WO2024252314A1

WO2024252314A1 - Group for driving a rolling mill for treating objects as well as a machine comprising such group

Info

Publication number: WO2024252314A1
Application number: PCT/IB2024/055529
Authority: WO
Inventors: Stefano Filippi
Original assignee: Muraro Srl
Current assignee: Muraro Srl
Priority date: 2023-06-06
Filing date: 2024-06-06
Publication date: 2024-12-12
Anticipated expiration: 2025-12-06
Also published as: IT202300011511A1

Abstract

The present invention relates to a group for driving a tool holder group or a component for shaping of a machine for treating objects, such as a rolling mill.

Description

“GROUP FOR DRIVING A ROLLING MILL FOR TREATING OBIECTS AS WELL AS A MACHINE COMPRISING SUCH GROUP”

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a drive unit for a machine for the treatment of objects, such as a rolling mill, as well as a machine for the treatment of objects, such as a rolling mill equipped with such a group, where rolling mill is to be understood naturally as an industrial machine for the hot or cold rolling and/or shaping of malleable materials, in particular metals.

DESCRIPTION OF THE STATE OF THE ART

In the rolling mill sector, solutions are known with a first variable flow rate pump to feed the work cylinder.

As regards the fast approach and return steps, these are typically achieved with the aid of a second motor pump group that acts on a second proportional valve of large dimensions and capable of ensuring inaccurate force and position regulation. Alternatively, applications are known where closed-circuit variable flow servo pumps are used where in the approach steps the rotation speed of the servomotor and the pump displacement are advantageously modulated in order to have high flow rates, and then the rotation speed of the servomotor and the pump displacement are reduced in the working step in order to have lower flow rates and lower torque to the servomotor.

US2017108014A1, US2016084280A1, JPH0639285U, EP0311779B1 and US6003429A teach respective prior solutions.

OBJECTS OF THE INVENTION

One object of the present invention is to provide a new drive group for a tool holder group or a shaping component of a machine for the treatment of objects, such as a new rolling mill.

Another object of the present invention is that of providing a group as indicated above that is capable of moving a rolling and/or shaping component moved by a hydraulic linear axis of a machine in a slow and accurate manner during working steps and in a rapid manner during return steps to the rest position.

Another object of the present invention is to provide a new machine for the treatment of objects, such as a rolling mill.

According to one aspect of the invention, a group according to claim 1 is provided.

According to another aspect of the invention, a machine according to claim 14 is provided.

According to another aspect of the invention, a method for moving or actuating a tool holder group or a shaping component of a machine according to claim 15 is provided.

The dependent claims refer to preferred and advantageous embodiments of the invention.

BRIEF DESCRIPTION OF THE FIGURES

Further advantages, objectives and characteristics as well as embodiments of the present invention are defined in the claims and will be clarified below by means of the following description, in which reference is made to the attached drawing tables; in the drawings, corresponding or equivalent characteristics and/or component parts of the present invention are identified by the same reference numbers.

In particular, in the figures:

- figures 1 and 2 represent a drive group of a rolling mill not according to the present invention;

- figures 3 to 10 represent respective embodiments of drive units of a rolling mill according to the present invention with schematic cross-sectional indication of the free or active sections of the cylinders.

DESCRIPTION OF FIGURES OF SOLUTIONS NOT ACCORDING TO THE PRESENT INVENTION

With reference first to figure 1, a “classic” group or system has been illustrated (better known to the art) in which in the actual working step of controlling the cylinder 61 (in which normally the area Al 1 is 2 times the area A12) the pump 31a supplies the proportional valve 51a, while the valve 51b is closed. The pump 31a, generally of the variable flow type, can supply various uses such as the one indicated, while the motor 21a is generally an asynchronous one controlled directly from the network or via an electronic power supply 41a.

In these systems, the fast approach and return steps of a rolling and/or shaping component are generally supported by a second motor pump group 21b- 31b that acts on a second high-flow proportional valve 5b that is not used in the working steps, since, having dimensions larger than the valve 5a, it is typically less accurate in the force and position adjustments. Generally, in addition to the motor pump 21b-3 lb, accumulators 81b are provided.

With regard to this aspect, considering that the flow rate required in the rapid return steps can be up to ten times that in the working steps, the part of the circuit with index “b” is particularly bulky and expensive, as well as dissipative from an energy point of view.

A variant of this group is illustrated in figure 2, where the cylinder can be of the identical area type and the quick and rapid return control is achieved by the hydrostatic servo pump 22-32-42, where the power supply 42 is a variable speed motor driver, the servomotor 22 is typically a brushless motor and the pump 32 is a variable flow rate closed circuit pump.

During the low force quick return steps, the maximum revolutions of the motor 22 and the maximum displacement of the pump 32 are used to generate the maximum flow rate, while in the working steps the displacement of the pump 32 is reduced to a minimum and the driver 42 controls the servomotor 22 to control the position and force of the cylinder 62 (where normally the area A12 is equal to the area A22).

EMBODIMENTS OF THE INVENTION

The present invention (see figures 3 to 9) concerns a drive unit 1 for a toolholder group or a shaping component of a machine for the treatment of objects, such as a rolling mill. In the present invention, the expression “free section” or “active section” of a chamber or a semi-chamber of a cylinder is to be understood as the section cross- or orthogonal to the axis of movement of a respective rod, which must be filled or deprived of fluid from time to time to move the rod in such chamber or semichamber.

Therefore, the free or active section (preferably annular) is defined between such rod and the internal walls of such chamber or semi-chamber, if the rod passes through the entire chamber/semi-chamber and thus the rod affects the entire extension of the chamber or semi-chamber in the direction of the axis of movement of the rod, whereas if the stem does not pass through the entire chamber/semi-chamber and thus the rod does not cover the entire extension of the chamber or semi-chamber in the direction of the axis of movement of the rod, then the free section or active section is to be understood as the section cross or orthogonal (preferably circular) to the axis of movement of said respective rod, called in this case plunging, defined by said chamber or semi-chamber (see chamber 11 of figure 4 as well as semichambers 1 lb and 9c of figures 6 and 9).

Group 1 includes at least one hydraulic or oleodynamic linear axis or at least one hydraulic or oleodynamic cylinder and piston unit 2, a circuit 3 for conveying fluid (for example water, oil, an emulsion or other liquid) to/from unit 2, valves 4a- 4e for opening and closing the ducts of circuit 3.

