CN109131951B

CN109131951B - Spatial radial unlocking mechanism driven by shape memory alloy SMA (shape memory alloy) tows

Info

Publication number: CN109131951B
Application number: CN201811019942.9A
Authority: CN
Inventors: 孙健; 周宝; 刘彦菊; 冷劲松; 王维昊
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2018-09-03
Filing date: 2018-09-03
Publication date: 2021-09-07
Anticipated expiration: 2038-09-03
Also published as: CN109131951A

Abstract

The invention provides a space radial unlocking mechanism driven by shape memory alloy SMA tows, wherein a base is fixed at the bottom of an outer cover of the mechanism, an upper cover is arranged at the top of the outer cover, a bolt is inserted from a through hole of the upper cover and positioned above a top block, a positioning block and two split nuts are sleeved on the periphery of the bolt, grooves are formed in the peripheries of the two split nuts, a rigid hoop is arranged in the grooves of the two split nuts, an H-shaped fixing frame is arranged at the closed position of the end of the rigid hoop, and the SMA shape memory alloy tows surround the periphery of the rigid hoop and are fixed on the fixing frame. The problem of the radial release mechanism in space among the prior art impact great, drive power is little, and the motion precision of ball is difficult to guarantee is solved, provide a radial release mechanism in space by shape memory alloy SMA silk bundle drive, adopt shape memory alloy SMA silk bundle radial drive mode, have low impact, drive displacement is big, drive precision is high, the unblock time is short, the motion precision is high, low friction, pollution-free advantage.

Description

Spatial radial unlocking mechanism driven by shape memory alloy SMA (shape memory alloy) tows

Technical Field

The invention relates to a space radial unlocking mechanism driven by SMA (shape memory alloy) tows, and belongs to the field of unlocking structures of aerospace systems.

Background

After the satellite is launched, a plurality of auxiliary devices such as an antenna and a solar panel are required to be successfully separated from a parent body so as to successfully complete the on-orbit task, most of releasing devices are initiating devices, the action time is short, the size is small, the smaller energy input is the advantages, however, the releasing devices easily cause higher impact load and space pollution, the treatment cost is huge, and therefore, a separating device capable of replacing the traditional initiating device is required to be researched, and the separating device has the advantages of low impact load, no pollution and reusability compared with the initiating device.

Due to the unique shape memory performance of the shape memory alloy SMA, under the deformation condition, when the temperature exceeds the corresponding phase transition temperature, the shape memory alloy SMA can recover the original shape, the recovery deformation can be repeated under a certain condition, although the maximum recovery strain can reach 8%, the linear driving displacement is small, and the use precision of the SMA as a driving source is low. The existing space radial unlocking mechanism mostly adopts linear driving, has larger impact and small driving force, and the movement precision of the ball is difficult to ensure.

Disclosure of Invention

The invention aims to solve the problems that the space radial unlocking mechanism in the prior art has large impact, small driving force and difficult guarantee of the movement precision of a ball, and provides the space radial unlocking mechanism driven by the shape memory alloy SMA wire bundle.

The invention adopts the following technical scheme for achieving the purpose:

the space radial unlocking mechanism driven by the shape memory alloy SMA tows comprises a base, an outer cover, a bushing, a compression spring, two split nuts, a rigid hoop, a fixing frame, a positioning block, a top block, the SMA shape memory alloy tows, an upper cover and a bolt; the outer cover is in a cylindrical shape, an opening is formed in the side wall of the outer cover, the fixing frame is arranged at the opening of the outer cover, a bushing is lined in the outer cover, a base is fixed at the bottom of the outer cover, an upper cover is installed at the top of the outer cover, a through hole is formed in the center of the upper cover, the compression spring is fixed on the base, the ejector block is fixed above the compression spring, the bolt is inserted into the through hole of the upper cover and is positioned above the ejector block, a positioning block and two split nuts are sleeved on the periphery of the bolt, the positioning block is positioned between the upper cover and the two split nuts, grooves are formed in the peripheries of the two split nuts, the rigid clamp is arranged in the grooves of the two split nuts, an H-shaped fixing frame is arranged at the closed end of the rigid clamp, and the two ends of the fixing frame are integrally formed with the two ends of, the two ends of the fixing frame are respectively provided with a mounting hole, the SMA shape memory alloy tows surround the periphery of the rigid hoop and are fixed on the fixing frame through the mounting holes, and the fixing frame is further provided with a power-on device used for powering on the SMA shape memory alloy tows.

