EP3177419B1

EP3177419B1 - Machine and method for shaping annular elements, such as rolling machine and a method for circular rolling annular elements

Info

Publication number: EP3177419B1
Application number: EP15767290.8A
Authority: EP
Inventors: Angelo SARTORI; Mario Sartori
Original assignee: Muraro Srl
Current assignee: Muraro Srl
Priority date: 2014-08-08
Filing date: 2015-08-06
Publication date: 2019-10-30
Anticipated expiration: 2035-08-06
Also published as: ES2773635T3; WO2016020869A1; EP3177419A1; PL3177419T3

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a machine and a method for shaping annular elements, such as a rolling machine, such as a radial-axial rolling mill.

STATE OF THE PRIOR ART

Machines are known for rolling annular elements, such as bearings, rims or the like, comprising a mandrel, a rolling plate, a support table as well as a pair of frustoconical rollers intended each to treat a portion of a respective side of the annular element.
The annular elements or rings to be produced with the rolling machines usually have recess portions and protruding portions and during the rolling process it is necessary to obtain a correct conveying of the material between respective zones of the annular element, a function that sometimes, with the rolling machines proposed thus far, cannot be implemented as desired and in a sufficiently versatile manner.
Moreover, during the production process, the protruding portions of the annular elements are subjected to very high shear forces and can therefore constitute blockage or obstacle zones, which involve the interruption of the process, or limit the production efficiency of the latter.
JPS56165507A and JPH02133131A teach respective machines according to the prior art.

OBJECTS OF THE INVENTION

One object of the present invention is to provide a new machine for shaping at least one annular element, such as a rolling machine.
Another object of the present invention is to provide a machine as stated above, which allows making annular elements in the desired shape effectively and quickly.
Another object of the present invention is to provide a machine as stated above, which is provided with such components as to allow making annular elements with protruding portions and/or undercut portions, without impairing the production efficacy or the quality of the finished products.
Another object of the present invention is to provide a new method for shaping annular elements.
According to one aspect of the invention, a machine according to claim 1 is provided.
According to another aspect of the invention, a method according to claim 17 is provided.
The dependent claims relate to preferred and advantageous embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become more apparent from the description of an exemplary embodiment of a machine, shown by way of an indication in the accompanying drawings, in which:

Figure 1 is a side view of a machine according to the present invention;
Figure 2 is a top view with sectional parts along trace II-II in Fig. 1;
Figure 3 is a view of an enlarged scale and sectional detail of the machine in Fig. 1;
Figure 4 is a sectional view along trace IV-IV in Fig. 3;
Figures 5 to 18 schematically show respective steps for carrying out a method according to the present invention.

In the accompanying drawings, equal parts or components are designated by the same reference numerals.