At least one pump or motor pump unit 5a-5c is then provided, with fixed or variable flow rate, designed to move the fluid in the circuit and in/from the cylinder and piston unit 2.

The motor pump unit comprises a pump 5a, for example with 1, 2 or 4 or more quadrants, with fixed or variable displacement, connected to a motor or servomotor 5b, optionally controlled by a driver or electronic power supply system 5c, for example capable of modulating the current and thus the torque of the motor itself.

Clearly, the electric motor 5b can be connected directly to the electrical network or via an electronic power supply 5c.

Furthermore, the cylinder and piston unit 2 can be operated by its own motor pump unit 5a-5c, but it is also possible to adopt a single pressure/flow rate source for multiple units 2 for moving a component of a machine for treating objects.

Group 1 then comprises at least one electronic control unit 6 (schematically shown in figures 3 and 4) of the at least one pump 5a and one or more of the valves 4a-4d.

As regards the cylinder and piston unit 2, it comprises at least two cylinders 8, 9 each delimiting a chamber 10, 11, the chamber 10 delimited by one of the cylinders 8 having advantageously a larger diameter than the chamber 11 delimited by the other or another 9 of the cylinders. Advantageously, but not limited to, the ratios between the chambers 10, 11 are greater than 1, for example in a ratio between 1 : 1 and 1 :10, for example between 1 :4 or 1 :7 or between 1 :5 and 1 :6.

Advantageously, the cylinders 8, 9 are also arranged or fixed or connected to each other so as to have a common end defining a communication opening CO between the chambers 10, 11 defined by the cylinders 8, 9 or facing ends each defining an opening aligned with the opening in the other cylinder. Clearly, the communication opening CO is provided for the passage of a respective rod and not of the fluid between one chamber or semi-chamber 10a and another 11. In this regard, gaskets are provided to prevent such passage.

In essence, the two cylinders 8, 9 are arranged substantially in series and, preferably, have a common end or are mounted one directly on one end of the other with their respective side walls coaxial.

Clearly, the cylinders 8, 9 comprise a body substantially with one or two bases 8a, 8b, 9a, 9b, preferably substantially circular and a lateral wall, preferably cylindrical 8c, 9c, so that they have the respective coaxial lateral walls 8c, 9c and, if desired, a common base 8b, 9b or in any case two respective bases 8b, 9b one close to or abutting the other.

At least one piston 12, 13, if desired disc-shaped, is then provided in the unit 1 mounted slidably in a sealed manner in the chamber 10, 11 of a respective cylinder 8, 9 so as to divide it into two half-chambers 10a, 10b, I la, 11b. Clearly, special gaskets or expedients are provided to allow the piston 12, 13 to slide so as to sealingly laterally or annularly engage the internal surface, preferably the lateral one, of the respective cylinder 8, 9.

The unit 2 is then provided with at least two rods 14, 15, 16 mounted within the chambers 10, 11 and/or the semi-chambers 10a, 10b, I la, 11b of the cylinders 8, 9. In this regard, advantageously there is a first rod 14 protruding from a first side or face of the at least one piston 12, which first rod 14 is mounted in a sealed sliding manner in the communication opening CO or in the aligned openings of the cylinders 8, 9, in a chamber or semi-chamber 10b of a first cylinder 8 and in a chamber 11 or semi-chamber 1 lb of another or second cylinder 9 as well as at least one second or further rod 15, 16 protruding from a second side or face of the piston 12, 13 in a chamber 10, 11 or semi-chamber 10a, I la of the first 8 or second 9 cylinder far from the other between the second 9 and the first 8 cylinder.

Alternatively or in addition to the characteristic according to which the cylinders 8, 9 are one 8 with a diameter greater than the other 9, it is possible that one or more 15 of the at least two rods has a diameter greater than another or other 14 of the rods.

Thanks to the fact that a cylinder 8 has a diameter greater than the other 9 and/or a rod 15 has a diameter greater than the other 14, it is obtained that the free or active section of the chamber 10 or of the half-chambers 10a, 10b delimited by one 8 of the two cylinders is greater than the free or active section of the chamber 11 or of the half-chambers I la, 11b delimited by another 9 of the two cylinders. In this regard, as will also be reiterated, by free or active section of a chamber or semichamber it is to be meant the section of the latter orthogonal to the axis of movement of a respective rod, which from time to time must be filled or deprived of fluid to move the rod 14, 15 in such chamber 10, 11 or semi-chamber or semi-chambers 10a, 10b, I la, 11b.

Advantageously, the free or active section of the chamber 10 or of the halfchambers 10a, 10b delimited by one 8 of the cylinders is greater than the free or active section of the chamber 11 or of the half-chambers I la, 11b delimited by another 9 of the cylinders in a ratio between 1 :2 and 1 : 10, for example between 1 :4 or 1:7 or between 1 :5 and 1 :6.

With reference to this aspect, if the chamber 10, 11 defined by a cylinder is divided into two half-chambers 10a, 10b, I la, 11b, then the half-chambers of the same cylinder can have the same or even different free or active section, but preferably substantially equal or in any case in a ratio between 1 : 1 and 1 :3 or better between 1 : 1 and 1 :2.

Preferably, circuit 3 is open, that is, it has respective ducts 3c, 3e open (optionally with interception of a pump 5a or other component of the group) towards a tank or container or drain 17 of group 1 (see figures 3 to 6).

Clearly, according to a less preferred variant, circuit 3 is closed, and thus it is not in communication with an external or additional tank (see figures 7, 8 and 9).

Advantageously, the free sections of the semi-chambers 10b, 11b of the cylinder in which both the first rod 14 and the second rod 15 are mounted and/or defined by one of these rods (see the semi-chamber 1 lb of figures 6 and 9), i.e. the section defined between each rod 14, 15 and the internal walls of the respective semi-chamber 10b, 11b or of the chamber/semi-chamber (see the definition given above for “free section”), are different from each other, for example in a ratio between 1 : 1 and 1 : 10.

As regards the rods 14, 15, 16, they can all have the same diameter (see figures 3 and 7) or one or some can have a diameter larger than the other or others (see figures 4, 5, 6, 8 and 9), for example in a ratio between 1 : 1 and 1 : 10, for example between 1 :4 or 1 :7 or between 1 :5 and 1 :6.

