IMPROVED LINEAR ELECTROMECHANICAL ACTUATOR

Description

TITLE: “Improved Linear Electromechanical Actuator” DESCRIPTION Scope of application This description concerns a linear electromechanical actuator in 5 agreement with the preamble of claim 1. In particular, but not exclusively, the present invention relates to a linear electromechanical actuator for controlling a control surface of a aircraft, for example, for vertical take-off, a vessel or the plant steering of a vehicle or similar applications. 10 A further object of the present invention is a method for verifying a fault electrical, electronic and / or mechanical in a linear electromechanical actuator Description of the prior art There are known linear electromechanical actuators equipped with electronics control and command which are operated by an electric motor whose task 15 is to transform the rotary motion of the electric motor into a linear motion of back and forth of a pusher so as to control the positioning of a surface of government. To this end, the electric motor is connected, through a reduction device, to the pusher which, in turn, is connected to the control surface to govern the 20 position that this surface must assume according to the commands received from the control and command electronics. Usually, the reduction gear comprises a nut screw on which a screw (or a screw on which a nut screw slides) which, in turn, is connected to the pusher and, thanks to an anti-rotation device, the screw (or nut) is allowed to 25 only linear and non-rotational movement so as to obtain the linear back-and-forth motion of the pusher. Such linear electromechanical actuators have been used, for example, for to control the so-called secondary control surfaces of an aircraft, such as for example airbrakes, spoilers, flaps, trim tabs but also for 5 enable the opening of hatches as well as for other uses requiring low power, speed and response times, that is, for all those so-called "non-standard" applications safety critical”. US 4179944 describes an example of an electromechanical actuator linear equipped with two motors directly coupled to a shaft via nuts 10 ball recirculation. This electromechanical actuator does not provide redundancy. sufficient to guarantee a “fault tolerance” for both mechanical and electrical failures electrical and electronic nature. In fact, this electromechanical actuator allows the identification of only two types of mechanical failures mainly related to the moving shaft, therefore it guarantees limited redundancy especially in the 15 cases of mechanical failure between the motor and the shaft. Furthermore, this electromechanical actuator it could have problems in case of electrical and / or electronic failure related to the motors electric. In fact, such motors should be sized to ensure a operation in both operational and failure conditions such as, for example for example, to win couples due to mechanical failures in case of stalling of one of the two 20 engines. Prior art problem However, the reliability of an electromechanical actuator of the type reported above in the US document 4179944 does not allow the use of the same in installation 25 dedicated to the control of an aircraft's primary control surfaces, the swashplate of a helicopter, the steering system of a vehicle or the rudder of a ship, that is, more in in general, of all those so-called “safety critical” applications. This is due to the low reliability of the electromechanical actuator described above resides both in the electrical part, i.e. in the electric motor, in the 5 control and command electronics as well as the possibility of a seizure of the part mechanics (the so-called mechanical “jamming”). To overcome this problem, architectures are used today, for example which have two identical actuators that move the same control surface allowing for electrical, electronic and mechanical redundancy, but typically with 10 consequent increases in weight and complexity of the system or a single actuator equipped with a differential gear box that allows the use of two independent electric motors and two independent electronics which, by moving the same mechanics. Furthermore, “safety critical” applications, such as those mentioned above, require 15 very fast operating dynamics that do not allow the use of boxes Differential gears generally characterized by excessive operating play high. Further documents US 2013249464, WO2010027701 and US 2005269887 describe examples of electromechanical actuators that do not provide redundancy 20 sufficient to guarantee a “fault tolerance” for mechanical and electrical failures and electronics. In particular, documents “US 464” and “WO 701” describe actuators equipped with two electric motors dependent on each other and directly coupled to the shaft move by means of ball nuts. Therefore, a mechanical failure, for example 25 example relating to the motor-shaft coupling for one or both motors, This causes the actuator itself to block. Furthermore, the motors must be sized to generate a torque capable of ensuring operation in both operating conditions that in conditions of electrical and / or electronic failure of one of the two engines. The document “US 887” instead describes an actuator equipped with a battery of 5 electric motors coupled directly to the shaft to be moved by recycling rollers. Therefore, even in this case, a mechanical failure related the motor-shaft coupling causes the actuator itself to stall, preventing the movement of the tree. Further documents describe bulky electromechanical actuators in terms of 10 in length to ensure a shaft travel length adequate for the specific applications. This longitudinal bulk translates into construction problems and assembly inside the relevant location with specific dimensions. Furthermore, there is an ever-increasing need to detect electrical, electronic and / or mechanical and in particular the so-called latent failures 15 of the actuator or actuators that are part of the architectures described above. The faults latent, as is known, can act on a component, whether it is mechanical or electrical / electronic, on a circuit, or on a system and are those faults that cannot be are still manifested, but whose activation event has already occurred without this is an impossibility of using the architecture. 20 In particular, the architectures described above are tested during the scheduled periodic inspections and, if no anomalies are highlighted, such architectures are deemed to be completely efficient and therefore usable. However, during their use, undetected and / or uncorrected faults may arise. detectable which impact more or less seriously on efficiency but, such failures, 25 remain latent until the next inspection, thus compromising the warranty proposed by redundancy. This is a serious problem especially when using the actuator electromechanical in “safety critical” applications. 