EXEMPLARY EMBODIMENTS OF THE INVENTION

With reference to Figures 1 to 18, a machine 1 for shaping annular elements AE is shown, such as a rolling machine, such as a so-called radial-axial rolling mill, for example for bearings, rims or the like, which comprises a support frame 2 of the machine components, among which components described hereinafter. The machine is also provided with at least one shaft or mandrel 3 extending around a first longitudinal axis x-x, such as vertical, which mandrel 3 is intended to be inserted or fitted within an annular element AE, or rather within the through gap AE1 delimited by an annular element AE. The annular element AE comprises a side connecting surface AE2 and also a first AE3 and a second AE4 side.
More in particular, the annular element AE comprises a body configured as a rotation solid around an axis of symmetry (in use substantially parallel to axis x-x) having more diameters and having, from one side to the other, a first substantially flat or slightly curved side AE3, then a side connecting surface AE2, e.g. substantially shaped or substantially cylindrical, such as with swollen portions AE5, AE6 alternating with recess portions AE7, and then a second substantially flat or slightly curved side AE4. The annular element AE delimits then a through gap or opening AE1 extending from one side AE3 to the other AE4 and along the axis of symmetry of the annular element AE.
Machine 1 then comprises at least one support plate or table 4 of the annular element AE which, in use, extends at least in part around the shaft or mandrel 3 and is intended to support the annular element AE at a first side AE3 thereof, such as a lower side, in use.
A bucking component 5 is also provided, such as a rolling plate, which extends, in use and during the shaping/rolling, next to the shaft or mandrel 3 and is intended to abut (following a displacement of mandrel 3 or of the bucking component 5 itself) against and to deform the side connecting surface AE2 of the annular element AE. The bucking component 5 may comprise a cylindrical component having a longitudinal symmetry axis w-w substantially parallel, in use, to the longitudinal axis x-x of the mandrel 3.
The bucking component 5 may have a suitably configured side surface 5a (or substantially cylindrical) so as to shape, in use, the annular element AE or rather the side connecting surface AE2 of the same as desired. More particularly, according to the specific embodiment example shown in the Figures, the side surface 5a of the bucking component 5 may have, from one side, such as upper in use, to the other, such as lower in use, a first cylindrical section 5a1, then a second slightly frustoconical section 5a2 with decreasing diameter, a third cylindrical section 5a3 with outer diameter smaller than the first cylindrical section 5a1, a fourth slightly frustoconical section 5a4 with increasing diameter and a fifth cylindrical section 5a5 with outer diameter substantially corresponding to the first cylindrical section 5a1.
The working section of the side surface 5a of the bucking component 5, i.e. the section of such a surface intended to abut and suitably shape the side wall AE2 of an annular element AE, is composed of the second 5a2, third 5a3 and fourth section 5a4.
Advantageously, the mandrel 3 and/or the bucking component 5 is/are moveable closer and apart one with respect to the other along a first direction A-A substantially transversal, preferably orthogonal, to the first longitudinal axis x-x and to the longitudinal axis of symmetry w-w and, to this end, the machine comprises appropriate actuation means. Preferably, the mandrel 3 can be moved along the first direction A-A by actuation means, while the bucking component 5 is fixed in position or better not movable along the first direction A-A.
Preferably, at least one between the mandrel 3 and the bucking component 5 is mounted for rotation, by means of suitable motor means, around the respective longitudinal axis x-x, w-w. Preferably, the mandrel 3 is mounted idle for rotation around axis x-x, while the bucking component 5 is mounted motorized for rotation by means of suitable motor means around the respective longitudinal axis w-w.
The actuating and the motor means motors may comprise, for example, an electric, pneumatic or other type of motor.
The machine is then provided with at least one first 6a, such as upper in use, and at least one second 6b, such as lower in use, roller element, which roller elements 6a, 6b are each intended to abut against a portion of a respective side AE4, AE3 of the annular element AE. The first 6a and the second 6b roller element are then each mounted for rotation around a respective axis, such as of longitudinal symmetry, respectively a second y-y and a third axis z-z of symmetry, which are transversal to the first longitudinal axis x-x. The second y-y and the third z-z axis of symmetry are preferably tilted relative to each other, such as converging towards a working zone WZ of the annular element AE and, if desired, they both lie in a same plane, such as vertical, passing through the first longitudinal axis x-x.
Preferably, the roller elements 6a, 6b are mounted for rotation around the respective axis of symmetry y-y and z-z, such as in a direction opposite to each other.
The first 6a and the second 6b roller element may be placed on the opposite side to the bucking component 5 with respect to the mandrel 3. Moreover, in use and during the shaping/rolling, the annular element AE is between the roller elements 6a, 6b, or better between a portion of respective working sections 6c, 6d, but there aren't placed other elements of the machine, so that a diameter growing zone of the annular element AE remains delimited between the roller elements 6a, 6b during the shaping/rolling, as will be better seen hereinafter.
Rollers 6a and 6b may, for example, have a substantially frustoconical configuration, more in particular they may have a substantially frustoconical configuration or outer engagement surface of the annular element.
