Field of the invention
[0001] The present invention relates to a pinch roll device for rolled metallurgic products.
State of the art
[0002] In the technical field of line processes for semi-finished metallurgic products,
e.g. wire rods, it is known to use pinch roll devices comprising systems for monitoring
both the distance between the rolls and the pressure exerted by the rolls on the product
when rolling.
[0003] Among the devices of the aforesaid type, the one described in Patent
US 6920772 is known, for example, in which the rolls are connected to two cranks, respectively,
connected to a single electric ratio motor. The controlled rotation of the ratio motor
controls, by means of the two cranks, the reciprocal approach of the two rolls in
one direction and the moving apart in the opposite direction. When a product being
machined is present between the rolls, the ratio motor by means of the two cranks
allows to adjust the thrust force of each roll against the other roll, thus also adjusting
the pressure exerted by the rolls on the product being rolled.
[0004] The device described in
US 6920772 has a series of drawbacks, caused by its constructional complexity and the inevitable
presence of backlash in the transmission chain between the servo motor and the rolls,
determined by the type and number of the mechanical members chosen to connect the
servo motor to the rolls. Therefore, such a device does not allow to effectively control
the distance between the rolls both during the waiting step, i.e. when the product
to be rolled is not present between the rolls, and during the working step, when the
product to be rolled is in contact with the rolls. During the working step, in devices
as the one described in
US 6920772, in which the distance between the rolls is adjusted only by means of a kinematic
chain comprising electromechanical members, the dynamic stresses caused by the contact
between product and rolls determine the juddering of the rolls, and the consequent
intermittent loss of contact between rolls and rolled product. The impossibility of
ensuring a constant pinching action implies the instability of the device which is
also transmitted upstream of the rolling line.
[0005] Furthermore, the juddering of the pinch rolls causes a surface fault of the rolled
product which reduces quality and increases material rejects.
[0006] Other pinch roll devices, as those described in
US2003/034376 (on which the preamble of claim 1 is based) and in
EP019298 are also known, which allow the distance between the rolls to be controlled by means
of hydraulic actuators comprising one or more hydraulic cylinders controlled by servo
valves. In this field, the use of hydraulic circuits comprising servo valves determines
a plurality of drawbacks, the main drawbacks being:
- low operating speed of the servo valve (of the order of 40-50 Hz), with consequent
low reactivity of the hydraulic circuit;
- open circuit operation with consequent need to provide external hydraulic attachments;
- high running and maintenance costs because the servo valves normally have low life
cycles.
[0007] The devices described in
US2003/034376 and in
EP0192982 are also improvable with regards to roll positioning accuracy.
Summary
[0008] It is the object of the present invention to provide a new pinch roll device for
rolled metallurgic products which allows to solve the mentioned drawbacks of the prior
art, thus allowing to accurately control both the reciprocal distance of the pinch
rolls and the pressure exerted by the rolls on the product when rolling, in order
to ensure a continuous, even contact between rolls and rolled product.
[0009] Another object is to make available a new pinch roll device for rolled metallurgic
products which is completely automatic and which does not require any manual intervention
by the operator, e.g. for compensating roll wear.
[0010] A further object is to allow a high through speed, up to 150 m/s, of the product
between the rolls to be achieved.
[0011] Another object of the present invention is to make available a pinch roll device
controlled by a hydraulic circuit having size, in terms of length of the hydraulic
line and amount of operating fluid, much smaller than the prior art.
[0012] A further object is to make available an operation method for the above-mentioned
pinch roll device.
[0013] In accordance with the invention, the aforesaid technical problem is solved by means
of a pinch roll device having the features set forth in independent claim 1, and by
means of a method having the features set forth in independent claim 8. Similarly
as described above with regards to the first aspect, the present invention allows
to obtain a method of operating a pinch roll device for metallurgic products with
an optimized control comprising a step of checking the position, which allows to set
the distance between the rolls before the passage of the product, and a step of checking
the pressure, which allows to adjust the roll thrust when rolling. The two steps are
carried out alternatively with respect to each other, allowing to optimize the control
cycle which thus may be carried out rapidly, thus favoring an increase of the through
speed of the product between rolls.
[0014] Other advantages of the present invention are achieved by means of a pinch roll device
in accordance with the dependent claims, as explained in greater detail in the description
that follows.
[0015] Including a first roll and a second roll reciprocally interconnected by means of
a mechanical and/or hydraulic connection allows to reciprocally approach or space
apart the two rolls in a symmetric manner with respect to the crossing axis, so as
to accurately and effectively control the size of the passage gap. In particular,
the hydraulic actuator being directly active on only one of the two rolls, while the
other is controlled by a geared transmission between the two rolls allows to synchronize
the movement due to the direct coupling of the first and second rolls, in a simpler
manner than the other known solutions, e.g. the one in
US 6920772, where a mechanical linkage transmission connects the operating member to both rolls.
Alternatively, the use of two hydraulic actuators respectively acting on the two rolls
and connected to each other by means of a compensation circuit allows to obtain the
same operating accuracy and the same constructional simplicity.
[0016] Using a hydraulic control circuit further allows to obtain a stabilization of the
system by damping the stresses between rolls and rolled product operated by the hydraulic
fluid. Furthermore, the hydraulic circuit being closed and pressurized allows to have
very small size with respect to the typical hydraulic circuits which include a hydraulic
unit.
[0017] In the hydraulic circuit, using a reversible pump controlled by an electric motor,
controlled in turn by a control unit connected to the position and pressure sensors,
allows to implement a hydroelectric type control system in which the hydraulic part
is used to control the reciprocal approach or spacing apart of the rolls, while the
electric part allows to effectively obtain position and pressure feedback control.
This allows to advantageously integrate the features of the hydraulic systems, in
particular the possibility of exerting high pressures, with the features of the electric
systems, in particular control speed and reliability.
[0018] Using the reversible pump controlled by the electric motor allows to omit the servo
valve normally used in hydraulic circuits and to additionally decrease the amount
of fluid needed by the hydraulic circuit and the overall length thereof.