Advantageously, the cylinder and piston unit 2 comprises at least two pistons 12 and 13, each mounted in a sealed sliding manner in the chamber 10, 11 of a respective cylinder 8, 9 so as to divide it or not into two half-chambers 10a, 10b, I la, 1 lb, the first rod 14 being a bridge connection of a first 12 and a second piston 13.

Advantageously, the electronic control unit 6 is designed to drive the pump 5 and one or more of the valves 4a-4d so as to switch between a first work cycle, for example a rolling or pressing or pushing cycle by means of a tool holder group or mobile component of an object treating machine, in which the delivery of the pump 5 is in fluid communication with a first chamber or half-chamber or sum of chambers or half-chambers and a second rapid approach or return cycle, for example a rapid approach or return cycle of the tool holder group or mobile component of an object treating machine, in which the delivery of pump 5 is in fluid communication with another or second chamber or semi-chamber or sum of chambers or semi-chambers.

In this case, the free or active section of the first chamber or semi-chamber or sum of chambers or semi-chambers is smaller than the second chamber or semichamber or sum of chambers or semi-chambers, so that the movement of the pistons 12, 13 during the first cycle is faster than the movement of the pistons 12, 13 during the second cycle, so that it is possible to move the at least one piston 12, 13 at a higher speed (and probably less precision) during the second cycle compared to the first cycle.

Conversely, since the second chamber or semi-chamber or sum of chambers or semi-chambers is larger than the first chamber or semi-chamber or sum of chambers or semi-chambers, during the work cycle the at least one piston 12, 13 is provided with a greater force (and probably less speed, but greater control precision) compared to the rapid approach or return cycle.

Preferably, the electronic control unit 6 is designed to control the pump 5 and one or more of the valves 4a-4d so that during the first working cycle the semichambers 10a, 10b of the first cylinder 8 in which both the first rod 14 and the second rod 15 are mounted are placed in fluid communication, one with a delivery port P (or control port A or B in the case of a closed circuit) of the pump 5a and the other with an exhaust 17 (open circuit) or with a control port (B or A in the case of a closed circuit) of the pump 5a. Advantageously, the electronic control unit 6 is designed to drive the pump 5a and one or more of the valves 4a-4d so that during the second rapid approach or return cycle, one of the half-chambers I la, 1 lb of the second cylinder 9 is placed in fluid communication with a delivery P or control B/A port of the pump 5a and another of the half-chambers 11b, I la of the second cylinder 9 is placed in fluid communication with a tank or container or drain 17 or with a suction S or control A/B port of the at least one pump 5a, while the half-chambers lOa-lOb of the first cylinder 8 are placed in fluid communication with each other and isolated from the pump 5 a, or the chamber 11 or one of the semi-chambers I la, 1 lb of the second cylinder 9 in placed fluid communication with a delivery port P or control port B/A of the pump 5a and one or both of the semi-chambers 10a- 10b of the first cylinder 8 are placed in fluid communication with a drain 17 or with a suction port S or control port A/B of said at least one pump 5a, or the chamber 11 or one of the half-chambers I la, 1 lb of the second cylinder 9 is placed in fluid communication with a drain 17 or with an intake port S or control port A/B of the pump 5a and one or both half-chambers 10a- 10b of the first cylinder 8 is/are placed in fluid communication with a delivery port P or control port B/A of the pump 5 a, or the chamber 10 or one of the half-chambers 10a, 10b of the first cylinder 8 is placed in fluid communication with a delivery port P or control port B/A of the pump 5a and another of the half-chambers 10b, 10a of the first cylinder 8 is placed in fluid communication with a tank or container or drain 17 or with an intake port S or control port A/B of the at least one pump 5a, while the half-chambers 1 la-1 lb of the second cylinder 9 are placed in fluid communication with each other and isolated from the pump 5a.

According to a variant, the cylinder and piston unit 2 comprises a third rod 16 rising from the piston 13 mounted in the second cylinder 9 in the semi-chamber I la far from the first cylinder 8; in this case clearly, the circuit 3 is designed to convey fluid to/from the semi-chambers 10a, 10b, I la, 11b of both cylinders 8, 9 (see, for example, figures 3 and 7). The third rod 16 may have the same diameter as one or more of the other rods 14, 15 and/or a diameter greater or less than one or more of the other rods 14, 15.

With reference now to the specific non-limiting embodiments of the invention illustrated in the figures, figure 3 illustrates a group with two cylinders 8, 9, two pistons 12, 13 and three rods 14, 15 and 16 all of equal diameter or width.

In this case, with reference to the free sections of the cylinders, i.e. the sections defined between each rod 14, 15, 16 and the internal walls of the halfchambers 10a, 10b, I la, 1 lb, the free sections of a cylinder 8 are indicated by A23 and A13, while the free sections of the other cylinder 9 are indicated as A33 and A43, where A13 and A33 are adjacent or proximal free sections, while A23 and A33 as well as Al 3 and A43 are distal.

Moreover, A13 and A23, advantageously equal, are greater than A33 and A43, the latter also being advantageously equal.

A main valve 4a is then provided, for example a proportional valve with high dynamics, which has a plurality of operating positions. This valve is advantageously small in size, as it is sized to supply only sections I la, 11b in the fast approach and return cycle and sections 10a, 10b or possibly the combination of sections 10a, l la/l lb and 10b, l la/l lb in the low speed working steps, ensuring high precision in controlling the position and speed and force of the axis.

With reference now to circuit 3, it is actually divided into two sections or parts 3a, 3b, one 3a between valve 4a and pump 5a and any tank 17 and the other 3b between the main valve 4a and the cylinder and piston unit 2.

Each section or part 3a has at least one inlet duct 3c, 3d in the main valve 4a and at least one outlet duct 3e, 3f from the main valve 4a. Clearly, the components of the group 1 can be controlled by the control unit 6 so as to switch an input to an output and vice versa.

As regards the section 3b of the circuit between the main valve 4a and the cylinder and piston unit 2, it, starting from the inlet ducts 3c, 3d and the outlet ducts 3e, 3f, has branches so as to reach the half-chambers 10a, 10b, I la, 1 lb as well as valves 4b-4d, preferably appropriately controlled by the control unit 6, to intercept them.