The machine further comprises actuation means 7 intended to move both the first 6a and the second 6b roller element along a second direction B-B, such as vertical, which is substantially parallel to the first longitudinal axis x-x, so that the roller elements 6a, 6b are movable closer and apart one with respect to each other in such a way as to tighten or release the annular element AE during the shaping/rolling.
More in particular, both roller elements 6a, 6b can be moved between a first position or rest or unloading position (see Figures 5, 6, 7, 8, 15, 16, 17, 18) and a second position or working or loading position (see Figures 11 and 12) in which they are closer to one another than in the first position.
The first actuation means may comprise at least one first actuator 7 intended to move the first roller element 6a along the direction B-B, as well as at least one second actuator intended to move the second roller element 6b along the direction B-B, so that the first 6a and the second 6b roller element are movable independently or better mechanically independently from one another along the direction.
Advantageously, the machine is also provided with control means of the first 6a and of the second 6b roller element, which are intended to synchronize the displacement of the same along the direction B-B substantially parallel to the first longitudinal axis x-x. The control means may comprise, for example, a program control unit, as well as, if desired, first sensor means, intended to detect the position of the roller elements 6a, 6b and to communicate it to the program control unit, which can then suitably control the actuation means 7.
If desired, the control means may also comprise second sensor means of the force applied to the annular element AE by the upper roller element 6a and by the lower roller element 6b, in particular of the force applied in a direction substantially parallel to the first longitudinal axis x-x. Based on the values measured by the second sensor means, which are in electrical communication with the program control unit, it is possible to confirm that the roller elements 6a, 6b are in contact with the annular element AE, as well as the force applied to the latter.
In the present patent application, in order to synchronize the displacement of the roller elements 6a, 6b, it may also be usefully considered that the law of motion with which the control means displace a roller element 6a or 6b is a function, according to a formula or a curve defined by a user and set in the control means, of the law of motion with which the control means displace the other roller element 6a or 6b. Such a formula/curve is or would be calculated or derived on the basis of tests or assessments, so as to ensure the correct position of the roller elements 6a, 6b with respect to or in thrust on a respective portion of the annular element AE during shaping.
Therefore, the roller elements 6a, 6b may be moved by the control means only as a function of the data detected by the sensor means, only as a function of their laws of motion set and correlated to one another in advance, or on the basis of a combination of such solutions, namely by setting ratios between the laws of motion of the roller elements 6a , 6b, and then making any changes or further checks of the positions of the roller elements on the basis of the data obtained from the first and/or second sensor means.
If desired, the machine may be provided with detection means (such as laser or the like) of the position and geometry, such as the diameter and/or height, of the annular element AE, which detection means could be in communication with the control means or with a program control unit intended to suitably control the actuation means 7.
The first actuator and/or the second actuator of the actuation means 7 may comprise, for example, a recirculating ball screw group, a planetary roller screw group, an oleodynamic bearing screw unit, a hydraulic actuator, a pneumatic actuator, an electric actuator or a rack and pinion group.
The machine may also be provided with means for displacing the roller elements 6a, 6b along a third direction C-C orthogonal to the first longitudinal axis x-x moving closer-apart to/from mandrel 3, which third direction C-C is preferably substantially parallel to the first direction A-A. The displacement means comprise, for example, a respective pneumatic, electric or other type of motor.
Advantageously, the support plate or table 4 is slidably mounted along a fourth direction substantially parallel to the first longitudinal axis x-x and means for displacing the support plate or table 4 along such a direction are provided. Even more advantageously, the support plate or table 4 is kinematically connected to the first 6a or to the second 6b roller, preferably to the second roller 6b as well as moveable together with it along the second direction B-B, in which case the actuation means actually comprise the displacement means.
Alternatively, the support table 4 can be moved along a fourth direction parallel to the longitudinal axis x-x by means of respective displacement means disengaged from the roller elements 6a, 6b and from the respective actuation means, so that the same can be moved in a completely independent manner with respect to the roller elements 6a, 6b also in such a direction (parallel to the longitudinal axis x-x).
If desired, the first 6a and the second 6b roller element have a working section 6c, 6d intended to engage a portion of a respective first AE3 or second AE4 side of the annular element AE, while the support plate or table 4 has a working surface 4a, for example a top surface, intended to support a portion of the first side AE3 of the annular element AE, which working surface 4a is substantially aligned or at the same level, in use, with the working section 6d of the second roller 6b. To this end, the support plate or table 4 may delimit at least one opening or window 4b for housing or positioning, in use, such as slidably, of the working section 6d of the second roller element 6b.
