A linear actuator for a spacecraft

Abstract

The application relates to a linear actuator for a spacecraft, and belongs to the technical field of spaceflight. The linear actuator comprises a screw rod, a nut, a motor and a fixing base, one end of the screw rod is connected with the inner wall of the fixing base, the other end of the screw rod is a push-pull end, the nut is threadedly connected with the screw rod, and the motor is used for driving the nut to rotate, thereby driving the screw rod to slide on the fixing base. The first bearing and the second bearing of the application are both superconducting magnetic suspension bearings, a bearing rotor provides a gradient magnetic field, a bearing stator is affected by the magnetic field to generate a magnetic suspension force, and the magnetic suspension force is used for maintaining the operation of the superconducting magnetic suspension bearing; the superconducting magnetic suspension bearing does not need to be lubricated and maintained, is stable and has a long service life, and is more suitable for being used in an on-orbit spacecraft compared with a rolling bearing.

Description

Technical Field

[0001] This invention belongs to the field of aerospace technology, and in particular relates to a linear actuator for spacecraft. Background Technology

[0002] With the continuous development of electric motors and precision machinery, linear actuators have been widely used in various fields. Linear actuators based on rotary electric motors mainly convert the rotational motion of the motor into linear motion by transmitting it to the lead screw through the nut of the lead screw pair. Compared with schemes using linear motors as the drive source, using rotary motors as the drive source can significantly reduce the axial dimension of the actuator, making miniaturization possible.

[0003] When orbiting in space, the surface of an Earth-orbiting spacecraft experiences frequent and significant temperature changes. The operating environment for its actuators is harsh, and maintenance is impossible during the spacecraft's orbital period, placing high demands on the maintenance-free lifespan of actuators used in orbital spacecraft. Currently, linear actuators utilize rolling bearings to reduce friction. However, rolling bearings require frequent lubrication to function properly. Since rolling bearings cannot be maintained on orbital spacecraft, the actuators have short lifespans and poor operational stability.

[0004] Therefore, there is an urgent need for a linear actuator for spacecraft to solve the problems of frequent lubrication of rolling bearings in order to work properly; the inability of spacecraft in orbit to maintain rolling bearings; short lifespan of actuators; and poor operational stability. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a linear actuator for spacecraft, solving the problems of the prior art where rolling bearings require frequent lubrication, rolling bearings cannot be maintained in orbital spacecraft, the actuator has a short service life, and poor operational stability.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] A linear actuator for a spacecraft includes a lead screw, a nut, a motor, and a fixed base. One end of the lead screw is connected to the inner wall of the fixed base, and the other end of the lead screw is a push-pull end. The nut is threadedly connected to the lead screw. The motor is used to drive the nut to rotate, thereby driving the lead screw to slide on the fixed base. The push-pull end is used to push and pull the rotating parts of the spacecraft, causing the rotating parts to deflect.

[0008] Furthermore, it also includes a housing, a first bearing, a second bearing, and an end cap. The end cap is disposed on the outer wall of the fixed base. One end of the nut is connected to the housing through the first bearing, and the other end of the nut is connected to the end cap through the second bearing. The nut can rotate within the housing and the end cap.

[0009] Furthermore, it also includes an anti-rotation component, which connects the outer casing and the end cap.

[0010] Furthermore, the motor is an external rotor motor and includes a rotor assembly and a stator assembly, with the stator assembly mounted on an anti-rotation component.

[0011] Furthermore, it also includes an adapter, through which the rotor assembly is connected to the outer wall of the nut.

[0012] Furthermore, the anti-rotation component is provided with a protrusion, and the lead screw is provided with a groove. The protrusion can connect with the groove to prevent the lead screw from rotating on the fixed seat.

[0013] Furthermore, both the first and second bearings are superconducting magnetic levitation bearings. The superconducting magnetic levitation bearing includes a bearing rotor and a bearing stator. The bearing rotor is a permanent magnet rotor, and the bearing stator is a superconducting stator.

[0014] Furthermore, the bearing stator includes a cryogenic Dewar, a first support, a liquid nitrogen chamber, a second support, and a superconducting block.

[0015] Furthermore, the bearing rotor includes a permanent magnet ring and a high-magnetic-weight ring.

[0016] A method for assembling a linear actuator for use in spacecraft.