More specifically, according to the non-limiting embodiment illustrated in the figures, a respective fluid supply/exhaust duct 3g, 3h, 3i, 3m is provided in/from each semi-chamber 10a, 10b, I la, 11b, which ducts 3g-3m open directly into a respective semi-chamber 10a, 10b, I la, 11b.

The supply/exhaust ducts 3g, 3h, 3i, 3m can flow or branch directly or via one or more connection ducts in/from an inlet duct 3d or outlet duct 3f.

In this regard, two or three (or even more) connection ducts 3n, 3p, 3q can be foreseen depending on how many pistons (one, two or more) or rods (two, three or more) are foreseen.

According to the non-limiting embodiment illustrated in the figures, the following is provided:

- a first connection duct 3n between the supply/exhaust duct 3h in/from a semi-chamber 10b of a cylinder 8, if desired the one with the largest diameter and the supply/exhaust duct 3g in/from the other semi-chamber 10a of the same cylinder 8,

- a second connection duct 3p between an inlet/outlet duct 3d and the meeting point or node of the first connection duct 3n and one of the supply/exhaust ducts 3g that it connects, if desired the duct that branches off from the semi-chamber 10a distal to the other cylinder 9.

In this case, one of the supply/exhaust ducts 3m can flow or branch directly into/from an inlet duct 3d, if desired after connection in a respective node with the second connection duct 3p.

Alternatively or in addition to what has now been indicated, a third connection duct 3q can be provided between the supply/exhaust duct 3g into/from a semi-chamber 10b of a cylinder 8, if desired the one with a larger diameter, and the supply/exhaust duct 3i into/from a semi-chamber 1 la of the other cylinder 9, if desired with a smaller diameter, if desired the duct that branches off from the semi- chamber I la distal to the other cylinder 8.

Advantageously, secondary valves 4b, 4c, 4d are provided to intercept the ducts of the second section 3b, for example the supply/exhaust ducts 3g, 3h, 3i, 3m and/or the connection ducts 3n, 3p, 3q.

According to the non-limiting embodiment illustrated in the figures, at least one secondary valve 4b, 4c, 4d is provided to intercept one or more of the connection ducts 3n, 3p, 3q.

The secondary valves 4b, 4c, 4d are of any suitable type, with two or more positions, if desired elastically loaded. Preferably, they are controlled by the control unit 6.

With reference now to the first section 3 a of the circuit 3, it could include a connecting duct 3r between the respective inlet duct 3c and outlet duct 3e.

As indicated above, the inlet ducts 3c and outlet ducts 3e could be open towards or flow into a tank or container 17 of the group 1. With regard to this aspect, the inlet duct 3c could be intercepted by the pump 5a, so it would comprise a first section 3cl upstream of the pump 5a deriving directly from the tank 17 and a second section 3c2 downstream of the pump 5b placed between the latter and the valve 4a.

Furthermore, a secondary valve could be provided to shut off the connection duct 3r.

The group could also be provided with at least one specific pressure regulator 18, if desired placed on the connection duct 3r.

In this case, the pressure regulator 18 has a variable output pressure, for example, a variable output pressure depending on the incoming fluid pressure and/or the structure/arrangement of its components and any forces applied to them.

In this case, in a first work cycle, for example a rolling or pressing or pushing cycle by the tool holder group or mobile component of an object treating machine, the unit 6 closes the secondary valve 4b, isolating the semi-chambers 10b (area Al 3) and 10a (A23), while opening the valves 4c and 4d, so that the inlet ducts 3d and outlet ducts 3f of the second section 3b of the circuit 3 and thus the respective mouths Bl and B2 of the main valve 4a are connected respectively to the sum of the semi-chambers 10b (area 13) and I la (area A43) (in fluid communication with each other because the secondary valve 4d is open) and to the sum of the semi-areas 10a (area A23) and 1 lb (A33) (in fluid communication with each other because the secondary valve 4c is open).

In this case, it is as if a cylinder with two semi-chambers of area A43+A13 and A33+A23 were provided. In this configuration, the area ratio remains preferably of the 1 :1 type, but the larger dimensions of the resulting areas allow for the development of a high force.

In accordance with a second operating cycle, for example a rapid approach or return cycle of the tool holder group or mobile component of an object treatment machine, by opening the secondary valve 4b and leaving the other valves 4c, 4d closed, the inlet ducts 3d and outlet ducts 3f of the second section 3b of the circuit 3 and thus the respective ports Bl and B2 of the main valve 4a are connected respectively to the semi-chambers I la (area A43) and 11b (A33), while the semichambers 10b (area A13) and 10a (A23) are connected only to each other by opening the secondary valve 4b.

In this configuration, the half-chambers 10b (area Al 3) and 10a (A23) are placed in communication with each other, thus the control fluid can pass freely from the half-chamber 10b (area Al 3) to the half-chamber 10a (A23) and vice versa.

In this case, by appropriately controlling the motor-pump group 5a-5c and the main valve 4a, one actually acts only thanks to the half-chambers 1 la (A43) and 1 lb (area A33) which are those connected to the main valve 4a, so that it is possible to perform rapid movements at high speed with low fluid flow rates (fed in the cylinder and piston unit 2) of a component moved by the cylinder and piston unit 2.

Furthermore, having preferably a ratio of the areas A43 and A33 advantageously equal to 1 : 1 or in any case corresponding to such ratio, it is possible to obtain the maximum dynamic control of the actuator or of the respective unit 2.

Relatively to this aspect, the ratio between the areas during the push or the braking is a ratio of 1 : 1, which means that it is possible to accelerate and brake with the same force, so it is possible to accelerate and brake quickly.

With reference now to the embodiment shown in figure 4, it is similar to the example in figure 3, but it comprises a single piston 12 and two rods 14, 15 only, which however have dimensions, one 14 smaller (for example according to the ratios indicated above) than the other 15, if desired the rod 14 with the smaller diameter is the one that slides through the communication opening CO between the chambers 10, 11 or the aligned opening of the cylinders 8, 9.

In this case, the chamber 11 defined by the second cylinder 9, preferably with a smaller diameter (for example according to the ratios indicated above) than the other or first cylinder 8, is not divided into half-chambers.