Brief description of the figures
[0019] Further features and advantages of the present invention will become more apparent
in the following detailed description of a preferred embodiment, provided by way of
non-exclusive, indicative non-limiting example, with reference to the accompanying
drawings, in which:
- figure 1 is a diagrammatic view of a pinch roll device for rolled metallurgical products
in accordance with the present invention,
- figure 2 is a front view of some of the components of the device in figure 1;
- figure 3 is a side view of the components in figure 2,
- figure 4 is a diagrammatic view of a constructional variant of the device in figure
1,
- figure 5 is a block diagram of a method for operating a pinch roll device for rolled
metallurgic products in accordance with the present invention.
Detailed description of the invention
[0020] With reference to accompanying figures 1-3, a pinch roll device for a round-section,
rolled metallurgic product is indicated by reference numeral 1 as a whole. In general,
a pinch roll device provided in accordance with the present invention may be appropriately
configured to hold any rolled metallurgic product, e.g. a flat-section rolled product.
[0021] Device 1 comprises a first pinch roll 2 and a second pinch roll 3 which is identical
to the first roll 3, between which a substantially circular passage gap 5 for a wire
rod 10 is defined. Gap 5 defines a crossing axis X, coaxial to gap 5, with which the
wire rod 10 is aligned in operation when passing passage gap 5.
[0022] The first and second rolls 2, 3 can rotate about a first rotation axis Y1 and a second
rotation axis Y2, respectively, to draw by friction the wire rod 10 through the passage
gap 5. The rotation axes Y1, Y2 are parallel to each other and equally spaced apart
from the crossing axis X, with respect to which they are arranged on the opposite
side. The shape and size of gap 5 comply with those of the wire rod 10, and gap 5
is delimited by two annular grooves 5a, 5b provided on the cylindrical peripheral
surface of the pinch rolls 2, 3, respectively. The first and second rolls 2, 3 are
restrained to a first lever arm 7 and second lever arm 8, respectively, so as to rotate
about respective rotation axes Y1, Y2. The rotation of the pinch rolls 2, 3 about
the respective axes Y1, Y2, integral with the first and second arms 7, 8, respectively,
is obtained by means of a conventional and known actuator comprising a drive motor
(not shown) connected to the rolls by means of a transmission comprising a pair of
driven toothed wheels 2a, 3a, coaxial with axes Y1, Y2, and a pair of drive toothed
wheels 2b, 3b, meshing with each other so as to be counter-rotating. The driven toothed
wheels 2a, 3a mesh with the toothed drive wheels 2b, 3b, respectively, from which
they receive motion. The rotation motion is transmitted by the drive motor to the
toothed drive wheel 3b, by means of a motion output shaft 3c. The motion is transmitted
from the drive toothed wheel 3b to the other drive toothed wheel 2b and to the driven
toothed wheel 3a. The motion is transmitted from the drive toothed wheel 2b to the
other driven toothed wheel 2a. Due to the described coupling, the driven toothed wheels
2a, 3a, and therefore the respective rolls 2, 3, are counter-rotating.
[0023] The first and second arms 7, 8 are equal to each other and rotationally supported
with respect to a fixed reference system integral with the crossing axis X by means
of a pair of respective hinges which define a third rotation axis Z1 and a fourth
rotation axis Z2, respectively, which are parallel to each other and equally spaced
apart from crossing axis X, respect to which they are arranged on opposite side. The
first and second arms 7, 8 can rotate about Z1 and Z2, respectively, to reciprocally
either approach or space apart the first and second rolls 2, 3, so as to reduce or
increase the width of the passage gap 5, respectively. The third and fourth rotation
axes Z1, Z2 are spaced apart along the respective arm 7, 8, from the first and the
second rotation axes Y1, Y2, respectively, and parallel thereto. In practice, the
four axes Y1, Y2, Z1 and Z2 form a parallel axis system in all operating conditions
of device 1.
[0024] In order to control the rotation of the lever arms 7, 8 and therefore to reciprocally
approach or space apart the first and the second rolls 2, 3, device 1 comprises a
hydraulic circuit 20 in which a hydraulic fluid, e.g. oil, circulates and a mechanical
gear transmission 11, by means of which the first and second rolls 2, 3 are interconnected.
[0025] The hydraulic circuit 20 is closed and pressurized, therefore no hydraulic control
unit is required, and comprises a hydraulic actuator 21 connected to the first roll
2 to approach it to or space it apart from the second roll 3. The actuator 21 comprises
a stem 31 hinged at a free end 31 a thereof to the first lever arm 7, close to the
first roll 2. The translation of stem 31 determines a corresponding rotation of the
lever arm 7 about the third rotation axis Z1. The same rotation is transmitted to
the second arm 8 by means of transmission 11.
[0026] The transmission 11, which thus allows the hydraulic actuator 21 to be connected
to the second roll 3, by means of the first roll 2, comprises the lever arms 7, 8
and a gear 12 between the first lever arm 7 and the second lever arm 8. Gear 12 comprises
a first toothed sector 12a and a second toothed sector 12b integral with the first
and second arms 7, 8, respectively, and meshing with each other so that each rotation
imparted by the actuator 21 to the first arm 7 is transmitted to the second arm 8.
[0027] The first and second toothed sectors 12a,b are provided at the end of a third arm
32 and of a fourth arm 33, respectively, being integral with the first and second
arms 7, 8, aligned with each other and orthogonal to crossing axis X. The arms 32,
33 are arranged on opposite sides with respect to the crossing axis X so that the
first and second toothed sectors 12a, b mesh with each other at the same crossing
axis X. The transmission ratio of the gear 12 is unitary so that each rotation of
the first arm 7 corresponds to an equal, opposite rotation of the second arm 8. Gear
12 allows to obtain a synchronous, coordinated movement of the first and second lever
arms 7, 8 and of the rolls 2, 3 restrained thereto. Therefore, the assembly consisting
of the first arm 7 and the first roll 2 restrained thereto is equal and symmetric,
with respect to axis X, to the assembly of the second arm 8 and the second roll 3
restrained thereto in all operating conditions.
[0028] According to another constructional variant of the invention (not shown), the first
and second rolls 2, 3 are interconnected to each other by means of another type of
mechanical connection, free from gears, comprising a plurality of linkages for example.