Preferably, the SMA shape memory alloy wire bundle comprises four SMA shape memory alloy wires.

The working principle of the space radial unlocking mechanism driven by the shape memory alloy SMA tows is as follows:

the split nut is matched with the rigid hoop, and in a locking state, as the split nut is subjected to the radial constraint force of the rigid hoop and the fixing frame, the radial movement of the split nut is limited, and the radial release of the split nut is limited; in an unlocking state, the four SMA shape memory alloy wires are electrified simultaneously, the SMA shape memory alloy wires can pull the rigid hoop and the fixing frame to move along the radial direction, the radial constraint force on the split nut is relieved, the compression spring acts on the top block with axial pressure to drive the top block to move upwards, the split nut is radially separated under the action of the top block, and the bolt is unlocked and released.

The space radial unlocking mechanism driven by the shape memory alloy SMA tows has the beneficial effects that:

(1) the invention adopts SMA shape memory alloy wires, and because the power supply synchronously energizes and heats four alloy wires, the power supply applies radial releasing force to the rigid hoop, thereby ensuring the synchronism of the radial restraint of the rigid hoop and the fixed frame to be removed, and the design can greatly improve the unlocking precision.

(2) The four SMA shape memory alloy wires are optimally assembled by adopting a binding mode and split nuts, so that the driving angular displacement and the driving force of the SMA can be ensured, the unlocking time is greatly reduced, and the locking force is increased.

(4) The invention adopts a shape memory alloy SMA radial driving mode, and has the advantages of low impact, large driving displacement, high driving precision, short unlocking time, high motion precision, low friction and no pollution.

Drawings

FIG. 1 is a schematic view of a spatial radial unlocking mechanism driven by a shape memory alloy SMA wire bundle according to the present invention;

FIG. 2 is a cross-sectional view of the locking state of the spatial radial unlocking mechanism driven by the shape memory alloy SMA wire bundle;

FIG. 3 is a schematic structural diagram of the cooperation of SMA shape memory alloy wire bundles and a rigid hoop of the spatial radial unlocking mechanism driven by the SMA wire bundles;

in the figure: 1-a base; 2-an outer cover; 3-a bushing; 4-compression spring; 5-split nut; 6, fixing a frame; 7-positioning blocks; 8-a top block; 9-SMA shape memory alloy wire; 10-upper cover; 11-bolt.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

First embodiment, the present embodiment is described with reference to fig. 1 to 3, and the spatial radial unlocking mechanism driven by the SMA wire bundle in the present embodiment includes a base 1, an outer cover 2, a bushing 3, a compression spring 4, two split nuts 5, a rigid clamp, a fixing frame 6, a positioning block 7, a top block 8, the SMA shape memory alloy wire bundle, an upper cover 10, and a bolt 11; the outer cover 2 is in a cylindrical shape, an opening is formed in the side wall of the outer cover 2, the fixing frame 6 is arranged at the opening of the outer cover 2, a bushing 3 is lined in the outer cover 2, the base 1 is fixed to the bottom of the outer cover 2, the top of the outer cover 2 is provided with the upper cover 10, a through hole is formed in the center of the upper cover 10, the compression spring 4 is fixed to the base 1, the ejector block 8 is fixed above the compression spring 4, the bolt 11 is inserted into the through hole of the upper cover 10 and located above the ejector block 8, the positioning block 7 and the two split nuts 5 are sleeved on the periphery of the bolt 11, the positioning block 7 is located between the upper cover 10 and the two split nuts 5, grooves are formed in the peripheries of the two split nuts 5, the rigid clamp is arranged in the grooves of the two split nuts 5, and an H-shaped fixing frame 6 is arranged at the closed end of the rigid clamp, the two ends of the fixing frame 6 are integrally formed with the two ends of the rigid hoop respectively, mounting holes are formed in the two ends of the fixing frame 6 respectively, the SMA shape memory alloy tows are wound on the periphery of the rigid hoop and fixed on the fixing frame 6 through the mounting holes, and the fixing frame 6 is further provided with a power-on device for powering on the SMA shape memory alloy tows.

