LINEAR ELECTROMECHANICAL ACTUATOR

Description

DESCRIPTION Attached to a patent application for an INDUSTRIAL INVENTION having by title “LINEAR ELECTROMECHANICAL ACTUATOR” On behalf of: UMBRAGROUP SpA Via Valter Baldaccini, 1 Loc. Paciana 06034 FOLIGNO PG Inventors: Nicola Borgarelli, Luciano Pizzoni Agents: Eng. Paolo Bellomia (registered no. 695 BM) Eng. Christian Bilotta (registered in 1887 B) domiciled in Rome, Via Sallustiana n. 15 at BUGNION SpA ******* The present invention relates to an electromechanical actuator linear and finds particular use in the aeronautical field in particular landing gear, flight surfaces and more generally where it is electrical and electronic redundancy required. Linear electromechanical actuators comprising a motor are known electric and a two-state transmission equipped with different pitches so such as to obtain an optimised reduction ratio and with a structure compact. The Applicant found that such actuators are further can be improved in order to ensure their versatility of use, in particular in agreement with different uses or with use under different conditions operational. The known architecture allows for optimization for a specific situation but does not allow adaptation to different situations of use. Furthermore, particularly in the aeronautical field, there is a demand for actuators increasingly reliable and therefore able to operate with a high margin of safety. In this context, the object of the invention is an actuator linear electromechanical comprising a containment frame, a movement group and a developing transmission element along a main axis and comprising a first threaded portion and a second threaded portion. The transmission element is configured to translate along the main axis and simultaneously rotate around it 5 to the main axis itself. The actuator, object of the present invention, also comprises a first rotary element moved by the rotating movement group around the main axis. The first rotary element is equipped with a first thread suitable for 10 to engage rotatably with the first threaded portion of the element transmission in order to define a first threaded connection. The actuator, object of the present invention, also comprises a second rotating element moved by the movement group in rotation around the main axis. 15 The second rotary element is equipped with a second thread suitable for to engage rotatably with the second threaded portion of the element transmission so as to define a second threaded connection. Preferably, the first and second threaded connection have an angle of opposite helix. 20 Alternatively, the first and second threaded connection have angle of concordant helix. In the latter case, it is preferable that the first and the second threaded connection have different modulus value. Preferably, the first and second threaded connection have identical modulus value. This is preferably expected in the case of threads 25 having opposite helix angle. Even more preferably, the first and second threaded connection have a pitch between 1 mm and 100 mm. Alternatively, the first and second threaded connection can have a different modulus value. This is preferably provided for in the 30 case of threads with concordant helix angle. The actuator, object of the present invention, also comprises a output translating element translating along the main axis and connected to the transmission element so that it rotates freely with respect to to the transmission element itself and in such a way as to present translational movement integral with the axial component of the movement 5 rotary-translating transmission element. Preferably, the output translating element is connected to the input element. transmission by one or more bearings. Preferably, the bearings are ball or roller bearings. Alternatively to the bearings, it is possible to foresee the presence of one or more supports 10 sliding, for example bronze bushings. In this way, the rotary component of the movement of the element of transmission is absorbed by the bearings and not transmitted to the element output translator, which instead receives the entire motion component axial of the transmission element. Preferably, the drive unit comprises a prime mover operationally associated with the first rotary element and a second motor operationally associated with the second rotary element. Preferably, the first and second motors are controllable in a independent of each other. Preferably, the first and second engines are mounted on the chassis of containment, particularly within their respective dedicated compartments. In the preferred embodiment, the first and second motors have respective axes of rotation coinciding with the principal axis and the first and the second motor are axially spaced along the axis principal. 15 In accordance with an alternative embodiment, the first and second engine could be concentric with each other. More specifically, the two engines could be nested inside each other. In this last configuration, one of the two engines is preferably inserted inside the transmission element and is configured with rotor 20 external, in particular engaged on the internal surface of the respective rotary element. In the preferred embodiment, the first and second motors are motors electric and have respective rotors fixed, preferably externally, to the first and second rotary element respectively. 5 In this situation, the first rotary element is coaxial to the first motor and integral with the rotor of the first engine, while the second rotating element is coaxial with the second motor and integral with the rotor of the second motor. In accordance with an alternative embodiment, the first and second engine have their respective rotation axes parallel to the main axis and 10 show the respective rotors connected to the respective rotary element by means of a gear connection. In accordance with an embodiment variant, the invention can also be explained through a mechanical transmission in which the first and second motors are absent and in which they are replaced by respective power take-offs 15 (input shafts) engageable by respective external motors and in particular protruding from the frame. In this configuration the actuator takes on more properly the structure of a mechanical transmission that can be coupled to respective engines by means of corresponding power couplings, for example splined receiving shafts or seats. 