[0029] The hydraulic actuator 21 is of the double-effect type, comprising a first chamber
21 a and a second chamber 21 b, with a piston 22 connected to stem 31 and to a secondary
stem 31 b sliding therebetween and being also opposed to stem 31 and having an equal
diameter. In order to control the movement of piston 22, the hydraulic circuit 20
comprises a reversible pump 9, connected to the first and second chambers 21 a, b
of the actuator by means of a first branch 20a and a second branch 20b of the hydraulic
circuit 20, respectively. The rotation of the reversible pump 9 in one direction or
in the other allows to send oil directly to either one or the other of the chambers
21a, b of actuator 21, respectively, thus determining the movement of piston 22 and
stem 31 in either one direction or in the opposite direction.
[0030] Pump 9 which controls the movement of piston 22 is operated by an electric motor
9a; the position of piston 22 inside the cylinder thus depends on the angular position
of the motor 9a of pump 9, while the movement speed of the cylinder depends on the
angular speed of pump 9.
[0031] As the hydraulic circuit 20 is closed and pressurized, i.e. free from hydraulic control
unit, the same amount of fluid always circulates therein. The motor 9a of pump 9 determines
each fluid movement in the hydraulic circuit 20: therefore, if motor 9a does not operate
the pump 9, the fluid flow in each point of the hydraulic circuit 20 is substantially
zero and the piston 22 does not move.
[0032] A connection branch is provided between the first branch 20a and the second branch
20b of the hydraulic circuit 20, being equipped with a maximum pressure valve 29 calibrated
so as to protect the hydraulic circuit from pressure overloads resulting from excessive,
even pulsing loads applied to the first roll 2 and transmitted to the actuator 2 through
stem 31. The first and second branches 20a, b are connected upstream of the reversible
pump 9 to a top-up source 27, which allows to top-up any leakage of fluid from the
hydraulic circuit 20. A first check valve 28a and a second check valve 28b, oriented
so as to prevent the flow from the pump 9 to the top-up source 27 and to allow the
flow in the opposite direction, are provided between the top-up source 27 and the
reversible pump 9 on the first and second branches 20a, b, respectively.
[0033] The amount of fluid needed for the operation of the hydraulic circuit 20, given by
the sum of the circulating fluid and the fluid present in the top-up source 27, may
advantageously range from 0.5 to 2 liters, preferably from 0.7 to 1.4 liters. As the
hydraulic circuit 20 is closed, it is also possible to contain its size: the overall
length of the hydraulic line in which the fluid circulates is advantageously from
0.5 to 1.5 meters, preferably from 0.7 to 1 meter.
[0034] The reversible pump 9 and thus the actuator 21 are actuated in a controlled manner.
A feedback control circuit 30 is included, comprising the electric motor 9a connected
to pump 9 by means of a connector 9b. The control circuit 30 further comprises a pressure
sensor 25, located in the first branch 20a of the hydraulic circuit 20, between the
actuator 21 and the maximum pressure valve 29, and a position sensor 24 in the actuator
21. The pressure sensor 25 allows to measure the pressure in the circuit, and in particular
in the chamber 21a, and thus to determine the force F1 transmitted by the actuator
21 to the first roll 2 through the stem 31. Force F1 is transmitted from the first
roll to the wire rod 10. In order to achieve the device balance, obtained through
the connection between the arms 7, 8 by means of transmission 11, an equal opposite
force F2 transmitted from the second roll 3 to the wire rod 10 corresponds to force
F1. The rolling force and pressure can be controlled by controlling the pressure in
the hydraulic circuit 20. The position sensor 24 allows to measure the movement of
piston 22, and thus to determine the movement of the first roll 2. The position of
the first roll 2 can be controlled by controlling the position of piston 22, therefore
by means of the transmission 11, the position of the second roll 3 can also be controlled,
thus adjusting the width of the passage gap 5. The control circuit 30 further comprises
a control unit 26 by means of which the electric motor 9a is controlled. The control
unit 26 is connected to the position sensor 24 and to the pressure sensor 25, so to
obtain a feedback control. The control unit 26 receives pressure and position data
measured by the sensors 25, 24 and processes them to determine the force F1 and width
values of the passage gap 5. The control unit 26 then compares these values to respective
reference values and therefore controls the electric motor 9a to either modify or
keep the force F1 and the width of the passage gap 5, according to an operation method
100, the significant steps of which are described below.
[0035] With reference to figure 4, a constructional variant of a pinch roll device for a
wire rod, indicated by reference numeral 40 as a whole, differs from device 1 in that
it comprises a different hydraulic circuit 41, as described in greater detail below.
Other components of device 40 are not described in detail because they are identical
to the above-described respective components of device 1. The hydraulic circuit 41
differs from the hydraulic circuit 20 of device 1 in that it comprises a pair of single-effect,
hydraulic actuators 42, 43 connected to the first roll 2 and to the second roll 3,
respectively, instead of the double-effect, hydraulic actuator 21. Each of the hydraulic
actuators 42, 43 comprises a piston 22 sliding between a respective upper first chamber
42a, 43a and a respective lower chamber 42b, 43b. The upper chambers 42a, 43a of the
hydraulic actuators 42, 43 are connected to the first and second branches 20a, b of
the hydraulic circuit 41, respectively. The lower chambers 42b, 43b of the hydraulic
actuators 42, 43 are connected to each other by means of a hydraulic connection consisting
of a compensation circuit 44, by means of which the first and second rolls 2, 3 are
interconnected so that when the first roll 2 is moved from and to said second roll
3, the latter is simultaneously moved from and to the first roll 2. As in the variant
in figure 3, in the variant in figure 4, the first roll 2 and the second roll 3 are
also either symmetrically spaced apart or approached with respect to the crossing
axis X. When the reversible pump 9 sends oil directly to the upper chamber 42a of
actuator 42 by means of the first branch 20a, the respective piston 22 moves towards
the lower chamber 42b, while simultaneously pushing the oil through the compensation
circuit 44, into the lower chamber 43b of actuator 43, the respective piston 22 of
which moves towards the respective upper chamber 43a. Alternatively, when the reversible
pump 9 sends oil directly to the upper chamber 43a of actuator 43 by means of the
second branch 20b, the respective piston 22 moves towards the lower chamber 43b, while
simultaneously pushing the oil through the compensation circuit 44, into the lower
chamber 42b of actuator 42, in which the respective piston 22 moves towards the respective
upper chamber 42a.
