CN108190051A - A kind of super large load tripper of SMA driving - Google Patents

Abstract

The present invention provides a kind of super large load tripper of SMA driving, and using valve nut and king-bolt is divided, as connector, scroll spring is as fastener, the SMA driving elements as separation for the mechanism；Mechanism is connected by king-bolt with separated structure, and valve nut is divided to lock king-bolt under the package of scroll spring；Scroll spring inner end is fixed on point valve nut, and outer end is connected with frame；Locking state lower frame is limited by the constraint system that briquetting and bayonet lock form；During separation, it is powered to SMA, it is made to be heated to undergo phase transition and shrink, driving briquetting movement releases the limiting to bayonet lock, the frame of constraint is lost under the effect of scroll spring restoring force, it is rotated with scroll spring, after scroll spring scatters, valve nut is divided to be opened under the effect of its thin-slab structure, discharge king-bolt, the separation of implementation mechanism.Present invention driving than it is high, load is big for release, reliability is high, anti-vibration, impact capacity are strong.

Description

An SMA wire-driven super-large load unlocking device

technical field

The invention relates to the technical field of unlocking devices for spacecraft, in particular to a split nut unlocking device.

Background technique

The spacecraft needs a variety of unlocking devices to realize the connection and unlocking functions, such as the separation of multi-stage launch vehicles, the deployment of solar wings on satellites or spacecraft, and so on. Most of these devices are pyrotechnic bolts (also known as explosive bolts) at present. At present, most of these devices are pyrotechnic bolts (also known as explosive bolts). The pyrotechnic bolts will cause impact during the process of unlocking and separating, and will leave explosive debris, dust, chemical gases, etc. in the spacecraft, causing pollution problems. With the development of technology, especially the emergence of a new generation of small satellites, the contradiction between the defects of pyrotechnic bolts and the rapidly growing application requirements has become increasingly prominent.

The split nut unlocking device is a mechanism that realizes the connection function through the complete thread in the connected state, and destroys the threaded connection relationship by splitting the nut during separation to realize the unlocking mechanism. In recent decades, some progress has been made in the development of new unlocking devices using split nuts, and split nut unlocking schemes based on various driving principles have been proposed, such as electromagnetic separation devices with electromagnetic force as the driving force, using The hoop limit locking mechanism driven by SMA wire, etc. These split nut connection release mechanisms have the advantages of complete unlocking and good synchronization, but also have the following major disadvantages:

(1) The electromagnetically driven mechanism has a complex structure, a large number of parts, high manufacturing costs and difficult release reliability;

(2) The electromagnetically driven split nut release device is driven by electromagnetic force, and the generated electromagnetic field has a great impact on the space environment, and its application range is limited;

(3) The SMA-driven mechanism relies on the heat shrinkage of the SMA wire to pull the hoop out of the split nut for unlocking, and has poor vibration and impact resistance;

(4) Relying on the contraction of the SMA wire to realize the drive, and the length of the SMA wire is short, so that the design margin of the mechanism is small. With the increase of the number of drives, the performance of the SMA wire will be attenuated, and the margin of the mechanism will be further reduced;

(5) The mechanism driven by the SMA wire has no redundant design, the separation reliability is poor, and the application range is limited;

(6) Existing SMA hoop limit locking mechanism, drive ratio is low (drive ratio among the present invention is similar to the principle of labor-saving lever, and it is defined as: drive ratio=the driving of the release load/drive element that mechanism can provide load), which cannot meet the requirements of the application environment with super large release load.

Contents of the invention

The invention mainly solves the problems in the prior art that the driving ratio is low, the super load cannot be released, the redundant design is not carried out, and the anti-vibration and shock performance are poor, and it provides a high driving ratio, which can release super large loads and is reliable. Split nut unlocking device driven by SMA wire with high anti-vibration and strong shock capacity.