As will be appreciated, since the roller elements 6a, 6b are preferably mounted for rotation around a respective axis of symmetry y-y and z-z, the working section 6c, 6d consists of a respective portion which, from time to time, during the rotation of the respective roller element, is in contact with a portion of a respective side AE3, AE4 of the annular element AE and, if provided, within the opening or window 4b. Preferably, the working section 6c of one roller element 6a is substantially parallel to the working section 6d of the other roller element 6b and, even more preferably, the working sections 6c, 6d are substantially transversal or orthogonal to the longitudinal axis x-x of the mandrel 3.
If desired, the support plate or table 4 defines a seat or abutment or limit switch 4c for a portion of the bucking component 5, such as a substantially curved seat of a curved portion of the bucking component 5.
According to the non-limiting embodiment example shown in the Figures, the support plate or table 4 may comprise two half-plates 4d-4e substantially aligned and side by side as well as delimiting therebetween or better, between the respective facing edges, opening 4b as well as an area 4f, such as substantially circular, within which a section of the mandrel 3 is placed during the rolling process; to this end, it is noted that plate 4 and the mandrel 3 are not in contact but there is a space therebetween, such as circular. Distancing-approach means (not shown in the drawings, such as an actuator) of the two half-plates 4d-4e may further be provided. If desired, the two half-plates 4d-4e may be moved along a direction parallel to axis x-x by respective displacement means, so that the same may be moved independently with respect to each other.
The machine may then comprise one or more (two according to the embodiment example shown in the Figures) centering elements 8a, 8b arranged next to the mandrel 3, which is/are angularly offset with respect to the bucking component 5. The or each centering element 8a, 8b is intended to press the annular element AE at a portion of the side connecting surface AE2 thereof angularly offset with respect to that engaged by the bucking component 5.
The centering elements 8a, 8b may comprise respective secondary rollers which can be moved closer and apart to/from the mandrel 3 along a radial direction angularly offset with respect to the rolling plate. The secondary rollers 8a, 8b may be mounted for rotation around a longitudinal axis of symmetry substantially parallel to the first longitudinal axis x-x.
Preferably, a pair of centering rollers 8a, 8b is provided, which centering rollers 8a, 8b are placed one opposite the other with respect to the mandrel 3 and mounted for rotation around respective axes of symmetry parallel to each other. More in particular, the centering rollers 8a, 8b are mounted for rotation in opposite directions. Even more preferably, the machine may also comprise translation means (such as one or more specific actuators) of the centering rollers 8a, 8b in a direction transversal or orthogonal to the first longitudinal axis x-x.
Preferably the side wall of the centering elements 8a, 8b is substantially configured as a respective working section of the side wall 5a of the bucking component 5, or better a central or intermediate section of the same, so that they will be shaped or cylindrical. More in particular, according to the specific non-limiting embodiment example shown in the Figures, the centering elements 8a, 8b from one side, such as upper in use, to the other, such as lower in use, have a first slightly frustoconical section 8c1 with decreasing diameter with inclination and extension substantially corresponding to that of the second slightly frustoconical section 5a2 of the side wall 5a of the bucking component 5, a second substantially cylindrical section 8c2 having extension substantially corresponding to the third section 5a3 of the side wall of the bucking component 5 and a third slightly frustoconical section 8c1 with increasing diameter and with inclination and extension substantially corresponding to the fourth slightly frustoconical section 5a4 of the side wall 5al of the bucking component 5.
A machine according to the present invention therefore delimits a working zone WZ around a portion of the mandrel 3, on which the annular element AE is fitted in use and between a portion of the side surface 5a of the bucking component 5, the surface 4a of the plate 4 and the annular elements 6a, 6b or better, the working sections 6c, 6d of the same.
If centering elements 8a, 8b are provided, then these also contribute to defining a working zone WZ together with the other machine components now listed.
Moreover, as stated above, no other machine elements are placed between the working sections 6c, 6d of the roller elements 6a, 6b, so that a diameter growing zone AZ of the annular element AE remains delimited between the roller elements 6a, 6b during the shaping/rolling.
With specific reference to the non-limiting embodiment example shown in Figures 1 to 4, the roller elements 6a, 6b may be supported each by a first group 9 mounted for rotation with respect to a second group 10, for example multicomponent, such as annular assembled and connected to one another, and angularly movable around axis y-y and z-z by a respective motor 11.
Specific bearings 12 may also be provided intended to allow the rotation between the first 9 and second 10 group, as well as in case conduits 13 for conveying cooling fluid in such groups.
Each roller element 6a, 6b further comprises a respective hollow element, such as frustoconical mounted around and dragged in rotation by a respective section or part of a respective first group 9.