The first section 3a of the circuit is substantially corresponding to that of the embodiment of figure 3, while the second section 3b is simplified compared to the latter.

More specifically, a first connection duct 3n and a second connection duct 3p are provided and not a third connection duct 3q.

Both connection ducts 3p, 3q are intercepted by at least one secondary valve 4b, 4c.

In this case, with reference to the free sections of cylinders, i.e. the (annular) sections defined between each rod 14, 15 and the internal walls of the semichambers 10a, 10b and the free (circular) section of the chamber 11, the free (annular) sections of a cylinder 8 are indicated by A24 and A14, while the free (circular) section of the other cylinder 9 is indicated as A34, where A14 and A34 are adjacent or proximal free sections, while A24 and A34 are distal.

According to this variant, in a first work cycle, for example a rolling or pressing or pushing cycle by the tool holder group or mobile component of an object treating machine, the valve 4b is closed, isolating chambers 10b (area A14) and 10a (area A24) and the valve 4c is opened, so that the inlet ducts 3d and outlet ducts 3f of the second section 3b of circuit 3 and thus the respective mouths Bl and B2 of the main valve 4a are connected, one, mouth B 1 to the subtraction of chambers 11 - 10a (subtraction of areas A34 and A24) and the other, mouth B2 to the semi- chamber 10b (area A 14).

In this case the area ratio will not necessarily be of the 1: 1 type, but the larger dimensions of the resulting areas would allow for the development of a high force.

In accordance with a second operating cycle, for example a rapid approach or return cycle of the tool holder group or mobile component of an object treatment machine, by opening the secondary valve 4b and leaving the other 4c closed, the inlet ducts 3d and outlet 3f of the second section 3b of circuit 3 and thus the respective mouths B 1 and B2 of the main valve 4a are connected respectively, one Bl to chamber 11 (area A34) and the other B2 to the subtraction of chambers 10b (area A14) and 10a (area A24), the latter two being connected to each other, so that the control fluid can pass freely from chamber 10b (area Al 3) to 10a (area A23) and vice versa.

In this case, by appropriately driving the motor-pump group 5a-5c and the main valve 4a, one actually acts only thanks to the semi-chambers 11 (A34) and 10b- 10a (subtraction of areas Al 4 and A24) which are those connected to the main valve 4a, so that it is possible to perform rapid movements at high speed with low fluid flow rates (fed in the cylinder and piston unit 2) of a component moved by the cylinder and piston unit 2.

In this case, the ratio of the chambers 11 and 10b- 10a will not be equal to 1 : 1 even if still close to this value, but the resulting actuator is still simpler than the case in figure 3.

With reference now to the embodiment of figure 5, the respective circuit 3 is almost identical to that of figure 4, but a second piston 13 is provided mounted in the chamber 11 of the second cylinder 9, so as to divide it into two half-chambers 1 la, 1 lb, one of which, in particular the one distal from the other cylinder 8, is not affected by a supply and exhaust duct. With regard to this aspect, an air filter 95 could be provided to protect the half-chamber 1 la, in which the control fluid does not act.

In this case, with reference to the free sections of cylinders, i.e. the (annular) sections defined between each rod 14, 15 and the internal walls of the half-chambers 10a, 10b or of the half-chamber 1 lb, the free (annular) sections of a cylinder 8 are indicated by A25 and Al 5, while the free section (always annular) of the other cylinder 9 is indicated as A35, where Al 5 and A35 are adjacent or proximal free sections, while A25 and A35 are distal.

Preferably, Al 5 is substantially equal to the sum of A25 and A35.

According to this variant, in a first work cycle, for example a rolling or pressing or pushing cycle by the tool holder group or mobile component of an object treating machine, the valve 4b is closed, isolating the chambers 10a and 10b and the secondary valve 4c is opened, so that the inlet ducts 3d and outlet 3f of the second section 3b of the circuit 3 and thus the respective mouths Bl and B2 of the main valve 4a are connected one, mouth Bl, to the chamber 10b (area Al 5) and the other, mouth B2, to the sum of the chambers 10a and 11b (sum of the areas A25 and A35), and thus it is as if the circuit 3 acted on a single cylinder with two chambers of area, respectively, Al 5 and A25+A35.

In this configuration, the area ratio is advantageously of the 1 : 1 type, but the larger dimensions of the resulting areas allow a high force to be developed.

In accordance with a second operating cycle, for example a rapid approach or return cycle of the tool holder group or mobile component of an object treating machine, by opening the secondary valve 4b and leaving the other 4c closed, the inlet ducts 3d and outlet ducts 3f of the second section 3b of the circuit 3 and thus the respective mouths B 1 and B2 of the main valve 4a are connected respectively, one, mouth B 1, to the semi-chamber 1 lb (area A35) and the other, mouth B2, to the subtraction of the chambers 10b (area Al 5) and 10a (area A25), the latter two being connected to each other, and thus the control fluid can pass freely from Al 5 to A25 and vice versa.

In this case, by appropriately controlling the motor-pump group 5a-5c and the main valve 4a, one actually acts only thanks to the semi-chambers 11b (A35) and 10b- 10a (subtraction of areas Al 5 and A25) which are those connected to the main valve 4a, so that it is possible to perform rapid movements at high speed with low fluid flow rates of a component moved by the cylinder and piston unit 2.

Furthermore, the ratio of the areas A35 and A15-A25 equal to 1 : 1 allows for maximum dynamic control of the actuator.

Referring now to figure 6, a group very similar to that of figure 5 has been illustrated, but instead of having a second piston 13 mounted slidingly in the chamber 11, the first rod 14a has a hollow configuration so as to define an opening or recessed zone far from the cylinder 8 or the piston 12, so it will have a connecting portion 14a and a hollow projecting portion 14b.

The cylinder 9 instead has a body with a single substantially circular base 9a and a cylindrical side wall 9c, so it is open at the distal end from the base 9a and proximal to the other cylinder 8.

The cylinder 9 also comprises an internal protrusion 9d extending along the respective axis of the cylindrical side wall, which can be inserted substantially to size in the recessed zone defined by the projecting portion 14b of the stem 14.