[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0018] (1) The first and second bearings of the actuator of the present invention are both superconducting magnetic levitation bearings. The high-temperature superconducting magnetic levitation bearing is composed of a bearing rotor and a bearing stator. The bearing rotor provides a gradient magnetic field, and the bearing stator is affected by the magnetic field to generate magnetic levitation force, which is used to maintain the operation of the superconducting magnetic levitation bearing. The superconducting magnetic levitation bearing does not require lubrication and maintenance, has good stability and long service life, and is more suitable for use in orbital spacecraft than rolling bearings.

[0019] (2) The permanent magnet ring of the present invention is composed of multiple permanent magnet ring blocks. The circumferential stress of the permanent magnet ring decreases from 134.9MPa to 74.1MPa of the circumferential stress of the permanent magnet ring block. The thickness of the non-magnetic protective sleeve can be made thinner, which can reduce the overall mass of the superconducting magnetic levitation bearing.

[0020] (3) The nut of the present invention is short, and the fixed seat is provided with an anti-rotation groove to prevent the lead screw from rotating. The second bearing and the anti-rotation component are removed, which further reduces the mass of the actuator, and the effective stroke of the lead screw is increased without changing the total length.

[0021] (4) The assembly method of the present invention first assembles the permanent magnet ring block and then magnetizes the permanent magnet ring, which can avoid mutual repulsion between the permanent magnet ring blocks with magnetic properties and facilitate the assembly of the permanent magnet ring; since the cold assembly method only freezes the nut to reduce its size, without heating or freezing the permanent magnet ring, the permanent magnet ring does not generate stress before assembly; after assembly, due to the expansion of the nut, the permanent magnet ring is subjected to radial compressive stress and the stress is uniform, and it is not easy to generate cracks.

[0022] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the specification or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained from the content specifically pointed out in the text and drawings. Attached Figure Description

[0023] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0024] Figure 1 A schematic diagram of the axial cross-sectional structure of an actuator in the prior art;

[0025] Figure 2 This is a schematic diagram of the shaft cross-section structure of the actuator in Example 1;

[0026] Figure 3 for Figure 2 Enlarged structural diagram of region A in the middle;

[0027] Figure 4 This is a schematic diagram of the exploded structure of a permanent magnet ring;

[0028] Figure 5 This is a schematic diagram of the circumferential stress distribution of an integral permanent magnet ring.

[0029] Figure 6 This is a schematic diagram of the circumferential stress distribution of a segmented permanent magnet ring.

[0030] Figure 7 This is a schematic diagram of the overall structure of the assembled tooling;

[0031] Figure 8 This is a schematic diagram of the exploded structure of the assembled tooling.

[0032] Figure label:

[0033] 1-Screw; 2-Nut; 3-Housing; 4-First Bearing; 5-Adapter; 6-Rotor Assembly; 7-Stator Assembly; 8-Second Bearing; 9-End Cap; 10-Anti-rotation Component; 11-Fixed Seat; 12-Cryogenic Dewar; 13-First Support Component; 14-Liquid Nitrogen Chamber; 15-Second Support Component; 16-Superconducting Block; 17-Permanent Magnet Ring; 18-Magnetic Ring; 19-Non-Magnetic Protective Sleeve; 20-First Half Ring; 21-Second Half Ring; 22-Connecting Pin; 23-First Connector; 24-Second Connector; 101-Threaded Section; 102-Anti-rotation Section; 111-Fixed Connection Section; 112-Modible Connection Section; 113-Anti-rotation Groove; 171-Permanent Magnet Ring Block. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0035] Existing external rotor linear actuators, such as Figure 1 As shown, the system includes a lead screw 1, a nut 2, a housing 3, a first bearing 4, an adapter 5, a rotor assembly 6, a stator assembly 7, a second bearing 8, an end cap 9, an anti-rotation component 10, and a fixed base 11. The nut 2 is threadedly connected to the lead screw 1. One end of the lead screw 1 is connected to the inner wall of the fixed base 11, and the other end of the lead screw 1 is a push-pull end, used to push and pull rotating components, causing them to deflect. Specifically, for spacecraft, linear actuators are used to push and pull components such as nozzles or servos. One end of the nut 2 is connected to the housing 3 via the first bearing 4, and the other end of the nut 2 is connected to the end cap 9 via the second bearing 8. The nut 2 can rotate within the housing 3 and the end cap 9. The housing 3 and the end cap 9 are connected by the anti-rotation component 10. The end cap 9 is mounted on the outer wall of the fixed base 11. The stator assembly 7 is mounted on the anti-rotation component 10, and the rotor assembly 6 is connected to the outer wall of the nut 2 via the adapter 5. The rotor assembly 6 and the stator assembly 7 constitute an external rotor motor and are used to drive the nut 2 to rotate, thereby driving the lead screw 1 to extend and retract on the fixed base 11.

