Switching device with pyrotechnic actuation

Abstract

The application relates to a switch device with a pyrotechnic actuation device, comprising a moving contact and a static contact for realizing a switching function, the pyrotechnic actuation device comprising a pushing medium for performing a downward movement, the pushing medium forcing the moving contact to move away from the static contact after a one-time downward movement, and further comprising a restraint member arranged at a position corresponding to the downward movement of the pushing medium, the restraint member being configured to be able to restrain the moving contact from being coupled to the static contact in a rebounding return, and the restraint member being made of a material capable of receiving the impact of the piston without restoring deformation. The application further widens the contact gap between the moving contact and the static contact by setting the restraint member to restrain the rebounding return of the moving contact to the static contact. A smaller downward movement distance is required to ensure that the contact gap is wide enough, so that the height and volume of the entire switch device can be reduced.

Description

Technical Field

[0001] This invention relates to the field of switching devices, and more specifically to switching devices having a pyrotechnic ignition device. Background Technology

[0002] Relays are widely used in remote control, telemetry, communication, automatic control, mechatronics, and power electronic equipment, serving as core components for controlling switch states in electrical circuits. With the continuous development and evolution of electrical technology, the load requirements of main circuits are increasing, consequently placing higher demands on the short-circuit withstand capabilities of relays. In recent years, some manufacturers have even proposed main circuit short-circuit withstand capabilities of 20kA or 30kA. Under such high short-circuit currents, a significant short-circuit electrodynamic repulsion force will occur between the relay contacts, forcing the moving spring to be repelled from the stationary contact. To resist this short-circuit electrodynamic repulsion force and maintain the closed state of the moving spring and moving contact, it is necessary to increase the pressure of the contact spring or the closing magnetic attraction force of the moving spring (i.e., the magnetic attraction force that drives the moving spring to close via an electromagnetic drive mechanism). However, while increasing the pressure of the contact spring or the closing magnetic attraction force of the moving spring, it also affects the normal breaking action of the moving spring. If the breaking is not timely when the short-circuit current further increases, circuit safety cannot be guaranteed. Therefore, some existing technologies use a pyrotechnic actuator to help the relay quickly disconnect. When the system detects that the short-circuit current has reached a critical value, the actuator is triggered to detonate the gunpowder. The impact force of the gunpowder explosion pushes the moving contact (moving spring) to quickly disconnect, thus achieving the circuit protection function.

[0003] Because a pyrotechnic ignition device is used to quickly break the contact, more space is needed to accommodate the piston stroke in the pyrotechnic ignition device. Moreover, because a pyrotechnic ignition device needs to be installed, the relay with the pyrotechnic ignition device is larger, which is not conducive to the miniaturization of the product. Summary of the Invention

[0004] Therefore, in view of the above problems, the present invention proposes a switch with an optimized structure and a pyrotechnic excitation device.

[0005] This invention is achieved using the following technical solution:

[0006] This invention proposes a switchgear with a pyrotechnic activation device, comprising a switchgear body and a pyrotechnic activation device mounted on the body. The switchgear body includes a direct-acting electromagnetic drive mechanism and a fixed stationary contact and a movable moving contact to perform a switching function. The direct-acting electromagnetic drive mechanism is used to drive the moving contact to move closer to or away from the stationary contact to achieve circuit connection or disconnection. The pyrotechnic activation device includes a pushing medium for performing downward movement. After a single downward movement, the pushing medium forces the moving contact away from the stationary contact. It also includes a constraint member, which is positioned corresponding to the downward movement of the piston. The constraint member is configured to constrain the moving contact to return to the stationary contact and is coupled to the moving contact. The constraint member is made of a material that can withstand the impact of the pushing medium without recovering its deformation.

[0007] The propellant is either high-pressure gas generated by the ignition of the pyrotechnic ignition device or a piston.

[0008] In one embodiment, the constraint member is preferably a constraint frame that is flattened by irreversible deformation after receiving the impact of the pushing medium, thereby constraining the moving contact portion to return to the stationary contact portion.

[0009] In one embodiment, the constraint is preferably made of stainless steel or low-carbon steel.

[0010] In one embodiment, based on manufacturing and installation considerations, the moving contact portion is preferably a plate-shaped structure, and the constraint frame spans across the plate-shaped moving contact portion to constrain its return to the stationary contact portion.