As regards the actuation means 7, according to the non-limiting embodiment example shown in Figures 1 to 4, they may comprise a recirculating ball screw group.
More in particular, such a group may comprise a corresponding motor 14, such as electrical, intended to operate a threaded shaft 15 with longitudinal axis extending along the direction B-B, in turn connected to a respective roller element 6a, 6b, or better kinematically connected along the direction B-B to a respective roller element 6a, 6b. The motor 14, optionally with the interposition of a gearbox component 16, is intended to set a nut screw component 17 delimiting, together with the threaded shaft 15, seats for the screw balls, in rotation. Specific bearings 18 may further be provided between threaded shaft 15 and nut screw 17.
By operating the motor 14, a displacement of the threaded shaft 15 and thereby of the respective annular element 6a, 6b along direction B-B is determined.
If a first group 9 and a second group 10 are provided as stated above, then the recirculating ball screw is, of course, intended to move such components along the direction B-B together with the respective roller element 6a, 6b.
The plate 4 is preferably connected or kinematically connected to a roller element, preferably to the second roller element 6b, as stated above. More in particular, the plate 4 is advantageously movable in the direction B-B together with the roller element 6b, although the roller element 6b is substantially free to rotate around the respective axis z-z, for example by operating the abovementioned first group 9, without dragging also the plate 4 in rotation.
To this end, a connection group 18 may be provided, intended to connect the roller element 6b, optionally the second group 10 to the plate 4.
Moreover, if the machine is also provided with displacement means of the roller elements 6a, 6b along a third direction C-C, then the connection group 18 would be structured and connected to the roller element 6b, in such a way as to make the roller element 6 and the plate 4 integral in translation along the direction B-B but disengaged and therefore free to be moved independently along the third direction C-C.
The connection group 18 may comprise a plurality of components, such as a bracket or connection plate 19, optionally U- or L-shaped, for example extending from a lower portion of the roller element 6b or better of the second group 10 or from the actuation means 7, as well as upright components 20 or the like extending from the connection bracket 18 and supporting the plate 4 at the top.
Moreover, as stated above, the support table 4 may also be movable along a direction parallel to the longitudinal axis x-x by respective displacement means disengaged from the roller elements 6a, 6b.
In this case, means may also be provided for synchronizing the movement along the second direction B-B of the second roller element 6b and of the plate 4, such as a control unit able to detect, for example by means of specific third sensor means, the position of such components and suitably move them by means of suitable displacement and actuation means along such a direction.
In the present patent application, in order to synchronize the displacement of the roller element 6b and of the plate 4, it may also be usefully considered that the law of motion with which the displacement means displace the plate 4 is a function, according to a formula or a curve defined by a user and set for example in the synchronization means, of the law of motion with which the actuation means displace the roller element 6b.
Therefore, the synchronization between the plate 4 and the roller element 6b may be achieved only as a function of the data detected by the third sensor means, only as a function of their laws of motion set and interrelated to one another in advance or based on a combination of such solutions.
A shaping or rolling method according to the present invention, such as a circular rolling method for annular elements, implemented with a machine as described above, provides first for arranging at least one annular element AE in its rough or cogged state.
Initially and at the end of the working cycle, the machine components are removed from the working zone WZ or from the rolling zone, so as to allow loading the annular elements in their rough state as well as the unloading of the finished (shaped/rolled) annular elements.
Preferably, both roller elements 6a, 6b can move along the direction B-B, such as vertical, preferably substantially parallel to the longitudinal axis x-x of the mandrel 3 and also along the direction C-C, such as horizontal, for example transversal or orthogonal to such an axis x-x.
The same applies to the plate 4, which can preferably move along an axis parallel to the longitudinal axis x-x of mandrel 3, such as vertical and along an axis transversal or orthogonal thereto, such as a horizontal axis. Preferably, as stated above, the vertical movement of the plate 4 is synchronized with that of the second roller element 6b, this being achievable also by kinematically connecting such components along the direction B-B.
Initially, the roller elements 6a, 6b are in the first position or rest or unloading position (see Figures 5 and 6) and, preferably, at a maximum distance from each other and, optionally, with respect to a working plane D-D which corresponds, in substance, to a transversal plane of the working zone, such as a transversal plane of symmetry of the bucking component 5.
Advantageously, from this moment onwards of the method and until the end of the shaping/rolling, the horizontal movement of the mandrel 3 will be integral to the horizontal movement of the table 4.
Thereafter, the support plate or table 4 is moved to a side AE3 of the annular element AE in its rough state, the bucking component 5 against a respective portion of the side connecting surface AE2 of the annular element AE in its rough state and the first 6a and the second 6b roller element are moved in abutment against a portion of a respective side AE4, AE3 of the annular element AE in its rough state (see Figures 7 and 8).