5 SUMMARY OF THE INVENTION The purpose of the invention in question is to create an actuator linear electromechanical system capable of solving the problems of the current state of the art described. These goals are achieved by means of a linear electromechanical actuator, in 10 agreement with claim 1 below. It is a further aim of the present invention to provide a method for check for an electrical, electronic and / or mechanical fault in an actuator linear electromechanical system capable of solving the problems of the current state of the art described. 15 Advantages of the invention By means of one embodiment of the present invention, it is possible to create a linear electromechanical actuator of the Fault Tolerant Differential type that It is also applicable for the control of primary control surfaces since it allows the translation of the pusher even in conditions of failure of the part 20 electrical, control electronics and / or a seizure of the mechanical part. Furthermore, thanks to an embodiment of the present invention, it is it is possible to create a linear electromechanical actuator whose dynamic performance are much higher than electromechanical actuators which require the use of differential systems such as gear boxes. 25 Furthermore, thanks to an embodiment of the present invention, it is it is possible to make a linear electromechanical actuator with a weight and smaller dimensions compared to electromechanical actuators which require the use of gear boxes and other differential devices as well as the use of a number high number of screw-nut couplings. Specifically, the present invention 5 allows to provide a longitudinally compact electromechanical actuator capable to maintain the same stroke length of the shaft and therefore of the pusher for the specific applications. Furthermore, thanks to an embodiment of the present invention, it is it is possible to create a linear electromechanical actuator with high reliability 10 compared to electromechanical actuators that require the use of gearboxes and other differential devices. Furthermore, thanks to an embodiment of the present invention, it is it is possible to create a linear electromechanical actuator capable of guaranteeing a tolerance to electronic, electrical, and mechanical faults. In particular, the use 15 of an intermediate stage increases the redundancies of the system ensuring a high reliability compared to electromechanical actuators currently used in the prior art as described above. Furthermore, thanks to an embodiment of the present invention, it is it is possible to create a linear electromechanical actuator that allows to minimize 20 frictions, especially at low temperatures, optimizing overall efficiency of the actuator compared to electromechanical actuators which require the use of gear boxes and other differential devices. Furthermore, thanks to an embodiment of the present invention, it is it is possible to create a linear electromechanical actuator that reduces the operating time 25 response for tree movement in case of jamming. Furthermore, thanks to an embodiment of the present invention, it is it is possible to create a linear electromechanical actuator with smaller dimensions and weights contents. BRIEF DESCRIPTION OF THE DRAWINGS 5 The features and advantages of this disclosure will be apparent from the following detailed description of a possible practical embodiment, illustrated by way of non-limiting example in the set of drawings, in which: - Figure 1 shows a sectional view of the linear electromechanical actuator in accordance with a first embodiment of the present invention in a 10 first retracted configuration; - Figure 2 shows a sectional view of the linear electromechanical actuator in accordance with the embodiment of figure 1 in a second extended configuration; - Figure 3 shows a sectional view of the linear electromechanical actuator in accordance with the embodiment of figure 1 in an extended configuration in case of 15 jamming; - Figure 4 shows a flowchart of the method for checking for the presence of an electrical, electronic and / or mechanical fault in an electromechanical actuator linear, in accordance with the present invention. 20 DETAILED DESCRIPTION Even if not explicitly highlighted, the individual characteristics described with reference to the specific creations, they must be understood as accessories and / or interchangeable with other features, described in reference to other examples of realization. 25 With reference to the attached figures, 1 represents a total of linear electromechanical actuator according to the present invention. With reference to figures 1-3, the actuator 1 comprises a structure of containment 2, preferably of the rigid type, and a pusher 3. This structure of containment extends from a bottom 2A to an exit opening 2B extending along a 5 prevalent direction of development. Pusher 3 represents the active element of actuator 1. In particular, the pusher 3 is designed to translate, with respect to the structure of containment 2, to at least partially escape from the containment structure 2, preferably from the outlet opening 2B, during actuator operation 10 1. The translation of the pusher 3 takes place through a special opening provided in containment structure 2. The actuator 1 comprises a mechanical reduction apparatus 4, arranged in the containment structure 2, which is configured to be rotatable about an axis of 15 rotation X. The actuator 1 comprises motor means 5, associated with the containment structure 2, preferably arranged inside the containment structure 2, which are operationally connected with the mechanical reduction apparatus 4 to place it in rotation around the X axis. 20 The actuator 1 comprises a shaft 6, inserted inside the apparatus of mechanical reduction 4, which is connected to the pusher 3. In particular, the shaft 6 comprises a first terminal end 6' and a second terminal end 6'', where the first terminal end 6' is connected to a 3' hooking eye. This first terminal end 6' can come out with the 25 pusher 3 at least partially from the containment structure 2 during the actuator operation 1. The actuator 1 includes an anti-rotation mechanism which is active on shaft 6 to prevent rotation of the shaft itself around the axis of rotation X. Specifically, the anti-rotation mechanism can be internal or external to the 5 containment structure 2. In accordance with a preferred embodiment, the anti-rotation mechanism is indicated with 7 in figure 1. The shaft 6 is therefore connected to the mechanical reduction apparatus 4 in such a way such that a rotation of the mechanical reduction apparatus 4 determines a translation of