The technical solution adopted in the present invention is: an SMA wire-driven super-large load unlocking device, which includes: SMA wire, insulating track, return spring, pressing block, bayonet, frame, bearing, split nut, reset tooling, scroll Spring, lower cover, upper cover, large bolts, pins. Among them, split nuts and large bolts are connectors, scroll springs are fasteners, and SMA wires are separate driving elements; the lower cover is connected to the fixed structure, the large bolts are connected to the separation structure, and the large bolts and split nuts are threaded. The pair fits and connects, and the split nut locks the large bolt under the wrapping of the scroll spring; the inner end of the scroll spring is fixed on the split nut, and the outer end is connected with the frame through a pin, and the split nut and the frame are connected with the inner ring of the bearing respectively. Cooperate with the outer ring; the head of the reset tool is fixed on the upper cover, and the lower part is inserted into the hexagonal hole on the top surface of the split nut; one end of the SMA wire is fixed on the lower cover, and the other end is connected to the pressing block through the insulating track, and the pressing block A return spring is arranged between the insulating track.

When the mechanism is locked, the frame is limited by the restraint system composed of the pressure block and the bayonet pin, and the inner and outer ends of the scroll spring are restrained, so that the split nut locks the large bolt.

When separating, energize the SMA wire to cause phase change and shrink when heated, drive the pressing block to move, and release the limit of the bayonet to the frame. Under the action of the restoring force of the scroll spring, the frame and the outer end of the scroll spring rotate together. The volute spring spreads out, the split nut opens, and the large bolt is released to realize the separation of the mechanism.

When it needs to be reset, rotate the frame to return the bayonet pin, the pressure block returns to the constrained position under the elastic force of the return spring, and the outer end of the scroll spring is restrained again, at this time, the rotating reset tool drives the split nut and scroll spring The inner end rotates, the volute spring re-tightens and locks the split nut, so that the mechanism is re-locked.

Further, the split nut is made of elastic material.

Further, the split nut is tightly wrapped by the scroll spring, and the friction between the turns of the scroll spring can ensure that the split nut will not open even if it is subjected to a large radial load.

Furthermore, a hexagonal hole is provided at the center of the top of the split nut, which cooperates with the reset tool to make the split nut rotate under the drive of the reset tool, thereby tightening the scroll spring and realizing the reset of the mechanism.

Further, the outer surface of the upper part of the split nut is stepped, and is matched with the upper cover and the inner ring of the bearing.

Further, the lower part of the split nut is a split body, and the number of split bodies is 3 or 4. When put together, it is a cylinder with a tapered step at the bottom. The outer surface of the cylinder is wrapped and locked by a scroll spring, and the inner surface Threads are available for large bolts.

Further, the conical step at the lower part of the split nut cooperates with the lower cover through the conical surface of the bottom surface, which has a self-centering effect and improves the ability to resist shock and vibration.

Further, the middle part of the split nut is a plurality of thin plate structures, the number of the thin plate structures corresponds to the number of the split bodies, and is evenly distributed along the circumferential direction, which acts as a spring steel sheet and has a tendency to expand outward. Under the condition of spring constraint, the thin plate structure can drive the split body to expand outward.

Furthermore, a hexagonal hole is provided in the center of the head of the reset tool, which is used for applying a preload and rotating the reset tool when coordinating with an inner hexagonal wrench.

Further, there are 3 arc-shaped through holes evenly distributed on the edge of the head of the reset tool. In the locked state, the reset tool can be fixed on the upper cover by using the arc-shaped through holes to cooperate with screws, and the position of the reset tool can be limited. , thereby indirectly restricting the rotational freedom of the split nut; when reset is required, the screw is removed to rotate the reset tool and drive the split nut to rotate. After reset, the screw is used to limit the reset tool again.

Further, two SMA wires are arranged in parallel, and the two SMA wires work at the same time, serving as mutual backup, so as to realize the redundant design of the driving element.

Further, the inner and outer ends of the scroll spring are respectively fixed on the split nut and the frame, and the split nut and the frame are respectively matched with the inner ring and the outer ring of the bearing, so the movements of the inner and outer ends of the scroll spring are mutually independent.

Further, the scroll spring is made of spring steel, and the tightening capacity of the scroll spring can be adjusted by designing the thickness and number of turns of the spring steel strip.