[0011] In one embodiment, the preferred direct-acting electromagnetic drive mechanism includes a push rod, the constraint frame is fixedly connected to the end of the push rod, the moving contact portion passes through the constraint frame, and an overtravel elastic element is fixedly installed inside the constraint frame. The elastic force of the overtravel elastic element pushes the moving contact portion against the upper end of the constraint frame. After the constraint frame moves upward so that the moving contact portion and the stationary contact portion abut against each other, the direct-acting electromagnetic drive mechanism drives the push rod and the constraint frame to continue moving upward to compress the overtravel elastic element, thereby realizing the overtravel of the moving contact portion.

[0012] In one embodiment, based on manufacturing and installation considerations, the constraint frame preferably includes an upper U-shaped bracket and a lower straight base. The U-shaped bracket includes a top plate and two side plates extending downward from both ends of the top plate. The two side plates are fixedly connected to both ends of the base to form a rectangular constraint frame. After receiving the impact of the pushing medium, the side plates bend, causing the constraint frame to be flattened without recovery of deformation. Alternatively, in another embodiment, the constraint frame preferably includes a lower U-shaped base and an upper straight top plate. The base includes a base and two side plates extending upward from both ends of the base. The two side plates are fixedly connected to both ends of the top plate to form a rectangular constraint frame. After receiving the impact of the pushing medium, the side plates bend, causing the constraint frame to be flattened without recovery of deformation.

[0013] In order to make the side panel easier to bend, in one embodiment, the side panel is preferably a hollow and / or sheet-like structure.

[0014] In order to make the side panel easier to bend, in one embodiment, the side panel is preferably a wavy bending structure.

[0015] Preferably, the switching device is a DC high-voltage relay.

[0016] The present invention has the following beneficial effects: By setting a constraint member that does not recover its deformation after being impacted by the piston, the present invention enables the restrained moving contact to rebound towards the stationary contact after the pyrotechnic ignition device is ignited. Furthermore, the height of the entire push rod assembly and the moving contact is further reduced, further widening the contact gap between the moving and stationary contacts, thus improving short-circuit safety. The present invention requires only a smaller downward movement distance to ensure a sufficiently large contact gap, therefore the height space of the contact cavity of the switchgear can be appropriately reduced, thereby reducing the overall height and volume of the switchgear. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the relay with a pyrotechnic ignition device in Example 1 (the relay is in the off state);

[0018] Figure 2 This is a schematic diagram of the pyrotechnic ignition device inserted and fixedly connected to the ceramic cover in Example 1;

[0019] Figure 3 This is an exploded view of the structure of the pyrotechnic ignition device in Example 1;

[0020] Figure 4 This is a cross-sectional view of the pyrotechnic ignition device in Example 1;

[0021] Figure 5 This is an exploded view (front view) of the exciter structure in Example 1;

[0022] Figure 6 This is an exploded view (three-dimensional view) of the exciter structure in Example 1;

[0023] Figure 7 This is a cross-sectional view of the relay with a pyrotechnic ignition device in Example 1 (the relay is in the on state);

[0024] Figure 8 This is a cross-sectional view of the relay with a pyrotechnic activation device in Example 1 (pyrotechnic activation device activated);

[0025] Figure 9 This is a three-dimensional schematic diagram of the push rod assembly in Embodiment 1;

[0026] Figure 10 This is an exploded view of the push rod assembly in Example 1;

[0027] Figure 11 This is a schematic diagram (front view) of the constraint frame being flattened by the piston impact in Example 1;

[0028] Figure 12 This is a schematic diagram (3D view) of the constraint frame being flattened by the piston impact in Example 1;

[0029] Figure 13 This is a schematic diagram of the constraint frame applied to the seesaw-type relay contact circuit in Example 2;

[0030] Figure 14 This is a schematic diagram (perspective view) of the push rod assembly in Embodiment 3;

[0031] Figure 15 This is a schematic diagram (front view) of the push rod assembly in Embodiment 3;

[0032] Figure 16 This is a three-dimensional schematic diagram (angle 1) of the U-shaped bracket in Example 4;

[0033] Figure 17 This is a three-dimensional schematic diagram (angle two) of the U-shaped bracket in Example 4. Detailed Implementation

[0034] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0035] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0036] Example 1:

[0037] See Figure 1-2 As shown, in a preferred embodiment of the present invention, a relay with a pyrotechnic ignition device is provided, including a relay body 100 and a pyrotechnic ignition device 5 mounted and attached to the relay body 100. The relay body 100 includes a stationary contact 1 (as a stationary contact portion) and a moving spring 2 (as a moving contact portion) to achieve its conduction or disconnection. The relay body 100 also includes a housing 3. One end of the stationary contact 1 protrudes from the housing 3 and is electrically connected to an external load, while the other end extends into the housing 3. The moving spring 2 is disposed inside the housing 3 and connected to an electromagnetic drive mechanism 4. The stationary contact 1 has an internal thread for threaded connection and fixation to an external terminal. The moving spring 2 is a bridge-type moving spring. Under the action of the electromagnetic drive mechanism 4, the moving spring 2 can move relatively closer to or away from the stationary contact 1. When the moving spring 2 simultaneously contacts two stationary contacts 1, the load is connected. For ease of description, the stationary contact 1 is defined as being relatively above the moving spring 2, and the moving spring 2 is relatively below the stationary contact 1.

[0038] The relay body 100 also includes a ceramic cover 6, which is fixed inside the outer casing 3 and covers the lower end of the stationary contact 1 and the moving spring 2 (i.e., covers the contact points between the stationary contact 1 and the moving spring 2), thus forming a contact cavity. The ceramic cover 6 isolates the contact points of the stationary contact 1 and the moving spring 2 from the outside air to achieve high withstand voltage performance, effectively ensuring low contact resistance, long life, and high reliability of the relay. Furthermore, when the relay is short-circuited, the arc resistance and high temperature resistance of the ceramic material ensure the safety and reliability of the circuit under short-circuit arc conditions.

[0039] The outer casing 3 further includes a base 32 and a top cover 31 that engage with each other. A ceramic cover 6 is disposed inside the top cover 31. A pyrotechnic ignition device 5 is inserted from the outside of the ceramic cover 6 and fixedly connected to it. The lower end of the pyrotechnic ignition device 5 extends into the contact cavity inside the ceramic cover 6, directly above the moving spring 2. The top cover 31 is then placed over the ceramic cover 6 and the pyrotechnic ignition device 5 to complete the overall assembly of the relay. (See also...) Figure 2The pyrotechnic ignition device 5 is an independent modular structure, roughly cylindrical in shape. An insertion hole 61 is provided at the upper end of the ceramic cover 6, through which the lower end of the pyrotechnic ignition device 5 extends into the contact cavity. The pyrotechnic ignition device 5 can be fixed to the ceramic cover 6 by welding, riveting, screwing, etc. In this embodiment, the pyrotechnic ignition device 5 is fixed to the ceramic cover 6 by brazing. Furthermore, in this embodiment, the top surface of the upper cover 31 has a through hole and a hollow cylindrical section to accommodate and match two stationary contacts 1 and one pyrotechnic ignition device 5, allowing the tops of the two stationary contacts 1 to protrude from the outer casing 3, while simultaneously protecting the exterior of the pyrotechnic ignition device 5. Additionally, to improve electrical safety, protective baffles (not shown in the figure due to angle) extend from both sides of the outer wall of the hollow cylindrical section in a direction perpendicular to the plane of the paper. In other embodiments, the pyrotechnic ignition device 5 can also be fixedly connected to the outer casing 3. However, in this embodiment, the pyrotechnic ignition device 5 is fixedly connected to the ceramic cover 6, which simplifies the assembly process. During final assembly, the pyrotechnic ignition device 5 and the stationary contact 1 are fixedly assembled on the ceramic cover 6, and then the top cover 31 is put on.

[0040] See Figure 3-6 The pyrotechnic ignition device 5 specifically includes an igniter 51, a piston 52 (as a propellant), and a base 53. The igniter 51 and the base 53 are joined and fixed together, one above the other, with the piston 52 housed between them. The igniter 51 further includes a hollow igniter base 512 and a connector 511, an igniter 513, and a sealing ring 514 fixedly installed inside the igniter base 512. The igniter base 512 and the base 53 are joined and fixed to form the outer shell of the pyrotechnic ignition device 5. The connector 511, the igniter 513, the sealing ring 514, and the piston 52 are arranged sequentially from top to bottom inside this outer shell, with the connector 511 connected to the lead 5131 of the igniter 513. The connector 511 is snapped and fixed to the inner wall of the igniter base 512. The sealing ring 514 is press-fitted into the igniter base 512 and presses the igniter 513 upward and fixes it. The upper and lower ends of the piston 52 are respectively pressed by the sealing ring 514 and the bottom shell 53. The sealing ring 514 can play the role of moisture prevention and gas sealing. The slight deformation generated by the pressure of the sealing ring 514 can further press the igniter 513 above and the piston 52 below, preventing vibration and loosening.