shaft 6 along the rotation axis X and therefore a linear displacement 10 of pusher comings and goings 3. Advantageously, the mechanical reduction apparatus 4 comprises a nut screw 8 and a longitudinal thrust element 9 which are independent of each other, that is, they are two separate and distinct elements. The nut screw 8 and the longitudinal thrust element 9 are rotatable around 15 to the rotation axis X under the action of the driving means 5. It is worth noting that the longitudinal thrust element 9 is inserted inside the nut screw 8 at least partially. The nut 8 has a first nut thread 8A having its relative preferably defined step. 20 The longitudinal thrust element 9 along the rotation axis X has a 9B linear guide preferably equipped with a movement step. Specifically, the longitudinal push member 9 may be a linear guide 9B. Preferably, in this embodiment the linear guide 9B defines a relative movement step. 25 In this case, the linear guide 9B has a relative external surface which may have one or more substantially smooth longitudinal grooves 9A suitable for define such linear guide 9B. It is worth noting that such grooves 9A extend substantially for the entire length of the longitudinal thrust member 9 and are configured to engage spheres as detailed below. 5 It is worth noting that the nut 8 and the longitudinal thrust element 9 They have a thread pitch and a drive pitch respectively. The nut screw 8 and the thrust element 9 have a prevailing direction of development which coincides with the aforementioned rotation axis X. Both the nut screw 8 and the thrust element 9 are enabled for the motion of 10 rotation around the rotation axis X while each of them is prevented from translation along the rotation axis X for example by means of special shoulders blocking or other solutions known to the technician in the sector and therefore not described. In order to obtain the rotation of the nut screw 8 and the thrust element longitudinal 9 around the rotation axis X, the actuator 1 comprises a pair of 15 bearings 13, 13' active at the ends of the containment structure 2 acting on the nut screw 8. The actuator 1 also includes a further pair of active bearings 14 one end in the containment structure 2 acting on the push element longitudinal 9. 20 Thus the nut screw 8 and the longitudinal thrust element 9 are rotatable around to the rotation axis X under the action of the motor means 5, which are connected to the nut screw and the longitudinal thrust element or by means of a kinematic chain (for example example a gear box including a differential) or directly connected to the nut 8 and the longitudinal thrust element 9. 25 In accordance with a preferred embodiment, the nut 8 comprises substantially cylindrical hollow body defining a thrust channel 8B configured for receive at least in part the shaft 6 and the longitudinal thrust element 9. In the specifically, the hollow body of the nut 8 has a threaded internal surface where a first 8A nut thread is obtained. 5 The longitudinal thrust element 9 comprises a cylindrical body defining the linear guide and inserted inside the hollow body 8B of the nut 8. This body cylindrical longitudinal thrust element 9 instead has the external surface equipped with longitudinal grooves 9A. In one aspect, the mechanical reduction apparatus 4 comprises means of 10 coupling 10, 11, 15, 16 configured to mechanically couple the nut 8 and the longitudinal thrust element 9 with the shaft 6, so that at a rotation of the nut screw 8 and / or of the longitudinal thrust element 9 determines a translation of shaft 6 along the rotation axis X. In other words, the actuator 1 is able to ensure a translation of the shaft 6 15 along the rotation axis X even in conditions of failure of one of the motor means 5, or of the related electronics, or of the seizure of the coupling means 11, 15 and 16 with the nut screw 8 and with the longitudinal thrust element 9 indistinctly in to ensure complete extraction of the shaft 6. To this end, the coupling means 10, 11, 15 and 16 comprise a stage 20 intermediate coupling 10 inserted between said nut screw 8 and said element longitudinal thrust 9. Specifically, this configuration provides that the intermediate stage 10 is inserted inside the thrust channel 8B, i.e. at least partly inside the cavity of the hollow body associated with the nut 8. 25 This intermediate coupling stage 10 is configured to rotate, translate or to rotate and translate with respect to the thrust channel. The intermediate coupling stage 10 is at least partly inserted inside of the nut 8 and in the shaft 6. The intermediate coupling stage 10 is configured to receive at least in 5 part the longitudinal thrust element 9. Specifically, the thrust element longitudinal 9 is at least partly inserted inside the intermediate stage 10 and changes the portion inserted into said stage depending on the extraction and / or of the presence of faults and / or jamming such as the intermediate stage with respect to the channel push 8B. 10 It is worth noting that the intermediate coupling stage 10 extends along a prevailing development direction between a first 10' end facing the bottom of the containment structure and an opposite second end 10''. In accordance with a preferred embodiment, the coupling means 10, 11, 15 and 16 include: 15 - first and second mechanical connection means 15, 16 configured for mechanically couple the intermediate coupling stage 10 with the nut screw 8 and the intermediate coupling stage 10 with the thrust element longitudinal 9, and - third mechanical connection means 11 configured to couple 20 mechanically the intermediate coupling stage 10 with the shaft 6. In accordance with a preferred embodiment, the intermediate stage of coupling 10 is inserted at least partially into shaft 6 and changes the inserted portion depending on the extraction and / or the presence of faults and / or jamming. Preferably, the shaft 6 is connected to the intermediate coupling stage 25 10 through third means of mechanical connection 11. In one aspect, the intermediate mating stage 10, develops around an axis that is coincident with the aforementioned rotation axis X. The intermediate coupling stage 10 has an internal cavity 10D, preferably of the through type, which develops along an axis, preferably, 5 coinciding with the aforementioned rotation axis X and which therefore gives a tubular conformation at the aforementioned intermediate coupling stage 10. In this way, the intermediate coupling stage 10 is configured to receive inside of the internal cavity 10D the longitudinal thrust element 9. This thrust element longitudinal changes the inserted portion depending on the extraction and / or presence 10 of failures and / or jamming. In accordance with a preferred embodiment, the shaft 6 is in