With such a configuration, the chamber 11 is separated into two halfchambers I la, 11b by the projecting portion 14b of the rod, and the half-chamber 1 lb is delimited in the recessed zone of the rod 14 between the tip of the internal protrusion 9b and the rod 14 itself, so that by feeding fluid into this half-chamber 1 lb the tip of the rod 14 is moved away from the bottom of the recessed zone and vice versa by suctioning fluid from the half-chamber 1 lb.

In this case, the semi-chamber 11b is, unlike the embodiment shown in figure 5, circular and not annular in cross-section.

The circuit 3 of this embodiment corresponds to that of figure 5, although in this case the supply/exhaust duct 3m in the semi-chamber 11b could have a section through the internal protrusion 9d.

In this case, with reference to the free sections of cylinders, i.e. the sections defined between each rod 14, 15 and the internal walls of the semi-chambers 10a, 10b or of the semi-chamber 11b, the free (annular) sections of a cylinder 8 are indicated by A26 and Al 6, while the free (circular) section of the other cylinder 9 is indicated as A36, where A16 and A36 are adjacent or proximal free sections, while A26 and A36 are distal.

Preferably, A16=A26+A36.

Also in this case, an air filter 96 could be provided to protect the semichamber 1 la, in which the control fluid does not act.

The operation of this embodiment substantially corresponds to that of the example in figure 5.

With reference now to the groups of figures 7, 8 and 9, they are structured substantially like the groups of figures 3, 5, 6 replacing the pressure-flow source with a closed circuit hydrostatic pump.

In this case, the valve 4a could not be foreseen.

Moreover, if one wishes, even in the absence of the valve 4a, to divide the circuit into two sections or parts, the first section 3a of the circuit could foresee a second connecting duct 3 s between the respective inlet duct 3c and outlet duct 3e.

A secondary valve could then be provided to shut off the connection pipe 3r.

The group could also be provided with at least one specific pressure regulator 19, if desired, placed on the connection duct 3 s.

In this case, the advantages are similar to those described above, but the control dynamics offered by the pumps is lower than that of the groups in figures 3 to 6.

With reference now to the embodiment illustrated in figure 10, a case has been illustrated in which the two cylinders 8, 9 are physically separate and are not arranged or fixed or connected to each other so as to have a common end defining a communication opening CO between the chambers 10, 11 defined by the cylinders 8, 9 or facing ends each defining an opening aligned with the opening in the other cylinder. Therefore, the two cylinders 8, 9 are not arranged substantially in series and do not have an end in common. They may instead be arranged in parallel or in any case not physically connected or not in a non-aligned position as mentioned above. In this case, at least two rods are provided including at least one first rod 14c, 15 slidably mounted in a first cylinder 8 and at least one other rod 14d, 16 slidably mounted in a second cylinder 9. However, no rod is in common between the two cylinders 8, 9.

Advantageously, two rods 14c, 15 and 14d, 16 are provided, rising from opposite sides of one or each piston 12, 13.

As will be understood, the configuration of figure 10 with two cylinders 8, 9, two pistons 12, 13 each in a respective cylinder 8, 9 and four rods 14c, 14d, 15 and 16, two for each cylinder 8, 9 and extending from opposite sides of a respective piston 12, 13 corresponds to the configuration of figure 3, but the two cylinders 8 and 9 have been separated and the common rod 14 has, in fact, been replaced by two rods 14c, 14d, one mounted in the chamber 10b of the first cylinder 8 and rising from one side of a piston 12 and the other mounted in the chamber 1 lb of the second cylinder 9 and rising from one side of a piston 13, but the two rods 14c, 14d are each dedicated to a respective cylinder 8, 9 and not shared between the cylinders 8, 9 themselves.

Using two separate cylinders 8, 9 without a common rod instead of as illustrated or described previously can clearly be applied to all the other embodiments described and illustrated, not only that of figure 3.

So for example, the embodiment of figure 4 could be replaced by an alternative example with two separate cylinders 8, 9, two rods 14c, 15 mounted in the first cylinder 8, one on the opposite side to the other with respect to the piston 12 and another rod 14d mounted in the second cylinder 9 as foreseen for the second cylinder 9 of the example of figure 4.

The embodiment of figure 5 could instead be replaced by an alternative example with two separate cylinders 8, 9, two rods 14c, 15 mounted in the first cylinder 8, one on the opposite side to the other with respect to the piston 12 and another rod 14d mounted in the second cylinder 9 with the further provision of a second piston 13 as foreseen for the second cylinder 9 of the example in figure 5.

Thus, with reference to the embodiment of figure 6, it could be replaced by an alternative example with two separate cylinders 8, 9, two rods 14c, 15 mounted in the first cylinder 8, one on the opposite side to the other with respect to the piston 12 and another rod mounted in the second cylinder 9 and configured as foreseen for the second cylinder 9 of the example of figure 6.

In this case, the other components as well as the operation of such variants of the groups of figures 3 to 6 are substantially corresponding to those of the latter figures.

Moreover, even in the case of such variants, the chamber 10 delimited by one of the cylinders 8 can have a diameter larger than the chamber 11 delimited by the other or by another 9 of the cylinders and/or one or more rods 15, 14c can have a diameter larger than the other or others 14d, 16.

Thus, it will be understood that in a group according to the present invention by switching, by means of the control unit 6, the proportional valve 4a and the other valves 4b-4d, it is possible to vary the chambers 10, 11 or semi-chambers 10a, 10b, I la, 11b or sum of chambers and/or semi-chambers in communication with the pump 5a and the tank or container or drain 17 and/or place two or more of them in fluid communication with each other, so that if the free section of the chambers 10, 11 or semi-chambers 10a, 10b, I la, 1 lb or sum of chambers and/or semi-chambers in communication with the pump 5a and the tank or container or drain 17 is smaller, it is possible to impart a fast movement to a tool-holder group or to a shaping component of a machine for the treatment of objects by means of a first flow rate of fluid in the cylinder and piston unit 2, while if the free section of the chambers 10, 11 or semi-chambers 10a, 10b, I la, 11b or sum of chambers and/or semichambers in communication with the pump 5a and the tank or container or drain 17 is greater it is possible to impart a slow movement to a tool-holder group or to a shaping component of an object-treating machine with a second flow rate of fluid in the cylinder-piston unit 2 greater than the first flow rate and, consequently, greater force and precision. If desired, the flow rate of fluid in the two steps could also be the same. The present invention also relates to a machine for the treatment of objects (not illustrated in the figures), such as a rolling mill or other machine for the deformation or shaping or rolling of objects, including a tool -hoi ding group or a shaping component as well as at least one group 1 with its own cylinder and piston unit 2 designed to operate or move the tool-holding group or said shaping component during the pressing or working, rapid approach or return to the rest position steps.