Compared with the existing technology, the present invention has the characteristics of large release load, high reliability, anti-vibration, strong impact load capacity, etc., which are specifically manifested in the following aspects:

(1) The present invention adopts a segmented split nut, whose degree of freedom is completely constrained by the bottom cover, scroll spring, reset tooling and upper cover, and can withstand large vibration and impact loads without accidental separation and connection. Higher reliability.

(2) The present invention releases the restraint of the scroll spring by shortening the heat of the SMA wire, and then opens the split nut to release the large bolt. Compared with the prior art, the driving ratio is higher, and the driving force of the SMA wire remains unchanged. Under the premise, it can provide a super large release load and is applicable to a wider range of occasions.

(3) The present invention adopts two parallel SMA wires as driving elements. When separation is required, no matter which SMA wire is heated, the large bolt can be released successfully. This redundant design improves the release reliability of the mechanism.

(4) In the whole mechanism of the present invention, before the scroll spring is scattered, there is no unrestricted or incomplete part, and the split nut and the lower cover are matched by a conical surface, which has a self-centering effect, so that When the mechanism is subjected to large vibration and impact loads in any direction, no parts will move and cause connection failure, and the vibration and impact resistance is strong.

(5) In the present invention, the SMA wire is protected by an insulating track, which not only prevents heat loss, shortens the heating and deformation time of the SMA wire, but also effectively avoids damage to the SMA wire by the external environment, further improving reliability.

Description of drawings

Fig. 1 is a schematic diagram of an overall structure diagram of the present invention;

Fig. 2 is the overall structure sectional view of the present invention;

Fig. 3 is a partial structural top view of the present invention;

Fig. 4 is the structure schematic diagram of split nut of the present invention;

Fig. 5 is a schematic diagram of the bayonet structure of the present invention;

Fig. 6 is a relationship curve between the stress of the inner ring of the scroll spring and the outer diameter of the scroll spring according to the present invention.

Meanings of reference signs: 1. SMA wire; 2. Insulation track; 3. Return spring; 4. Press block; 5. Bayonet pin; 6. Frame; 7. Bearing; 8. Split nut; .Scroll spring; 11. Lower cover; 12. Upper cover; 13. Large bolt; 501. Rotating shaft; . Bearing mating surface; 804. Thin plate structure; 805. Split body; 806. Conical steps.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

The present invention provides an SMA wire-driven super-large load unlocking device, the structure of which is shown in FIGS. 1 to 3 . The lower cover 11 is connected with the fixed structure, the large bolt 13 is connected with the separation structure, the large bolt 13 is connected with the split nut 8 by a thread pair, and the split nut 8 locks the large bolt 13 under the wrapping of the scroll spring 10, thereby realizing Connection function; the inner end of the scroll spring 10 is fixed on the split nut 8, and the outer end is connected with the frame 6 through a pin, and the split nut 8 and the frame 6 cooperate with the inner ring and the outer ring of the bearing 7 respectively; The head is fixed on the upper cover 12, and the lower part is inserted into the hexagonal hole on the top surface of the split nut 8; one end of the SMA wire 1 is fixed on the lower cover 11, and the other end is connected to the pressing block 4 through the insulating track 2, and the pressing block 4 and A return spring 3 is arranged between the insulating tracks 2 .

The split nut 8 is one of the connectors of the present invention, and Fig. 4 shows its structure diagram. It includes a hexagonal hole 801 , an upper cover fitting surface 802 , a bearing fitting surface 803 , a thin plate structure 804 , a split body 805 and a tapered step 806 . Among them, the hexagonal hole 801 is used to cooperate with the lower part of the reset tooling 9. When the reset tool is rotated, the split nut can be driven to rotate, thereby tightening the scroll spring; the upper cover matching surface 802 is matched with the upper cover 12; the bearing matching surface 803 is matched with the bearing The inner ring of 7 fits; the number of split bodies 805 is 3 or 4 (the scheme of 4 split bodies is shown in the figure), the structure of each petal is the same, and it is a cylinder when put together, and the outer surface of the cylinder Wrapped and locked by the scroll spring 10, the thread on the inner surface can cooperate with the large bolt 13; the thin plate structure 804 is evenly distributed along the circumference, and its number matches the number of the split body 805. When the scroll spring 10 is constrained, the thin plate structure 804 can drive the split body 805 to open outward; the conical step 806 is under the split body 805, and the conical surface of the bottom surface cooperates with the lower cover, which has a self-centering effect , Improved resistance to shock and vibration.