turn a shaft cable configured to receive inside a relative shaft cavity 6C at least in the intermediate coupling stage 10 and the longitudinal thrust element 9 are part in turn inserted at least partially inside the internal cavity 10D of the stage 15 intermediate 10 as shown in the figures. It is noted that the shaft 6 is in turn inserted at least partly inside the nut 8 in the thrust channel 8B. Specifically, the electromechanical actuator provides that: - the shaft 6 has a relative cavity 6C configured to receive at least in the intermediate coupling stage 10 and the longitudinal thrust element 9 are part; 20 - the intermediate coupling stage 10 has an internal cavity 10D configured to receive at least part of the longitudinal thrust member 9; - the nut 8 has a thrust channel 8B configured to receive at least partly the shaft 6, the longitudinal thrust element 9 and the intermediate stage of coupling 10, in accordance with the previous relationships between the shaft 6, the element of 25 longitudinal thrust 9 and the intermediate coupling stage 10. In accordance with a preferred embodiment illustrated in the figures, it is found that shaft 6 is coaxial with respect to the intermediate coupling stage 10 which with respect to the nut screw 8 and the longitudinal thrust element 9 along the axis of rotation X as well as the intermediate coupling stage 10 turns out to be 5 coaxial with respect to the nut screw 8 and the longitudinal thrust element 9 always along the rotation axis X. In one aspect, the first mechanical connection means 15 comprise, preferably, a screw-nut coupling or, alternatively, a coupling made by satellite rollers, recirculating rollers or recirculating ball screws. 10 In one aspect, the second mechanical connection means 16 comprise, preferably, a ball recirculation coupling via the grooves longitudinal 9A or a spline type coupling between the intermediate stage of coupling 10 equipped with coupling grooves and the grooves longitudinal 9A. 15 In accordance with a preferred embodiment, the third means of connection mechanics 11 include a screw-nut coupling or, alternatively, a coupling achieved by satellite rollers, recirculating rollers or recirculating screw balls between said shaft 6 and said intermediate coupling stage 10, so that that upon rotation of said nut screw 8 and / or of the longitudinal thrust element 9 20 determines a rotation or a translation or a rototranslation of the intermediate stage of coupling 10 along the rotation axis X and that the intermediate stage of coupling 10, in turn, determines a translation of the shaft 6 along the axis of X rotation. In accordance with the present preferred embodiment, the shaft 6 is at least 25 partly threaded. The third mechanical connection means 11 comprises a screw-nut coupling between shaft 6 with the intermediate coupling stage 10. Specifically, the shaft 6 includes a thread 6A machined internally, in other words on the entire surface of the hollow 6A shaft. It is noted that the shaft 6 may be a hollow shaft and the third connecting means 5 mechanics 11 include a screw-nut coupling between the screw shaft 6 with the intermediate mating stage 10. Preferably, the thread of the shaft 6 is arranged in proximity to the second end of said shaft 6''. Furthermore, the shaft may have an external surface smooth extended between said first and second ends 6', 6''. In other words, the shaft 6 10 has a smooth portion 6B on the external surface and a threaded portion 6A on the inner surface. In accordance with a preferred embodiment, the intermediate stage of coupling 10 is interconnected with the nut 8 through a respective screw-nut coupling obtained with the respective first connection means 15 mechanics 15. Alternatively, the first mechanical connection means 15 can be materialize in a mechanical coupling of the satellite roller type, roller recirculation or ball screw. The intermediate coupling stage 10 is interconnected with the coupling element longitudinal thrust 9 through a respective linear guide coupling obtained 20 with the respective second mechanical connection means 16. Following a rotation of the nut screw 8 and / or the thrust element longitudinal 9 imparted by the motor means 5, a rotation or a translation or a rototranslation of the intermediate coupling stage 10 along the rotation axis X and that the latter, i.e. the intermediate coupling stage 25 10, in turn determines a translation of the shaft 6 along the said rotation axis X. In accordance with a preferred embodiment, the intermediate stage of coupling 10 presents externally, i.e. on its external surface, in correspondence of the first end 10' a first thread 10A configured for mate to the nut 8, preferably to the first thread of nut 8A. 5 Furthermore, the intermediate coupling stage 10 has internally, i.e. on its internal surface, at the first terminal end 10' a coupling element 10B for coupling with the respective push element longitudinal 9. It is worth noting that the first 10A thread preferably covers only one 10 portion of the outer surface of the intermediate coupling stage 10 in near the respective 10' end and extends towards the central area of ​​the stadium intermediate coupling 10. The coupling element 10B is arranged internally to the surface of the intermediate stage 10 in proximity of the first terminal end 10' interposing 15 between the intermediate coupling stage 10 and the longitudinal thrust element 9. Specifically, the first 10A thread can only cover a portion of the outer surface intermediate coupling stage 10, in particular a portion which originates from the respective 10' terminal end and extends towards the area central of the intermediate coupling stage 10. The remaining external surface 20 has a shape that allows it to mate with shaft 6 as shown below. In accordance with a preferred embodiment, such coupling element 10B features a 40 ball screw device coupled to the 9B linear guide. Specifically, the device 40 is mechanically associated with the grooves longitudinal 9A by means of ball recirculation coupling. 