[0036] When flying in the space environment, the surface of an orbiting spacecraft experiences frequent and significant temperature changes. The operating environment for spacecraft actuators is harsh, and maintenance is impossible during the spacecraft's orbital period, placing high demands on the maintenance-free lifespan of actuators used in orbital spacecraft. Linear actuators typically use rolling bearings to reduce friction. However, rolling bearings require frequent lubrication to maintain the rolling components and ensure proper functioning. During spacecraft orbit, the inability to maintain rolling bearings leads to short actuator lifespan and poor operational stability.

[0037] Example 1

[0038] A specific embodiment of the present invention, such asFigure 2 As shown, a linear actuator (hereinafter referred to as the actuator) for spacecraft is disclosed, including a lead screw 1, a nut 2, a housing 3, a first bearing 4, an adapter 5, a rotor assembly 6, a stator assembly 7, a second bearing 8, an end cap 9, an anti-rotation component 10, and a fixed base 11. The nut 2 is threadedly connected to the lead screw 1. One end of the lead screw 1 is connected to the inner wall of the fixed base 11, and the other end of the lead screw 1 is a push-pull end, which is used to push and pull rotating components, causing the rotating components to deflect. Specifically, for spacecraft, the linear actuator is used to push and pull components such as nozzles or servo motors. One end of the nut 2 is connected to the housing 3 via the first bearing 4, and the other end of the nut 2 is connected to the end cover 9 via the second bearing 8. The nut 2 can rotate within the housing 3 and the end cover 9. The housing 3 and the end cover 9 are connected by an anti-rotation member 10. The end cover 9 is set on the outer wall of the fixed seat 11. The stator assembly 7 is set on the anti-rotation member 10. The rotor assembly 6 is connected to the outer wall of the nut 2 via the adapter 5. The rotor assembly 6 and the stator assembly 7 constitute an external rotor motor and are used to drive the nut 2 to rotate, thereby driving the lead screw 1 to extend and retract on the fixed seat 11. The anti-rotation member 10 is provided with a protrusion, and the lead screw 1 is provided with a groove. The protrusion can connect with the groove to prevent the lead screw 1 from rotating on the fixed seat 11.

[0039] In this design, both the first bearing 4 and the second bearing 8 are superconducting magnetic levitation bearings. These high-temperature superconducting magnetic levitation bearings consist of a bearing rotor and a bearing stator. The bearing rotor provides a gradient magnetic field, and the bearing stator, influenced by the magnetic field, generates magnetic levitation force to maintain the operation of the superconducting magnetic levitation bearing. Therefore, superconducting magnetic levitation bearings require no lubrication or maintenance, exhibit good stability and long lifespan, making them suitable for use in orbital spacecraft.

[0040] Preferably, such as Figure 3 As shown, the superconducting magnetic levitation bearing includes a bearing rotor and a bearing stator. The bearing rotor is a permanent magnet rotor, and the bearing stator is a superconducting stator.

[0041] Preferably, the bearing stator includes a cryogenic Dewar 12, a first support 13, a liquid nitrogen chamber 14, a second support 15, and a superconducting block 16. The outer wall of the cryogenic Dewar 12 is connected to the outer shell 3. The superconducting block 16 is fixedly mounted on the liquid nitrogen chamber 14. The liquid nitrogen chamber 14 is fixedly connected to the cryogenic Dewar 12 through the first support 13 and the second support 15. Liquid nitrogen can be introduced into the liquid nitrogen chamber 14, and the liquid nitrogen temperature range is 77K. The liquid nitrogen chamber 14 is made of copper material with good thermal conductivity. The cryogenic Dewar 12 can maintain a vacuum environment. Vacuum has a good heat insulation effect and can maintain the low temperature environment of the liquid nitrogen chamber 14 for a long time. The liquid nitrogen cools the superconducting block 16 to the superconducting temperature range through contact heat transfer.

