CN102377176A - Surge protection device - Google Patents

Abstract

The invention provides a surge protection device, comprising: a variable resistance device; a drive mechanism; a drive limiting mechanism, which is fixedly connected with the variable resistance device; an actuation mechanism, which is driven by a displacement force applied by the drive mechanism to move It remains relatively stationary due to the joint action of the limiting force exerted by the drive limiting mechanism that is opposite to the displacement force and restricts its movement; the movable electrode is fixedly connected to the actuating mechanism and can be electrically connected to the variable resistance device or Electrical disconnection; the first electrical connection device, which is electrically connected between the variable resistance device and the external circuit; the second electrical connection device, which is electrically connected between the movable electrode and the external circuit; wherein, when the limit force disappears In the case of , the displacement force drives the actuating mechanism to move, so that the movable electrode fixed on the actuating mechanism moves from a position electrically connected to the variable resistance device to an electrically disconnected position.

Description

surge protection device

technical field

The present invention relates to a surge protection device for providing overvoltage protection to a circuit.

Background technique

Surge protection device (Surge Protection Device, SPD), also known as surge protector, overvoltage protector. Surge protection equipment can protect the load in the circuit so that it can withstand the impact of instantaneous overvoltage or lightning current. More specifically, the overvoltage protector is generally connected in parallel with the load and installed on the upper stage of the load. When the circuit is operating normally, the overvoltage protector is in a high-impedance state, which does not affect the normal operation of the load; When the voltage or lightning current strikes, the overvoltage protector will show a very low resistance state, which is equivalent to instantaneous conduction, and the current will be shunted into the ground, so as to ensure that the residual voltage level at both ends of the lower parallel load is within a certain safe range that the load can withstand .

Known surge protection devices include varistor devices such as metal oxide varistors MOV (voltage limiting type) or gas discharge tubes GDT (voltage switching type) and thermal trip units. The variable resistance device exhibits a high resistance state under the normal operating voltage of the circuit, and a very low resistance state during an instantaneous overvoltage such as a lightning strike, thereby realizing the function of SPD with low resistance at high voltage and high resistance at low voltage . The thermal trip unit is usually connected in series with the variable resistance device through low temperature solder. For high-performance SPDs, the thermal release is required to have good tolerance when subjected to overvoltage or lightning current impact, that is, the welding part of the thermal release and the variable resistance device maintains good ultra-low resistance characteristics , so that the high current can be introduced into the ground through the SPD, and the lower load in parallel can be reliably protected; it is also required that the thermal release will be damaged when the variable resistance device is gradually increased due to the leakage current over time or after being subjected to multiple impacts. When the body temperature is gradually rising or the variable resistance device is subjected to an overcurrent impact exceeding its design nominal value, the variable resistance device conducts abnormal redundant heat to melt the solder, and the thermal tripper trips to separate the dynamic and static electrodes and cut off The circuit causes the SPD to exit the circuit, and the user is notified to replace a new SPD. Solder is a special alloy. SPD has high requirements for this solder. The quality of solder directly affects the performance of SPD, such as reliability, safety and service life.

Contents of the invention

The present invention is made in view of the above-mentioned problems in the prior art, and according to an embodiment of the present invention, a surge protection device that does not use solder is provided. Specifically, a surge protection device according to an embodiment of the present invention includes: a variable resistance device; a drive mechanism; a drive limiting mechanism, which is fixedly connected to the variable resistance device; an actuating mechanism, which is controlled by the drive mechanism remains relatively stationary due to the combined action of the displacement force applied to drive its movement and the stop force applied by the drive limit mechanism to limit its movement opposite to the displacement force; the movable electrode, which is connected to the actuation The mechanism is fixedly connected and can be electrically connected or disconnected from the variable resistance device; the first electrical connection device is electrically connected between the variable resistance device and the external circuit; the second electrical connection device is Electrically connected between the movable electrode and an external circuit; wherein, when the limiting force disappears, the displacement force drives the actuating mechanism to move, thereby making the actuating mechanism fixed on the actuating mechanism The movable electrode moves from a position electrically connected to the variable resistance device to an electrically disconnected position.

