor for detecting the axial position of the or each inner annular piston comprises one or more longitudinally movable rods which extend parallel to the axial direction of the roll through the or each annular piston which is closer to the associated end of the roll, the rod being constrained to move with the said inner annular piston, an annular plate connected to the outer end of each rod, a magnetic rod which is urged into contact with the annular plate and a detector coil within the seal ring arranged to produce a signal indicative of the position of the magnetic rod and thus indirectly of the said inner annular piston also. The longitudinally movable rod may be constrained to move with the said inner annular piston by a bias spring or by being connected to it, for instance by means of enlarged head accommodated within an undercut groove in the said piston. Further features and details of the present invention will be apparent from the following description of certain specific embodiments which is given by way of example with reference to Figures 3 to 8 of the accompany drawings, in which:- Figure 3 is a scrap sectional elevation of a rolling roll equipped with sensors for detecting the positions of the annular pistons in accordance with one embodiment of the present invention; Figure 4 is a similar view of a modification thereof; Figure 5 is a diagrammatic view showing the control circuit for controlling the positions of the annular pistons; Figure 6 is a diagram explaining the mode of operation of the inner and outer annular pistons by solenoid and servo valves (or solenoid valves); Figure 7 is a graph illustrating the roll-shape deformations of a roll in accordance with the present invention; and Figure 8 is a scrap view illustrating a further embodiment of a sensor for detecting the position of the outer or a single annular piston. Figure 3 shows a variable profile rolling roll 1 equipped with sensors for detecting the positions of two annular pistons. Inner and outer annular or ring pistons 45 and 46 of tapered shape are positioned in the annular cylindrical space 5 between the roll core 1a and the end of the sleeve 2 and are in intimate contact with the surfaces defining the tapered space 5. Oil chambers 50,51 and 52, to which working oil is supplied through respective oil passages 47,48 and 49 defined in the roll core 1a, are defined respectively at the end of the inner piston 45 remote from the outer piston 46, between the inner and outer pistons 45 and 46 and between the outer piston 46 and a seal ring 25. A plurality of, in this case four, equiangularly spaced shift rods 53 extend through the outer piston 46 in the axial direction. Each shift rod 53 has a head 54 at its inner end which is normally urged against the outer end surface of the inner piston 45 under the force of a biassing spring 55 in a space within the outer piston 46. An annular plate 57 is securely joined to the outer end of each shift rod 53 by means of a screw 56 adapted to prevent rotation of the annular plate 57. Guide openings 58 and 59 are formed in the outer piston to permit the movement of and to guide the head 54 and the annular plate 57 in the axial direction. Inner piston position sensors 61, which are equiangularly spaced, in this case by 180°, in the circumferential direction, extend through the seal ring 25 in the axial direction. Each sensor 61 comprises a magnetic rod 60 which is pressed against the outer surface of the annular plate 57 and whose position is detected by a detecting coil (not shown). Outer piston position sensors 62 which are illustrated diagrammatically in Figure 3 and are in fact angularly offset from the sensors 61 by 90° and similar to the sensors 61 are also provided in the seal ring 25. The sensors 62 also include a magnetic rod 60 which is urged against the outer surface of the outer piston 46 and whose position is similarly sensed by a detecting coil (not shown) whereby the axial position of the outer piston 46 may be detected. When the axial position of the inner piston 45 changes, the shift rods 53, which are urged against the outer end surface of the inner piston 45 by the biassing springs 55, are shifted in unison with the inner piston 45 and with the annular plate 57, which is securely joined to the shift rods 53. The axial position of the inner piston 45 can thus be directly detected by the inner piston position sensors 61 which are urged against the outer end face of the plate 57. In the modified embodiment of Figure 4, the head portion 54′ of each shift rod 53 is fitted into an engaging groove 63 formed in the outer periphery of the inner piston 45 so that the inner piston 45 and the shift rod 53 are constrained to move in unison. In all other respects this construction is substantially the same as the embodiment of Figure 3. Figure 5 illustrates the control circuit for controlling the positions of the annular piston. The hydraulic circuit includes oil passages in communication with the oil chambers 50,51,52 and the corresponding passages 50′,51′ and 52′ at the other end of the roll which extend through the roll core 1a and communicate through a rotary joint 64 at