CN110500923B

CN110500923B - Steady-state overload recognition and safety circuit based on double acceleration switches and control circuit

Info

Publication number: CN110500923B
Application number: CN201910796862.2A
Authority: CN
Inventors: 李波; 安晓红; 张亚; 李世中
Original assignee: North University of China
Current assignee: North University of China
Priority date: 2019-08-27
Filing date: 2019-08-27
Publication date: 2021-09-21
Anticipated expiration: 2039-08-27
Also published as: CN110500923A

Abstract

The invention discloses a steady-state overload recognition and safety circuit and a control circuit based on a double-acceleration switch, relates to the technical field of inertial sensor application, mainly comprises a normally-open acceleration switch and a normally-closed acceleration switch, and can simultaneously output blocking and bypass signals. The double acceleration switch is used as overload insurance, short circuit protection and reliable isolation can be carried out on a target circuit before an acceleration signal with a specified threshold value appears, and bypass and blocking of the target circuit can be simultaneously relieved after the acceleration signal with the specified threshold value and the specified direction appears. The device is combined with a peripheral circuit, can also realize the self-reset function after the output state is kept until the fighting task is finished, can be repeatedly used, and brings convenience for detection, quality evaluation and iterative update. The working reliability and the use safety of the high-reliability product are improved.

Description

Steady-state overload recognition and safety circuit based on double acceleration switches and control circuit

Technical Field

The invention relates to the technical field of inertial sensor application, in particular to a steady-state overload identification and safety circuit and a control circuit in ammunition fuze, aerospace and automobile safety technologies.

Background

The inertial acceleration overload measurement and control is one of the key technologies in the fields of ammunition fuzes, aerospace, automobile electronics and the like. Common inertial elements include an acceleration sensor, an acceleration switch, and the like, wherein the acceleration switch (also called g-switch, inertial switch, and the like) is used for sensing an acceleration signal, and when an acceleration signal exceeding a threshold value occurs, an inertial conductor inside the acceleration switch moves to perform a switching action. The acceleration switch can be regarded as a threshold acceleration sensor, has higher response speed than the acceleration sensor, simple signal processing and low cost; when the switch is closed, the switch contact can pass through a large current of more than 1A and can be directly connected to a main power supply circuit or an initiating explosive device ignition circuit, so that the acceleration switch can also be used as an actuator. For example, an ammunition fuse utilizes an acceleration switch to identify that the safety of a rocket engine is relieved after thrust overload or rotating centrifugal overload in the outer ballistic flight process of ammunition, and automobile electrons quickly start an air bag after identifying a valid collision signal of a vehicle through the acceleration switch.

Transient impact overload comprises accidental falling and impact in the moving and transporting process, collision and bump between a fuse and a gun tail caused by incorrect operation when ammunition is loaded, linear forward-impact motion and sudden stop of the ammunition are pushed by an ammunition feeder, radial linear recoil force borne by a projectile in a gun barrel in the launching process, lateral impact force between the projectile and the gun barrel and the like, and the transient overload can lead an inertia switch to act in advance before a preset safety relief program starts, thereby causing potential safety hazards; the steady-state acceleration overload comprises centrifugal force caused by self rotation of a projectile in the flying process, linear inertia force caused by rocket thrust when a rocket engine works and the like, obviously, the steady-state acceleration overload corresponds to the flying state of the projectile and the outer ballistic environment, if an overload identification circuit based on a double-acceleration switch can identify the steady-state acceleration overload action of the projectile in the outer ballistic flying process, and is insensitive to transient impact overload, the action of relieving the safety of the projectile can only occur outside the safety distance of the outer ballistic, and the safety of the projectile is greatly improved.

The existing steady-state overload recognition and safety relief circuit usually relies on a single acceleration switch to provide signals, an inertial electric conductor (movable electrode) in the acceleration switch usually adopts a mechanical structure such as a spring and a mass block, and also adopts conductive liquid drops such as mercury, but the inertial body rebounds after colliding with a fixed electrode in the working process of the switch, the switch is repeatedly closed and the like, so that the electrical contact is unstable, the acceleration switch which is triggered in a universal mode is difficult to distinguish overload from a sensitive direction and interference from a non-sensitive direction, part of the acceleration switches contain a closing locking mechanism, and the acceleration switches can only be triggered in a one-way and one-time mode and are used once, so that the difficulty is brought to detection and quality evaluation. In addition, a single acceleration switch cannot simultaneously output blocking and bypass signals, the requirement of diversified signal output of a user cannot be met, and due to the fact that the acceleration switch is prone to interference, especially an acceleration switch which is conducted in an omnidirectional mode, if the acceleration switch is applied to ammunition fuzes, switching action can be caused when the acceleration switch is interfered and works normally, and potential safety hazards are caused. The one-way disposable trigger switch containing the closed locking mechanism can not restore the initial state after being triggered, if the one-way disposable trigger switch is used on an ammunition fuse, the one-way disposable trigger switch is in a standby state after correspondingly relieving the safety, and the one-way disposable trigger switch can not restore the safety without detonation to form a dummy ammunition.