The shaft or mandrel 3 is then inserted within the annular element AE in its rough or non-processed state or within the through gap AE1 of the same (see Figures 9 and 10), thus placing the shaft or mandrel in position with respect to the other components of machine 2, optionally within area 4f delimited by the plate 4. If desired, the mandrel 3 may be moved to the working position even before arranging the annular element AE in its rough state, thus fitting the annular element AE on the mandrel 3.
If the mandrel 3 is movable along the first direction A-A by actuation means, while the bucking component 5 is fixed in position along such a direction, the displacement of the mandrel 3 (after the suitable placement of the same within the through gap AE1) will allow moving the annular element AE in its rough state towards the bucking component 5 and thus moving the bucking component 5 against or in abutment on a respective portion of the side connecting surface AE2 of the annular element AE in its rough state.
Then, a control step of the machine or better of the components of the same is carried out, so as to shape or roll the annular element AE in its rough state and to obtain an annular element AE in its finished state (see Figures 11 to 14).
According to a method according to the present invention, a control step of the actuation means is provided during the control step so as to move the at least one first 6a and the at least one second 6b roller element approaching towards each other along the second direction B-B from the first position to the second position or towards the second position, so as to tighten the annular element AE at respective portions of sides AE4, AE3 thereof. If desired, the roller elements 6a, 6b during this step are also moved along the third direction C-C. Moreover, a control step of the displacement means is provided during the control step so as to move the support table 4 together or synchronized according to a programmed law of motion with the second roller element 6b.
Advantageously, the roller elements 6a, 6b are moved in a substantially synchronized manner along the second direction B-B and, if desired, along the third direction C-C, symmetrically or not (with reference to the working plane D-D) depending on the configuration of the annular element AE, in particular depending on the configuration of the annular element AE to be obtained, so as to adjust the height of the annular element AE and keep it on or at the working plane. Even more advantageously, the actuation means are controlled so that when the first roller element 6a is moved by a first distance approaching towards the second roller element 6b, the second roller element 6b is moved towards the first roller element 6a by a second extension distance corresponding to the first distance. This of course depends on the configuration of the annular element AE and, as will be understood, in particular if such a component is not symmetrical, with respect to the working plane D-D or in height during the shaping/rolling, different displacements of the roller elements 6a, 6b will be controlled.
During the control step, the annular elements 6a, 6b, the mandrel 3 and the bucking component 5 and, if provided, the centering elements 8a, 8b are brought into contact and thrust with a respective portion of the annular element AE, so as to suitably shape the latter, leaving a growing zone AZ free, as stated above, preferably between the roller elements 6a, 6b. Preferably, the rolling plate 5 can be kept fixed in position while the height of ring AE can be managed by the movement of the mandrel 3, although the contrary is also possible. Moreover, during the control step, the support table 4 is also displaced (with displacement integral or synchronized with that of the lower roller element 6b) so as to properly support the annular element AE during shaping/rolling.
As regards the centering elements or components 8a, 8b, they keep the annular element in the working zone and contribute to "accompanying" or driving the substantially diametrical growth thereof and to ensuring the substantial cylindricity or cylindrical development. To this end, the centering elements 8a, 8b push the annular element or better a portion of the side wall AE2 of the same at angularly offset zones with respect to the centering component 5 and to the roller elements 6a, 6b.
During this step, the side connecting surface of the annular element AE is shaped mainly as a function of the configuration of the side surface of the bucking component 5.
According to the specific and non-limiting embodiment example shown in the Figures, during the shaping or rolling step, the side connecting surface AE2 of the annular element AE is configured so as to have swollen portions AE5, AE6 alternating with recess portions AE7, and during such a step the outer diameter of the annular element AE as well as the diameter or cross-section of the through gap AE1 of the annular element increase gradually.
This is achieved particularly by suitably and jointly controlling the displacement along a direction parallel to the axis of the mandrel 3 of the first 6a and of the second 6b roller element, such a control ensuring the holding of the annular element AE in or at the working plane as well as the squashing of the same at the respective sides AE3, AE4 throughout the shaping/rolling.
At the end of the shaping/rolling cycle, the annular elements 6a, 6b and, if provided, the centering elements 8a, 8b end the rolling cycle by suitably calibrating the dimensions of the annular element AE (see Figures 13 and 14).
