A SMA wire driven rotary actuator

Abstract

The utility model provides a rotary driver driven by an SMA wire, wherein the square head sections at both ends of the output shaft are connected to the fixed end, and a torque transmission disc and a driving disc are installed on the middle circular shaft section; the driving disc is fixedly connected to the output shaft, and the torque transmission disc is supported on the output shaft through a bearing. The SMA wire passes through the axial circular holes on the torque transmission disc and the driving disc and is arranged in a folded or parallel manner, and the outer edge of the torque transmission disc is fixedly connected to the driving end through a torque transmission housing to output torque. When subjected to an external load, the torque transmission housing rotates relative to the output shaft, and the torque transmission disc rotates relative to the driving disc, and the driver maintains balance under the action of the external load and the tension of the SMA wire; when driving is required, the SMA wire is electrically heated to cause it to undergo phase change deformation and shrink, and the torque transmission disc is driven to rotate, thereby realizing relative rotation between the driving end and the fixed end; after the driving is completed, the SMA wire is powered off and cooled, and the driver returns to the state before driving under the action of the external load. The utility model has a simple structure, a small radial dimension, a large output torque, and a high driving efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of spacecraft driving devices, in particular to a rotary driving device. Background Art

[0002] As a power source for mechanical movements, rotary actuators are widely used in many fields such as machinery, electronics, and chemicals. Aircraft, automobiles, robots, and spacecraft have put forward new requirements for the rotary actuators required. The rotary actuators used in these scenarios are different from conventional actuators and need to meet the following requirements: (1) The actuator has a limited working stroke and only needs to rotate a limited angle when driving; (2) The actuator is highly miniaturized and integrated, with a small size, light weight, high power density, and controllable cost; (3) The actuator has a large output torque. The output lever arm of a miniaturized actuator is short, and the actuator needs to output a large torque when driving the load.

[0003] Currently, rotary drives are widely used on spacecraft, and the most typical type is the SMA-driven rotary drive. There are two main types of high-torque SMA drives: one is the use of SMA tubes as driving elements, which has a small driving stroke and a complex structure; the other is the SMA wire-spring drive, which has a large output stroke but a small output torque and is limited in use. Summary of the invention

[0004] The utility model solves the technical deficiencies of the existing rotary drivers and proposes a rotary driver driven by SMA wires. The driver has a simple structure, a small radial size and a large output torque.

[0005] The technical solution adopted by the utility model is: a rotary driver driven by SMA wire, which mainly includes SMA wire, output shaft, left torsion transmission disc, right torsion transmission disc, driving disc, torsion transmission housing and bearing. Among them, SMA wire is a driving element, and the output shaft and two torsion transmission discs are connecting parts.

[0006] The two ends of the output shaft are connected to the fixed end, and the two ends of the middle circular shaft section support the left and right torque transmission discs through bearings. The left and right torque transmission discs have the same structure and are generally annular, with the center matched with the bearing; there are several axial circular holes for SMA wires to be passed evenly distributed on the circumference of the torque transmission disc, and the outer edge of the torque transmission disc is fixedly connected to the torque transmission housing, and the outside of the torque transmission housing is connected to the driving end. The middle of the circular shaft section of the output shaft is fixedly connected to the driving disc, and the circumference of the driving disc is provided with axial circular holes corresponding to the axial circular holes of the torque transmission disc. The SMA wire is arranged axially through the axial circular holes on the left torque transmission disc, the driving disc and the right torque transmission disc in turn, and the two ends of the wire are fixed on the outside of the left torque transmission disc or the right torque transmission disc.

[0007] When subjected to external load, the torque transmission housing rotates relative to the output shaft; accordingly, the left and right torque transmission discs rotate a certain angle relative to the drive disc; the entire driver maintains balance under the external load and the tension of the SMA wire. When driving is required, the SMA wire is energized to increase its temperature, causing phase change deformation and contraction, driving the torque transmission disc to rotate, thereby achieving relative rotation between the drive end and the fixed end. After the drive is completed, the SMA wire is stopped from being energized, the temperature of the SMA wire decreases, and the driver returns to the state before the drive under the action of the external load.