[0041] See also Figure 7-8Connector 511 is used to fix the ignition lead of the monitoring and excitation circuit to transmit the excitation electrical signal emitted by the monitoring and excitation circuit to excite the igniter 513. The monitoring and excitation circuit can emit an excitation electrical signal after the monitored current value (or current ramp-up rate) reaches a certain threshold, which is then conducted downward through connector 511 to excite the igniter 513 for ignition. An air gap 50 is provided between piston 52 and igniter 513. After igniter 513 ignites the gunpowder, high-pressure gas is generated in this air gap 50 (i.e., ignition occurs), pushing piston 52 downward to break through bottom shell 53. In turn, piston 52 pushes moving spring 2 downward, helping moving spring 2 to disengage from stationary contact 1, thereby realizing the rapid disconnection of the relay.

[0042] The bottom shell 53 is a hollow cylindrical structure, and the piston 52 is a rotating structure with a shaft hole fitted inside the bottom shell 53. Thus, the bottom shell 53 can guide the piston 52, so that after the igniter 513 is ignited, the piston 52 moves axially downward along the hollow cylindrical inner cavity of the bottom shell 53.

[0043] In this embodiment, piston 52 is used to execute the downward movement of the pyrotechnic ignition device. In other embodiments, the pyrotechnic ignition device may not have a piston, and may simply rely on the igniter 513 to ignite the gunpowder and generate high-pressure gas to break through the bottom shell 53 and push the moving spring 2. That is to say, the pushing medium used to push the moving spring 2 downward in the pyrotechnic ignition device can be either the high-pressure gas itself or piston 52.

[0044] The electromagnetic drive mechanism 4 is used to drive the moving spring 2 to move. (See reference) Figure 7-8 The electromagnetic drive mechanism 4 specifically includes a stationary iron core 41, a coil 42, a moving iron core 43, a push rod assembly 44, and a return spring 45. It also includes a first yoke 46, a second yoke 47, and a magnetic cylinder 48 for transmitting magnetic lines of force and improving magnetic energy utilization. The lower end of the push rod assembly 44 is fixedly connected to the moving iron core 43, and the upper end is linked to the moving spring 2. One end of the return spring 45 acts on the stationary iron core 41, and the other end acts on the moving iron core 43. When the coil 42 is energized, the stationary iron core 41 attracts the moving iron core 43 upwards, causing the push rod 44 to push the moving spring 2 upwards. When the coil 42 is de-energized, the electromagnetic drive mechanism 4 resets under the elastic force of the return spring 45. As a common direct-acting magnetic circuit structure, the operating principle of the electromagnetic drive mechanism 4 will not be elaborated further in this example.

[0045] See Figure 9-10 The push rod assembly 44 includes a push rod 441, a spring seat 442 (as a base frame), and a U-shaped bracket 443. The push rod 441 is used to output the driving force of the electromagnetic drive mechanism 4, and its lower end is fixedly connected to the moving iron core 43 (see attached diagram). Figure 8The upper end of the U-shaped bracket 443 is fixedly connected to the spring seat 442. The U-shaped bracket 443 is a sheet structure, including a top plate 4431 placed horizontally above the spring seat 442 and two side plates 4432 extending downward from both ends of the top plate 4431. The lower ends of the two side plates 4432 are fixedly connected to both ends of the spring seat 442, so that the spring seat 442 and the U-shaped bracket 443 are connected to form a square hollow constraint frame 400. The lower end of the overtravel spring 445 abuts against the spring seat 442, and the moving spring 2 passes through the constraint frame 400 and abuts against the top plate 4431 under the elastic force of the overtravel spring 445. Thus, with the help of the elastic force of the overtravel spring 445, the overtravel spring 445 and the moving spring 2 are stably installed in the constraint frame 400. Furthermore, when the push rod assembly 44 pushes the moving spring 2 upward to contact the stationary contact 1, the spring seat 442 can further compress the overtravel spring 445, realizing the overtravel of the contact in the relay conducting state.