[0042] Preferably, the bearing rotor includes a permanent magnet ring 17 and a magnet ring 18, with multiple permanent magnet rings 17 and magnet rings 18, and the multiple permanent magnet rings 17 and magnet rings 18 are arranged alternately. The outer wall of the nut 2 is connected to the central hole wall of the permanent magnet ring 17 and the magnet ring 18. The same poles of the two permanent magnet rings 17 are arranged opposite each other. The magnetizing effect of the magnet ring 18 can increase the peak magnetic field of the permanent magnet ring 17.

[0043] Compared with the prior art, the first bearing 4 and the second bearing 8 of the actuator in this embodiment are both superconducting magnetic levitation bearings. The high-temperature superconducting magnetic levitation bearing is composed of a bearing rotor and a bearing stator. The bearing rotor provides a gradient magnetic field, and the bearing stator is affected by the magnetic field to generate magnetic levitation force, which is used to maintain the operation of the superconducting magnetic levitation bearing. The superconducting magnetic levitation bearing does not require lubrication and maintenance, has good stability and long service life, and is suitable for use in orbital spacecraft.

[0044] Example 2

[0045] Currently, superconducting magnetic levitation bearings are in a high-speed rotating state, such as Figure 3 As shown, the permanent magnet ring 17 has high circumferential stress, so a non-magnetic protective sleeve 19 needs to be installed to protect the permanent magnet ring 17 and prevent it from breaking. The non-magnetic protective sleeve 19 has high strength requirements, resulting in high overall quality of the superconducting magnetic levitation bearing.

[0046] Another specific embodiment of the actuator of the present invention is as follows: Figure 4 As shown, in order to reduce the circumferential stress of the permanent magnet ring 17, the thickness of the non-magnetic protective sleeve 19 is reduced. Based on Example 1, this embodiment improves the structure of the permanent magnet ring 17. The permanent magnet ring 17 is a segmented permanent magnet ring, which reduces the circumferential stress of the permanent magnet ring 17.

[0047] Preferably, the permanent magnet ring 17 in this embodiment is composed of multiple permanent magnet ring blocks 171. The permanent magnet ring blocks 171 are arc-shaped blocks, and the multiple permanent magnet ring blocks 171 can be connected to each other in the circumferential direction to form the permanent magnet ring 17.

[0048] Preferably, there are 4 to 12 permanent magnet ring blocks 171, specifically, there are 4, 6 or 8 permanent magnet ring blocks 171.

[0049] The following comparison of circumferential stress calculations is performed using the integral permanent magnet ring 17 and eight permanent magnet ring blocks 171 as examples. The permanent magnet ring 17 is made of neodymium iron boron magnetic material with a tensile strength of approximately 80 MPa. Excessive edge linear velocity can easily lead to the permanent magnet ring disintegrating and breaking.

[0050] Analysis of the complete circumferential stress distribution of the permanent magnet ring 17 (e.g.) Figure 5 (as shown) and the circumferential stress distribution of the permanent magnet ring block 171 (as shown) Figure 6As shown in the diagram, the segmented structure significantly reduces the circumferential stress of the permanent magnet. This also means that the rotor speed can be increased, the thickness of the non-magnetic protective sleeve 19 can be reduced, the suspension gap of the superconducting magnetic bearing can be decreased, and the suspension force can be improved.

[0051] Simulation calculations show that the outer diameter of the permanent magnet ring 17 is 35mm, and the maximum circumferential stress of the permanent magnet ring 17 at a rotation speed of 40,000rpm is 134.9MPa, while the maximum circumferential stress of the permanent magnet ring block 171 is 74.1MPa.

[0052] Preferably, the permanent magnet ring blocks 171 are bonded together with adhesive, and the adhesive strength is greater than 120 MPa.

[0053] Compared with Example 1, the permanent magnet ring 17 in this example is composed of multiple permanent magnet ring blocks 171. The circumferential stress of the permanent magnet ring 17 decreases from 134.9 MPa to 74.1 MPa of the circumferential stress of the permanent magnet ring block 171. The thickness of the non-magnetic protective sleeve 19 can be made thinner, which can reduce the overall mass of the superconducting magnetic levitation bearing.

[0054] Example 3

[0055] Another embodiment of the actuator of the present invention, such as Figure 7 As shown, in order to further reduce the mass of the actuator, this embodiment improves the structure of the nut 2 and the fixed seat 11 based on embodiment 1 or embodiment 2, and removes the second bearing 8 and the anti-rotation component 10 (that is, the actuator of this embodiment is composed of lead screw 1, nut 2, housing 3, first bearing 4, adapter 5, rotor assembly 6, stator assembly 7, end cover 9 and fixed seat 11), thereby further reducing the mass of the actuator.