The bayonet structure is an important component in the restraint system of the present invention, and the whole bayonet structure actually consists of two parts, namely the rotating shaft part and the bayonet main body. According to the orientation shown in Figure 5, the left end of the bayonet main body is provided with a through hole, and the rotating shaft 501 is installed in the through hole, and the bayonet main body can rotate around the rotating shaft 501; 4 contacts, the frame mating surface 503 is in contact with the frame 6, and the detent 5 is balanced under the joint action of the pressing block 4 and the frame 6, and remains stationary; when separated, the pressing block 4 is driven by the SMA wire to move, and the pressing block fits The constraint on the surface 502 is lost, causing the bayonet pin 5 to lose balance and rotate around the rotating shaft 501 , thereby releasing the bayonet pin 5 from limiting the frame 6 .

Scroll spring 10 is the fastening element of the present invention, is wrapped in split nut 8 to realize fastening to large bolt 13, and its inner and outer ends are respectively fixed on split nut 8 and frame 6, and split nut 8 And the frame 6 cooperates with the inner and outer rings of the bearing 7 respectively, so that the motions of the two ends of the scroll spring 10 are independent of each other. The main load borne by the scroll spring 10 during work comes from the pressure from the inside to the outside of the split nut 8, and the stress of the innermost ring is the largest (abbreviated as the inner ring stress). The design parameters of the scroll spring 10 include the number of turns and the thickness of the steel strip, both of which are positively related to the outer diameter of the scroll spring. In practical applications, the specific values of the parameters can be determined by analyzing the relationship between the stress of the inner ring and the outer diameter of the spring. Since the volute spring looks like a disc-shaped structure as a whole after being tightened, it is regarded as a hollow disc of equal thickness, and is solved according to the stress method. After analysis, the relationship curve between the stress of the inner ring of the scroll spring 10 and its outer diameter is shown in FIG. 6 . Preferably, the material of the scroll spring 10 is 65Mn spring steel, the thickness of the steel strip is 0.2mm, and the number of turns is 8 turns. Such a design can obtain the best locking performance.

The working process of the present invention is as follows:

The complete working process of the mechanism of the present invention includes three stages of locking, separation and reset. When locking, the frame 6 is limited by the constraint system composed of the pressure block 4 and the bayonet pin 5, the inner and outer ends of the scroll spring 10 are restrained, and the split nut 8 is tightly wrapped, thereby locking the large bolt 13 to realize a fixed structure and separation structures. When separating, energize the SMA wire 1 to cause it to undergo a phase change and shrink when heated, drive the pressing block 4 to move, release the limit to the bayonet pin 5, and then make the frame 6 lose its restraint, under the action of the restoring force of the scroll spring 10 , the frame 6 rotates with the outer end of the scroll spring 10, the scroll spring 10 spreads out, the split body 805 at the bottom of the split nut 8 is driven by the thin plate structure 804 to open, and the large bolt 13 is released to complete the separation. When resetting, the frame 6 is rotated to return the bayonet pin 5, and the pressure block 4 returns to the constrained position under the elastic force of the resetting spring 3, and the outer end of the scroll spring 10 is constrained again. At this time, the resetting tool 9 is rotated to drive the split The inner end of the nut 8 and the scroll spring 10 rotates, the scroll spring 10 is tightened again and wraps the split nut 8 tightly, the reset of the mechanism is completed, and the locked state is re-entered.