[0036] According to a further constructional variant of the invention (not shown), a pinch
roll device according to the present invention comprises a hydraulic circuit similar
to circuit 41 but not including the transmission 11.
[0037] With reference to the diagram in figure 5, the operation method 100 of device 1,
which may be implemented in the control unit 26, comprises an initial step 50 in which
the method checks whether the rolls 2, 3 are stationary with respect to the respective
rotation axes Y1, Y2, or are rotating. If the rolls 2, 3 are stationary, the method
100 ends going to a next stopping step 51. If the rolls 2, 3 are rotating by means
of the pair of toothed wheels 2a, 3a, the method 100 continues with a next step 52
in which it checks whether the control motor 9a of pump 9 is off or running. If the
motor 9a is off, the method 100 ends and goes to the stopping step 51. If the motor
9a is running, the method 100 continues with a next step of setting the reference
values 53, in which the type and features of the product being machined, e.g. the
wire rod 10, are identified and a first reference value 61 of the position of piston
22 and a second reference value 71 of the pressure in the circuit 20 are set as a
function of the identified product.
[0038] The method 100 continues with a next step 54 of checking the presence or absence
of the metallurgic product to be machined, e.g. the wire rod 10, in the passage gap
5 between the rolls 2, 3. In order to carry out the checking step 54, the control
unit 26 receives an external datum which identifies the presence or absence of the
metallurgic product to be machined, obtained by means of one or more sensors (not
shown), e.g. photocells, arranged upstream of the passage gap 5 and connected to the
control unit 26.
[0039] When the absence of the metallurgic product to be machined in the passage gap 5 is
identified during the checking step 54, the method 100 continues with a step 110 of
checking the position of piston 22 and thus of the first roll 2. Alternatively, when
the presence of metallurgic product to be machined is identified in the passage gap
5 in the checking step 54, the method 100 continues with a pressure checking step
120, in which the pressure within actuator 21 is checked.
[0040] At the end of either the position checking step 110 and the pressure checking step
120, the method 100 includes the step 80 of checking the end of machining, in which
it checks, by means of a signal supplied by the control unit 26, e.g. by means of
a switch or other type of control actuatable by an operator, whether the machining
process is underway or has ended. If the rolling process has ended, the method 100
ends with a final step 81 in which the first and second rolls 2, 3 are taken to the
maximum reciprocal distance. Alternatively, if the rolling process has not ended,
the method 100 continues by repeating step 53 of setting the reference values.
[0041] If the position checking step 110 comprises a first sub-step 60 of determining, by
means of the measurement supplied by the position sensor 24, a measured value of the
current position of piston 22, which can be associated with the position of the first
roll 2 due to the connection by means of stem 31. A second position comparing sub-step
62 follows the first sub-step in order to compare the measured value of the position
identified by the first sub-step 60 with the reference position value 61. The comparison
is carried out by subtracting the measured value from the reference value. The position
checking step 110 continues with a third checking sub-step 64, in which the method
checks whether the subtraction carried out during the second sub-step 62 has a zero
result or a result different from zero. If the result is zero, the position checking
step 110 ends and the method 100 continues with the machining-end checking step 80,
while if the result if other than zero, the position checking step 110 continues with
a fourth sub-step 63, in which a movement is imposed by means of the motor 9a and
the reversible pump 9 on the piston 22 to reach the position corresponding to the
reference value 61. The movement imposed on the piston 22 is proportional to the difference
between the measured position value and the reference position value 61. At the end
of the fourth sub-step 63, the position checking step 110 ends and the method 100
continues with the machining-end checking step 80.
[0042] The pressure checking step 120 comprises a fifth fast approaching sub-step 59, in
which the rolls 2, 3 are approached to the metallurgic product to be machined, which
is followed by a sixth sub-step 70 of determining a measured value of the pressure
in the first branch 20a of the hydraulic circuit 20, upstream of the reversible pump
9, by means of the measurement supplied by the pressure sensor 25, which pressure
value can be associated with the pressure of the first chamber 21a of actuator 21
due to the proximity of the pressure sensor 25 to the actuator 21. A seventh pressure
comparing sub-step 72 follows the sixth sub-step to compare the measured pressure
value identified in the sixth sub-step 70 with the reference position value 71. The
comparison is carried out by subtracting the measured value from the reference value.
The pressure checking step 120 continues with a eighth checking sub-step 75, in which
the method checks whether the result of the subtraction carried out in the seventh
sub-step 72 is zero or different from zero, If the result is zero, the pressure checking
step 120 proceeds with a ninth sub-step 74 of refreshing the reference position, in
which the first reference value 61 of the position of piston 22 is updated to the
current value. At the end of the ninth sub-step 74, the pressure checking step 120
is carried out, and the method 100 continues with the machining-end checking step
80. If the result of the subtraction calculated in the eighth checking sub-step 75
is not zero, but other than zero, the pressure checking step 120 proceeds with a tenth
sub-step 73, in which a movement is imposed by means of the motor 9a and the reversible
pump 9 on the piston 22 to reach the pressure corresponding to the reference value
71. The movement imposed on the piston 22 is proportional to the difference between
the measured pressure value and the reference pressure value 71. At the end of the
tenth sub-step 73, the pressure checking step 120 ends and the method 100 continues
with the machining-end checking step 80.
[0043] The above-described method, in which the force checking step 110 and the position
checking step 120 are carried out alternatively to each other, may be carried out
very rapidly, at a frequency typically of the order of 3000 Hz. This results in the
possibility of reaching feeding speeds along the crossing axis X for the products
to be machined of the order of 150 m/s.
[0044] The above-described method 100 may be also used in pinch roll devices other than
device 1, provided that they comprise:
- a first pinch roll and a second pinch roll, a passage gap for a rolled metallurgic
product being defined therebetween, which are rotatable about a first rotation axis
Y1 and second rotation axis Y2, respectively, to draw by friction said metallurgic
product through the passage gap,
- a hydraulic actuator connected to the rolls to approach them or space them apart in
a controlled manner, so as to reduce or increase the width of the passage gap, respectively,
- a reversible pump connected to the hydraulic actuator to slidingly move the piston
connected to the first and/or second pinch roll.