[0056] Preferably, the fixed base 11 includes a fixed connecting section 111 and a movable connecting section 112, and the end cover 9 is connected to the fixed connecting section 111. The stator assembly 7 is disposed on the outer wall of the movable connecting section 112, so the anti-rotation member 10 can be removed.

[0057] Preferably, the lead screw 1 includes a threaded section 101 and an anti-rotation section 102. The threaded section 101 is used to connect with the nut 2, and the anti-rotation section 102 is provided with an anti-rotation block (not shown in the figure). The fixed base 11 also includes an anti-rotation groove 113, which is disposed on the inner wall of the fixed connection section 111. The anti-rotation block can connect with the anti-rotation groove 113 and slide on the anti-rotation groove 113, thereby preventing the lead screw 1 from rotating.

[0058] Preferably, after removing the second bearing 8, the nut 2 is no longer connected to the second bearing 8, the length of the nut 2 can be shortened, and the total mass of the actuator in this embodiment can be reduced.

[0059] When the lead screw is in operation, the length of the nut represents the ineffective stroke of the lead screw. With the lead screw length remaining constant, the shorter the nut, the longer the effective stroke of the lead screw. In this embodiment, the effective stroke of the actuator's lead screw 1 can be increased without changing its overall length because the length of the nut 2 is shortened.

[0060] Compared with Embodiment 1 or Embodiment 2, the nut 2 provided in this embodiment is shorter, an anti-rotation groove 113 is provided on the fixed seat 11 to prevent the lead screw 1 from rotating, and the second bearing 8 and the anti-rotation element 10 are removed, further reducing the mass of the actuator, and the effective stroke of the lead screw 1 can be increased without changing the total length.

[0061] Example 4

[0062] Another specific embodiment of the present invention discloses a method for assembling the linear actuator of embodiment 1, 2 or 3.

[0063] The assembly method in this embodiment includes the following steps:

[0064] Step 1: Assemble the permanent magnet ring 17;

[0065] Adhesive is evenly applied to the side wall of the permanent magnet ring block 171, and multiple non-magnetic permanent magnet ring blocks 171 are sequentially pasted into a ring shape and then placed on an aluminum alloy disc.

[0066] Preferably, the assembly method in this embodiment also requires the use of assembly tooling, such as... Figure 7 and Figure 8 As shown, the assembled tooling is a circular sleeve, including a first half-ring 20, a second half-ring 21, and a connecting pin 22. The first half-ring 20 and the second half-ring 21 have the same structure. One end of the first half-ring 20 is provided with a first connecting member 23, which is a connecting ring. The other end of the first half-ring 20 is provided with a second connecting member 24, which is two connecting rings. The first connecting member 23 of the first half-ring 20 can be connected to the second connecting member 24 of the second half-ring 21. The connecting pin 22 can be inserted into the first connecting member 23 and the second connecting member 24 respectively, thereby connecting the first half-ring 20 and the second half-ring 21 into the assembled tooling. The assembled tooling includes two sets of first connecting members 23 and second connecting members 24.

[0067] Preferably, the tooling is an aluminum alloy retaining ring.

[0068] The first set of first connectors 23 and second connectors 24 are connected by connecting pins 22. Then, the first half ring 20 is placed on the multiple permanent magnet ring blocks 171 that are pasted into a ring shape. The second half ring 21 is pressed tightly towards the first half ring 20. The second set of first connectors 23 and second connectors 24 are connected by connecting pins 22 to ensure that the multiple permanent magnet ring blocks 171 that are pasted into a ring shape can be glued into a whole.

[0069] Preferably, pay close attention to any excess adhesive on the surface of the permanent magnet ring 17 and wipe it off promptly to avoid affecting subsequent assembly.

[0070] Step 2: Magnetize permanent magnet ring 17;

[0071] Assemble the permanent magnet ring block 171 first, and then magnetize the permanent magnet ring 17. This can avoid mutual repulsion between the magnetic permanent magnet ring blocks 171 and facilitate the assembly of the permanent magnet ring 17.