According to the embodiments of the present invention, since the surge protection device does not use solder, the limitation of the quality of the solder on the performance of the surge protection device is overcome.

The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of preferred embodiments of the invention considered in conjunction with the accompanying drawings, in accordance with embodiments of the invention.

Description of drawings

FIG. 1 shows a general structural block diagram of a surge protection device according to an embodiment of the present invention;

Fig. 2 shows a structural block diagram of a surge protection device in an assembled state according to an embodiment of the present invention;

Fig. 3 shows the structure before tripping of the surge protection device according to the embodiment of the present invention;

Fig. 4 shows the structure after tripping of the surge protection device according to the embodiment of the present invention;

Fig. 5 shows the electrical connection structure before tripping of the surge protection device according to an embodiment of the present invention;

Fig. 6 shows the electrical connection structure after tripping of the surge protection device according to an embodiment of the present invention;

FIG. 7 shows a pre-trip state of a surge protection device according to an embodiment of the present invention; and

FIG. 8 illustrates a post-trip state of a surge protection device according to an embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 shows a general structural block diagram of a surge protection device according to an embodiment of the present invention. The surge protection device comprises: a variable resistance device 4; a driving mechanism 8; a drive limiting mechanism 11, which is fixedly connected with the variable resistance device 4; Force and drive limiting mechanism 11 apply the joint action of limiting force that limits its movement opposite to displacement force and keep relatively static; Movable electrode 7, it is fixedly connected with actuating mechanism 5, and can be connected with variable resistance device 4 maintain electrical connection or electrical disconnection, as shown by dotted line in Fig. 1; first electrical connection device 9, which is electrically connected between the variable resistance device 4 and the external circuit; It is connected between the movable electrode 7 and the external circuit; wherein, when the limiting force disappears, the displacement force drives the actuating mechanism 5 to move, so that the movable electrode 7 fixed on the actuating mechanism 5 can move from The electrical connection position with the variable resistance device 4 moves to the electrical disconnection position.

Fig. 2 shows a structural block diagram of a surge protection device in an assembled state according to an embodiment of the present invention. As shown in FIG. 2, the surge protection device may also include a bracket 1 to accommodate the variable resistance device 4, the driving mechanism 8, the driving limiting mechanism 11, the actuating mechanism 5 and the movable electrode 7, wherein the actuating mechanism 5 can be completely Located within the range of the bracket 1 , it may be partially aligned with the edge of the bracket 1 , or partially located outside the range of the bracket 1 . The entire surge protection device may also include a casing 100 that can cover the rest of the components in a closed manner. As shown in FIG. 7 and FIG. 8 later, a transparent window 110 may be opened on one side of the casing 100 .

The variable resistance device 4 may be a conventional metal oxide varistor MOV (voltage limiting type) or a gas discharge tube GDT (voltage switching type). In this embodiment, the variable resistance device 4 is a sheet-shaped MOV with a certain thickness. The sheet has two main surfaces with large areas, and the outer contour around the main surfaces basically reaches the bracket 1 . Those skilled in the art can recognize that as long as the variable resistance device 4 can meet the connection and positional relationship with other components described in the specification, it can be in any other shape, such as a cube, a cuboid, a cylinder, an ellipse, etc. .

The driving mechanism 8 can be any device capable of storing potential energy and exerting force by doing work externally, for example, it can be at least one of a spring and an elastic bending rod, which is used to apply a displacement force that can make the actuating mechanism 5 move. , the spring can be at least one of tension spring, compression spring, torsion spring and bending spring, and the elastic bending rod can be at least one of bending push rod and bending pull rod, or can be a combination of the above-mentioned various springs, each A combination of elastic bending rods or a combination of any spring and any elastic bending rod.

The drive limiting mechanism 11 may be a bimetallic or trimetallic strip, which can be bent and deformed when heated. Those skilled in the art can recognize that the drive limiting mechanism 11 can be any type of heat-deformable part, and its material can be any material that can be bent or displaced when heated, and can be a metal material or other materials, such as Plastic, etc., its shape can be any shape that can be bent or displaced when heated, and can be in the form of a sheet or other shapes, such as a spring shape, a rod shape, and the like.