one end of the shaft with a position control panel 65 disposed outside the rolling roll 1. Solenoid valves 66 and 66′ are provided in the oil passages respectively in communication with the oil chambers 50 and 52, 50′ and 52′ and a servo valve (or solenoid valve) 67 is provided in the oil passage communicating through the solenoid valve 66 with the oil chamber 51 and a similar servo valve (or solenoid valve) 67′ is provided in the oil passage in communication with the oil chamber 51′ through the solenoid valve 66′. The working oil is supplied from a pump P through a remote-controlled type reducing valve 68 to the servo valves (or solenoid valves) 67 and 67′. The other communication ports of the valves 66,67,66′,67′ communicate with an oil tank T. The output signals from the position sensors 61,62 and the corresponding sensors 61′ and 62′ at the other end of the roll are transmitted through the roll core 1a and slip rings 88 disposed in the rotary joint 64 to a control unit 69. The solenoid valves 66 and 66′ and the servo valves (or solenoid valves) 67 and 67′ are controlled in response to control signals 70 from the control unit 69. When the axial positions of the outer annular pistons 46 and 46′ change, the magnetic rods 60 of the outer piston position sensors 62 and 62′, which are urged against the outer end faces of the outer annular pistons 46 and 46′, change their positions so that the positions of the outer pistons 46 and 46′ are directly detected. When the axial positions of the inner annular pistons 45 and 45′ change, the shift rods 53 move with them under the action of the biassing springs 55 or due to the engagement of the heads 63 with them. As a result, the axial positions of the inner annular pistons 45 and 45′ are directly detected by the sensors 61 and 61′. The output signals from the inner and outer piston position sensors 61,61′,62 and 62′ are transmitted through the slip rings 88 to the control unit 69 and are compared with predetermined position signals 71. If there are differences between the output signals on the one hand and the predetermined position signals 71 on the other hand, the control unit 69 emits control signals 70 which control the switching of the solenoid valves 66 and 66′ and the servo valves (or solenoid valves) 67 and 67′, whereby the actual axial positions of the pistons 45,45′,46 and 46′ coincide with their desired positions. Figure 6 shows an example of the mode of operation for controlling the positions of the inner and outer pistons by means of the valves 66 and 67. Figure 6 in fact shows the position control of the inner and outer pistons 45 and 46 but it will be understood that the control of the positions of the inner and outer pistons 45′ and 46′ may be similar. Thus, the positions of the ring pistons 45,45′,46 and 46′ are controlled by means of the servo valves (or solenoid valves) 67 and 67′ so that their positions can be controlled with a higher degree of accuracy. When the working oil under pressure is supplied to associated oil chambers to adjust the displacement of each piston, the outer diameter of the end of the variable profile roll 1 can be varied as shown in Figure 7. Extremely complicated desired roll profiles can be obtained if the taper angle of the annular pistons and sleeve end and/or the number of annular pistons is varied in a suitable manner. The embodiments described above are what may be termed double-piston type rolling rolls. In the case of a rolling roll with a single piston at each end, the piston position can be controlled by means of the outer piston position sensors 62 and 62′, the oil passages in communication with the oil chambers 51,52,51′ and 52′ and two servo valves (or solenoid valves) 67 and 67′. Instead of the outer piston position sensor of the type described above with reference to Figure 3, a sensor of the type shown in Figure 8 may be used. In this case, the seal ring 25 extends toward the journal box 21 to form an extension 72 in which a transmission antenna 74 is embedded and an eddy current position sensor 73 is embedded in the seal ring 25 adjacent to the annular space 5, the transmission antenna 74 being electrically connected to the position sensor 73. A receiving antenna 75 is embedded in the journal box 21 on the side directed towards the sleeve end 3 and adjacent to the antenna 74 so as to receive the output signal from the position sensor 73. This detection system in which the output signal is transmitted from a transmitting antenna to a receiving antenna may be equally employed to detect the position of the inner annular piston. Even in a rolling roll with more than three annular pistons at each end, the construction described above can be equally applied to detect and control the position of each annular piston with a high degree of accuracy. In this event, the position of the outer annular piston may be detected as described above and each inner piston may be associated with one or more shift rods which pass through each piston outside it, i.e. closer to the end of the roll. The shift rods of each inner piston may be associated with an annular ring which cooperates with a respective sensor.