25 In accordance with an alternative embodiment to the previous one, this element 10B coupling features mating grooves configured for mate with the longitudinal grooves 9A so as to define a coupling grooved. It is worth noting that these mating grooves can also extend along the intermediate stage being obtained on the internal surface of the stage 5 intermediate coupling 10. Preferably, such coupling element 10B can extend along the intermediate mating stage 10. In one aspect, the longitudinal grooves 9A can have shapes different in the case of ball recirculation coupling and in the case of coupling grooved. Specifically, in the grooved coupling embodiment the 10 longitudinal grooves 9A and the corresponding mating grooves can have trapezoidal shape or other shapes known to those skilled in the art. Preferably, the coupling between the intermediate coupling stage 10 and the nut screw 8 is realized in the screw-nut screw coupling or, alternatively, a coupling achieved by satellite rollers, recirculating rollers or recirculating screw 15 spheres where for example the intermediate coupling stage 10 is the screw and the nut 8 is the nut screw and the coupling between intermediate coupling stage 10 and the longitudinal thrust element 9 is realized in the coupling between the linear guide 9B of the thrust element 9 and ball recirculation of the intermediate stage of coupling 10 acting on the linear guide or grooved type. 20 For example, the first 10A thread is mated with the thread of the nut screw 8 and the ball recirculation device 40 of the coupling element 10B is coupled with the outer surface of the longitudinal thrust element 9, i.e. to the longitudinal grooves 9A. Alternatively, the first thread 10A is coupled with the thread of the nut 8 and the coupling element 10B is coupled 25 with the outer surface of the longitudinal thrust element 9, i.e. to the grooves longitudinal 9A by means of relative coupling grooves. Preferably, it is worth noting that since the nut 8 is the thrust element longitudinal 9 are independent of each other but are still constrained mechanically with the screw-nut engagement or, alternatively, a coupling 5 made by satellite rollers, recirculating rollers or ball screw and guide linear ball recirculation with the intermediate coupling stage 10, then also the first thread 10A and the ball recirculation device 40 of the element coupling 10B of the intermediate coupling stage 10 are with each other constrained by the intermediate element 10 being made on the same. 10 In accordance with a preferred embodiment, the intermediate stage of coupling 10 includes externally a second thread 10C. This second 10C thread is configured to mate with a 6A thread on shaft 6. Preferably, such second 10C thread extends onto the outer surface of the hollow body of the intermediate stage 10 preferably between the first thread 10A and 15 second end 10''. In accordance with a preferred embodiment, the intermediate stage of coupling 10 includes a shoulder 10F between the first thread 10A and the second thread 10C. This shoulder 10F also defines an end stop for the shaft 6 against which it abuts. It is worth noting that the first thread 10A and the 20 second thread 10C of the intermediate stage of coupling 10 are mutually spaced with respect to a direction perpendicular to the direction of X development due to the presence of the 10F shoulder. Specifically, the shaft 6 has a relative thread, which has a certain pitch and direction and which is interconnected with the second 10C thread so as to 25 create the screw-nut coupling between them. Preferably, the thread pitch of the shaft 6 is different, e.g. greater or less than or equal in modulus but opposite in sign, with respect to the step of the thread of the nut 8 and the movement pitch of the push element longitudinal 9. 5 As previously described, the nut 8 and the thrust element longitudinal 9 are rotatable around the axis of rotation X under the action of the means motors 5, which are preferably connected to the nut screw and the thrust element longitudinal. To this end, the motor means 5 comprise two electric motors 5A and 5B each of which is operationally connected and active on the nut screw 8 and 10 on the longitudinal thrust element 9. Specifically, the first 5A electric motor is directly connected to the nut screw 8 and comprises a stator fixed to the containment structure 2 and a rotor fixed to said nut screw 8. The second electric motor 5B is connected to the longitudinal push element 9 by means of a kinematic chain 5B'. 15 It is worth noting that the rotor of the 5A electric motor is in rigid connection with the nut screw 8 which is set in rotation by the electromagnetic interaction of the respective rotor (generally with permanent magnets) and stator. The actuator 1 comprises braking means 12A, 12B active respectively on the nut screw 8 and on the longitudinal thrust element 9 to brake the rotation around 20 to the X-axis of rotation of one and / or both, depending on the operating conditions actuator 1 is subjected to as described in more detail below. In particular, the braking means 12A, 12B comprise two brakes of the type electric each of which is active respectively on the nut screw 8 and on the element longitudinal thrust 9. 25 The brakes are specifically electromagnetic coil brakes, for example. In accordance with a preferred embodiment, the actuator 1 comprises a command and control electronics for each electric motor 5A, 5B and for the first and second braking means 12A, 12B, hereinafter electric brakes. It is worth noting that each electric motor 5A and 5B as well as each electric brake 12A and 12B is 5 served by its own control electronics (not shown in the figures), which is responsible for controlling and commanding the operating status and the operation of the above mentioned electric motors 5A and 5B and electric brakes 12A and 12B. Therefore, in the preferred embodiments described, the actuator 1 comprises two independent 5A and 5B electric motors and two independent electronics that 10 move a mechanical part (i.e. the nut screw 8, the longitudinal thrust element 9, an intermediate stage 10 and a shaft 6) fully redundant and comprises the use of a nut screw 8 and a longitudinal thrust element 9, independent on which the rotors of the two electric motors 5A and 5B are directly connected. nut screw 8 and longitudinal thrust element 9 engage intermediate stage 10 15 which has on the outside and inside relative coupling portions to engage the nut screw 8 and the longitudinal thrust element 9 and the shaft 6. The intermediate stage 10 therefore has a threaded element that engages the thread of the shaft 6 which does not rotates thanks to the anti-rotation device. In accordance with a preferred embodiment, the actuator comprises a 20 plurality of sensors 17, 18 arranged within said containment structure 2 operationally connected with the command and control electronics. The plurality of sensors 17, 18 are designed to detect the position of the shaft 6 (and the rotations of the motors 5A and 5B) so as to detect its movements along the X axis. Specifically, the actuator comprises a plurality of sensors, arranged 25 inside and / or outside the containment structure 2 and appropriately configured to be in signal communication with the control electronics and control, which are designed to detect the position of the shaft 6 so as to detect the its movements along the X axis. For example, the plurality of sensors may comprise one or more of the following: 5 types of sensors: - a linear sensor (indicated with 17 in accordance with the embodiment illustrated in the figures positioned inside the shaft 6), and configured to detect the axial position of the shaft 6; - rotary sensors 18 associated respectively with the nut screw 8 and the element of 10 longitudinal thrust 9 and each configured to detect its relative rotation; - any sensors, not shown in the figures, configured to read the position axial of the intermediate coupling stage 10. - current and / or voltage sensors, not shown in the figures, integrated inside of the control electronics. 