Then, once the rolling or shaping has been completed, the plate 4 with the mandrel 3 and the roller elements 6a, 6b are optionally moved away from the bucking component 5, the roller elements 6a, 6b are displaced, such as lifted up to the maximum opening, and the mandrel 3 is removed from the annular element, such as by lifting it or the annular element AE is removed therefrom. If the centering elements 8a, 8b are provided, these are moved away from the annular element AE.
Both the mandrel 3 and the roller elements 6a, 6b are then moved away from the working zone WZ so as to free it and so as to allow unloading the shaped/rolled annular element AE (see Figures 15 to 18).
A new rough annular element may thus be loaded and the working cycle repeated.
With a machine and a method according to the present invention, as will be understood, it is possible to obtain an annular element in a simple and effective manner.
The control and actuation of both roller elements along a direction substantially parallel to the axis of the mandrel also allows suitably tightening the annular element and correctly conveying the material of the annular element to obtain the desired configuration.
This also ensures a uniform distribution of forces on the annular element, in particular of the shear forces on the protruding or swollen portions AE5, AE6 of the annular elements, in particular on intermediate swollen portions AE5, i.e. swollen portions intended to be affected and shaped between protruding parts of the bucking component. Otherwise, in particular when one of the two roller elements 6a or 6b is not movable along the direction B-B, then there might be very strong shear forces in particular on the protruding or swollen portions.
With reference to the teachings of documents JPS56165507A and JPH02133131A , as will be understood, they do not teach a machine with roller elements or cones that can be moved closer or apart to/from each other, so as to tighten or release said at least one annular element during the shaping, nor a machine provided with a table intended to support the annular element and to be moved in an integral or synchronized manner with the lower roller element.
More in particular, JPS56165507A explains how to control the movement kinematics of a ring rolling mill and describes in detail the operation of the rolling mill using mathematical formulas and block diagrams.
To this end, it is clear from the analysis of the mathematical formulas shown in such a Japanese document that it does not contemplate the possibility of vertically moving the two cones synchronously so as to deform the ring in height.
With reference to this aspect, in fact, it will be seen that the only formula representative of the volume of a rolled ring shown in JPS56165507A is the following: $V = π * {((D_{0} - I_{0}) / 2)}^{2} * H_{0}$
wherein the height indicated as H₀ represents the total height of the initial ring (subscript 0).
As for the mathematical law that describes the change in height of the ring over time and therefore the various dimensions to be imparted as machine movement control (Δt), the following formula is given: $H = H_{0} + h (t)$
From the analysis of these formulas, it is clear that the operating method of the machine of JPS56165507A provides for no movement of the lower cone in the ring rolling step, this because if the two cones were to travel different vertical deformation strokes, the mathematical formulas for operating the rolling mill should clearly indicate two different h(t), such as hi(t) and h2(t), one for each cone, while there is no trace of this aspect in JPS56165507A .
Therefore, as can be seen, according to such a prior art document a displacement of the lower cone is only provided before and after but not during the actual ring rolling step, as it is also clear from an examination of the figures of JPS56165507A and of the description thereof, taking into account that the actual rolling step is said to be that shown in figures 1b and 1c, in which the lower cone remains at the same height that it had before starting the rolling.
As for JPH02133131A , it teaches a machine wherein the inner and outer cylindrical surface of a ring is heated up by Joule effect, so as to compensate for heat loss during the circular rolling. To do this, it is necessary to discharge highfrequency electric current through cones acting as electrodes; for the electrical discharge to occur, the electrodes/cones must be well in contact with the surface of the ring, therefore cylinders intended to press the cones towards the ring are provided. Therefore, according to JPH02133131A there is not an actuation and a control of the cone position, in particular of the lower cone, but the cylinder associated with the lower cone actually acts like a spring able to compensate for any detachments of the cone from the ring.
Moreover, as already mentioned, JPS56165507A and JPH02133131A do not provide a support plate or table sliding along a direction substantially parallel to the longitudinal axis of the respective mandrel, and considering the above with reference to the displacement of the respective lower cone, there would be no reason to provide such a technical feature in the machines of such Japanese documents.
To this end, it should be noted that in addition to not teaching a machine like the one object of this patent application, the above Japanese patent documents do not teach the technical problem underlying the latter, i.e. providing a machine for shaping a ring which allows creating annular elements of desired shape in a simple and effective manner, suitably tightening the annular element and correctly conveying the material of the same to obtain the desired configuration and with suitable distribution of the forces on the annular element.
In fact, JPS56165507A does not provide for moving the lower cone during the rolling process, while JPH02133131 A provides for cylinders only for keeping the lower cone in pressure on the ring for the reasons mentioned above, but there is no control and relative actuation of such a cone.
Changes and variants of the invention are possible within the scope of protection as defined by the claims.

