Slender high-torque-density actuator

Abstract

The invention relates to a slender high-torque-density actuator and an aircraft. The actuator comprises a motor, a first-stage lead screw nut and a second-stage lead screw nut. The motor is provided with a motor shell and a motor shaft, the motor shaft is provided with an external thread, the first-stage lead screw nut is provided with an internal thread and an external thread, the first-stage lead screw nut is connected to the motor shaft through the internal thread, the first-stage lead screw nut is in limiting fit with the motor shell, and the motor shell limits the first-stage lead screw nut to move only in the length direction of the motor shaft. The second-stage lead screw nut is in threaded connection with an external thread on the first-stage lead screw nut, the second-stage lead screw nut is rotatably connected to the motor shell, a motor shaft of the motor rotates to drive the first-stage lead screw nut to linearly move, and the first-stage lead screw nut linearly moves to drive the second-stage lead screw nut to rotate. According to the rotary actuator, all transmission parts are of coaxial structures, compared with a conventional rotary actuator, the size in the diameter direction is small, and compared with a linear actuator, the rotary actuator can be matched with rotary structures such as flaps, ailerons, cabin doors and control surfaces more easily.

Description

Technical Field

[0001] The present invention relates to the field of electromechanical technology, and particularly to a slender high-torque density actuator. Background Art

[0002] Currently, hydraulic actuators are mostly used in aircraft actuators. However, with the development of motors, power semiconductors, and new transmission mechanisms, electromechanical actuators can also achieve high output loads and high response frequencies, and their use in aircraft is becoming increasingly common.

[0003] For example, linear actuators are currently used in many aircraft. A linear actuator generally includes a motor, a lead screw, and a nut. The motor drives the lead screw to rotate through a speed reducer. The lead screw can be a sliding lead screw, a ball screw, or a planetary roller screw. The rotation of the lead screw drives the nut to translate, thereby converting the rotational motion of the motor into a linear motion output. Again, rotary actuators are also used in many aircraft. Their working principle is generally that the motor outputs a rotational motion through a multi-stage reduction mechanism, but the volume of the rotary actuator is generally large. Currently, the existing electromechanical actuators generally have problems such as large volume, difficult installation and maintenance, or protruding from the original aerodynamic surface after installation, requiring an additional fairing. Summary of the Invention

[0004] To solve one of the above technical problems, the present application provides a slender high-torque density actuator.

[0005] The present application provides the following technical solutions:

[0006] A first object of the present application is to provide a slender high-torque density actuator, comprising:

[0007] A motor, the motor having a motor housing and a motor shaft, the motor shaft being rotatably disposed in the motor housing, and the motor shaft having an external thread;

[0008] A first-stage lead screw nut, the first-stage lead screw nut having an internal thread and an external thread, the first-stage lead screw nut being sleeved on the motor shaft and connected to the motor shaft through the internal thread, the first-stage lead screw nut and the motor housing being in limit fit, and the motor housing restricting the first-stage lead screw nut to move only along the length direction of the motor shaft;

[0009] A second-stage lead screw nut, the second-stage lead screw nut having an internal thread, the second-stage lead screw nut being threadedly connected to the external thread on the first-stage lead screw nut, and the second-stage lead screw nut being rotatably connected to the motor housing;

[0010] When the motor shaft of the motor rotates, it can drive the first-stage lead screw nut to perform linear motion, and the linear movement of the first-stage lead screw nut can drive the second-stage lead screw nut to rotate.

[0011] Optionally, the first-level lead screw nut has a nut portion and a lead screw portion, and the lead screw portion has an external thread;

[0012] The motor housing has a cylindrical housing portion;

[0013] The cylindrical housing portion is sleeved outside the motor shaft;

[0014] The nut portion is located inside the cylindrical housing portion and is threadedly connected to the motor shaft, and the cylindrical housing portion and the nut portion are in limit fit;

[0015] The lead screw portion extends out of the cylindrical housing portion, and the second-level lead screw nut is threadedly connected to the lead screw portion.

[0016] Optionally, the pitch of the motor shaft is smaller than the pitch of the lead screw portion.

[0017] Optionally, one of the inner wall of the cylindrical housing portion and the outer wall of the nut portion is provided with a spline, and the other is provided with a keyway, and the spline is slidably embedded in the keyway.