[0008] Furthermore, the output shaft is provided with 6 annular grooves, the positions of the grooves correspond to the front and rear edges of the left and right torque transmission discs and the driving disc, and a limiting structure is fixed in the grooves for axially limiting the torque transmission disc and the driving disc.

[0009] Furthermore, the drive disc and the output shaft are matched with a keyway, and the drive disc and the output shaft are circumferentially locked.

[0010] Furthermore, the bearing between the torque transmission disc and the output shaft is a rolling bearing or a sliding bearing, which allows the torque transmission disc to rotate freely on the output shaft. Under the action of external load or SMA wire tension, the torque transmission disc and the output shaft can rotate relative to each other.

[0011] Furthermore, one or more radial threaded holes are distributed on the rims of the left torque transmission disc and the right torque transmission disc, which can be connected to the torque transmission housing and the driving end through bolts to output torque.

[0012] Furthermore, both ends of the torque transmission housing are connected to end covers, and an axial small hole is provided on the end cover. A wire connected to an external power source is passed through the hole to supply power to the SMA wire.

[0013] Furthermore, insulating tubes are provided in the axial circular holes on the torque transmission disk and the driving disk, and the SMA wire is arranged through the insulating tubes, which can ensure that the SMA wire is electrically insulated from the torque transmission disk and the driving disk.

[0014] Furthermore, the portion of the SMA wire between the driving disk and the torque transmission disk is covered with a heat shrink tube or other insulating and high temperature resistant materials, so that the entire section of the SMA wire can be electrically insulated from the metal structural parts in the driver.

[0015] Furthermore, in order to obtain a greater output torque, the driver needs to arrange the longest possible SMA wire in a limited space. To this end, the utility model can arrange the SMA wire in a single-wire folded arrangement or in a plurality of wires in parallel. When the folded arrangement is adopted, the SMA wire is arranged through an insulating elbow at the folded portion; when the parallel arrangement is adopted, a plurality of SMA wires are arranged in parallel and driven simultaneously, thereby realizing a redundant design of the drive.

[0016] Compared with the existing technology, the utility model has the characteristics of small radial size, large output torque, small energy loss, etc., which are specifically manifested in the following aspects:

[0017] (1) The SMA wire of the utility model is arranged along the axial direction, which greatly reduces the radial space required for arranging the SMA wire. This design greatly reduces the radial size of the driver;

[0018] (2) The utility model has a plurality of axial circular holes on the circumference of the torque transmission disk and the driving disk, and a single SMA wire can be folded back or multiple SMA wires can be arranged in parallel as needed, so that a greater output torque can be obtained under the premise that the axial size of the driver remains unchanged;

[0019] (3) The SMA wire of the utility model is provided with insulating devices along the entire path, which can effectively prevent the SMA wire from contacting or entangled with other structures during the driving process, thereby reducing the internal friction loss of the mechanism and improving the driving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the appearance structure of the utility model;

[0021] Figure 2 This is a schematic diagram of the internal structure of the utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the output shaft of the utility model;

[0023] Figure 4 This is a schematic diagram of the structure of the torque transmission disc of the utility model;

[0024] Figure 5 This is a schematic diagram of the structure of the drive disk of the utility model;

[0025] Figure 6 It is a structural schematic diagram of the torque transmission housing of the utility model.

[0026] The meanings of the markings in the figure are: 1. Output shaft; 2. Torque transmission housing; 3. End cover; 4. SMA wire; 5. Left torque transmission disc; 6. Driving disc; 7. Right torque transmission disc; 8. Bearing; 9. Circlip; 10. Key; 11. Insulation tube; 12. Insulation elbow; 13. Wire fixing head. DETAILED DESCRIPTION

[0027] The utility model is described in detail below in conjunction with the accompanying drawings and embodiments.