[0046] See Figure 8 as well as Figure 11-12 In this embodiment, a constraint frame 400 is formed by a spring seat 442 and a U-shaped bracket 443. When the pyrotechnic ignition device 5 is activated, the piston 52 impacts downward on the constraint frame 400, causing the push rod assembly 44 and the moving spring 2 to move downward. After the spring seat 442 is stopped by the internal structure of the relay, the overtravel spring 445 is further compressed under the impact force of the piston 52. The two side plates 4432 of the U-shaped bracket 443 are bent under pressure, producing plastic deformation, which flattens the entire constraint frame 400 and makes it impossible to recover. As a result, the height of the entire push rod assembly 44 and the moving spring 2 is further reduced. Since the U-shaped bracket 443 is straddling the plate-shaped moving spring 2, it can constrain the rebound of the moving spring 2 toward the stationary contact 1. Moreover, since the downward impact of the piston 52 compresses and flattens the constraint frame 400, it can further widen the contact gap between the moving spring 2 and the stationary contact 1, improving short-circuit safety. From another perspective, since the constraint frame 400 formed by the spring seat 442 and the U-shaped bracket 443 in this embodiment can be compressed and flattened, compared with other solutions where the push rod assembly cannot be compressed and flattened, when the push rod assembly 44 and the moving spring 2 are impacted by the piston 52, they only need a smaller downward movement distance (after the constraint frame 400 is flattened and compressed) to ensure that a sufficiently large contact gap is opened. Therefore, the height space of the contact cavity of the ceramic cover 6 can also be appropriately set to be smaller, which can be consistent with the specifications of the relay without the pyrotechnic ignition device 5 (existing relays with the pyrotechnic ignition device 5 need to increase the height space of the contact cavity), thereby reducing the overall height volume of the relay.

[0047] Preferably, the U-shaped bracket 443 is made of a non-recoverable deformation material such as stainless steel or low-carbon steel. Furthermore, in this embodiment, the side plate 4432 is a hollow, thin sheet structure, making it easier to bend under pressure.

[0048] Besides using the constraint frame 400 of this embodiment to limit the installation of the movable spring 2 and to constrain the movable spring 2 to rebound toward the stationary contact 1, other constraint components can be used to replace the constraint frame 400 in other embodiments. For example, the movable spring 2 can be fixedly connected to the end of a rod, but the rod body is designed to withstand impact and axial compression without recovering its deformation. Any constraint component configured to constrain the movable spring 2 to rebound toward the stationary contact 1 and coupled with the movable spring 2 is feasible.

[0049] This embodiment illustrates the function and effect of structures such as the pyrotechnic ignition device 5 and the push rod assembly 44 using a relay structure. In addition to relays, the same structure can also be applied to other switching electrical appliances, such as contactors.

[0050] Example 2:

[0051] See Figure 13 This embodiment proposes a relay, including a stationary contact 1A and a moving contact 2A, wherein the moving contact 2A has a seesaw structure and is driven by an electromagnetic drive mechanism 4A to contact or disengage from the stationary contact 1A. The relay also includes a pyrotechnic activation device, which includes a piston 52A. When the piston 52A moves downward, it forces the moving contact 2A away from the stationary contact 1A. A constraint frame 400A is provided below the piston 52A, straddling the seesaw-like moving contact 2A. After receiving the impact of the piston 52A, the constraint frame 400A is irreversibly flattened, thereby constraining the moving contact 2A to return towards the stationary contact 1A.

[0052] That is, in addition to applying the constraint member (constraint frame 400A) to the direct-acting contact circuit of Embodiment 1, it can also be applied to the contact circuit of the seesaw in this embodiment. Any contact circuit structure that utilizes the non-recoverable deformation characteristic of the constraint member to constrain the moving contact part is feasible.

[0053] Example 3:

[0054] This embodiment proposes a relay whose structure is similar to that of the relay in Embodiment 1, except for the constraint frame structure of the push rod assembly. (See also...) Figure 14-15In this embodiment, the constraint frame includes a U-shaped spring seat 442A (as a base frame) and a top plate 443A. The spring seat 442A includes a base 442A-2 and side plates 442A-1 extending upward from both ends of the base 442A-2. The side plates 442A-1 are fixedly connected to the top plate 443A, thereby connecting the spring seat 442A and the top plate 443A to form the constraint frame. When impacted by the piston, the side plates 442A-1 bend, thereby flattening the entire constraint frame.

[0055] The difference between this embodiment and Embodiment 1 is that Embodiment 1 uses an inverted U-shaped bracket 443 connected to a straight spring seat 442 below it to construct the constraint frame 400, while this embodiment uses a U-shaped spring seat 442A connected to a top plate 443 above it to construct the constraint frame 400. Although this example has a different structure from Embodiment 1, it has the same technical effect.