[0045] The described technical solutions allow to fully solve the set task and objects with
reference to the mentioned prior art, thus obtaining a plurality of further advantages,
including:
- using a high-efficiency, closed hydraulic circuit in which only a minimum amount of
fluid is moved, i.e. only that needed for moving the piston of the hydraulic actuator.
This allows to obtain a hydraulic circuit characterized by high reactivity. This is
further encouraged by the use of a hydraulic pump controlled by an electric motor
which allows to reach operating speeds (up to 200 - 300 Hz), which are significantly
higher than those which can be achieved by means of servo valves;
- obtaining a device which is not affected by the inevitable wear of the pinch rolls,
which may be compensated by the rotation of the lever arms which support the rolls;
- providing a self-damping system, in which the damping function is performed by the
fluid in the hydraulic control circuit and which thus does not require the insertion
of additional damping elements;
- using a hydraulic system free from servo valves thus allowing to significantly reduce
running and maintenance costs.
1. A pinch roll device (1, 40) for rolled metallurgic products, comprising:
- a first pinch roll (2) and a second pinch roll (3), between which a passage gap
(5) for a rolled metallurgic product (10) is defined, said first and second rolls
(2, 3) being rotatable about first and second rotation axes (Y1, Y2), respectively,
to draw by friction said metallurgic product (10) through said gap (5),
- a hydraulic circuit (20, 41) acting on said first and second rolls (2, 3) to reciprocally
either approach or space apart said first and second rolls (2, 3) so as to either
reduce or increase the width of said passage gap (5), respectively, said hydraulic
circuit (20) comprising at least one hydraulic actuator (21, 42, 43) connected to
said first roll (2) and/or to said second roll (3) to either reciprocally approach
or space apart said first and second rolls (2, 3),
- a pressure sensor (25) in said hydraulic circuit (20, 41) to determine the force
transmitted by said actuator (21, 42) to said first roll (2) and/or to said second
roll (3),
- a position sensor (24) in said actuator (21, 42) to determine the movement of said
first roll (2) and/or of said second roll (3),
characterized in that said hydraulic circuit (20, 41) is a based and pressurized circuit and in that it further comprises:
- a reversible pump (9) in said hydraulic circuit (20, 41), said pump (9) being connected
to a first chamber (21 a, 42a) and a second chamber (21 b, 43a) of said at least one
hydraulic actuator (21, 42, 43) to slidingly move a piston (22) of said at least one
hydraulic actuator (21, 42, 43), said piston being connected to said first roll (2)
and/or to said second roll (3), the rotation of said reversible pump (9) in one direction
or in the other allowing to send a fluid directly to either one or the other of said
first and second chambers (21 a, 42a; 21 b, 43a), respectively and wherein said reversible
pump (9) is operated by an electric motor (9a) which determines each fluid movement
in said hydraulic circuit.
2. A pinch roll device (1) according to claim 1, wherein said first and second rolls
(2, 3) are reciprocally interconnected by means of a mechanical and/or hydraulic connection
(11, 44).
3. A pinch roll device (1) according to claim 2, wherein said hydraulic circuit (20,
41) comprises a hydraulic actuator (21, 42) connected to said first roll (2) and said
connection (11, 44) comprises a geared transmission (11) between said first and second
rolls (2, 3) to connect said hydraulic actuator (21, 42) to said second roll (3),
by means of said first roll (2).
4. A pinch roll device (1) according to claim 2 or 3, wherein said hydraulic circuit
(41) comprises a pair of hydraulic actuators (42, 43) connected to said first and
second rolls (2, 3), respectively, to move said first roll (2) from and to said second
roll (3) while moving said second roll (3) from and to said first roll (2), said connection
(11, 44) comprising a compensation circuit (44) between said first and second rolls
(2, 3).
5. A pinch roll device (1) according to claim 3 or 4, wherein said transmission (11)
comprises first and second lever arm (7, 8), said first and second rolls (2, 3) being
respectively restrained thereto, so as to rotate about respective rotation axes (Y1,
Y2), said first and second arm (7, 8) being rotatable about a third rotation axis
and a fourth rotation axis (Z1, Z2), respectively, to reciprocally either approach
or space apart said first and second rolls (2, 3), said gear (12) comprising at least
a first toothed sector (12a) and a second toothed sector (12b), integral with said
first and second arms (7, 8), respectively, said first and second toothed sectors
(12a, 12b) being meshed with each other to transmit the rotation between said first
and second levers (7, 8).
6. A pinch roll device (1) according to claim 5, wherein said first, second, third and
fourth rotation axes (Y1, Y2, Z1, Z2) are parallel to one another.
7. A pinch roll device (1) according to claim 1, wherein said pump (9) is controlled
by an electric motor (9a) controlled means of a control unit (26) connected to said
position sensor (24) and to said pressure sensor (25), the position of said piston
(22) depending on the angular position of said motor (9a), the speed of said piston
(22) depending on the angular speed of said pump (9).
8. A method (100) of operating a pinch roll device (1) for rolled metallurgic products,
said device comprising:
- a first pinch roll (2) and a second pinch roll (3), between which a passage gap
(5) for a rolled metallurgic product (10) is defined, said first and second rolls
(2, 3) being rotatable about first and second rotation axes (Y1, Y2), respectively,
to draw by friction said metallurgic product (10) through said gap,
- a hydraulic closed and pressurized circuit (20, 41) comprising at least one hydraulic
actuator (21, 42, 43) connected to said first roll and second roll (2, 3) to reciprocally
either approach or space apart said rolls (2, 3) so as to either reduce or increase
the width of said passage gap (5), respectively,
- a reversible pump (9) connected to a first chamber (21a, 42a) and a second chamber
(21b, 43a) of said at least one hydraulic actuator (21, 42, 43) to slidingly move
a piston (22) of said at least one hydraulic actuator (21, 42, 43), said piston being
connected to said first roll (2) and/or to said second roll (3), and wherein said
reversible pump (9) is operated by an electric motor (9a) which determines each fluid
movement in said hydraulic circuit
said method (100) comprising:
- a step (54) of checking either the presence or absence of said metallurgic product
(10) in said passage gap (5),
- a step (110) of checking the position of said first roll (2), implemented when the
absence of said metallurgic product (10) in said passage gap (5) is identified in
said checking step (54),
- a step (120) of checking the pressure of said hydraulic actuator (21), implemented
when the presence of said metallurgic product (10) in said passage gap (5) is identified,
said pressure checking step (120) comprising a sub-step (74) of refreshing said position
reference value, said sub-step (74) of refreshing said position reference value is
operated when said measured pressure value is identified as equal to said pressure
reference value in said pressure comparing sub-step (72).