[0018] Optionally, the outer diameter of the nut portion is larger than the outer diameter of the lead screw portion.

[0019] Optionally, the second-level lead screw nut is sleeved on the cylindrical housing portion, and a support bearing is provided between the second-level lead screw nut and the cylindrical housing portion.

[0020] Optionally, the second-level lead screw nut includes a thick-diameter cylinder and a thin-diameter cylinder, the thick-diameter cylinder and the thin-diameter cylinder are connected, the thick-diameter cylinder is sleeved on the cylindrical housing portion, and the support bearing is provided between the thick-diameter cylinder and the cylindrical housing portion, the thin-diameter cylinder has an internal thread, and the thin-diameter cylinder is threadedly connected to the lead screw portion.

[0021] Optionally, both ends of the motor shaft extend out of the motor housing, external threads are provided at both ends of the motor shaft, and the thread helix directions of the external threads at both ends of the motor shaft are opposite;

[0022] First-level lead screw nuts and the second-level lead screw nuts are provided at both ends of the motor housing, and the first-level lead screw nuts on both sides are respectively threadedly connected to both ends of the motor shaft;

[0023] The two-side structures of the slender high-torque density actuator are symmetrically arranged along the extension direction of the motor shaft.

[0024] Optionally, the slender high-torque density actuator includes a fixed earpiece and a rotating earpiece;

[0025] The fixed earpiece is connected to the motor housing;

[0026] The rotating earpiece is connected to the second-level lead screw nut.

[0027] The second object of the present application is to provide an aircraft, comprising:

[0028] An aircraft body;

[0029] A movable part, which is movably connected to the aircraft body;

[0030] The above-mentioned slender high-torque density actuator, the motor housing of the slender high-torque density actuator is connected to the aircraft body, and the second-stage lead screw nut of the slender high-torque density actuator is connected to the movable part.

[0031] By adopting the above technical solutions, the present application has the following beneficial effects:

[0032] In the slender high-torque density actuator of the present application, all transmission components are coaxial structures. Compared with conventional rotary actuators, the dimensions in the diameter direction are smaller. Compared with linear actuators, it is easier to cooperate with rotary structures such as flaps, ailerons, hatches, and rudder surfaces. The slender high-torque density actuator in the present application can achieve the effects of small occupied space, small weight cost, and easy installation and implementation. Description of the Drawings

[0033] The drawings, as a part of the present application, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation to the present invention. Obviously, the drawings in the following description are only some embodiments, and those of ordinary skill in the art can obtain other drawings according to these drawings without creative efforts.

[0034] Figure 1 Showing a front view of the slender high-torque density actuator provided by an embodiment of the present disclosure;

[0035] Figure 2 Showing Figure 1 A sectional view taken along the line A-A in

[0036] In the drawings: 1, motor; 11, motor housing; 111, cylinder housing part; 12, motor shaft; 2, first-stage lead screw nut; 21, nut part; 22, lead screw part; 3, second-stage lead screw nut; 31, thick-diameter cylinder; 32, thin-diameter cylinder; 4, support bearing; 5, fixed earpiece; 6, rotating earpiece. Detailed Embodiments

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the preferred embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are some, but not all, of the embodiments of the present invention. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. The embodiments of the present invention will be described in detail below with reference to the drawings.

[0038] In the description of this embodiment, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing this embodiment and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the scope of protection of this embodiment.

[0039] As Figure 1 and Figure 2 shown, an embodiment of the present application provides a slender high-torque density actuator, including: a motor 1, a first-stage lead screw nut 2, and a second-stage lead screw nut 3. The motor 1 has a motor housing 11 and a motor shaft 12. The motor shaft 12 is rotatably arranged in the motor housing 11, and the motor shaft 12 has an external thread. The first-stage lead screw nut 2 has an internal thread and an external thread. The first-stage lead screw nut 2 is sleeved on the motor shaft 12 and is connected to the motor shaft 12 through the internal thread. The first-stage lead screw nut 2 and the motor housing 11 are in limit fit, and the motor housing 11 restricts the first-stage lead screw nut 2 to move only along the length direction of the motor shaft 12. The second-stage lead screw nut 3 has an internal thread. The second-stage lead screw nut 3 is threadedly connected to the external thread on the first-stage lead screw nut 2, and the second-stage lead screw nut 3 is rotatably connected to the motor housing 11. When the motor shaft 12 of the motor rotates, it can drive the first-stage lead screw nut 2 to move linearly, and the linear movement of the first-stage lead screw nut 2 can drive the second-stage lead screw nut 3 to rotate.