Ammunition fuze safety systems often utilize inertial components such as acceleration switches to identify ballistic environments and non-ballistic environments and release fuze insurance under the action of the ballistic environments. Usually, when the acceleration switch is regulated to be more than a certain threshold value, the acceleration switch can reliably act, and when the acceleration switch is smaller than the certain threshold value, the acceleration switch can not act, but the acceleration switch can not distinguish transient impact overload or steady acceleration overload only by the threshold value, and the acceleration switch has the defects of easy oscillation, poor interference resistance, large contact resistance and the like, and the output signal is relatively single. The universal-triggered acceleration switch is difficult to distinguish overload from interference in a sensitive direction and interference in a non-sensitive direction, and the requirement of high reliability and diversified signal output of a user cannot be met by singly using one acceleration switch, so that a steady-state overload identification and safety relief circuit based on a double-acceleration switch is needed.

Disclosure of Invention

The embodiment of the invention provides a steady-state overload identification and safety circuit and a control circuit based on a double-acceleration switch, which are used for solving the problems in the prior art.

The steady-state overload recognition and safety circuit based on the double acceleration switches comprises a normally-open acceleration switch S1 and a normally-closed acceleration switch S2, wherein an input end Vin is connected with a target circuit in series through the normally-open acceleration switch S1 and then grounded, the target circuit is connected with the normally-closed acceleration switch S2 in parallel and then grounded, the normally-open acceleration switch S1 blocks power supply to the target circuit, and the normally-closed acceleration switch S2 bypasses and grounds the target circuit.

Preferably, the normally-open acceleration switch S1 and the normally-closed acceleration switch S2 each include a transparent insulating top cover, a metal droplet and a conductive substrate, wherein the metal droplet is located in an enclosed space formed by the transparent insulating top cover and the conductive substrate in snap-fit combination;

the transparent insulating top cover comprises a cover body, wherein the inside of the cover body is a hollow cavity, and b > d >2c is satisfied, wherein b is the width of the cavity, c is the height of the cavity, and d is the diameter of the metal liquid drop before being filled into the cavity; the cross section of the chamber along the switch sensitive direction is a figure with a corner lacking at the upper part of a rectangle, and the chamber is divided into a bulge chamber and a wedge-shaped chamber along a dividing dotted line;

the conducting substrate comprises an insulating substrate and a conducting metal layer arranged on the upper surface of the insulating substrate, the conducting metal layer comprises a first inner electrode and a second inner electrode which are oppositely arranged along a switch sensitive direction, bonding seal rings are arranged on the outer sides of the first inner electrode and the second inner electrode, and an insulating groove is formed among the first inner electrode, the second inner electrode and the bonding seal rings;

the area of the first inner electrode is larger than that of the second inner electrode, and the first inner electrode is a normally-open metal droplet acceleration switch, the first inner electrode of the normally-open metal droplet acceleration switch is located below the bulge cavity and the wedge-shaped cavity, and the second inner electrode of the normally-open metal droplet acceleration switch is located below the wedge-shaped cavity; the area of the first inner electrode is smaller than that of the second inner electrode, and the first inner electrode of the normally-closed metal droplet acceleration switch is located below the bulge cavity, and the second inner electrode of the normally-closed metal droplet acceleration switch is located below the bulge cavity and the wedge cavity.

More preferably, the material of the transparent insulating top cover is glass or transparent epoxy resin.

More preferably, the metal droplet is mercury or a liquid amalgam containing 8.5% thallium.

More preferably, one end of the first inner electrode, which is far away from the second inner electrode, is connected to a first pin, one end of the second inner electrode, which is far away from the first inner electrode, is connected to a second pin, and the switch sensitivity direction is a direction in which the first pin points to the second pin.

More preferably, the normally open acceleration switch S1 and the normally closed acceleration switch S2 are placed in parallel, so that the sensitive directions are the same, and are packaged into a double acceleration switch with 4 pins.

More preferably, the dual acceleration switch includes a normally closed transparent insulating top cover and a normally open transparent insulating top cover fixed side by side, a normally closed conducting substrate and a normally open conducting substrate fixed side by side, and a first metal droplet and a second metal droplet, the first metal droplet is fastened in the internal cavity by the normally closed transparent insulating top cover and the normally open conducting substrate, and the second metal droplet is fastened in the internal cavity by the normally open transparent insulating top cover and the normally open conducting substrate.

More preferably, the insulation trench is filled with UV glue, and the UV glue is cured to fill the insulation trench and is consistent with the height of the first inner electrode, the height of the second inner electrode and the height of the bonding sealing ring.

A steady state overload recognition and control circuit with filtering and output maintaining functions based on a steady state overload recognition and safety circuit based on a double acceleration switch comprises a normally-open acceleration switch S3 and a normally-closed acceleration switch S4 which are packaged side by side to form a whole with the same sensitive direction, an input end Vin is connected with the normally-open acceleration switch S3 and then sequentially connected with a resistor R1 and a capacitor C1 in series and then grounded, one end of the normally-closed acceleration switch S4 close to the input end Vin is grounded, the other end of the normally-closed acceleration switch S4 is connected with a voltage stabilizing diode V1 and a capacitor C1 in parallel, the other end of the voltage stabilizing diode V1 is grounded, and the resistor R1, the voltage stabilizing diode V1 and the capacitor C1 form a low-pass filtering circuit;