[0028] like Figure 1 , 2As shown, the utility model provides a rotary driver driven by an SMA wire, which adopts an output shaft 1 and a torque transmission disc as connecting parts, wherein both ends of the output shaft 1 are fixedly connected to the fixed end, and the middle part is fixedly connected to the driving disc 6; the torque transmission disc comprises a left torque transmission disc 5 and a right torque transmission disc 7, both of which are supported on the output shaft 1 through a bearing 8; a cylindrical torque transmission housing 2 is fixedly connected to the left torque transmission disc 5 and the right torque transmission disc 7 by bolts, the outside of the torque transmission housing 2 is connected to the driving end, and both ends thereof are connected to the end covers 3; a driving element SMA wire 4 is arranged through the left transmission disc 5, the driving disc 6 and the right transmission disc 7.

[0029] The structure of output shaft 1 is as follows Figure 3 As shown, the left and right ends are square head sections, which can be easily and efficiently connected to the fixed end; the middle part is a round shaft section, and an axial groove is provided in the middle of the round shaft section, which is used to cooperate with the key 10 to fix the drive disc 6; the left and right ends of the round shaft section are connected to the left transmission torsion disc 5 and the right transmission torsion disc 7 through bearings 8. The drive disc 6, the left transmission torsion disc 5 and the right transmission torsion disc 7 are all axially limited by a retaining ring 9, and the retaining ring 9 is fixed in 6 annular grooves on the output shaft 1.

[0030] The left transmission torsion plate 5 and the right transmission torsion plate 7 of the utility model have the same structure. Taking the left transmission torsion plate 5 as an example, Figure 4 As shown, the overall shape is annular, and the large circular hole 501 in the center can cooperate with the bearing 8; a number of axial circular holes 502 are distributed on the circumference of the torque transmission disk for installing the insulating tube 11, and the interval angles between adjacent circular holes 502 are the same, and insulating bent tubes 12 are arranged at the intervals; radial threaded holes 503 are provided on the edge of the torque transmission disk for connecting the torque transmission disk with the torque transmission housing 2.

[0031] The SMA wire 4 is arranged through the insulating tubes 11 on the left torsion disc 5, the driving disc 6 and the right torsion disc 7 in the axial direction, and the two ends of the wire are fixed to the outside of the left torsion disc 5 or the right torsion disc 7 through the wire fixing heads 13, and the return part of the SMA wire 4 is arranged through the insulating curved tube 12. In this example, the insulating tube 11 and the insulating curved tube 12 are both made of ceramic materials, which can not only ensure that the SMA wire 4 is electrically insulated from the two torsion discs and the driving disc 6, but also effectively reduce the friction between the SMA wire 4 and other parts during the phase change driving process.

[0032] The structure of the drive disk 6 of the utility model is as follows Figure 5 As shown, a center hole with an axial groove is provided in the center, and an axial groove is also provided at the corresponding position of the output shaft 1. The mating key 10 can circumferentially lock the drive disc 6 and the output shaft 1. An axial circular hole corresponding to the circular hole 502 of the left transmission torsion disc 5 is provided on the disc edge of the drive disc 6 for fixing the insulating tube 11.

[0033] The torque transmission housing 2 of the utility model is a cylindrical structure, and its specific structure is as follows Figure 6As shown, the wall of the torque transmission housing 2 is provided with multiple rows of holes evenly distributed along the circumferential direction. The circular holes near the middle are used for bolt connection with the left torque transmission disc 5 and the right torque transmission disc 7, and the circular holes near the ends are used for bolt connection with the end cover 3.

[0034] The working process of the utility model driver is:

[0035] Before driving, under the action of external load, the torque transmission housing 2 rotates relative to the output shaft 1; accordingly, the left torque transmission disc 5 and the right torque transmission disc 7 rotate a certain angle relative to the driving disc 6; the driver is balanced under the action of the external load and the tension provided by the SMA wire 4.

[0036] When driving is required, the SMA wire 4 is energized to cause it to undergo phase change deformation and shrink due to heat, thereby driving the left transmission torsion disk 5 and the right transmission torsion disk 7 to rotate relative to the driving disk 6, thereby achieving relative rotation between the fixed end and the driving end.

[0037] After the driving is finished, the SMA wire 4 is de-energized, the SMA wire 4 is cooled down, and the driver returns to the state before the driving under the action of the external load.