15 These sensors are connected via the command / control electronics and a suitable software in order to monitor the relative movements between the shaft 6, the nut screw 8, the longitudinal thrust element 9, the intermediate coupling stage 10 and the containment structure 2. For example, the sensor that detects the axial position of the intermediate element 20 coupling 10 and linear sensor 17 are capable of homing the rotary sensors. Advantageously, the sensor that detects the axial position of the element intermediate coupling 10e the linear sensor identifies a point of reference for the first and second rotary sensor obtaining the position of the 25 nut screw 8 and longitudinal thrust element 9. Advantageously, the presence of multiple sensors ensures redundancy for the measurement of the axial position of the shaft 6. It is worth noting that only two sensors among the foreseen plurality would be sufficient to obtain, through mathematical correlations, the axial position of shaft 6. 5 Advantageously, the control / command electronics correlates the outputs of the sensors to identify a mechanical failure (so-called “jamming”) between shaft 6 and intermediate coupling stage 10 or between the nut 8 and the thrust element longitudinal 9 and the intermediate coupling stage 10. It is also worth noting the introduction of the longitudinal thrust element 9, 10 given a certain linear travel of the shaft 6, allows to minimize: - the strokes of the intermediate stage 10 on the respective nut 8 and on the element longitudinal thrust element 9. - the travel of the shaft 6 on the respective intermediate stage 10. Consequently the axial length of the nut 8, of the element of 15 longitudinal thrust 9 and shaft 6 can be minimized with the following advantages in terms of size and weight. Furthermore, the use of a linear guide allows to reduce the possible number of jamming. It is worth noting that if jamming were to occur, actuator 1 allows 20 to extract the tree as illustrated in figure 3 fulfilling the extraction task of tree 6 in case of failure. The operation of actuator 1 in its preferred form will now be described. realization. Normal operating mode 25 During normal operation only motor 5A is powered. Motor 5B is de-energized and held in position by the brake 12B. The nut 8 rotates while the longitudinal thrust element 9 is stationary. The intermediate stage 10 translates and the shaft 6 moves together with the intermediate stage 10, thanks to the anti-rotation device. In this way, the back-and-forth motion of shaft 6 is achieved. 5 Operating mode in case of failure (failure of the 5A engine or its electronics without distinction) In case of a failure of the 5A motor or its electronics, only the Motor 5B is powered. Motor 5A is powered off and held in place by the brake 12A activated following the failure of motor 5A. In this way, the nut 10 8 is stationary. In this scenario, the longitudinal pusher 9 rotates thanks to upon activation of the relevant motor 5B. With the rotation of the push element longitudinal 9 the intermediate stage 10 rotates-translates. The shaft 6, thanks to the action of the anti-rotation device, translates along the rotation axis X due to the effect of translation and rotation of the intermediate stage 10. 15 The translation of the shaft 6 allows to obtain the linear back-and-forth motion, always along the rotation axis X, of the pusher 3. Operating mode in case of failure (seizure of the intermediate stage with the nut and / or the thrust element 9) In case of mechanical failure (so-called “jamming”) of the stadium 20 intermediate 10 with the nut screw 8 and / or with the longitudinal thrust element 9. The motors 5A and 5B are powered. The nut 8 and the longitudinal thrust element 9 rotate. at the same speed. The intermediate stage 10 rotates around the rotation axis X integrally with the nut 8 and the longitudinal thrust element 9. The shaft 6, thanks to the action of the anti-rotation device, it translates along the rotation axis X as follows 25 to obtain the linear back-and-forth motion, always along the rotation axis X, of the pusher 3 Operating mode in case of failure (seizure of the shaft with the stage intermediate) In case of failure (so called “jamming”) of shaft 6 with the 5 intermediate stage 10, the actuator operates in the same way as the “Mode” situation normal operating” It is a further aim of the present invention to provide a method for check for an electrical, electronic and / or mechanical fault in the actuator linear electromechanical 1 previously described. 10 By means of one embodiment of the present invention, it is possible to realize a method for verifying in a linear electromechanical actuator, of the type Fault Tolerant Differential, any electrical, electronic and / or mechanical faults, such as latent faults. Advantageously, the method according to the present invention allows to 15 Identify the type of fault in a linear electromechanical actuator more quickly compared to the known technique described above. Furthermore, thanks to an embodiment of the present invention, it is It is possible to create a method that identifies the type of mechanical failure in the actuator linear electromechanical and which activates the electric motors in order to overcome the failure 20 found. In particular, the actuator is equipped with a series of sensors that work together between them to identify the type of failure. With reference to the operating modes previously described, it will be now described the method to check for the existence of any problems or faults, in in particular the latent faults, in the electromechanical actuator 1 in accordance with the scheme 25 of figures 8. Operating method to check for any faults During normal operation, it is possible to check for faults, such as electrical, electronic, and / or mechanical in the linear electromechanical actuator 1 through the phases of: 5 - activate 23 the electric motor 5A, block 23, to move rotationally the nut 8 and keep the brake 12B engaged to hold the push element longitudinal 9 stop in position; - check 24, block 24, during said activation phase 23, that the shaft 6 translate with respect to said containment structure 2. 