[0072] Step 3: Bond and assemble the bearing rotor;

[0073] The magnetic ring 18 and permanent magnet ring 17 are alternately installed on the non-magnetic protective sleeve 19. During the installation process, adhesive should be evenly applied to each surface. The non-magnetic protective sleeve 19 is installed outside the magnetic ring 18. It is necessary to ensure that there is no gap between the components. Use a heavy object to press on the non-magnetic protective sleeve 19 to squeeze out the excess adhesive between the components. Wipe it clean in time to avoid affecting the subsequent grinding of the outer end face.

[0074] Step 4: Cold assembly of nut 2;

[0075] First, nut 2 is placed in liquid nitrogen for cooling and shrinkage. After nut 2 is cooled, its outer diameter decreases.

[0076] Place nut 2 into the bearing rotor that is bonded together as a whole.

[0077] Since the cold assembly method only freezes the nut 2 to reduce its size, without heating or freezing the permanent magnet ring 17, the permanent magnet ring 17 does not generate stress before assembly; after assembly, due to the expansion of the nut 2, the permanent magnet ring 17 is subjected to radial compressive stress and the stress is uniform, making it less prone to cracking.

[0078] Step 5: Assemble the remaining components of the linear actuator;

[0079] Step 6: Complete the assembly of the linear actuator;

[0080] Compared with existing technologies, assembling the permanent magnet ring block 171 first and then magnetizing the permanent magnet ring 17 can avoid mutual repulsion between the magnetic permanent magnet ring blocks 171, making it easier to assemble the permanent magnet ring 17. Since the cold assembly method only freezes the nut 2 to reduce its size, without heating or freezing the permanent magnet ring 17, the permanent magnet ring 17 does not generate stress before assembly. After assembly, due to the expansion of the nut 2, the permanent magnet ring 17 is subjected to radial compressive stress, and the stress is uniform, making it less prone to cracking.

[0081] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A linear actuator for spacecraft, characterized in that, It includes a lead screw (1), a nut (2), a motor and a fixed base (11). One end of the lead screw (1) is connected to the inner wall of the fixed base (11), and the other end of the lead screw (1) is a push-pull end. The nut (2) is threadedly connected to the lead screw (1). The motor is used to drive the nut (2) to rotate, thereby driving the lead screw (1) to slide on the fixed base (11). The push-pull end is used to push and pull the rotating parts of the spacecraft, causing the rotating parts to deflect.

2. The linear actuator for spacecraft according to claim 1, characterized in that, It also includes a housing (3), a first bearing (4), a second bearing (8) and an end cap (9). The end cap (9) is set on the outer wall of the fixed base (11). One end of the nut (2) is connected to the housing (3) through the first bearing (4), and the other end of the nut (2) is connected to the end cap (9) through the second bearing (8). The nut (2) can rotate inside the housing (3) and the end cap (9).

3. The linear actuator for spacecraft according to claim 2, characterized in that, It also includes an anti-rotation component (10), and the outer shell (3) and the end cap (9) are connected by the anti-rotation component (10).

4. The linear actuator for spacecraft according to claim 3, characterized in that, The motor is an external rotor motor and includes a rotor assembly (6) and a stator assembly (7), with the stator assembly (7) mounted on an anti-rotation member (10).

5. The linear actuator for spacecraft according to claim 4, characterized in that, It also includes an adapter (5), through which the rotor assembly (6) is connected to the outer wall of the nut (2).

6. The linear actuator for spacecraft according to claim 1, characterized in that, The anti-rotation component (10) is provided with a protrusion, and the lead screw (1) is provided with a groove. The protrusion can connect with the groove to prevent the lead screw (1) from rotating on the fixed seat (11).

7. The linear actuator for spacecraft according to claim 2, characterized in that, The first bearing (4) and the second bearing (8) are both superconducting magnetic levitation bearings. The superconducting magnetic levitation bearing includes a bearing rotor and a bearing stator. The bearing rotor is a permanent magnet rotor and the bearing stator is a superconducting stator.

8. The linear actuator for spacecraft according to claim 7, characterized in that, The bearing stator includes a cryogenic dewar (12), a first support (13), a liquid nitrogen chamber (14), a second support (15), and a superconducting block (16).

9. The linear actuator for spacecraft according to claim 7, characterized in that, The bearing rotor includes a permanent magnet ring (17) and a high-magnetic ring (18).

10. A method for assembling a linear actuator, characterized in that, Assemble the linear actuator for a spacecraft as described in any one of claims 1-9.

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