an input end Vin is connected with a positive power end of an operational amplifier U1, a negative power end of the operational amplifier U1 is grounded, one end, far away from the ground, of a capacitor C1 is connected with a homodromous input end of the operational amplifier U1, an inverting input end of the operational amplifier U1 is connected with an output end of an operational amplifier U1, an output end of the operational amplifier U1 is connected with a light-emitting diode V2 in series and then connected with a capacitor C2, a resistor R2 and a resistor R3 in parallel, the other end of the capacitor C2 and the other end of the resistor R2 are grounded, and the capacitor light-emitting diode V2, the capacitor C2 and the resistor R3 form an output holding circuit; the other end of the resistor R2 is connected with a pin 1 at the input side of an optical relay J1, a pin 2 at the input side of the optical relay J1 is grounded, a pin 3 at the output side of the optical relay J1 is connected with a target circuit and then is grounded, a pin 4 at the output side of the optical relay J1 is connected with a Vcc end of a main power supply loop, and the input sides of the capacitor C2, the resistor R2 and the optical relay J1 form an optical relay driving circuit.

More preferably, the optical relay J1 includes a normally open optical relay for open circuit fuse use and a normally closed optical relay for short circuit fuse use, pin 1 of the normally open optical relay is connected to one end of the resistor R2, pin 2 of the normally open optical relay is grounded, pin 3 of the normally open optical relay is connected to a target circuit, and pin 4 of the normally open optical relay is connected to a power supply;

pin 1 of the normally-closed type optical relay is connected with one end of the resistor R2, pin 2 of the normally-closed type optical relay is grounded, and pin 4 and pin 3 of the output side of the normally-closed type optical relay are connected with two ends of a target circuit power supply loop, namely the output side of the normally-closed type optical relay is connected with a target circuit in parallel.

The invention has the beneficial effects that: the invention adopts the patch packaging to realize the double-liquid dropping speed switch, is formed by combining a normally open type liquid drop acceleration switch and a normally closed type acceleration switch, and can simultaneously output blocking and bypass signals. The double acceleration switch is used as overload insurance, short circuit protection and reliable isolation can be carried out on a target circuit before an acceleration signal with a specified threshold value appears, and bypass and blocking of the target circuit can be simultaneously relieved after the acceleration signal with the specified threshold value and the specified direction appears.

The double acceleration switch overload fuse adds a filter circuit and a voltage holding circuit and drives an optical relay to act so as to filter repeated actions of the acceleration switch caused by transient impact at the initial launching stage of the projectile, ensure that the acceleration switch is sensitive to steady acceleration signals of the projectile in the flight process, such as centrifugal force of rotating projectiles and thrust of rocket engines, control the optical relay to be switched on an ignition circuit or a fuse main circuit in a delayed manner on an outer trajectory, meet the requirement of remotely relieving the fuse of the ammunition, and simultaneously ensure that the optical relay can keep an output state and reset until the fighting mission is finished, thereby realizing self-holding and recovering the fuse.

The traditional acceleration switch with the locking function cannot be automatically released after being locked, can be used only once, and brings inconvenience to use, detection and quality evaluation.

Drawings

Fig. 1 is a schematic structural diagram of a steady-state overload identification and safety circuit based on a dual acceleration switch according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional structural view of a transparent insulating top cover of a steady-state overload recognition and safety circuit based on a dual-acceleration switch according to an embodiment of the present invention;

fig. 3 is a schematic top view of a conductive substrate of a steady-state overload recognition and safety circuit based on a dual acceleration switch according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a normally closed metal droplet acceleration switch of a steady-state overload recognition and safety circuit based on a dual acceleration switch according to an embodiment of the present invention;

FIG. 5 is a graph of the output of a conventional spring-mass acceleration switch under transient impact overload;

fig. 6 is an output curve of a normally open metal droplet acceleration switch in a steady-state overload recognition and safety circuit based on a dual acceleration switch under a transient impact overload according to an embodiment of the present invention;

fig. 7 is an output curve of a normally open metal droplet acceleration switch in a steady-state overload recognition and safety circuit based on a dual acceleration switch according to an embodiment of the present invention under a steady-state acceleration overload;

fig. 8 is a diagram illustrating a packaging effect of a dual-fluid dropping speed switch of a steady-state overload recognition and safety circuit based on a dual-acceleration switch according to an embodiment of the present invention;

fig. 9 is a switch closing condition of a normally open droplet acceleration switch of a double acceleration switch based steady-state overload recognition and safety circuit when the switch is acted by dual environmental forces of recoil and centrifugal force during a launching process;

fig. 10 is a steady-state overload recognition and control circuit with filtering and output holding functions for a steady-state overload recognition and safety circuit based on a dual acceleration switch according to an embodiment of the present invention.

Description of reference numerals:

1-transparent insulating top cap, 101-cap, 102-boss chamber, 103-wedge chamber, 2-metal droplet, 3-conductive substrate, 301-insulating substrate, 302-first internal electrode, 303-second internal electrode, 304-adhesive sealing ring, 305-insulating trench, 306-first pad, 307-second pad, 4-first pin, 5-second pin, 601-normally closed transparent insulating top cap, 602-metal droplet one, 603-normally closed conductive substrate, 701-normally open transparent insulating top cap, 702-metal droplet two, 703-normally open conductive substrate.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, but it should be understood that the scope of the present invention is not limited by the specific embodiments.