Claims: A roll for a rolling mill comprising a roll core (1a) on which a sleeve (2) is shrink-fitted, an annular space (5) being defined between the roll core and the sleeve at each end of the roll, at least one annular piston (45,46) within the annular space and a hydraulic fluid supply including hydraulic fluid lines which extend through the roll core and communicate with hydraulic fluid chambers (50,51,52) at each end of the or each piston and, in use, with a hydraulic fluid source through a rotary joint at one end of the roll characterised by valves (66,67,66′,67′) in the hydraulic fluid lines, one or more position sensors (61,62) arranged to produce a signal indicative of the axial position of the or each piston (45,46) and a control unit (69) connected to the position sensors and arranged to control the valves in response to the said signal. A roll as claimed in claim 1, characterised in that a seal ring (25) seals the outer end of the annular space (5) and that the sensor or at least one of the sensors (61,62) is arranged in the seal and comprises a magnetic rod (60) and an associated detector coil, the magnetic rod being urged into engagement with the outer end face of the piston or one of the pistons (45,46) or a member (57) arranged to move therewith. A roll as claimed in claim 1 or claim 2, characterised by an electrical connection between the or each position sensor (61,62) and a control unit (69), which connection extends through the roll core (1a) and through slip ring means (64) at the said one end of the roll. A roll as claimed in claim 1, characterised in that a seal ring (25) seals the outer end of the annular space (5) and that the sensor or at least one of the sensors (61,62) is arranged in the seal and comprises an eddy current type position sensor (73) arranged to detect the position of the outer end face of the piston or one of the piston (45,46) or a member (57) arranged to move therewith. A roll as claimed in claim 4, characterised by transmitting antenna means (74) disposed on the seal ring (25) and connected to the position sensor (73) and by receiving antenna means (75) which is arranged on a stationary member (21) and coupled to the transmitting antenna means (74) and to the control unit (69). A roll as claimed in any one of the preceding claims characterised in that the valves (66,67,66′,67′) are servo and/or solenoid valves. A roll as claimed in any one of the preceding claims characterised in that two or more annular pistons (45,46) are arranged in the axial direction of the roll in the annular space (5) and that one or more position sensors (61,62) are provided to detect the axial position of each piston independently. A roll as claimed in claim 7 characterised in that the position sensor (60) for detecting the axial position of the or each inner annular piston (45) comprises one or more longitudinally movable rods (53) which extend parallel to the axial direction of the roll through the or each annular piston (46) which is closer to the associated end of the roll, the rod (53) being arranged to move with the said inner annular piston (45), an annular plate (57) connected to the outer end of the or each rod (53), a magnetic rod (60) which is urged into contact with the annular plate (57) and a detector coil within the seal ring arranged to produce a signal indicative of the position of the magnetic rod (60). A roll as claimed in claim 8 characterised by a spring (55) which urges the inner end (54) of the rod (53) into contact with the outer face of the said inner annular piston (45). A roll as claimed in claim 8 characterised in that the inner end (54′) of the rod (53) is connected to the said inner annular piston (45) to move with it.

Inventors: HIGUCHI, KINICHI, HOSOI, KOHEI, ICHIKAWA, MITSUHIKO, IMAI, ISAO, KATO, HEIJI, MORI, TAKAAKI, NITANDA, MASAO, OYAUCHI, TSUKASA
Applicants: ISHIKAWAJIMA-HARIMA  JUKOGYO KABUSHIKI KAISHA
Application year: 1988
Main classification: B21B27
IPC codes: B21B27