Fig. 3 shows the structure of the surge protection device before tripping according to the embodiment of the present invention; Fig. 4 shows the structure of the surge protection device after tripping according to the embodiment of the present invention.

As shown in FIG. 3 , the first electrical connection device 9 and the second electrical connection device 3 are outside the bracket 1 , and the variable resistance device 4 is inside the bracket 1 , and a fixing clip 10 is fixed thereon. The driving mechanism 8 is located between the bracket 1 and the actuating mechanism 5 and applies a displacement force to the actuating mechanism 5 to make it move.

As shown in FIG. 4 , the drive limiting mechanism 11 has a first end 111 and a second end 112 . The first end 111 may be directly connected to the variable resistance device 4, that is, the fixing clip 10 may not be used, or as shown in FIGS. 3 and 4, the first end 111 may be connected to the variable resistance device 4. On the fixing clip 10, the fixing clip 10 may be metal or non-metal with good thermal conductivity and certain strength. The connection mode between the first end 111 and the variable resistance device 4 and the connection mode between the fixing clip 10 and the variable resistance device 4 can be welding, or can be bonded with a high temperature resistant adhesive. The first end 111 and the variable resistance device 4 The fixing clip 10 can be connected by riveting, welding or bonding with high temperature resistant adhesive. Those skilled in the art can recognize that any other connection mode that makes the relative positions of the two connected parties fixed is also feasible.

The second end 112 exerts a limiting force on the actuating mechanism 5. Specifically, the second end 112 can be bent, and the actuating mechanism 5 can be locked or hooked through the bent part. Those skilled in the art can Recognize that, as long as it can be guaranteed that the second end 112 can limit the actuating mechanism 5 under normal (for example, not being heated) conditions and the second end 112 can be in contact with the actuating mechanism 5 under the condition that the driving limiting mechanism 11 is bent when heated. If disengaged, the second end 112 can be in any other structure, and can be in any other structure and positional relationship with the actuating mechanism 5 .

The connection position where the first end 111 is directly connected to the variable resistance device 4 or the connection position between the above-mentioned fixing clip 10 and the variable resistance device 4 can be located on the outer surface of the variable resistance device 4, so that abnormal redundant heat can be transferred To a drive limiting mechanism 11 such as a bimetal or trimetal, bending the drive limiting mechanism 11 such as a bimetal or trimetal can be achieved by using metals that deform differently when equally heated.

The variable resistance device 4 can be provided with a second fixed electrode 41 , and the movable electrode 7 can be electrically connected with the variable resistance device 4 by being in contact with the second fixed electrode 41 . However, it is also possible that the movable electrode 7 and the variable resistance device 4 are in direct contact without the second fixed electrode 41 .

As shown in FIG. 3 , the actuating mechanism 5 includes a first status indicating device 13 and a second status indicating device 12 indicating an electrical disconnection status. The first status indicating device 13 may be, for example, a local status indicating device, and the second status indicating device 12 may be, for example, a remote communication status indicating device. Those skilled in the art can recognize that the first status indicating device 13 may also be used to indicate the status in a remote communication manner, while the second status indicating device 12 is used to indicate the status locally. (It is recommended to use the first and second terms in the following text, and it is better to distinguish and define it here) The first status indicating device 13 protrudes from the outside of the bracket 1, and its outer side has a color different from that of the outer side of the housing as an indication Color, preferably a striking indicator color. The first state indicating device 13 shown in FIG. 3 is in a state indicating that the equipment is normal.

As shown in FIG. 4 , after the driving limiting mechanism 11 such as a bimetallic or trimetallic strip is heated and bent, the bent part of the second end 112 that catches/hooks the actuating mechanism 5 is separated from the actuating mechanism 5, and this , the limiting force disappears, and the actuating mechanism 5 is moved to the tripping position by the displacement force exerted by the driving mechanism 8 . At this time, the movable electrode 7 moves along with the actuating mechanism 5 to be electrically disconnected from the second fixed electrode 41 . The side of the indicating color on the first state indicating device 13 reaches the position of the indicating window 110, so that a part of the side of the first state indicating device 13 having the indicating color can expose the casing 100 from the window 110, and the first state indicating device 13 is in the position of the indicating window 110. In the indication state of equipment failure, the side with a striking indicator color can be observed from the window 110 as shown in FIG. 6 so that the trigger pin 6 is pressed to the inside of the bracket 1 by the external pressing force, so that the trigger pin 6 can send a remote signal. That is, the surge protection device transitions from the state shown in FIG. 7 described later to the state shown in FIG. 8 described later, so that the user can notice, so as to notify the user to replace the surge protection device.