Referring to fig. 1-10, the present invention provides a steady state overload recognition and safing circuit and control circuit based on a dual acceleration switch,

examples

Referring to fig. 1, the acceleration switch system comprises a normally-open acceleration switch S1 and a normally-closed acceleration switch S2, an input end Vin is connected in series with a target circuit through the normally-open acceleration switch S1 and then grounded, the target circuit is connected in parallel with the normally-closed acceleration switch S2 and then grounded, the normally-open acceleration switch S1 blocks power supply to the target circuit, the normally-closed acceleration switch S2 bypasses the target circuit to the ground, the two acceleration switches are both one-way sensitive triggering and reusable acceleration switches, the sensitive directions of the two acceleration switches are the same, and the acceleration switch system is suitable for occasions requiring the acceleration switch to be used as a passive device and requiring simple, reliable and anti-interference structures.

At ordinary times, the normally open acceleration switch S1 is connected in series with the target circuit and outputs a blocking signal, which in the circuit corresponds to a circuit breaker. The normally closed acceleration switch S2 outputs a bypass (short-circuit) signal in parallel with the target circuit, and corresponds to a short-circuit fuse in the circuit. Before the acceleration signal with the specified threshold value appears, the target circuit can be reliably isolated and protected by short circuit, so that the target circuit becomes double insurance with open circuit insurance and short circuit insurance. When the acceleration signal with the specified threshold value and direction appears, the two switches act simultaneously, and the blocking and the bypass of the target circuit can be simultaneously removed; when the acceleration signal with the specified threshold value and direction disappears, the blocking and bypass of the target circuit can be recovered.

Because the double acceleration switches with different action forms are adopted to protect the same target circuit, as long as any one of the normally-open acceleration switch S1 and the normally-closed acceleration switch S2 does not act, the target circuit cannot completely relieve the insurance, the blocking and the bypass can be simultaneously relieved only if the normally-open acceleration switch S1 and the normally-closed acceleration switch S2 are synchronous, the target circuit can be electrified to work, and the insurance on the target circuit can be completely relieved, so that the safety and the anti-interference performance of the safety circuit are greatly improved, the acceleration switches with different action forms usually have different response speeds and oscillation frequencies, after the transient acceleration impact occurs, the two switches can oscillate, but the probability of synchronous action is small, and the double acceleration switches can effectively reduce the false operation caused by the oscillation of the acceleration switches.

Vin is an ignition current input end of a target circuit, the installation area of a double switch consisting of a normally-open acceleration switch S1 and a normally-closed acceleration switch S2 is 4mm multiplied by 4mm, the sensitive direction points to the radial direction of a projectile during installation, the threshold value is 40g, and the centrifugal force generated by rotation in the projectile flying process is 50-200 g, so that at ordinary times, S1 is disconnected, S2 is closed, S1 blocks the power-on of the target circuit, and S2 forms short-circuit protection on the target circuit.

Only when the projectile is in a flying state, centrifugal overload closes S1 and simultaneously S2 is opened, the safety of the target circuit can be relieved, the target circuit is in a working state, when the target circuit is an electric detonator, the computer on the projectile outputs an ignition command, Vin outputs an ignition current, and the target circuit detonates. If the ammunition does not hit the target, S1 and S2 may self-restore to the original state after the projectile falls to the ground, restoring double insurance to the target circuit.

Referring to fig. 2, each of the normally open acceleration switch S1 and the normally closed acceleration switch S2 includes a transparent insulating top cover 1, a metal droplet 2 and a conductive substrate 3, wherein the metal droplet 2 is located in an enclosed space formed by the transparent insulating top cover 1 and the conductive substrate 3 in a snap-fit manner;

the transparent insulating top cover 1 comprises a cover body 101, wherein the inside of the cover body 101 is a hollow cavity, and b > d >2c is satisfied, wherein b is the width of the cavity, c is the height of the cavity, and d is the diameter of the metal liquid drop 2 before being filled into the cavity; the cross section of the chamber along the switch sensitive direction is a figure with a corner lacking at the upper part of a rectangle, and the chamber is divided into a bulge chamber 102 and a wedge-shaped chamber 103 along a dividing dotted line; the transparent insulating top cover 1 is made of glass or transparent epoxy resin, the position and the shape of a metal liquid drop can be observed through the insulating top cover 1, dynamic detection and analysis evaluation can be performed on the switch by using a high-speed camera in a research and development stage, the acceleration threshold value of the switch can be accurately determined, and visual inspection and fault analysis can be performed on the switch in a use stage.

The metal droplet 2 is mercury or a liquid amalgam containing 8.5% thallium. The solidifying point of the thallium amalgam is-60 ℃, and the requirements of high-reliability products such as ammunition and the like on the working temperature range can be met. The volume of the metal liquid drop 2 accounts for more than 50% of the volume of the chamber, the metal liquid drop 2 has a tendency of self-gathering into a sphere in a static state and occupies in the bulge chamber 102, when acceleration overload exceeding a threshold value occurs in a sensitive direction, the whole metal liquid drop slides to the wedge chamber 103, the on-off state of the switch is changed while being extruded and deformed by the wedge chamber, and after the acceleration overload is finished, the metal liquid drop 2 rebounds to the bulge chamber 102, and the switch is restored to the initial state. Due to the limited space of the chamber, the metal droplet 2 occupies most of the chamber and remains bonded as a unit regardless of the deformation of the metal droplet.