And each component of the spatial radial unlocking mechanism driven by the SMA tows is made of light alloy, so that the overall light weight of the mechanism is ensured.

The fixing frame 6 is H-shaped and used for fixing the rigid hoop and the SMA shape memory alloy tows, when the SMA shape memory alloy tows are electrified, the tensile force of the SMA shape memory alloy tows is larger than the radial driving force of the rigid hoop, and the rigid hoop drives the two ends of the fixing frame 6 to move radially along the two sides to complete the unlocking process.

The outer cover 2 is provided with an opening, so that the fixing frame 6 is guided, the unlocking of the fixing frame 6 is guaranteed to move along the radial direction, and the unlocking precision of the structure is guaranteed.

The SMA shape memory alloy wire bundle comprises four SMA shape memory alloy wires 9. The more the SMA shape memory alloy wires 9, the faster the unlocking mechanism unlocks, and the specific number thereof can be adjusted according to actual conditions.

The function realization process of the spatial radial unlocking mechanism driven by the SMA wire bundle comprises the following steps:

1) when the split nut is in a locking state (the SMA tows are not electrified), the split nut 5 is subjected to the action of radial constraint force of the rigid hoop and the fixing frame 6, so that the radial movement of the split nut is limited, and the radial release of the split nut 5 is limited;

2) in an unlocking state, the SMA shape memory alloy wire bundle is electrified, and due to the fact that the SMA has shape memory effect and special mechanical property, when the angular displacement required for recovery is generated, a large radial driving force is generated, the driving force is larger than the radial constraint force of the rigid hoop and the fixing frame 6 on the split nut 5, at the moment, the rigid hoop and the fixing frame 6 are pulled by the four SMA shape memory alloy wires 9 to move in the radial direction, the radial constraint force on the split nut 5 is relieved, due to the fact that the compression spring 4 exerts axial pressure on the top block 8, the top block 8 is driven to move upwards, the split nut 5 is radially separated under the action of the top block 8, and the bolt 11 is unlocked and released.

Although the invention has been described with reference to specific embodiments and examples, it is not intended to be limited thereto, and modifications in the parameters set forth herein can be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A space radial unlocking mechanism driven by shape memory alloy SMA tows is characterized by comprising a base (1), an outer cover (2), a bushing (3), a compression spring (4), two split nuts (5), a rigid hoop, an H-shaped fixing frame (6), a positioning block (7), a top block (8), the SMA shape memory alloy tows, an upper cover (10) and a bolt (11); the outer cover (2) is in a cylindrical shape, an opening is formed in the side wall of the outer cover (2), an H-shaped fixing frame (6) is arranged at the opening of the outer cover (2), a bushing (3) is lined in the outer cover (2), a base (1) is fixed at the bottom of the outer cover (2), an upper cover (10) is installed at the top of the outer cover (2), a through hole is formed in the center of the upper cover (10), a compression spring (4) is fixed on the base (1), a top block (8) is located above the compression spring (4), a bolt (11) is inserted into the through hole of the upper cover (10) and located above the top block (8), a positioning block (7) and two split nuts (5) are sleeved on the periphery of the bolt (11), the positioning block (7) is located between the upper cover (10) and the two split nuts (5), and grooves are formed in the peripheries of the two split nuts (5), the rigidity clamp sets up in the recess of two split nuts (5), the closed department of end of rigidity clamp is provided with "H" type mount (6), the both ends of "H" type mount (6) respectively with the both ends head integrated into one piece of rigidity clamp, the both ends of "H" type mount (6) are provided with the mounting hole respectively, SMA shape memory alloy silk bundle is fixed on "H" type mount (6) around the periphery of rigidity clamp and through the mounting hole, still be provided with the closing means on "H" type mount (6) for circular telegram to SMA shape memory alloy silk bundle.

2. Spatial radial unlocking mechanism actuated by shape memory alloy SMA tows according to claim 1, characterized in that said SMA shape memory alloy tows comprise four SMA shape memory alloy wires (9).