9. An operation method (100) according to claim 8, wherein said step (110) of checking
the position of said first roll (2) comprises a position comparing sub-step (62) to
compare a measured position value, which may be associated with the position of said
first roll (2), with a reference position value.
10. An operation method (100) according to claim 8 or 9, wherein said step (120) of checking
the pressure in said hydraulic actuator (21) comprises a pressure comparing sub-step
(72) to compare a measured pressure value, which may be associated with said hydraulic
actuator (21), with a reference pressure value.
1. Abziehrollenvorrichtung (1, 40) für gewalzte metallurgische Produkte, umfassend:
- eine erste Abziehrolle (2) und eine zweite Abziehrolle (3), zwischen denen ein Durchgangsspalt
(5) für ein gewalztes metallurgisches Produkt (10) definiert ist, wobei die erste
und zweite Rolle (2, 3) um eine erste bzw. zweite Rotationsachse (Y1, Y2) drehbar
sind, um durch Reibung das metallurgische Produkt (10) durch den Spalt (5) zu ziehen,
- einen Hydraulikkreislauf (20, 41), der auf die erste und zweite Rolle (2, 3) wirkt,
um die erste und zweite Rolle (2, 3) hin- und herbewegbar entweder anzunähern oder
zu beabstanden, um so die Breite des Durchgangsspalts (5) entweder zu reduzieren oder
zu erhöhen, wobei der Hydraulikkreislauf (20) zumindest einen Hydraulikaktor (21,
42, 43) umfasst, der mit der ersten Rolle (2) und/oder der zweiten Rolle (3) verbunden
ist, um die erste und zweite Rolle (2, 3) hin- und herbewegbar entweder anzunähern
oder zu beabstanden,
- einen Drucksensor (25) in dem Hydraulikkreislauf (20, 41), um die Kraft zu bestimmen,
die von dem Aktor (21, 42) auf die erste Rolle (2) und/oder die zweite Rolle (3) übertragen
wird,
- einen Positionssensor (24) in dem Aktor (21, 42), um die Bewegung der ersten Rolle
(2) und/oder der zweiten Rolle (3) zu bestimmen,
dadurch gekennzeichnet, dass
- der Hydraulikkreislauf (20, 41) ein geschlossener und druckbeaufschlagter Kreislauf
ist und dass er ferner umfasst:
- eine reversible Pumpe (9) in dem Hydraulikkreislauf (20, 41), wobei die Pumpe (9)
mit einer ersten Kammer (21 a, 42a) und einer zweiten Kammer (21 b, 43a) des zumindest
einen Hydraulikaktors (21, 42, 43) verbunden ist, um einen Kolben (22) des zumindest
einen Hydraulikaktors (21, 42, 43) gleitend zu bewegen, wobei der Kolben mit der ersten
Rolle (2) und/oder der zweiten Rolle (3) verbunden ist, wobei eine Rotation der reversiblen
Pumpe (9) in einer Richtung oder in der anderen zulässt, dass ein Fluid direkt zu
entweder einer oder der anderen der ersten und zweiten Kammern (21 a, 42a; 21 b, 43a)
geliefert wird, und wobei die reversible Pumpe (9) durch einen Elektromotor (9a) betrieben
wird, der jede Fluidbewegung in dem Hydraulikkreislauf bestimmt.
2. Abziehrollenvorrichtung (1) nach Anspruch 1, wobei die erste und zweite Rolle (2,
3) hin- und herbewegbar mittels einer mechanischen und/oder hydraulischen Verbindung
(11, 44) verbunden sind.
3. Abziehrollenvorrichtung (1) nach Anspruch 2, wobei der Hydraulikkreislauf (20, 41)
einen Hydraulikaktor (21, 42) umfasst, der mit der ersten Rolle (2) verbunden ist,
und die Verbindung (11, 44) ein Zahnradgetriebe (11) zwischen der ersten und zweiten
Rolle (2, 3) umfasst, um den Hydraulikaktor (21, 42) mit der zweiten Rolle (3) mittels
der ersten Rolle (2) zu verbinden.
4. Abziehrollenvorrichtung (1) nach einem der Ansprüche 2 oder 3, wobei der Hydraulikkreislauf
(41) ein Paar von Hydraulikaktoren (42, 43) umfasst, die mit der ersten bzw. zweiten
Rolle (2, 3) verbunden sind, um die erste Rolle (2) zu und von der zweiten Rolle (3)
zu bewegen, während die zweite Rolle (3) zu und von der ersten Rolle (2) bewegt wird,
wobei die Verbindung (11, 44) einen Kompensationskreislauf (44) zwischen der ersten
und zweiten Rolle (2, 3) umfasst.
5. Abziehrollenvorrichtung (1) nach einem der Ansprüche 3 oder 4, wobei das Getriebe
(11) einen ersten und zweiten Hebelarm (7, 8) umfasst, wobei die erste und zweite
Rolle (2, 3) jeweils daran beschränkt sind, um so um jeweilige Rotationsachsen (Y1,
Y2) zu drehen, wobei der erste und zweite Arm (7, 8) um eine dritte Rotationsachse
bzw. eine vierte Rotationsachse (Z1, Z2) drehbar sind, um die erste und zweite Rolle
(2, 3) hin- und herbewegbar entweder anzunähern oder zu beabstanden, wobei das Zahnrad
(12) zumindest einen ersten gezahnten Sektor (12a) und einen zweiten gezahnten Sektor
(12b) einteilig mit dem ersten bzw. zweiten Arm (7, 8) umfasst, wobei der erste und
zweite gezahnte Sektor (12a, 12b) miteinander kämmen, um die Drehung zwischen dem
ersten und zweiten Hebel (7, 8) zu übertragen.
6. Abziehrollenvorrichtung (1) nach Anspruch 5, wobei die erste, zweite, dritte und vierte
Rotationsachse (Y1, Y2, Z1, Z2) parallel zueinander sind.