The normally-open type metal droplet acceleration switch and the normally-closed type metal droplet acceleration switch both adopt a flat cavity to place metal droplets, namely the height of the cross section of the interior of the cavity along the sensitive direction is smaller than the width of the metal droplet acceleration switch in the horizontal direction, after the metal droplet 2 is placed into the cavity, the metal droplet 2 is flattened by the cavity in the bonding process and is in contact with the top and the bottom of the cavity, and the droplets flow in the direction vertical to the sensitive direction in the flattening process and simultaneously have certain prestress, so that the contact area between the droplets and a first electrode belt and the contact area between the droplets and a second electrode belt are increased. As can be seen from the view a-a in fig. 2, when the metal droplet 2 moves in the sensitive direction, it slides in contact with the top and bottom of the chamber, and at the same time, there is enough exhaust space left on both sides, and there is no need to specially design the exhaust channel.

Because a flat cavity structure is adopted, the metal liquid drop is naturally flattened in the process of packaging in the cavity, the liquid drop flows in the direction vertical to the sensitive direction in the flattening process, and meanwhile, a certain prestress is provided, the packaged liquid drop cannot freely flow, the anti-interference performance is improved, the initial prestress ensures the anti-interference performance of the metal liquid drop, the self-oscillation can be inhibited, the two sides of the metal liquid drop can naturally exhaust in the moving process of the metal liquid drop, and a special exhaust channel is not needed. The whole structure is simple, and the consistency and the yield of the processing technology are easy to ensure.

Referring to fig. 3 and 4, the conductive substrate 3 includes an insulating substrate 301 and a conductive metal layer disposed on an upper surface of the insulating substrate 1, the conductive metal layer includes a first inner electrode 302 and a second inner electrode 303 disposed opposite to each other along a switch sensitivity direction, a bonding seal ring 304 is disposed outside the first inner electrode 302 and the second inner electrode 303, and an insulating trench 305 is disposed between the first inner electrode 302, the second inner electrode 303, and the bonding seal ring 304; UV glue is injected into the insulation trench 305, and after the UV glue is cured, the insulation trench 305 is filled and leveled, and the height of the insulation trench is consistent with the height of the first inner electrode 302, the height of the second inner electrode 303 and the height of the bonding seal ring 304. One end of the first inner electrode 302, which is far away from the second inner electrode 303, is connected to a first pin 4, one end of the second inner electrode 303, which is far away from the first inner electrode 302, is connected to a second pin 5, and the switch sensitivity direction is a direction in which the first pin points to the second pin.

The area of the first inner electrode 302 is larger than that of the second inner electrode 303, and the first inner electrode 302 of the normally-open metal droplet acceleration switch is located below the bulge cavity 102 and the wedge cavity 103, and the second inner electrode 303 of the normally-open metal droplet acceleration switch is located below the wedge cavity 103; the area of the first inner electrode 302 is smaller than that of the second inner electrode 303, and the first inner electrode 302 of the normally-closed metal droplet acceleration switch is located below the bulge chamber 102, and the second inner electrode 303 of the normally-closed metal droplet acceleration switch is located below the bulge chamber 102 and the wedge chamber 103.

Referring to fig. 5, which is an output curve of a conventional spring-mass type acceleration switch under transient impact overload, it can be seen that, in the conventional acceleration switch with "solid-solid" contact, the mass and the fixed electrode are separated from contact with each other along with the rebound of the mass, the closing time of the switch is extremely short, and the closing time is represented as a short time "point".

Referring to fig. 6, the output curve of the normally open metal droplet acceleration switch under the transient impact overload is shown, in which the peak value of the impact acceleration measured by the piezoelectric acceleration sensor is about 2000g, the acceleration pulse width is 2.6ms, and the normally open metal droplet acceleration switch is closed for about 30ms after the acceleration overload occurs due to the viscosity of the metal droplet, and the closing time is represented as a longer time "segment".

Referring to fig. 7, the output curve of the normally open type metal droplet acceleration switch under the steady state acceleration overload is shown, the test is carried out on a centrifugal overload testing machine, after the centrifugal overload testing machine is started, the switch state is changed from off to on, and the signal is stable and has no bounce.

Referring to fig. 8, the normally open acceleration switch S1 and the normally closed acceleration switch S2 are placed in parallel, so that the sensing directions are the same, and are packaged into a double acceleration switch with 4 pins. The dual-acceleration switch comprises a normally closed transparent insulating top cover 601 and a normally open transparent insulating top cover 701 which are fixed side by side, a normally closed conducting substrate 603 and a normally open conducting substrate 703 which are fixed side by side, a first metal droplet 602 and a second metal droplet 702, wherein the first metal droplet 602 is buckled in an internal cavity by the normally closed transparent insulating top cover 601 and the normally closed conducting substrate 603, and the second metal droplet 702 is buckled in the internal cavity by the normally open transparent insulating top cover 701 and the normally open conducting substrate 703.