As will be understood, a group according to the present invention, allows to use a classic architecture for the motor pump part 5a-5c and control valve 3a, benefiting from the fact that this solution ensures maximum control accuracy.

However, by coupling this part with a cylinder and piston unit 2 as described above, it is possible to effectively realize the slow (work) and fast (ascent or return) steps without using complex and bulky systems, such as those in figures 1 and 2.

Claims

1. Group for driving a tool holder group or a component for shaping of a machine for treating objects, such as a rolling mill, said group including:

- at least one hydraulic or oleodynamic linear axis or at least one hydraulic or oleodynamic cylinder and piston unit (2),

- a circuit (3) for conveying fluid to/from said cylinder and piston unit (2),

- valves (4a-4d) for opening and closing the ducts of said circuit (3),

- at least one pump (5a) designed to move said fluid in said circuit (3) and in/from said cylinder and piston unit (2),

- at least one electronic control unit (6) of said at least one pump (5a) and of one or more of said valves (4a-4d), wherein said cylinder and piston unit (2) comprises:

- at least two cylinders (8, 9) each delimiting a chamber (10, 11),

- at least one piston (12, 13) slidably and hermetically mounted in the chamber (10, 11) of a respective cylinder (8, 9) so as to divide it into two halfchambers (10a, 10b, I la, 11b), and

- at least two rods (14, 15, 16) mounted inside the chambers (10, 11) and/or half-chambers (10a, 10b, I la, 1 lb) of said at least two cylinders (8, 9), wherein the chamber (10) delimited by one (8) of said at least two cylinders has a diameter greater than the chamber (11) delimited by the other of said at least two cylinders (9) and/or one (15) of said at least two rods has a diameter greater than another (14, 14c, 14d) of said at least two rods, so that the free or active section of the chamber (10) or half-chambers (10b, 1 lb) delimited by one (8) of said at least two cylinders is greater than the free or active section of the chamber (11) or halfchambers (I la, 1 lb) delimited by another (9) of said at least two cylinders, whereas for free or active section (A13, A23, A33, A43, A14, A24, A34, A15, A25, A35, A16, A26, A36) of a chamber (10, 11) or half-chamber (10a, 10b, I la, 11b) it is meant the section of the latter orthogonal to the axis of movement of a respective rod, which from time to time must be filled or deprived of fluid to move the rod (14, 14c, 14d, 15, 16) in this chamber (10, 11) or half-chamber or half-chambers (10a, 10b, I la, 11b).

2. Group according to claim 1, wherein said circuit is open, i.e. it has respective ducts (3 c, 3e) open towards a tank or container or drain (17) of the group.

3. Group according to claim 1 or 2, wherein the free or active section of the chamber (10) or half-chambers (10b, 1 lb) delimited by one (8) of said at least two cylinders is greater than the free or active section of the chamber (11) or halfchambers (I la, 1 lb) delimited by another (9) of said at least two cylinders in a ratio between 1 :2 and 1 : 10.

4. Group according to any one of the preceding claims, comprising a proportional valve (4a), the circuit (3) being divided into two sections or parts (3a, 3b), a section (3a) between said proportional valve (4a) and said at least one pump (5a) and tank or container or drain (17) and the other section (3b) between the proportional valve (4a) and the cylinder and piston unit (2), each section or part (3a, 3b ) of the circuit (3) having at least one inlet duct (3c, 3d) in the proportional valve (4a) and at least one outlet duct (3e, 3f) from the proportional valve (4a), so that by suitably switching said proportional valve (4a) and the other valves (4b-4d) it is possible to vary the chambers (10, 11) or half-chambers (10a, 10b, I la, 1 lb) or the sum of chambers and/or half-chambers communicating with the pump (5a) and the tank or container or drain (17) and/or placing two or more of them in fluid communication with each other.

5. Group according to claim 4, wherein if the free section of the chambers (10, 11) or half-chambers (10a, 10b, I la, 11b) or the sum of chambers and/or halfchambers in communication with the pump ( 5a) and the tank or container or drain (17) is smaller it is possible to impart a fast motion to a tool holder assembly or to a component for shaping of a machine for treating objects via a first flow rate of fluid into the cylinder unit and piston (2), while if the free section of the chambers (10, 11) or half-chambers (10a, 10b, I la, 1 lb) or the sum of chambers and/or halfchambers in communication with the pump (5a) and the reservoir or container or drain (17) is larger it is possible to impart slow motion to a tool holder assembly or to a component for shaping of a machine for treating objects with a second flow rate of fluid in the cylinder and piston unit (2) greater than or equal to the first flow rate.

6. Group according to any one of the preceding claims, wherein: said at least two cylinders (8, 9) are arranged or fixed or connected to each other so as to have a common end defining an opening of communication (CO) between the chambers (10, 11) defined by said at least two cylinders (8, 9) or facing ends each defining an opening aligned with the opening in the other cylinder (8, 9), and wherein said at least two rods include a first rod (14) projecting from a first side or face of said at least one piston (12) and mounted sliding and hermetically in said communication opening (CO) or in the aligned openings of said at least two cylinders (8, 9), in a chamber (10) or half-chamber (10b) of a first cylinder (8) and in a chamber (11) or half-chamber (1 lb) of another or second cylinder (9) as well as at least one second or further rod (15, 16) projecting from a second side or face of said at least one piston (8, 9) in a chamber (10, 11) or half-chamber (10a, 1 la) of said first (8) or second (9) cylinder far from the other between said second (9) and said first (8) cylinder.

7. Group according to any one of claims from 1 to 5, wherein said at least two cylinders (8, 9) are separated from each other and wherein said at least two rods include a first rod (14c, 15) slidably mounted in a first cylinder (8) and another rod (14d, 16) slidably mounted in a second cylinder (9), no rod being in common among said at least two cylinders (8, 9).