That is to say, as shown in FIG. 3 , the second state indicating device 12 is inside the bracket 1 and is in contact with the trigger pin 6 , and the trigger pin 6 is blocked by the second state indicating device 12 and is in an untriggered state. As shown in Figure 4, when the actuating mechanism 5 drives the second state indicating device 12 to move to the tripping position, the movable electrode 7 is electrically disconnected from the second fixed electrode 41, and the second state indicating device 12 makes the trigger pin 6 emit Signal, which can remotely notify the user to replace the surge protection device. Those skilled in the art can imagine that the above-mentioned signal can be sent through various existing methods, such as dry contact signal or high-low level signal.

In a specific embodiment, the trigger pin 6 is slidably arranged on the bracket 1, and it is pressed against the outer surface of the second state indicating device 12. When the second state indicating device 12 moves to trip position, the reaction force applied by the second state indicating device 12 to the trigger pin 6 disappears, the trigger pin 6 is displaced and sends a signal to a remote control system not shown, so that the user can be notified to replace the surge protection device.

Those skilled in the art can realize that the above two means of drawing the user's attention by exposing the indicator color from the housing and notifying the user by sending a signal do not have to be used at the same time, but one of them can also be selected according to needs. .

The second electrical connection device 3 may be electrically connected to the movable electrode 7, for example, through a flexible conductive connection body. The second electrical connection device 3 is located outside the bracket 1 , and the flexible conductive connecting body passes through the bracket 1 to electrically connect the movable electrode 7 fixedly connected to the actuating mechanism 5 with the second electrical connection device 3 . In a specific embodiment, the flexible conductive connector can be a metal wire 2, and the two ends of the metal wire 2 are respectively connected to the second electrical connection device 3 and the movable electrode 7, and the connection method can be, for example, welding, or can Any other connection that conducts electricity.

Those skilled in the art can recognize that the second electrical connection device 3 and the movable electrode 7 can also be directly connected without a flexible conductive connector. In the case of a rigid connection between the second electrical connection device 3 and the movable electrode 7, the second The two electrical connection devices 3 can be made movable along the bracket 1, so as not to affect the displacement of the movable electrode 7 before and after the surge protection device trips.

Fig. 5 shows the electrical connection structure of the surge protection device before tripping according to the embodiment of the present invention; Fig. 6 shows the electrical connection structure of the surge protection device after tripping according to the embodiment of the present invention.

As shown in Figure 5, the first fixed electrode 42 can be set on the variable resistance device 4, and the first electrical connection device 9 can be electrically connected with the variable resistance device 4 through the first fixed electrode 42, however, the first electrical connection device 9 It is also possible to directly contact the variable resistance device 4 without the first fixed electrode 42 . The first electrical connection device 9 is located outside the bracket 1 , and the first fixed electrode 42 passes through the bracket 1 to electrically connect the first electrical connection device 9 with the variable resistance device 4 .

It can be clearly seen from Fig. 5 that the current path before tripping, the current can pass through the first electrical connection device 9, the first fixed electrode 42, the variable resistance device 4, and the second fixed electrode 41 in sequence (not marked in Fig. 5 , see FIG. 6), the movable electrode 7, the wire 2 and the second electrical connection device 3, or the current may flow in reverse through the above-mentioned current path.

The current path after tripping can be seen clearly from FIG. 6 , the movable electrode 7 is electrically disconnected from the second fixed electrode 41 , and the current path is cut off.

Fig. 7 shows the pre-trip state of the surge protection device according to the embodiment of the present invention; Fig. 8 shows the post-trip state of the surge protection device according to the embodiment of the present invention.