7. Abziehrollenvorrichtung (1) nach Anspruch 1, wobei die Pumpe (9) von einem Elektromotor
(9a) gesteuert ist, der mittels einer Steuereinheit (26) gesteuert ist, die mit dem
Positionssensor (24) und dem Drucksensor (25) verbunden ist, wobei die Position des
Kolbens (22) von der Winkelposition des Motors (9a) abhängt und die Geschwindigkeit
des Kolbens (22) von der Winkelgeschwindigkeit der Pumpe (9) abhängt.
8. Verfahren (100) zum Betreiben einer Abziehrollenvorrichtung (1) für gewalzte metallurgische
Produkte, wobei die Vorrichtung umfasst:
- eine erste Abziehrolle (2) und eine zweite Abziehrolle (3), zwischen denen ein Durchgangsspalt
(5) für ein gewalztes metallurgisches Produkt (10) definiert ist, wobei die erste
und zweite Rolle (2, 3) um eine erste bzw. zweite Rotationsachse (Y1, Y2) drehbar
sind, um durch Reibung das metallurgische Produkt (10) durch den Spalt zu ziehen,
einen geschlossenen und druckbeaufschlagten Hydraulikreislauf (20, 41) der umfasst:
- zumindest einen Hydraulikaktor (21, 42, 43), der mit der ersten Rolle und der zweiten
Rolle (2, 3) verbunden ist, um die Rollen (2, 3) hin- und herbewegbar entweder anzunähern
oder zu beabstanden, um die Breite des Durchgangsspalts (5) jeweils entweder zu reduzieren
oder zu erhöhen,
- eine reversible Pumpe (9), die mit einer ersten Kammer (21 a, 42a) und einer zweiten
Kammer (21 b, 43a) des zumindest einen Hydraulikaktors (21, 42, 43) verbunden ist,
um einen Kolben (22) des zumindest einen Hydraulikaktors (21, 42, 43) gleitend zu
bewegen, wobei der Kolben mit der ersten Rolle (2) und/oder der zweiten Rolle (3)
verbunden ist und wobei die reversible Pumpe (9) von einem Elektromotor (9a) betrieben
ist, der jede Fluidbewegung in dem Hydraulikkreislauf bestimmt,
wobei das Verfahren (100) umfasst:
- einen Schritt (54) zum Prüfen entweder der Anwesenheit oder Abwesenheit des metallurgischen
Produkts (10) in dem Durchgangsspalt (5),
- einen Schritt (110) zum Prüfen der Position der ersten Rolle (2), der implementiert
ist, wenn die Abwesenheit des metallurgischen Produkts (10) in dem Durchgangsspalt
(5) bei Prüfschritt (54) identifiziert ist,
- einen Schritt (120) zum Prüfen des Drucks des Hydraulikaktors (21), der implementiert
ist, wenn die Anwesenheit des metallurgischen Produkts (10) in dem Durchgangsspalt
(5) identifiziert ist, wobei der Druckprüfschritt (120) einen Teilschritt (74) zum
Auffrischen des Positionsreferenzwertes umfasst, wobei der Teilschritt (74) zum Auffrischen
des Positionsreferenzwertes betrieben wird, wenn der gemessene Druckwert als gleich
dem Druckreferenzwert des Druck vergleichenden Teilschritts (72) identifiziert ist.
9. Betriebsverfahren (100) nach Anspruch 8, wobei der Schritt (110) zum Prüfen der Position
der ersten Rolle (2) einen positionsvergleichenden Teilschritt (62) umfasst, um einen
gemessenen Positionswert, der der Position der ersten Rolle (2) zugeordnet werden
kann, mit einem Referenzpositionswert zu vergleichen.
10. Betriebsverfahren (100) nach einem der Ansprüche 8 oder 9, wobei der Schritt (120)
zum Prüfen des Drucks in dem Hydraulikaktor (21) einen Druck vergleichenden Teilschritt
(72) umfasst, um einen gemessenen Druckwert, der dem Hydraulikaktor (21) zugeordnet
werden kann, mit einem Referenzdruckwert zu vergleichen.
1. Dispositif à rouleaux pinceurs (1, 40) pour produits métallurgiques roulés, comprenant
:
- un premier rouleau pinceur (2) et un second rouleau pinceur (3), entre lesquels
est définie une fente de passage (5) pour un produit métallurgique roulé (10), lesdits
premier et second rouleaux (2, 3) étant capables de tourner respectivement autour
de premier et second axes de rotation (Y1, Y2), pour tirer par friction ledit produit
métallurgique (10) à travers ladite fente (5),
- un circuit hydraulique (20, 41) agissant sur lesdits premier et second rouleaux
(2, 3) pour rapprocher ou bien éloigner réciproquement lesdits premier et second rouleaux
(2, 3) de sorte à réduire ou bien augmenter respectivement la largeur de ladite fente
de passage (5), ledit circuit hydraulique (20) comprenant au moins un actionneur hydraulique
(21, 42, 43) relié audit premier rouleau (2) et/ou audit second rouleau (3) pour rapprocher
ou bien éloigner réciproquement lesdits premier et second rouleaux (2, 3),
- un capteur de pression (25) dans ledit circuit hydraulique (20, 41) pour déterminer
la force transmise par ledit actionneur (21, 42) audit premier rouleau (2) et/ou audit
second rouleau (3),
- un capteur de position (24) dans ledit actionneur (21, 42) pour déterminer le mouvement
dudit premier rouleau (2) et/ou dudit second rouleau (3), caractérisé en ce que ledit circuit hydraulique (20, 41) est un circuit fermé et sous pression et en ce qu'il comprend en outre :
- une pompe réversible (9) dans ledit circuit hydraulique (20, 41), ladite pompe (9)
étant reliée à une première chambre (21a, 42a) et une seconde chambre (21b, 43a) dudit
au moins un actionneur hydraulique (21, 42, 43) pour déplacer de manière coulissante
un piston (22) dudit au moins un actionneur hydraulique (21, 42, 43), ledit piston
étant relié audit premier rouleau (2) et/ou audit second rouleau (3), la rotation
de ladite pompe réversible (9) dans une direction ou dans l'autre permettant d'envoyer
un fluide directement vers l'une ou l'autre desdites première et seconde chambres
(21a, 42a ; 21b, 43a), respectivement, et dans lequel ladite pompe réversible (9)
est actionnée par un moteur électrique (9a) qui détermine chaque mouvement de fluide
dans ledit circuit hydraulique.