[0040] All the transmission components in the slender high-torque density actuator of the present application are coaxial structures. Compared with conventional rotary actuators, the dimensions in the diameter direction are smaller. Compared with linear actuators, it is easier to cooperate with rotary structures such as flaps, ailerons, hatches, and control surfaces. The slender high-torque density actuator in the present application can achieve the effects of small occupied space, small weight cost, and easy installation and implementation.

[0041] In some possible embodiments, the first-stage lead screw nut 2 has a nut portion 21 and a lead screw portion 22. The lead screw portion 22 has an external thread. The motor housing 11 has a cylindrical housing portion 111. The cylindrical housing portion 111 is sleeved outside the motor shaft 12. The nut portion 21 is located inside the cylindrical housing portion 111 and is threadedly connected to the motor shaft 12. The cylindrical housing portion 111 and the nut portion 21 are in limiting cooperation. The cylindrical housing portion 111 restricts the nut portion 21 to translate only along the length direction of the motor shaft 12. The lead screw portion 22 extends out of the cylindrical housing portion 111, facilitating cooperation with the second-stage lead screw nut 3. The second-stage lead screw nut 3 is threadedly connected to the lead screw portion 22.

[0042] When the motor shaft 12 rotates, it can act on the nut portion 21, causing the nut portion 21 to translate along the cylindrical housing portion 111. At this time, the lead screw portion 22 moves synchronously with the nut portion 21. The lead screw portion 22 acts on the second-stage lead screw nut 3, causing the second-stage lead screw nut 3 to perform a rotational motion.

[0043] It should be noted that in a lead screw nut mechanism, when the pitch is small, there is a problem of self-locking. In this application, the lead screw portion 22 and the second-stage lead screw nut 3 can be of a sliding lead screw, ball screw or planetary roller screw structure, and the pitch is large. Therefore, the linear motion of the lead screw portion 22 can be converted into the rotational motion of the second-stage lead screw nut 3. Considering the requirements of high efficiency and small outer diameter, the lead screw portion 22 and the second-stage lead screw nut 3 can be ball screws.

[0044] In some possible embodiments, the pitch of the motor shaft 12 is smaller than the pitch of the external thread of the lead screw portion 22.

[0045] The motor shaft 12 of the slender high-torque density actuator provided by the embodiment of the present application is a small-pitch lead screw. Through the first-stage lead screw nut 2 cooperating with it, the rotational motion of the motor 1 can be converted into a linear motion. The lead screw portion 22 connected to the nut portion 21 is a large-pitch lead screw. The linear motion of the large-pitch lead screw is converted into a rotational motion through the second-stage lead screw nut 3 cooperating with it. Without considering the transmission efficiency, the pitch ratio of the small-pitch lead screw and the large-pitch lead screw is the amplification ratio of the motor output torque. Since the pitch ratio can be made very large, a very large torque amplification ratio can be achieved.

[0046] For example, the motor shaft 12 and the nut portion 21 are small-pitch lead screws with a pitch of 3 mm, and the lead screw portion 22 and the second-stage lead screw nut 3 are large-pitch lead screws with a pitch of 90 mm. The output torque of the motor is 1 Nm. Then, without considering friction losses, the torque at the output end is 30 Nm. Since the pitch ratio can be made very large, a very large torque amplification ratio can be achieved. At the same time, the diameter direction size of the lead screw structure is small, making the radial size of the entire actuator small.

[0047] In some possible embodiments, splines are provided on one of the inner wall of the barrel portion 111 and the outer wall of the nut portion 21, and keyways are provided on the other. The splines are slidably fitted in the keyways, thereby restricting the rotational movement of the nut portion 21 such that the nut portion 21 can only move along the length direction of the barrel portion 111.