[0038] The above is only an implementation example of the utility model and does not limit the utility model in any form. The technology not elaborated in detail in the utility model belongs to the known technology in the field. Any modification, equivalent change, modification, improvement, etc. made to the above implementation examples based on the principle and technical essence of the utility model shall be included in the protection scope of the utility model.

Claims

1. A rotary driver driven by an SMA wire, comprising an output shaft (1), a torque transmission housing (2), an SMA wire (4), a left torque transmission disc (5), a driving disc (6), a right torque transmission disc (7) and a bearing (8); characterized in that: The output shaft (1) and the torque transmission disc (5, 7) are connecting parts; the two ends of the output shaft (1) are connected to the fixed end, the two end parts of the middle circular shaft section respectively support the left torque transmission disc (5) and the right torque transmission disc (7) through bearings (8), and the middle of the circular shaft section of the output shaft (1) is fixedly connected to the driving disc (6); the outer edge of the torque transmission disc (5, 7) is fixedly connected to the torque transmission housing (2), and the outside of the torque transmission housing (2) is connected to the driving end; the circumference of the torque transmission disc (5, 7) and the driving disc (6) is provided with an axial circular hole for passing the SMA wire (4); The SMA wire (4) is a driving element, and is arranged axially through axial circular holes on the left torsion transmission disc (5), the driving disc (6) and the right torsion transmission disc (7); When subjected to an external load, the torque transmission housing (2) rotates relative to the output shaft (1), and accordingly the left torque transmission disc (5) and the right torque transmission disc (7) rotate relative to the driving disc (6), and the entire driver maintains balance under the action of the external load and the tension of the SMA wire (4); when driving is required, the SMA wire (4) is energized and heated to cause it to undergo phase change deformation and contraction, driving the torque transmission discs (5, 7) to rotate, thereby achieving relative rotation between the driving end and the fixed end; after the driving is completed, the SMA wire (4) is de-energized, the temperature of the SMA wire (4) decreases, and the driver returns to the state before the driving under the action of the external load.

2. The SMA wire driven rotary actuator according to claim 1, characterized in that: The parts where the two ends of the output shaft (1) are connected to the fixed end are square head sections.

3. The SMA wire driven rotary actuator according to claim 1, characterized in that: The output shaft (1) is provided with 6 annular grooves, the positions of which correspond to the front and rear edges of the left transmission torsion disc (5), the right transmission torsion disc (7) and the driving disc (6), respectively. A retaining ring (9) is fixed in the grooves for axially limiting the transmission torsion disc (5, 7) and the driving disc (6).

4. The SMA wire driven rotary actuator according to claim 3, characterized in that: The driving disc (6) and the output shaft (1) are matched with a keyway, and the driving disc (6) and the output shaft (1) are circumferentially locked.

5. The SMA wire driven rotary actuator according to claim 1, characterized in that: The bearing (8) is a rolling bearing or a sliding bearing.

6. The SMA wire driven rotary actuator according to any one of claims 1 to 5, characterized in that: The driver also includes an end cover (3) connected to the two ends of the torque transmission housing (2). The end cover (3) is provided with an axial small hole, and a wire for supplying power to the SMA wire (4) is inserted into the hole.

7. The SMA wire driven rotary actuator according to claim 1, characterized in that: An insulating tube (11) is provided in the axial circular holes on the torque transmission disc (5, 7) and the driving disc (6), and the SMA wire (4) is arranged through the insulating tube (11).

8. The SMA wire driven rotary actuator according to claim 1 or 7, characterized in that: The portion of the SMA wire (4) between the torque transmission disk (5, 7) and the drive disk (6) is covered with a heat shrink tube, so that the entire section of the SMA wire (4) is electrically insulated from the metal structural parts in the driver.

9. The SMA wire driven rotary actuator according to claim 1, characterized in that: The SMA wire (4) is arranged in a single-wire folded arrangement or in parallel arrangement of multiple wires; when the folded arrangement is adopted, the SMA wire (4) is arranged through an insulating curved tube (12) at the folded position; when the parallel arrangement is adopted, multiple SMA wires (4) are arranged in parallel and driven simultaneously.

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