20 In accordance with an aspect of the present invention, the transmission is made in the form of a hollow body and the connections threaded are arranged on opposite surfaces of the element transmission. In particular, one of the threaded connections is made on a surface 25 internal of the transmission element and the other threaded connection is arranged on the external surface of the transmission element in such a way that the transmission element is arranged between the first rotary element and the second rotary element. In other words, the first threaded connection and the second connection threaded are arranged on surfaces opposite each other, that is on the external cylindrical surface and on the internal cylindrical surface, of the transmission element. In the preferred embodiment, the transmission element, e.g. being made with a tubular shape, it has a hole central and the first rotary element is inserted into the hole while the second rotary element is arranged externally to the transmission element. The first threaded connection and the second threaded connection can be arranged in an overlapping or partially overlapping position in axial sense or occupy respective regions between them axially staggered. Preferably, the threaded connections are at least partially connected to each other overlapping in an axial direction. Further features and advantages of the present invention will appear. clearer from the indicative, and therefore non-limiting, description of an embodiment of a linear electromechanical actuator in agreement with the invention. This description will be set out below with reference to the attached drawing, provided for indicative purposes only and therefore not limiting, in which figure 1 shows a sectional view of an actuator subject of the present invention. In the attached figures, a total of 100 was represented linear electromechanical actuator according to the invention. The actuator 100 includes a containment frame 200, preferably box-shaped and defining an internal volume. The actuator 100 also includes a movement group in motorized particular and in particular arranged in the volume of containment. The actuator 100 comprises a transmission element 300 extending along a main axis “X” and comprising a first threaded portion 5 3a and a second threaded portion 3b. The transmission element 300 is configured to translate along the axis main “X” and simultaneously rotate around the main axis “X”. In other words, the transmission element 300 is configured to assume a rotary motion component around the main axis “X” and an axial motion component along the main axis “X”, that is, to rotate and translate. The actuator 100 further comprises a first rotary element 400 moved by the movement group rotating around the axis main “X”. 5 The first rotary element 400 is equipped with a first thread 4a suitable for to engage rotatably with the first threaded portion 3a of the element transmission 300 so as to define a first threaded connection 3a, 4th. The actuator 100 further comprises a second rotary element 500 10 moved by the movement group rotating around the axis main “X” and equipped with a second 5b thread suitable for engaging rotatable to the second threaded portion 3b of the element transmission 300 so as to define a second threaded connection 3b, 5b. 15 In the embodiment illustrated, the first and second connections threaded 3a, 4a; 3b, 5b have identical modulus value. Preferably, the modulus value is between 1mm and 100mm. In the embodiment illustrated, the first and second connections threaded 3a, 4a; 3b, 5b have opposite helix angle. 20 In accordance with a further possible embodiment not illustrated, the first and second threaded connection 3a, 4a; 3b, 5b have identical the value of the modulus and the helix angle are the same. In accordance with a further possible embodiment not illustrated, the first and second threaded connection 3a, 4a; 3b, 5b have different 25 value of modulus and opposite helix angle. In accordance with a further possible embodiment not illustrated, the first and second threaded connection 3a, 4a; 3b, 5b have value of different module and consistent helix angle. In use therefore, when the first and second rotary element 400, 500 are operated in rotation around the main axis “X”, the first and the second threaded connection 3a, 4a; 3b, 5b ensure that 5 the transmission element 300 rotates around the main axis “X” and, at the same time, translate along the main “X” axis. Preferably, to operate the first and second rotary elements 400, 500, the movement group includes a first motor “M1” operationally associated with the first rotary element 400 and a second 10 “M2” engine operationally associated with the second rotary element 500. Preferably, the first and second motor “M1”, “M2” are housed in the containment volume of the containment frame, in particular in a dedicated compartment or in respective dedicated compartments. Preferably, the first and second motor “M1”, “M2” are controllable independently of each other. In accordance with the embodiment shown in figure 1, the first and the second engine “M1”, “M2” have respective rotation axes coinciding with the main axis “X” and are axially spaced from each other along the main axis “X”. In this situation, the first and second motors 15 “M1”, “M2” are electric motors and have respective fixed rotors, preferably externally, respectively to the first and second rotary element 400, 500. In accordance with an embodiment not illustrated instead, the first and the second engine “M1”, “M2” have their respective rotation axes parallel 20 to the main axis “X” and have the respective rotors connected to the corresponding rotary element 400, 500 by means of a connection to gears. In accordance with a further embodiment not illustrated, the first and the second engine “M1”, “M2” have their respective rotation axes between them 25 coincident. More specifically, the first and second engines "M1", "M2" could assume nested configuration where one engine is radially internal to the other engine. With reference to the embodiment shown in figure 1, the element of