10 In particular, thanks to the command and control electronics and the plurality of sensors 17, 18 it is possible to identify whether the shaft 6 is actually translated with respect to to the containment structure 2. According to one aspect, if there are no faults, branch SI of block 24, then it is it is expected that the activation phase of the 5A electric motor will occur with a 15 predetermined activation interval T, block 26. For example, the activation interval T can have a repetition rate of constant or variable duration. If shaft 6 does not translate with respect to containment structure 2, branch NO of block 24, then it is expected to intervene according to one of the methods foreseen for 20 ensure correct operation of actuator 1, block 27 determination phase of the type of fault, and to report the type of anomaly found, block 28. In particular, in the event that the command and control electronics does not detect the translation of shaft 6, then the control electronics enters a mode so-called failure operation. 25 To this end, the command and control electronics through the sensors identifies which electrical or electronic component (for example one of the two electric motors or of the electronics itself) or mechanical component (e.g. seizure of the stage intermediate with one between nut screw and longitudinal thrust element indistinctly or shaft seizure with the intermediate stage) present a fault. 5 Below are ways to identify and remedy the in the event of a failure of an electrical or electronic component or a component actuator mechanic 1. In such scenarios, the method always involves informing about the detected fault, blocking 28. 10 Operating mode in case of failure of one of the two electric motors or of the relative electronics without distinction The method determines what type of failure occurred, and, if so, where the failure is in one of the two electric motors 5A or 5B or in the related electronics indistinctly, block 29, then a phase of activating the 12A electric brake is expected 15 or 12B so as to block the rotation of the nut screw 8 or the thrust element longitudinal 9 on the engine / electronics side not working, block 30. Operating mode in case of failure (seizure of the intermediate stage with the nut screw and / or with the longitudinal thrust element 9) The method determines what type of failure occurred and, if so, 20 where the failure is a mechanical failure (so-called “jamming”) of the intermediate stage 10 with the nut 8 and / or the longitudinal thrust element 9, block 31, for example seizure of the intermediate stage 10 with the nut 8 and / or the thrust element longitudinal 9, then a phase of operating the two electric motors 5A and 5B is foreseen from the respective electronics in the same direction of rotation, block 32. 25 Operating mode in case of failure (seizure of the shaft with the stage intermediate) The method determines what type of failure occurred and if so, the failure is a failure (so-called “jamming”) of shaft 6 with the intermediate stage 10, block 33, then there is a phase of activating the electric motor 5A from the respective 5 electronics and activate the electric brake 12B, block 34. Obviously, a technician in the field, in order to satisfy contingent needs and specifications, will be able to make numerous changes to the variants described above, all however, contained within the scope of protection as defined by the following

Claims

1. Linear electromechanical actuator (1), comprising: - a containment structure (2); - a pusher (3) designed to move with respect to the containment structure (2) for 5 escape at least partially from the containment structure during the actuator operation; - a mechanical reduction apparatus (4) arranged in the containment structure (2) and rotating around an axis of rotation (X); - motor vehicles (5) arranged in the containment structure (2) and operationally 10 connected with said mechanical reduction apparatus (4) to rotate it around to the said axis of rotation (X); - a shaft (6) extended between a first end (6') connected to the pusher (3) and a opposite second end (6''), said shaft (6) being inserted inside said mechanical reduction apparatus (4) and connected to said pusher (3), said shaft (6) 15 being mechanically connected with said mechanical reduction apparatus (4) in such that a rotation of said mechanical reduction apparatus (4) determines a translation of the shaft (6) along said rotation axis (X); - an anti-rotation mechanism active on said shaft (6) to prevent rotation of the shaft (6) around said axis of rotation (X); 20 characterised in that said mechanical reduction apparatus (4) comprises: - a nut screw (8) having a thread pitch; - a longitudinal thrust element (9) along the rotation axis (A) and featuring a linear guide (9B), called nut screw (8) and called longitudinal thrust element (9) being independent of each other and rotating around the said axis of rotation (X) under the action of said motor means (5); said longitudinal thrust element (9) being inserted inside said nut screw (8); - coupling means (10, 11, 15, 16) configured to mechanically couple said nut screw (8) and said longitudinal thrust element (9) with said shaft (6), in 5 such that upon rotation of said nut screw (8) and / or said thrust element longitudinal (9) determines a translation of said shaft (6) along said axis of rotation (X); said coupling means (10, 11, 15, 16) comprising: - an intermediate coupling stage (10) placed between the nut screw (8) and the longitudinal thrust element (9), called intermediate coupling stage (10) 10 being inserted at least in part into said shaft (6) and into said nut (8) and said longitudinal thrust element (9) being inserted at least in part in said stage intermediate (10) and in said tree (6).

2. Linear electromechanical actuator according to claim 1, wherein said 15 coupling means (10, 11, 15, 16) include: - first and second mechanical connection means (15, 16) for coupling respectively in a mechanical manner called intermediate coupling stage (10) with said nut screw (8) and said intermediate coupling stage (10) with said longitudinal thrust element (9) 20 - third means of mechanical connection (11) for coupling in a manner mechanics said intermediate coupling stage (10) with said shaft (6) 3. Linear electromechanical actuator according to claim 2, wherein: - said first mechanical connection means (15) comprise a coupling 25 lead screw or satellite rollers, recirculating roller or ball screw; - said second mechanical connection means (16) comprise a coupling ball recirculation by means of longitudinal grooves (9A) obtained on the linear guide (9B) or a spline type coupling between the intermediate coupling stage (10) equipped with coupling grooves and longitudinal grooves (9A).