8. Group according to any one of the preceding claims, wherein said cylinder and piston unit (2) comprises at least two pistons (12, 13) each sliding and hermetically mounted in the chamber (10, 11) of a respective cylinder (8, 9).

9. Group according to claims 6 and 8, wherein said first rod (14) is a bridge connection of a first (12) and a second (13) piston of said at least two pistons.

10. Group according to any one of the preceding claims, wherein said electronic control unit (6) is set to drive said at least one pump (5a) and said valves (4a-4d) so as to switch between a first work cycle in which the delivery of said at least one pump (5a) is in fluid communication with a first chamber or half-chamber or sum of chambers or half-chambers delimited by said cylinders (8, 9) and a second cycle of rapid approach or return in which the delivery of the pump (5a) is in fluid communication with another or second chamber or half-chamber or sum of chambers or half-chambers delimited by said cylinders (8, 9), and wherein the free or active section of the first chamber or half-chamber or sum of chambers or halfchambers is greater than the free or active section of the second chamber or halfchamber or sum of chambers or half-chambers, so that it is possible to move said at least one piston (12, 13) at speed during said second cycle higher than in said first cycle.

11. Group according to claim 10, wherein said electronic control unit (6) is set to drive said at least one pump (5a) and said valves (4a-4d) so that during said first work cycle (10a, 10b), the half-chambers of a first cylinder (8), in which both a first rod (14) and a second rod (15) are mounted, are arranged in fluid communication one (10a, 10b) with a delivery (P) or control (A/B) port of said at least one pump (5a) and the other (10b, 10a) with a tank or container or drain (17) or with a suction (S) or control (B/A) port of said at least one pump (5a).

12. Group according to claim 10 or 11, wherein said electronic control unit (6) is set to drive said at least one pump (5a) and said valves (4a-4d) so that during said second rapid approach or return cycle:

- one of the half-chambers (I la, 1 lb) of a second cylinder (9) is set in fluid communication with a delivery (P) or control (B/A) port of said at least one pump (5a) and another of the half-chambers (1 lb, I la) of the second cylinder (9) is set in fluid communication with a tank or container or drain (17) or with a suction (S) or control (A/B) port of said at least one pump (5a), while the half-chambers (10a- 10b) of a first cylinder (8) are in fluid communication with each other and isolated from said at least one pump (5a), or

- the chamber (11) or one of the half-chambers (I la, 11b) of a second cylinder (9) is set in fluid communication with a delivery port (P) or control port (B/A) of said at least one pump (5a ) and one or both half-chambers (10a- 10b) of a first cylinder (8) is/are set in fluid communication with a drain (17) or with an suction (S) or control (A/B) port of said at least one pump (5a), or

- the chamber (11) or one of the half-chambers (I la, 11b) of a second cylinder (9) is set in fluid communication with a drain (17) or with an suction (S) or control (A, B) port of said at least one pump (5a) and one or both half-chambers (lOa-lOb) of a first cylinder (8) is/are set in fluid communication with a delivery (P) or control (B/A) port of said at least one pump (5a), or

- the chamber (10) or one of the half-chambers (10a, 10b) of a first cylinder (8) is set in fluid communication with a delivery port (P) or control port (B/A) of said at least one pump (5a) and another of the half-chambers (10b, 10a) of the first cylinder (8) is set in fluid communication with a tank or container or drain (17) or with a suction (S) or control (A/B) port of the at least one pump (5a), while the half chambers (1 la-1 lb) of a second cylinder (9) are in fluid communication with each other and isolated from the pump (5a).

13. Group according to any one of the preceding claims when depending upon claim 9, wherein said cylinder and piston unit (2) comprises a third rod (16) protruding from the piston (13) mounted in said second cylinder (9) in the halfchamber (I la) far from the first cylinder (8) and wherein said circuit (3) is designed to convey fluid into/from the half-chambers (10a, 10b, I la, 11b) of both said cylinders (8, 9).

14. Machine for treating objects, such as a rolling mill or another machine for deforming or shaping or laminating objects, including a tool holder group or a shaping component as well as at least one group according to any one of the preceding claims with its cylinder and piston unit (2) designed to actuate or move said tool holder group or said shaping component during the steps of pressing or working or rapid approach or return to the rest position.

15. Method for moving or actuating a tool holder group or a shaping component of a machine according to claim 14, wherein said electronic control unit (6) drives said at least one pump (5a) and said valves (4a-4d) so as to switch between a first work cycle in which the delivery of said at least one pump (5a) is in fluid communication with a first chamber or half-chamber or sum of chambers or halfchambers delimited by said cylinders (8, 9) and a second cycle of rapid approach or return in which the delivery of the pump (5a) is in fluid communication with another or second chamber or half-chamber or sum of chambers or half-chambers delimited by said cylinders (8, 9), and wherein the free or active section of the first chamber or half-chamber or sum of chambers or half-chambers is greater than the free or active section of the second chamber or half-chamber or sum of chambers or half-chambers, so that it is possible to move said at least one piston (12, 13) at speed during said second cycle higher than in said first cycle.

16. Method according to claim 15, wherein said electronic control unit (6) drives said at least one pump (5a) and said valves (4a-4d) so that during, said first work cycle (10a, 10b), the half-chambers of a first cylinder (8) are arranged in fluid communication one with a delivery (P) or control (A/B) port of said at least one pump (5a) and the other (10b, 10a) with a tank or container or drain (17) or with a suction (S) or control (B/A) port of said at least one pump (5a).

17. Method according to claim 15 or 16, wherein said electronic control unit (6) drives said at least one pump (5a) and said valves (4a-4d) so that during said second rapid approach or return cycle:

- the chamber (11) or one of the half-chambers (I la, 11b) of a second cylinder (9) is set in fluid communication with a delivery port (P) or control port (B/A) of said at least one pump (5a ) and one or both the half-chambers (lOa-lOb) of a first cylinder (8) is/are set in fluid communication with a drain (17) or with an suction (S) or control (A/B) port of said at least one pump (5a), or - the chamber (11) or one of the half-chambers (I la, 11b) of a second cylinder (9) is set in fluid communication with a drain (17) or with an suction (S) or control (A, B) port of said at least one pump (5a) and one or both the halfchambers (lOa-lOb) of a first cylinder (8) is/are set in fluid communication with a delivery (P) or control (B/A) port of said at least one pump (5a), or