transmission 300 is made in the form of a hollow body and the connections threaded 3a, 4a; 3b, 5b are arranged on opposite surfaces of the element 5 transmission 300. In particular, one of the threaded connections 3a, 4a; 3b, 5b is made on an internal surface of the transmission element 300 and the other threaded connection 3a, 4a; 3b, 5b is arranged on the outer surface of the transmission element 300 so that the transmission element 10 transmission 300 is arranged between the first rotary element 400 and the second rotary element 500. Preferably, the threaded connections 3a, 4a; 3b, 5b are at least partially overlapping in the axial direction. In other words, the connections threaded 3a, 4a; 3b, 5b are arranged in such a position that one of them is at least partially (that is, at least for an axial portion of it) nested inside the other. Alternatively, threaded connections 3a, 4a; 3b, 5b could be axially spaced from each other so as not to overlap in axial direction, preferably while still remaining one arranged internally and one externally located on the transmission element 300. Preferably, the transmission element 300 has the shape of a tubular and has a central hole. In this situation, the first rotary element 400 is inserted into the hole to engage internally with the element transmission 300 through the first threaded connection 3a, 4a while the second rotary element 500 is arranged externally to the element of transmission 300 and engages with it via the second connection threaded 3b, 5b. In this situation, preferably, the first portion 3rd thread (engaged with the first 4th thread of the first element rotary 400) has a smaller axial extension than the extension axial of the second threaded portion 3b (engaged with the second thread 5b of the second rotary element 500). The actuator 100 further comprises an output translating element 600. translating along the main axis “X” and connected to the element of transmission 300 so that it rotates freely relative to the element of transmission 300 and in such a way as to present movement of 5 translation integral with the axial component of the rotary-translating movement of the transmission element 300 itself. In other words, the rotary motion of the transmission element 300 does not is transmitted to the output translating element 600 (unless otherwise specified) frictional couples) while the translational motion of the transmission element 300 is transmitted to the output translating element 600. Preferably, the translating element 600 is connected to the transmission 300 by one or more bearings, e.g. ball bearings balls or rollers. 10 Alternatively, the translating element 600 is connected to the transmission 300 by means of one or more sliding supports, for example bronzes. In use, therefore, the output translating element 600 is slidable along the axis main “X” and is connected to the transmission element 300 in such a way to present a joint translation movement (i.e. synchronous and integral) to the translational component of the motion of the element transmission 300. The present invention also provides a method for operating the actuator 100 in accordance with the above. 15 The method comprises a step of operating the movement group to rotate the first rotary element 400 and the second element rotary 500 with individually selected rotation speeds in order to move the transmission element 300 in rototranslation and, consequently, put the translating element 600 into translation 20 exit. Preferably, the actuation phase is performed by activating the first and the second engine “M1”, “M2” independently from each other. Once the “M1”, M2” motors have been activated and the first and the second one have been set in rotation, second rotary element 400, 500, the transmission element 300 finds itself rototranslating along the main axis “X” (or possibly 5 only to translate as a function of the rotation speeds of the elements rotary 400, 500). In this situation, thanks to the presence of the bearings, the rotational motion component of the transmission element 300 not is transmitted to the output translating element 600 while the translational motion component of the transmission element 300 is 10 transmitted to the output translating element 600 which then translates along the main “X” axis. In accordance with a further aspect of the present invention, for each rotary element 400, 500, the actuator 100 comprises a respective braking device “B” active on the rotary element 400, 500 itself and / or 15 on the rotor of the respective motor “M1”, “M2”, individually activatable, in controlled mode, to block the rotation of the respective rotary element 400, 500. The braking device “B” can work by friction, preferably for electromagnetic interaction. 20 In this way, the braking action has a locking action on the element rotary 400, 500 associated with the engine “M1”, “M2” braked in such a way that the respective thread 4a, 5b is stationary like a thread fixed. This creates a possible working condition of the actuator 100, which can be operated in a similar manner to a traditional double actuator 25 thread. The braked “M1”, “M2” motor is therefore equal to a electromechanical redundancy, which can remain inactive allowing however the operation of the actuator 100, increasing the reliability actuator total 100. This aspect is particularly advantageous, for example, if one 30 of the two engines “M1”, “M2” should fail, that is, if one of the two engines “M1”, “M2” should not be operational. In this situation, being one of the two engines “M1”, “M2” inoperative, i.e. braked, the actuator 100 is still operable, and in particular operable in similar to a traditional double-thread actuator. In other words, the architecture of the actuator 100 which is the subject of this 5 invention allows to obtain, if one of the two engines “M1”, “M2” was not operational, a redundant system of the “fail-safe” type, i.e. a system still capable, although affected by a "breakage", of notable resistance and reliability. The invention achieves the proposed goals, overcoming the drawbacks complained in the prior art. The actuator is in fact extremely versatile. Furthermore, the peculiar The actuator's construction allows for increased reliability. THE AGENCY Eng. Paolo Bellomia