On the basis of the normally open type liquid drop acceleration switch, a normally closed type acceleration switch is added to form a double acceleration switch. The two switches are acceleration switches which are triggered in a one-way sensitive mode and can be used repeatedly, and are sensitive to long-pulse impact overload and constant acceleration overload in sensitive directions. The anti-interference capability is better than that of a universal trigger type acceleration switch. The acceleration sensitive direction is that the first pin 4 of the switch points to the direction of the second pin 5. The two switches can be placed in parallel, the sensitive directions are enabled to be the same, the two switches are packaged into a whole, 4 pins are totally formed, the double-acceleration switch is formed, the switch is compatible with SMA packaging, the size is small, integration is convenient, and recoil impact overload during launching of medium and large caliber grenades can be resisted. When the unidirectional steady-state acceleration overload signal exceeding the threshold value appears, the states of 2 switches change simultaneously and can be stably maintained, when the acceleration signal disappears, the switches can restore to the initial state, the on-state resistance is about 0-20 omega when the switches are closed, and the off-state resistance is more than 1M omega

The invention can be set to be a normally open type or a normally closed type by adjusting the area ratio of the first inner electrode and the second inner electrode, belongs to an acceleration switch which is triggered in a unidirectional sensitive manner and can be repeatedly used, and is sensitive to long-pulse impact overload and constant acceleration overload in a sensitive direction. The anti-interference capability is better than that of a universal trigger type acceleration switch. The acceleration sensitive direction is that the first pin 4 of the switch points to the direction of the second pin 5. The switch is compatible with SMA encapsulation, has small volume and convenient integration, and can resist recoil impact overload during the launching of medium and large caliber grenades. When a unidirectional steady-state acceleration overload signal exceeding a threshold value appears, the switch state changes (normally closed type conduction and normally open type closure) and can be stably maintained, and when the acceleration signal disappears, the switch can restore the initial state.

Referring to fig. 9, the switches in the acceleration switches S1 and S2 adopt liquid drops as inertia bodies, have good buffering shock resistance, and can still keep electric contact after the liquid drops vibrate and deform after collision. The switch action time is far longer than that of an acceleration switch with a spring-mass block structure.

On the basis of figure 1, a filter circuit and a voltage sampling and holding circuit are additionally arranged to drive an optical relay to act so as to filter the oscillation of an acceleration switch caused by transient impact during the initial launching stage of a projectile, ensure that the acceleration switch is only sensitive to steady acceleration signals of the projectile in the flying process, such as the centrifugal force of a rotating projectile and the thrust of a rocket engine, control the optical relay to be switched on a target circuit, such as an ignition circuit or a fuse main circuit, in a delayed manner on an outer trajectory, and meet the requirement of remotely relieving the safety of the ammunition.

Referring to fig. 10, a steady-state overload recognition and control circuit with filtering and output holding functions based on the steady-state overload recognition and safety circuit based on the dual acceleration switch includes a normally-open acceleration switch S3 and a normally-closed acceleration switch S4 packaged side by side into a whole with the same sensitive direction, an input terminal Vin is connected with the normally-open acceleration switch S3 and then sequentially connected with a resistor R1 and a capacitor C1 in series and then grounded, one end of the normally-closed acceleration switch S4 close to the input terminal Vin is grounded, the other end of the normally-closed acceleration switch S4 is connected with a zener diode V1 and a capacitor C1 in parallel, the other end of the zener diode V1 is grounded, wherein the resistor R1, the zener diode V1 and the capacitor C1 form a low-pass filter circuit;

the operational amplifier U1 is a voltage sampling circuit, an input end Vin is connected with a positive power end of an operational amplifier U1, a negative power end of the operational amplifier U1 is grounded, one end, far away from the ground, of the capacitor C1 is connected with a same-direction input end of the operational amplifier U1, an inverting input end of the operational amplifier U1 is connected with an output end of the operational amplifier U1, an output end of the operational amplifier U1 is connected with the light emitting diode V2 in series and then connected with the capacitor C2, the resistor R2 and the resistor R3 in parallel, the other end of the capacitor C2 and the other end of the resistor R2 are both grounded, the capacitor V2, the capacitor C2 and the resistor R3 form an output holding circuit, values of the R3 and the C2 are adjusted, and output signal holding time can be adjusted.

The other end of the resistor R2 is connected with a pin 1 at the input side of an optical relay J1, a pin 2 at the input side of the optical relay J1 is grounded, a pin 3 at the output side of the optical relay J1 is grounded after being connected with a target circuit, a pin 4 at the output side of the optical relay J1 is connected with a Vcc end of a main power supply loop, a capacitor C2, a resistor R2 and the output side of the optical relay J1 form an optical relay driving circuit, wherein the optical relay J1 can select a normally-open optical relay or a normally-closed optical relay according to user requirements, the normally-open optical relay can be used as a circuit breaker, and the normally-closed optical relay can be used as a short circuit breaker.

Pin 1 of the normally-open type optical relay is connected with one end of the resistor R2, pin 2 of the normally-open type optical relay is grounded, pin 3 of the normally-open type optical relay is connected with a target circuit, and pin 4 of the normally-open type optical relay is connected with a main power supply, as shown in FIG. 10.