Fig. 7 shows the state before the tripping of the surge protection device, at this time, the first state indicating device 13 has not reached the position of the window 110 of the housing 100, the window 110 is in the state A where no indicating color is displayed, and the second state indicating device 12 Interacting with the trigger pin 6, the trigger pin 6 is in the untriggered state B.

Figure 8 shows the state of the surge protection device after tripping. At this time, the first state indicating device 13 of the actuating mechanism 5 moves to the tripped position, and the window 110 exposes the eye-catching indicator color on the outside of the first state indicating device 13. The window 110 In the state A' displaying the indicator color; at the same time, the second state indicating device 12 of the actuating mechanism 5 also moves to the tripping position, the second state indicating device 12 is separated from the trigger pin 6 without interaction, and the trigger pin 6 is controlled by the outside The extrusion force extends into the inside of the bracket 1, so that the trigger pin 6 becomes the triggered state B', and sends out a remote signal.

The invention has been described in detail with reference to specific embodiments. However, it is obvious that those skilled in the art can perform changes and substitutions to the embodiments without departing from the spirit of the present invention. In other words, the present invention has been disclosed in an illustrative form and not construed restrictively. To judge the gist of the present invention, the appended claims should be considered.

Claims (17)

1. A surge protection device comprising: variable resistance device; Drive mechanism; a drive limiting mechanism, which is fixedly connected to the variable resistance device; The actuating mechanism is kept relatively stationary under the joint action of the displacement force applied by the driving mechanism to drive it to move and the limiting force applied by the drive limiting mechanism to limit its movement opposite to the displacement force; a movable electrode fixedly connected to the actuating mechanism and capable of being electrically connected or disconnected from the variable resistance device; a first electrical connection means, which is electrically connected between the variable resistance means and an external circuit; a second electrical connection means electrically connected between said movable electrode and an external circuit; Wherein, when the limiting force disappears, the displacement force drives the actuating mechanism to move, so that the movable electrode fixed on the actuating mechanism is separated from the variable resistance device The electrically connected position moves to the electrically disconnected position. 2. The surge protection device according to claim 1, the variable resistance device is a voltage limiting type variable resistance device or a voltage switch type variable resistance device. 3. The surge protection device of claim 1, the drive mechanism being at least one of a spring and a resiliently bent rod. 4. The surge protection device of claim 3, where the drive mechanism includes a spring, the spring is at least one of an extension spring, a compression spring, a torsion spring, and a bending spring. 5. The surge protection device according to claim 3, where the driving mechanism comprises an elastically curved rod, the elastically curved rod is at least one of a curved push rod and a curved pull rod. 6. The surge protection device of claim 1, the drive limiting mechanism is a bimetal or a trimetal. 7. The surge protection device of claim 6, the drive limiting mechanism has a first end connected to the variable resistance device. 8. The surge protection device according to claim 7, the connection position between the first end and the variable resistance device is located on the outer surface of the variable resistance device. 9. The surge protection device of claim 6, the drive limiting mechanism has a first end connected to a clip connected to the variable resistance device. 10. The surge protection device according to claim 9, the connection position between the fixing clip and the variable resistance device is located on the outer surface of the variable resistance device. 11. The surge protection device of claim 6, the drive limiting mechanism having a second end that applies the limiting force to the actuating mechanism. 12. The surge protection device of claim 1, said actuating mechanism comprising indicating means for indicating an electrical disconnection state. 13. The surge protection device according to claim 1, the variable resistance device is provided with a first fixed electrode, and the first electrical connection device is electrically connected to the variable resistance device through the first fixed electrode . 14. The surge protection device according to claim 1, the variable resistance device is provided with a second fixed electrode, and the movable electrode is electrically connected to the variable resistance device by being in contact with the second fixed electrode. connect. 15. The surge protection device according to claim 1, wherein the second electrical connection means is electrically connected to the movable electrode through a flexible conductive connection body. 16. The surge protection device of claim 1, further comprising a trigger pin that signals an electrical disconnection when the movable electrode is electrically disconnected from the variable resistance device. 17. The surge protection device of claim 1, further comprising a bracket housing the variable resistance device, the drive mechanism, the drive limit mechanism, the actuation mechanism, and the movable electrode.

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