Claims

1. Electromechanical linear actuator (100), comprising: - a containment frame (200); - a drive unit; - a transmission element (300), extending along a main axis (X) and comprising a first threaded portion (3a) and a second threaded portion (3b), said transmission element (300) being configured to translate along said main axis (X) and simultaneously rotate around said main axis (X); - a first rotary element (400), moved by said drive unit in rotation around the main axis (X) and equipped with a first thread (4a) suitable for rotatably engaging said first threaded portion (3a) of the transmission element (300) so as to define a first threaded connection (3a, 4a);- a second rotary element (500) moved by said drive unit in rotation around the main axis (X) and equipped with a second thread (5b) suitable for rotatably engaging said second threaded portion (3b) of said transmission element (300) so as to define a second threaded connection (3b, 5b); - an output translating element (600), translating along said main axis (X) and connected to the transmission element (300) so as to rotate freely with respect to the transmission element (300) and so as to present a translational movement integral with the axial component of the rototranslating movement of the transmission element (300).; 2. Actuator according to claim 1, wherein said movement group comprises a first motor (M1) operatively associated with said first rotary element (400) and a second motor (M2) operatively associated with said second rotary element (500), said first and second motor (M1, M2) being controllable independently of each other.

3. Actuator according to claim 2, wherein said first and second motors (M1, M2) have respective rotation axes coinciding with said main axis (X) and wherein said first and second motors (M1, M2) are axially spaced from each other along said main axis (X).

4. Actuator according to claim 3, wherein said first and second motors (M1, M2) are electric motors and have respective rotors fixed, preferably externally, to the first and second rotary element (400, 500) respectively.

5. Actuator according to claim 2, wherein said first and second motors (M1, M2) have their respective rotation axes parallel to the main axis (X) and have their respective rotors connected to the respective rotary element (400, 500) by means of a gear connection.

6. Actuator according to any of the preceding claims, wherein said transmission element (300) is made in the form of a hollow body and wherein said threaded connections (3a, 4a; 3b, 5b) are arranged on opposite surfaces of said transmission element (300), in particular one of said threaded connections (3a, 4a; 3b, 5b) being made on an internal surface of the transmission element (300) and the other threaded connection (3a, 4a; 3b, 5b) being arranged on the external surface of the transmission element (300) such that said transmission element (300) is arranged between said first rotary element (400) and said second rotary element (500).

7. Actuator according to claim 6, wherein said threaded connections (3a, 4a; 3b, 5b) are at least partially overlapped in an axial direction. 11.U2006.12.IT.27 Eng. Paolo Bellomia (Registered no. 695 BM) 8. Actuator according to any of the preceding claims, wherein the first and second threaded connections (3a, 4a; 3b, 5b) have identical modulus value.

9. Actuator according to any of the preceding claims, wherein the first and second threaded connections (3a, 4a; 3b, 5b) have opposite helix angle.

10. Actuator according to any of the preceding claims, wherein the translating element (600) is connected to the transmission element (300) by one or more bearings, preferably said bearings being ball or roller bearings.

11. Actuator according to any of the preceding claims, comprising for each rotary element (400, 500), a respective braking device (B) individually activatable, in a controlled manner, to block the rotation of said respective rotary element (400, 500).

12. A method for operating the actuator (100) in accordance with any of the preceding claims, comprising a step of actuating said drive unit to rotate said first rotary element (400) and said second rotary element (500) with respective individually selected rotation speeds so as to move the transmission element (300) in rototranslation and, consequently, to translate the translating element (600).