Pin 1 of the normally-closed type optical relay is connected with one end of the resistor R2, pin 2 of the normally-closed type optical relay is grounded, and pin 3 and pin 4 of the normally-closed type optical relay are connected with a target circuit in parallel.

Normally, C1 is opened by S1, C1 is short-circuited by S2, the terminal voltage of C1 is guaranteed to be 0, when transient impact overload interference is encountered, S1 is closed from open, S2 is opened from closed, but the terminal voltage cannot be stably maintained, C1 is accompanied by intermittent discharge of S2 in the intermittent charging process, because the charging time constant of C1 is R1C 1, because the transient impact overload usually lasts within 30ms, R1C 1 can be more than or equal to 100ms, when C1 is discharged through S2, the C is basically in short-circuit discharge, the charging time constant is far larger than the discharging time constant, the discharging speed is far higher than the charging speed, so the charging of C1 cannot be completed, the optical relay J1 cannot be driven to act, low-pass filtering is realized, and interference caused by transient impact is filtered.

When steady-state acceleration overload in a sensitive direction is encountered, such as rotating centrifugal overload and engine linear thrust overload, S1 is switched from open circuit to closed circuit, S2 is switched from closed circuit to open circuit and can be stably maintained, at the moment, C1 is continuously charged, at the same time, U1 adopts a voltage follower connection method to sample the voltage of the C1 end and then output the voltage to V2 and C2, so that the voltage of C2 can follow the voltage change of C1 (the voltage of C2 is lower than that of C1 by the conduction voltage of a diode V2), when the voltage of C1 end rises, C2 and the current flowing into pin 1 of J1 also rise synchronously, and when the input current of pin 1 of J1 exceeds 1.4mA (the average action LED current IFON of J1 is 1.4mA), J1 acts to drive the state change of pins 3 and 4 (conduction, turn-over or turn-over) so as to realize the relief.

When the steady-state acceleration overload lasts for a period of time, the voltage of the C1 is increased to the regulated value of the V1 voltage regulator tube, the voltage of the C2 is further increased synchronously, and meanwhile, when the input current of the J1 pin 1 is far more than 1.4 mA. At this time, when the interference overload or the steady acceleration overload disappears, the optical relay J1 can also keep the output state unchanged, thereby realizing the output maintenance.

When the battle mission is finished, if the projectile is not detonated at the moment, the input current of the pin 1 of the J1 of the optical relay also synchronously decreases along with the decrease of the terminal voltage of the C2, and when the input current decreases to be less than 1.3mA (the average reset LED current IFOff of the J1 is set to be 1.3mA), the optical relay is reset, so that the recovery insurance is realized.

When VCC is 20V, a voltage-stabilizing tube V1 is 12V, C2 is 6800uF, R2 is 2K omega, R3 is 100K omega, and R1 and C1 are valued to ensure that R1 is equal to or more than 100ms and C1 is equal to or more than 100ms, the self-holding output state of the optical relay can be kept unchanged for more than 10 seconds after the action, if the self-holding time needs to be prolonged, C2 can be increased, and R3 can be reduced.

In summary, the invention adopts patch packaging to realize the double-liquid dropping speed switch, is formed by combining a normally-open type liquid drop acceleration switch and a normally-closed type acceleration switch, and can simultaneously output blocking and bypass signals. The double acceleration switch is used as overload insurance, short circuit protection and reliable isolation can be carried out on a target circuit before an acceleration signal with a specified threshold value appears, and bypass and blocking of the target circuit can be simultaneously relieved after the acceleration signal with the specified threshold value and the specified direction appears.

The above disclosure is only one specific embodiment of the present invention, however, the present invention is not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.

Claims

1. The steady-state overload identification and safety circuit based on the double acceleration switches is characterized by comprising a normally-open acceleration switch S1 and a normally-closed acceleration switch S2, wherein an input end Vin is connected with a target circuit in series through the normally-open acceleration switch S1 and then grounded, the target circuit is connected with the normally-closed acceleration switch S2 in parallel and then grounded, the normally-open acceleration switch S1 is used for blocking power supply to the target circuit, and the normally-closed acceleration switch S2 is used for bypassing the target circuit and grounding;

the normally-open acceleration switch S1 and the normally-closed acceleration switch S2 both comprise a transparent insulating top cover (1), a metal liquid drop (2) and a conductive substrate (3), wherein the metal liquid drop (2) is positioned in a closed space formed by buckling and combining the transparent insulating top cover (1) and the conductive substrate (3);

the transparent insulating top cover (1) comprises a cover body (101), wherein the inside of the cover body (101) is a hollow cavity, and b > d >2c is satisfied, wherein b is the width of the cavity, c is the height of the cavity, and d is the diameter of the metal liquid drop (2) before being filled into the cavity; the cross section of the chamber along the switch sensitive direction is a pentagon with a corner lacking on the upper part of the rectangle, and the chamber is divided into a bulge chamber (102) and a wedge-shaped chamber (103) along a dividing dotted line;

the conducting substrate (3) comprises an insulating substrate (301) and a conducting metal layer arranged on the upper surface of the insulating substrate (301), the conducting metal layer comprises a first inner electrode (302) and a second inner electrode (303) which are oppositely arranged along a switch sensitive direction, a bonding sealing ring (304) is arranged outside the first inner electrode (302) and the second inner electrode (303), and an insulating groove (305) is arranged among the first inner electrode (302), the second inner electrode (303) and the bonding sealing ring (304);

the area of the first inner electrode (302) is larger than that of the second inner electrode (303) to form a normally-open metal droplet acceleration switch, the first inner electrode (302) of the normally-open metal droplet acceleration switch is located below the bulge chamber (102) and the wedge chamber (103), and the second inner electrode (303) of the normally-open metal droplet acceleration switch is located below the wedge chamber (103); the area of the first inner electrode (302) is smaller than that of the second inner electrode (303), and the first inner electrode (302) of the normally-closed metal droplet acceleration switch is located below the bulge chamber (102), and the second inner electrode (303) of the normally-closed metal droplet acceleration switch is located below the bulge chamber (102) and the wedge chamber (103).