2. Dispositif à rouleaux pinceurs (1) selon la revendication 1, dans lequel lesdits premier
et second rouleaux (2, 3) sont réciproquement interconnectés à l'aide d'un raccord
mécanique et/ou hydraulique (11, 44).
3. Dispositif à rouleaux pinceurs (1) selon la revendication 2, dans lequel ledit circuit
hydraulique (20, 41) comprend un actionneur hydraulique (21, 42) relié audit premier
rouleau (2) et ledit raccord (11, 44) comprend une transmission à engrenage (11) entre
lesdits premier et second rouleaux (2, 3) pour relier ledit actionneur hydraulique
(21, 42) audit second rouleau (3), au moyen dudit premier rouleau (2).
4. Dispositif à rouleaux pinceurs (1) selon la revendication 2 ou 3, dans lequel ledit
circuit hydraulique (41) comprend une paire d'actionneurs hydrauliques (42, 43) reliés
respectivement auxdits premier et second rouleaux (2, 3), pour déplacer ledit premier
rouleau (2) depuis et vers ledit second rouleau (3) tout en déplaçant ledit second
rouleau (3) depuis et vers ledit premier rouleau (2), ledit raccord (11, 44) comprenant
un circuit de compensation (44) entre lesdits premier et second rouleaux (2, 3).
5. Dispositif à rouleaux pinceurs (1) selon la revendication 3 ou 4, dans lequel ladite
transmission (11) comprend des premier et deuxième bras de levier (7, 8), lesdits
premier et second rouleaux (2, 3) étant respectivement limités à ceux-ci, de sorte
à tourner autour d'axes de rotation respectifs (Y1, Y2), lesdits premier et second
bras (7, 8) étant capables de tourner respectivement autour d'un troisième axe de
rotation et d'un quatrième axe de rotation (Z1, Z2), pour rapprocher ou bien éloigner
réciproquement lesdits premier et second rouleaux (2, 3), ledit engrenage (12) comprenant
au moins un premier secteur denté (12a) et un second secteur denté (12b), solidaires
respectivement desdits premier et second bras (7, 8), lesdits premier et second secteurs
dentés (12a, 12b) étant engrenés l'un avec l'autre pour transmettre la rotation entre
lesdits premier et second leviers (7, 8).
6. Dispositif à rouleaux pinceurs (1) selon la revendication 5, dans lequel lesdits premier,
deuxième, troisième et quatrième axes de rotation (Y1, Y2, Z1, Z2) sont parallèles
l'un à l'autre.
7. Dispositif à rouleaux pinceurs (1) selon la revendication 1, dans lequel ladite pompe
(9) est commandée par des moyens commandés par un moteur électrique (9a) d'une unité
de commande (26) connectée audit capteur de position (24) et audit capteur de pression
(25), la position dudit piston (22) dépendant de la position angulaire dudit moteur
(9a), la vitesse dudit piston (22) dépendant de la vitesse angulaire de ladite pompe
(9).
8. Procédé (100) de fonctionnement d'un dispositif à rouleaux pinceurs (1) pour produits
métallurgiques roulés, ledit dispositif comprenant :
- un premier rouleau pinceur (2) et un second rouleau pinceur (3), entre lesquels
est définie une fente de passage (5) pour un produit métallurgique roulé (10), lesdits
premier et second rouleaux (2, 3) étant capables de tourner respectivement autour
des premier et second axes de rotation (Y1, Y2), pour tirer par friction ledit produit
métallurgique (10) à travers ladite fente,
- un circuit hydraulique fermé et sous pression (20, 41) comprenant au moins un actionneur
hydraulique (21, 42, 43) relié audit premier rouleau et second rouleau (2, 3) pour
rapprocher ou bien éloigner réciproquement lesdits rouleaux (2, 3) de sorte à réduire
ou bien augmenter respectivement la largeur de ladite fente de passage (5),
- une pompe réversible (9) reliée à une première chambre (21a, 42a) et une seconde
chambre (21b, 43a) dudit au moins un actionneur hydraulique (21, 42, 43) pour déplacer
de manière coulissante un piston (22) dudit au moins un actionneur hydraulique (21,
42, 43), ledit piston étant relié audit premier rouleau (2) et/ou audit second rouleau
(3), et dans lequel ladite pompe réversible (9) est commandée par un moteur électrique
(9a) qui détermine chaque mouvement de fluide dans ledit circuit hydraulique
ledit procédé (100) comprenant :
- une étape (54) de vérification de la présence ou bien de l'absence dudit produit
métallurgique (10) dans ladite fente de passage (5),
- une étape (110) de vérification de la position dudit premier rouleau (2), mise en
oeuvre lorsque l'absence dudit produit métallurgique (10) dans ladite fente de passage
(5) est identifiée dans ladite étape de vérification (54),
- une étape (120) de vérification de la pression dudit actionneur hydraulique (21),
mise en oeuvre lorsque la présence dudit produit métallurgique (10) dans ladite fente
de passage (5) est identifiée, ladite étape de vérification de la pression (120) comprenant
une sous-étape (74) de rafraîchissement de ladite valeur de référence de position,
ladite sous-étape (74) de rafraîchissement de ladite valeur de référence de position
est mise en oeuvre lorsque ladite valeur de pression mesurée est identifiée comme
égale à ladite valeur de référence de pression dans ladite sous-étape de comparaison
de pression (72).
9. Procédé de fonctionnement (100) selon la revendication 8, dans lequel ladite étape
(110) de vérification de la position dudit premier rouleau (2) comprend une sous-étape
de comparaison de position (62) pour comparer une valeur de position mesurée, qui
peut être associée à la position dudit premier rouleau (2), à une valeur de position
de référence.
10. Procédé de fonctionnement (100) selon la revendication 8 ou 9, dans lequel ladite
étape (120) de vérification de la pression dans ledit actionneur hydraulique (21)
comprend une sous-étape de comparaison de pression (72) pour comparer une valeur de
pression mesurée, qui peut être associée audit actionneur hydraulique (21), à une
valeur de pression de référence.