In addition, it can be understood that the discrete thin plate structure 804 is an elastic element of the spring steel sheet type, and of course other known elastic elements can also be used instead; the material and parameters of the scroll spring 10 can also be adjusted as required.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (12)

1. a kind of super large load tripper of SMA driving, which is characterized in that including：SMA (1), insulated track (2) are answered Position spring (3), bayonet lock (5), frame (6), bearing (7), divides valve nut (8), resets tooling (9), scroll spring briquetting (4) (10), lower cover (11), upper cover (12), king-bolt (13)；Wherein, divide valve nut (8) and king-bolt (13) is connector, scrollwork bullet Spring (10) is fastener, and SMA (1) are the driving elements of separation；Lower cover (11) is connect with fixed structure, and king-bolt (13) is with dividing It is connected from structure, king-bolt (13) divides valve nut (8) in scroll spring with valve nut (8) is divided to be connected using screw thread pair (10) king-bolt (13) is locked under package；Scroll spring (10) inner end is fixed on point valve nut (8), outer end and frame (6) It is connected, valve nut (8) and frame (6) is divided to coordinate respectively with the inner ring and outer rings of bearing (7), makes point valve nut (8) interior outer end Movement is mutual indepedent；The head for resetting tooling (9) is fixed in upper cover (12), and the hexagonal for dividing valve nut (8) top surface is inserted into lower part In hole；SMA (1) one end are fixed on lower cover (11), and the other end is connected to across insulated track (2) on briquetting (4), briquetting (4) resetting spring (3) is equipped between insulated track (2)；

When mechanism locks, frame (6) is limited by the constraint system that briquetting (4) and bayonet lock (5) form, and inside and outside the two of scroll spring (10) End is restrained, makes point valve nut (8) locking king-bolt (13)；

It during separation, is powered to SMA (1), it is made to be heated and undergoes phase transition and shrinks, driving briquetting (4) is mobile, releases to bayonet lock (5) limiting loses the frame (6) of constraint under the effect of scroll spring (10) restoring force, with scroll spring (10) outer end Rotation, scroll spring (10) scatter, and valve nut (8) is divided to open, release king-bolt (13), the separation of implementation mechanism；

When needing to reset, rotating frame (6) makes bayonet lock (5) playback, and briquetting (4) returns under the action of resetting spring (3) elastic force Constrained, the outer end of scroll spring (10) is again restrained, at this moment spinning reduction tooling (9), and drive divides valve nut (8) and whirlpool Coil spring (10) inner ends thereof, scroll spring (10) retighten and wrap a point valve nut (8), and mechanism is made to lock again.

2. the super large load tripper of SMA driving according to claim 1, which is characterized in that described to divide valve nut (8), it is made of elastic material.

3. the super large load tripper of SMA driving according to claim 1, which is characterized in that described to divide valve nut (8), top center is equipped with hex hole, coordinates with resetting tooling (9).

4. the super large load tripper of SMA driving according to claim 1, which is characterized in that described to divide valve nut (8), outer surface of upper is stepped, coordinates with upper cover (12) and bearing (7) inner ring.

5. the super large load tripper of SMA driving according to claim 1, which is characterized in that described to divide valve nut (8), lower part be several split bodies, piece together be a bottom belt type conical bench cylinder, cylindrical outer surface is by scrollwork bullet Spring package locking, inner surface are equipped with the screw thread coordinated with king-bolt (13).

6. the super large load tripper of SMA driving according to claim 5, which is characterized in that described to divide valve nut (8) the split body number of lower part, can be set as 3 or 4.

7. the super large load tripper of SMA driving according to claim 5, which is characterized in that described to divide valve nut (8) type conical bench of lower part, bottom surface are circular conical surface, are coordinated with lower cover.

8. the super large load tripper of SMA driving according to claim 1, which is characterized in that described to divide valve nut (8), middle part is several thin-slab structures, and the number of thin-slab structure is corresponding with split body number, has the trend opened outside.

9. the super large load tripper of SMA driving according to claim 1, which is characterized in that the reset tooling (9), head center is equipped with hexagon ring, coordinates with allen wrench.

10. the super large load tripper of SMA driving according to claim 1, which is characterized in that the reset tooling (9), uniformly there are three arc-shaped through-holes for head edge.

11. the super large load tripper of SMA driving according to claim 1, which is characterized in that SMA described (1), parallel setting two, two SMA work at the same time, and backup each other.

12. the super large load tripper of SMA driving according to claim 1, which is characterized in that the scroll spring (10), material selection 65Mn spring steel, the thickness of steel band is 0.2mm, and the number of turns is 8 circles.