4. Linear electromechanical actuator according to claim 3, wherein said intermediate coupling stage (10) extends along the axis (X) between a first end (10') facing towards the inside of said containment structure (2) and an opposite one second end (10'') and includes: 10 - externally at the first end (10') a first thread (10A) configured to mate with the first lead screw thread (8A); - internally at the first end (10') of the element coupling (10B) configured to mate with the respective pusher element longitudinal (9); 5. Linear electromechanical actuator according to claim 4, wherein the coupling element (10B) has a ball recirculation device (40) coupled to the longitudinal grooves (9A) of the linear guide (9B). 20 6. Linear electromechanical actuator according to any of the claims from 2 to 5, said third mechanical connection means (11) comprising a screw-lead screw coupling, satellite rollers, roller recirculation or ball screw between said shaft (6) with said intermediate coupling stage (10), so that that upon rotation of said nut screw (8) and / or of said longitudinal thrust element 25 (9) determines a rotation or a translation or a rototranslation of said stage intermediate coupling (10) along said rotation axis (X) and that said stage intermediate coupling (10), in turn, determines a translation of said shaft (6) along the said axis of rotation (X). 5 7. Linear electromechanical actuator according to any of claims 4 to 6, where: - said intermediate coupling stage (10) comprises externally a second thread (10C) configured to mate with the shaft (6) and extended between the first thread (10A) and the second terminal end (10', 10''); 10 - said shaft (6) is a hollow shaft and includes a thread (6A) internally configured to mate with the second thread (10C) of the intermediate stage of coupling (10) 8. Linear electromechanical actuator according to claim 7, wherein 15 - the thread of said shaft (6) is arranged near the second end of said shaft (6'') and configured to mate with the thread of said element threaded (10C).

9. Linear electromechanical actuator according to any of the claims 20 from 1 to 8, wherein said shaft (6) is coaxial with respect to both said intermediate stage of coupling (10) which in relation to said nut screw (8) and said thrust element longitudinal (9) along said axis of rotation (X), said intermediate stage of coupling (10) being coaxial with respect to said nut screw (8) and said element of longitudinal thrust (9) along said axis of rotation (X).

10. Linear electromechanical actuator in accordance with any of the claims 1 to 9, where - the motor means (5) include a first electric motor (5A) operationally connected with the nut screw (8) and a second electric motor (5B) 5 operationally connected to the longitudinal thrust element (9) to rotate them around the said axis of rotation (XX); - first and second braking means (12A, 12B) active respectively on said nut screw (8) and said longitudinal thrust element (9) to brake the rotation around the said axis of rotation (XX); 10 - a command and control electronics for each electric motor (5A, 5B) and for the first and second braking means (12A, 12B) comprising a plurality of sensors (17-18) arranged within said containment structure (2) operationally connected to the command and control electronics, called plurality of sensors (17-18) being designed to detect the position of the tree (6) so as to detect its 15 displacements along the X-axis and rotations of the motors (5A, 5B).

11. Linear electromechanical actuator according to claim 10, wherein: - the first electric motor (5A) is directly connected to the nut screw (8) and comprising a stator fixed to the containment structure (2) and a rotor fixed 20 to the said nut screw (8); - the second electric motor (5B) is connected to the longitudinal thrust element (9) by means of a kinematic chain (5B').

12. Method for checking for an electrical, electronic and / or mechanical fault 25 in a linear electromechanical actuator (1), called linear electromechanical actuator (1) including - provide a linear electromechanical actuator (1) in accordance with any of claims 1 to 11; - provide for the motor vehicles (5) respective electric motors (5A, 5B) 5 mechanically operating respectively on said nut screw (8) and on said element longitudinal thrust (9) to move said nut screw (8) and said element longitudinal thrust (9); - provide first and second active braking means (12A, 12B) respectively on said nut screw (8) and said longitudinal thrust element (9) to brake the 10 rotation around said axis of rotation (X); - provide command and control electronics for electric motors (5A, 5B) and for the first and second braking means (12A, 12B) comprising a plurality of sensors (17-18) arranged within said containment structure (2) operationally connected to the command and control electronics, called plurality of sensors (17-18) 15 being designed to detect the position of the shaft (6) so as to detect its movements along the (X) axis; the said method being characterised by the following phases: - activate (23) the electric motor (5A) to move the said nut screw (8) rotationally and keep the brake (12B) engaged to maintain the thrust element 20 longitudinal (9) stop; - verify (24), through said plurality of sensors (17, 18), during said phase of activation of the electric motor (5A), that said shaft (6) translates with respect to said containment structure (2) and if said shaft (6) does not translate with respect to the structure containment (2): - check (31) whether there is a mechanical failure of the intermediate stage (10) with the nut screw (8) and / or with the longitudinal thrust element (9), so as to operate (23), the two electric motors (5A and 5B) in the same direction of rotation; - check (33) whether there is a mechanical failure of the shaft (6) with the stage 5 intermediate (10), so as to operate (34), the electric motor (5A) and the electric brake (12B).

13. Method for checking for an electrical, electronic and / or mechanical fault in a linear electromechanical actuator (1) according to claim 12, 10 including the phases, if said shaft (6) does not translate with respect to the structure of containment (2), of: - check whether one or both of the two electric motors (5A, 5B) or the said control electronics are faulty (29); - activate (30) the first or second braking means (12A, 12B) so as to prevent 15 the rotation of said nut screw (8) or of said longitudinal thrust element (9) from the side of the motors / electronics not working.