2. The double acceleration switch based steady state overload recognition and safety circuit according to claim 1, characterized in that the material of the transparent insulating top cover (1) is glass or transparent epoxy.

3. The double acceleration switch based steady state overload recognition and safety circuit according to claim 1, characterized in that the metal droplet (2) is mercury or a liquid amalgam containing 8.5% thallium.

4. The double-acceleration-switch-based steady-state overload recognition and safety circuit as claimed in claim 1, wherein the end of the first inner electrode (302) far away from the second inner electrode (303) is connected with a first pin (4), the end of the second inner electrode (303) far away from the first inner electrode (302) is connected with a second pin (5), and the switch sensitivity direction is that the first pin points to the second pin direction.

5. The dual acceleration switch based steady state overload recognition and safing circuit according to claim 4, wherein the normally open acceleration switch S1 and the normally closed acceleration switch S2 are placed in parallel with the sensing direction in the same direction, packaged as a dual acceleration switch with 4 pins.

6. The dual-acceleration-switch-based steady-state overload recognition and safety circuit according to claim 5, wherein the dual-acceleration switch comprises a normally-closed transparent insulating top cover (601) and a normally-open transparent insulating top cover (701) which are fixed side by side, a normally-closed conducting substrate (603) and a normally-open conducting substrate (703) which are fixed side by side, a first metal drop (602) and a second metal drop (702), wherein the first metal drop (602) is fastened in the internal cavity by the normally-closed transparent insulating top cover (601) and the normally-closed conducting substrate (603), and the second metal drop (702) is fastened by the normally-open transparent insulating top cover (701) and the normally-open conducting substrate (703).

7. The double acceleration switch-based steady-state overload recognition and safety circuit according to claim 1, wherein the insulation groove (305) is filled with UV glue, and the UV glue is cured to fill the insulation groove (305) and is consistent with the height of the first inner electrode (302), the height of the second inner electrode (303) and the height of the adhesive sealing ring (304).

8. A steady-state overload recognition and control circuit with filtering and output holding functions based on a steady-state overload recognition and safety circuit of a double-acceleration switch as claimed in claim 1, characterized in that the circuit comprises a normally-open acceleration switch S1 and a normally-closed acceleration switch S2 which are packaged side by side into a whole with the same sensitive direction, an input end Vin is connected with the normally-open acceleration switch S1 and then sequentially connected with a resistor R1 and a capacitor C1 in series and then grounded, one end of the normally-closed acceleration switch S2 close to the input end Vin is grounded, the other end of the normally-closed acceleration switch S2 is connected with a voltage stabilizing diode V1 and a capacitor C1 in parallel, the other end of the voltage stabilizing diode V1 is grounded, wherein the resistor R1, the voltage stabilizing diode V1 and the capacitor C1 form a low-pass filter circuit;

an input end Vin is connected with a positive power supply end of an operational amplifier U1, a negative power supply end of the operational amplifier U1 is grounded, one end, far away from the ground, of a capacitor C1 is connected with a homodromous input end of the operational amplifier U1, an inverting input end of the operational amplifier U1 is connected with an output end of an operational amplifier U1, an output end of the operational amplifier U1 is connected with a capacitor light-emitting diode V2 in series and then connected with the capacitor C2, a resistor R2 and a resistor R3 in parallel, the other end of the capacitor C2 and the other end of the resistor R2 are grounded, and the capacitor light-emitting diode V2, the capacitor C2 and the resistor R3 form an output holding circuit; the other end of the resistor R2 is connected with the input side of an optical relay J1, the output side of the optical relay J1 is connected with a target circuit and then grounded, and the input sides of the capacitor C2, the resistor R2 and the optical relay J1 form an optical relay drive circuit.

9. The filter and output hold function with steady state overload recognition and control circuit as claimed in claim 8, wherein the optical relay J1 comprises a normally open type optical relay for open circuit fuse use and a normally closed type optical relay for short circuit fuse use, pin 1 of the normally open type optical relay is connected to one end of the resistor R2, pin 2 of the normally open type optical relay is grounded, pin 3 of the normally open type optical relay is connected to a target circuit, and pin 4 of the normally open type optical relay is connected to a power supply;

pin 1 of the normally-closed type optical relay is connected with one end of the resistor R2, pin 2 of the normally-closed type optical relay is grounded, pin 4 and pin 3 of the output side of the normally-closed type optical relay are connected with two ends of a target circuit power supply loop, and the output side of the normally-closed type optical relay is connected with a target circuit in parallel.