Claims

Machine for shaping at least one annular element (AE), comprising:
- a support frame (2);

- at least one shaft or mandrel (3) extending around one first longitudinal axis (x-x) and intended to be inserted or fitted inside said at least one annular element (AE);

- at least one plate or table (4) for supporting said at least one annular element (AE) and extending at least partly around said at least one shaft or mandrel (3), said at least one plate or table (4) being designed to support said at least one annular element (AE) at one side (AE3) thereof;

- one bucking component (5) extending to the side of said at least one shaft or mandrel (3) and intended to abut against and to deform the side connecting surface (AE2) of said at least one annular element (AE);

- at least one first (6a) and one second (6b) roller elements, each intended to abut against a portion of a respective side (AE4, AE3) of said at least one annular element (AE),

- actuation means (7) intended to move said at least one first (6a) and said at least one second (6b) roller elements along one direction (B-B) substantially parallel to said first longitudinal axis (x-x), so that said first (6a) and said second (6b) roller elements can be moved closer and apart with respect to each other in such a way as to tighten or release said at least one annular element (AE),

- displacement means for displacing said support plate or table (4) along a direction substantially parallel to said first longitudinal axis (x-x).
Machine according to claim 1, characterized in that said actuation means comprise at least one first actuator (7) intended to move said at least one first roller element (6a) along said direction (B-B) as well as at least one second actuator (7) intended to move said at least one second roller element (6b) along said direction (B-B), so that said first (6a) and said second (6b) roller elements are movable independently one from the other along said direction (B-B).
Machine according to claim 1 or 2, characterized in that said first actuator and/or said second actuator comprise/comprises a recirculating ball screw group, a planetary roller screw group, an oleodynamic bearing screw unit, a hydraulic actuator, a pneumatic actuator, an electric actuator or a rack and pinion group.
Machine according to any one of the preceding claims, characterized in that it comprises means for synchronizing the displacement of said second roller element (6b) and of said at least one plate (4) along a direction substantially parallel to said first longitudinal axis (x-x)
Machine according to any one of claims from 1 to 3, characterized in that said support plate or table (4) is kinematically connected to said first (6a) or to said second (6b) roller so as to be displaceable together with it along said direction (B-B) substantially parallel to said first longitudinal axis (x-x).
Machine according to any one of the preceding claims, characterized in that at least one between said at least one mandrel (3) and said bucking component (5) can be moved closer and apart with respect to the other along one direction (A-A) substantially transversal to said first longitudinal axis (x-x).
Machine according to any one of the preceding claims, characterized in that at least one between said at least one mandrel (3) and said bucking component (5) is mounted for rotation around said first longitudinal axis (x-x) or parallel to it (w-w).
Machine according to any one of the preceding claims, characterized in that said at least one first roller element (6a) and said at least one second roller element (6b) have a respective working section (6c, 6d) intended to engage a portion of a respective second (AE4) or first (AE3) side of said at least one annular element (AE), while said at least one support plate or table (4) has a working surface (4a) intended to support said first side (AE3), said working surface being substantially aligned or at the same level of said working section (6d) of said second roller element (6b).
Machine according to claim 8, characterized in that said at least one support plate or table (4) delimits at least one opening or window (4b) for housing or positioning said working section (6d) of said second roller element (6b).
Machine according to any one of the preceding claims, characterized in that said at least one first (6a) and said at least one second (6b) roller elements are placed opposite to said bucking component (5) with respect to said at least one mandrel (3).
Machine according to any one of the preceding claims, characterized in that it comprises at least one centering element (8a, 8b) placed to the side of said at least one shaft or mandrel (3) and angularly offset with respect to said bucking component (5), said at least one centering element (8a, 8b) being intended to press said annular element (AE) at a portion of the side connecting surface (AE2) thereof angularly offset with respect to that engaged by said bucking component (5).
Machine according to any one of the preceding claims, characterized in that it comprises means of displacement of said roller elements (6a, 6b) along a third direction (C-C) orthogonal to said first longitudinal axis (x-x) moving closer to or apart from said mandrel (3).
Machine according to any one of the preceding claims, characterized in that it comprises control means of said at least one first (6a) and said at least one second (6b) roller elements, intended to synchronize the displacement of said roller elements (6a, 6b) by said actuation means along said direction (B-B) substantially parallel to said first longitudinal axis (x-x).
Machine according to claim 13, characterized in that said control means comprise a program control unit as well as first sensor means intended to detect the position of said roller elements (6a, 6b) and to communicate it to said program control unit, so that said program control unit is intended to control said actuation means (7) and said displacement means in such a way as to keep during the shaping one annular element (AE) on said support table (4) and in such a way as to squash said annular element (AE) at respective sides (AE3, AE4) by said roller elements (6a, 6b).
Machine according to claim 14, characterized in that said control means comprise second sensor means of the force applied to an annular element (AE) by said roller elements (6a, 6b), said second sensor means being in communication with said program control unit.
Machine according to any one of the preceding claims, characterized in that said actuation means (7) are intended to displace said at least one first (6a) and said at least one second (6b) roller element during the shaping of at least one annular element (AE).
A method for shaping at least one annular element (AE) by a machine according to any one of the preceding claims, characterized in that it comprises:
- arranging at least one annular element (AE) in its rough state;

- inserting said at least one shaft or mandrel (3) into said at least one annular element (AE) in its rough state;

- bringing said at least one support plate or table (4) at one side (AE3) of said at least one annular element (AE) in its rough state;

- moving said mandrel (3) and/or said bucking component (5) so that said bucking component (5) is against the side connecting surface (AE2) of said at least one annular element (AE) in its rough state;

- bringing said at least one first (6a) and said at least one second (6b) roller elements in abutment against one portion of a respective side (AE4, AE3) of said at least one annular element (AE);

- carrying out a control step of said machine so as to shape said at least one annular element (AE) in its rough state and to obtain at least one annular element (AE) in its finished state;
said control step including at least one checking step of said actuation means (7) so as to move said at least one first (6a) and said at least one second (6b) roller elements closer to each other along said direction (B-B) substantially parallel to said first longitudinal axis (x-x), so as to tighten said at least one annular element (AE), said control step further comprising a checking step of said displacement means so as to move said support table (4) together or synchronized with said second roller element (6b).
Method according to claim 17, characterized in that said roller elements (6a, 6b) are moved in a substantially synchronized manner along said direction (B-B) substantially parallel to said first longitudinal axis (x-x), so as to adjust the height of said annular element (AE) squashing it at the respective sides (AE3, AE4) during the shaping.
Method according to claim 18, characterized in that said displacement means are controlled so as to keep, during the shaping, said annular element (AE) on or at said support table (4).