[0048] The first-stage lead screw nut 2 and the barrel portion 111 of the motor housing 11 are fitted with each other through a sliding spline or a ball spline. The first-stage lead screw nut 2 can only move linearly relative to the barrel portion 111 and cannot rotate. The nut portion 21 and the motor shaft 12 are small-pitch lead screws, and both can be of a sliding lead screw, a ball lead screw or a planetary roller screw structure.

[0049] In some possible embodiments, the outer diameter of the nut portion 21 is greater than the outer diameter of the lead screw portion 22. The large outer diameter of the nut portion 21 is more suitable for the limit fit with the barrel portion 111, while the outer diameter of the lead screw portion 22 is much smaller than the inner diameter of the barrel portion 111, and there will be no frictional interference with the barrel portion 111, reducing the moving resistance.

[0050] In some possible embodiments, the second-stage lead screw nut 3 is sleeved on the barrel portion 111, and a support bearing 4 is provided between the second-stage lead screw nut 3 and the barrel portion 111.

[0051] The second-stage lead screw nut 3 and the motor housing 11 are supported by a bearing. This bearing can bear axial loads and radial loads, and can only rotate relative to the motor housing 11 and cannot perform relative linear motion, regardless of the transmission efficiency.

[0052] In some possible embodiments, the second-stage lead screw nut 3 includes a thick-diameter cylinder 31 and a thin-diameter cylinder 32. The thick-diameter cylinder 31 and the thin-diameter cylinder 32 are connected. The thick-diameter cylinder 31 is sleeved on the barrel portion 111, and the support bearing 4 is provided between the thick-diameter cylinder 31 and the barrel portion 111. The thin-diameter cylinder 32 has an internal thread, and the thin-diameter cylinder 32 is threadedly connected to the lead screw portion 22. The second-stage lead screw nut 3 is generally in the shape of a tapered shell.

[0053] In some possible embodiments, both ends of the motor shaft 12 extend out of the motor housing 11. External threads are provided at both ends of the motor shaft 12, and the thread helix directions of the external threads at both ends of the motor shaft 12 are opposite. First-stage lead screw nuts 2 and the second-stage lead screw nuts 3 are provided at both ends of the motor housing 11, and the first-stage lead screw nuts 2 on both sides are respectively threadedly connected to both ends of the motor shaft 12. The two-side structures of the slender high-torque density actuator are symmetrically arranged along the extension direction of the motor shaft 12.

[0054] The motor of the slender high-torque density actuator provided by the embodiment of the present application uses a double-output shaft motor. The axial loads on the motor shafts 12 at both ends cancel each other out, thereby reducing the load transmitted to other structures. If a single-output shaft motor is used, the motor output shaft needs to be supported on a bearing that can withstand a large axial load, resulting in a complex structure and a high weight cost.

[0055] The second object of the present application is to provide an aircraft, including: an aircraft body, a movable part, and the above-mentioned slender high-torque density actuator. The movable part is movably connected to the aircraft body. The motor housing 11 of the slender high-torque density actuator is connected to the aircraft body, and the second-stage lead screw nut 3 of the slender high-torque density actuator is connected to the movable part.

[0056] In some possible implementation manners, the slender high-torque density actuator includes a fixed lug 5 and a rotating lug 6. The fixed lug 5 is connected to the motor housing 11, and the rotating lug 6 is connected to the second-stage lead screw nut 3.

[0057] The fixed lug 5 is a structural feature of the actuator motor housing 11. Through the fixed lug 5, the actuator can be fixed to the aircraft body, and the aircraft body can include a fuselage and wings. For example, the fixed lug 5 can be fixed to the spar of the wing structure or the frame of the fuselage structure. The rotating lug 6 is a structural feature of the actuator second-stage lead screw nut 3. As the output end of the actuator, the movable part of the aircraft can be any one or more of a flap, aileron, rudder surface, and hatch. The rotating lug 6 is connected to and drives the connected components to generate the required movement. The second-stage lead screw nut 3 and the motor housing 11 (such as the outer wall of the cylindrical housing part 111) are supported by a support bearing 4, which bears both axial and radial loads at the same time. The support bearing 4 also serves as the rotating support bearing for the flap, aileron, rudder surface, hatch, etc., thereby simplifying the structure.