[0056] In this embodiment and Embodiment 1, the side plate is either integrally connected to the spring seat (i.e., the structure of the U-shaped spring seat 442A) or integrally connected to the top plate (i.e., the structure of the U-shaped bracket 443). In other embodiments, the side plate can also be set as a separate structure, and the two ends of the side plate are fixedly connected to the top plate and the spring seat respectively during assembly to obtain a constraint frame.

[0057] Example 4:

[0058] This embodiment proposes a relay whose structure is similar to that of the relay in Embodiment 1, except for the structure of the U-shaped bracket. (See also...) Figure 16-17 In this embodiment, the side plate 4432B of the U-shaped bracket 443B is wavy, rather than the flat sheet shape in Embodiment 1. The structure of the wavy side plate 4432B in this embodiment makes the side plate 4432B easier to bend under pressure, thereby adaptively reducing the explosive force of the pyrotechnic ignition device.

[0059] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail made to the invention without departing from the spirit and scope of the invention as defined in the appended claims fall within the protection scope of the invention.

Claims

1. A circuit breaker with pyrotechnic actuation device, comprising a circuit breaker body and a pyrotechnic actuation device arranged on the circuit breaker body, the circuit breaker body comprising a direct-acting electromagnetic drive mechanism for driving a movable contact part towards or away from a fixed contact part to achieve circuit conduction or disconnection, and the pyrotechnic actuation device comprising a propelling medium for performing a downward movement, the propelling medium forcing the movable contact part away from the fixed contact part after a one-off downward movement, characterized in that: It also includes a constraint member disposed at a position corresponding to the downward movement of the pushing medium. The constraint member is capable of receiving the impact of the pushing medium and deforming. The constraint member is configured to constrain the moving contact portion to return to the position of the stationary contact portion and to couple with the moving contact portion. The constraint member is made of a material that can receive the impact of the pushing medium without recovering its deformation.

2. The switching device with a pyrotechnic ignition device according to claim 1, characterized in that: The propellant is high-pressure gas generated by the ignition of the pyrotechnic device, or the propellant is a piston.

3. The switching device with a pyrotechnic ignition device according to claim 1, characterized in that: The constraint member is a constraint frame that is flattened by irreversible deformation after receiving the impact of the pushing medium, thereby constraining the moving contact portion to return to the stationary contact portion.

4. The switching device with a pyrotechnic ignition device according to claim 1, characterized in that: The restraints are made of stainless steel or low-carbon steel.

5. The switching device with a pyrotechnic ignition device according to claim 3, characterized in that: The moving contact portion has a plate-like structure, and the constraint frame spans across the moving contact portion of the plate-like structure to constrain it to return to the stationary contact portion.

6. The switching device with a pyrotechnic ignition device according to claim 5, characterized in that: The direct-acting electromagnetic drive mechanism includes a push rod, a constraint frame fixedly connected to the end of the push rod, a moving contact portion passing through the constraint frame, and an overtravel elastic element fixedly installed inside the constraint frame. The moving contact portion is pushed against the upper end of the constraint frame by the elastic force of the overtravel elastic element. After the constraint frame moves upward so that the moving contact portion and the stationary contact portion abut against each other, the direct-acting electromagnetic drive mechanism drives the push rod and the constraint frame to continue moving upward to compress the overtravel elastic element, thereby realizing the overtravel of the moving contact portion.

7. The switching device with a pyrotechnic ignition device according to claim 3, characterized in that: The constraint frame includes an upper U-shaped support and a lower straight base. The U-shaped support includes a top plate and two side plates extending downward from both ends of the top plate. The two side plates are fixedly connected to both ends of the base to form a rectangular constraint frame. After the constraint frame receives the impact of the pushing medium, the side plates bend, thereby flattening the constraint frame by irreversible deformation. Alternatively, the constraint frame includes a lower U-shaped base and an upper straight top plate. The base includes a base and two side plates extending upward from both ends of the base. The two side plates are fixedly connected to both ends of the top plate to form a rectangular constraint frame. After the constraint frame receives the impact of the pushing medium, the side plates bend, thereby flattening the constraint frame by irreversible deformation.

8. The switching device with a pyrotechnic ignition device according to claim 7, characterized in that: The side panel is a perforated and / or sheet-like structure.

9. The switching device with a pyrotechnic ignition device according to claim 7, characterized in that: The side panel has a wavy, bent structure.

10. The switching device with a pyrotechnic ignition device according to any one of claims 1-9, characterized in that: The switchgear body is a DC high-voltage relay.

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