[0058] Among them, the slender high-torque density actuator can include two fixed lugs 5 and two rotating lugs 6. The two fixed lugs 5 are respectively connected to both ends of the motor housing 11 along the length direction. The two rotating lugs 6 can be respectively connected to the outer walls of the two second-stage lead screw nuts 3. For example, the two rotating lugs 6 are respectively connected to the outer walls of the thick-diameter cylinders 31 of the two second-stage lead screw nuts 3.

[0059] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent replacements or changes, which are all covered by the protection scope of the present invention.

Claims

1. A slender high torque density actuator, characterized in that: include: A motor, wherein the motor comprises a motor housing and a motor shaft, wherein the motor shaft is rotatably disposed on the motor housing and has an external thread; A first-level lead screw nut, the first-level lead screw nut having an internal thread and an external thread, the first-level lead screw nut is sleeved on the motor shaft and connected to the motor shaft through the internal thread, the first-level lead screw nut and the motor housing are limitedly matched, and the motor housing limits the first-level lead screw nut to move only along the length direction of the motor shaft; A secondary lead screw nut, the secondary lead screw nut having an internal thread, the secondary lead screw nut being threadably connected to the external thread on the primary lead screw nut, and the secondary lead screw nut being rotatably connected to the motor housing; The motor shaft of the motor rotates to drive the primary lead screw nut to move linearly, and the linear movement of the primary lead screw nut can drive the secondary lead screw nut to rotate.

2. The slender high torque density actuator according to claim 1, characterized in that: The primary lead screw nut comprises a nut portion and a lead screw portion, wherein the lead screw portion comprises an external thread; The motor housing has a cylindrical housing portion; The cylindrical shell portion is sleeved on the outer side of the motor shaft; The nut part is located inside the cylindrical shell part and is threadedly connected to the motor shaft, and the cylindrical shell part and the nut part are limitedly matched; The lead screw portion extends out of the cylindrical shell portion, and the secondary lead screw nut is threadedly connected to the lead screw portion.

3. The slender high torque density actuator according to claim 2, characterized in that: The pitch of the motor shaft is smaller than the pitch of the lead screw portion.

4. The slender high torque density actuator according to claim 2, characterized in that: One of the inner wall of the cylindrical shell part and the outer wall of the nut part is provided with a spline, and the other is provided with a key groove, and the spline is slidably embedded in the key groove.

5. The slender high torque density actuator according to claim 2, characterized in that: An outer diameter of the nut portion is greater than an outer diameter of the screw portion.

6. The slender high torque density actuator according to claim 2, characterized in that: The secondary lead screw nut is sleeved on the cylindrical shell portion, and a support bearing is arranged between the secondary lead screw nut and the cylindrical shell portion.

7. The slender high torque density actuator according to claim 6, characterized in that: The secondary screw nut includes a large diameter cylinder and a small diameter cylinder, the large diameter cylinder and the small diameter cylinder are connected, the large diameter cylinder is sleeved on the cylinder shell, and the support bearing is arranged between the large diameter cylinder and the cylinder shell, the small diameter cylinder has an internal thread, and the small diameter cylinder and the screw part are threadedly connected.

8. The slender high torque density actuator according to any one of claims 1 to 7, characterized in that: Both ends of the motor shaft extend out of the motor housing, and both ends of the motor shaft are provided with external threads, and the thread rotation directions of the external threads at both ends of the motor shaft are opposite; Both ends of the motor housing are provided with a primary lead screw nut and the secondary lead screw nut, and the primary lead screw nuts on both sides are respectively threadedly connected to the two ends of the motor shaft; The slender high torque density actuator is symmetrically arranged along the extension direction of the motor shaft at both sides.

9. The slender high torque density actuator according to any one of claims 1 to 7, characterized in that: It includes a fixed ear piece and a rotating ear piece; The fixing ear piece is connected to the motor housing; The rotating ear is connected to the secondary lead screw nut.

10. An aircraft, characterized in that: include: Aircraft body; a movable portion, the movable portion being movably connected to the aircraft body; According to any one of claims 1 to 9, the motor housing of the slender high torque density actuator is connected to the aircraft body, and the secondary screw nut of the slender high torque density actuator is connected to the movable part.

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