CN116052971A - Thermal tripping protection piezoresistor - Google Patents
Thermal tripping protection piezoresistor Download PDFInfo
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- CN116052971A CN116052971A CN202310035631.6A CN202310035631A CN116052971A CN 116052971 A CN116052971 A CN 116052971A CN 202310035631 A CN202310035631 A CN 202310035631A CN 116052971 A CN116052971 A CN 116052971A
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- thermal
- piezoresistor
- electrode
- thermal tripping
- tripping
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
- H01C7/12—Overvoltage protection resistors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
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- Microelectronics & Electronic Packaging (AREA)
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- Thermistors And Varistors (AREA)
Abstract
The invention discloses a thermal tripping protection piezoresistor, and belongs to the technical field of overvoltage protection of piezoresistors. The thermal tripping protection piezoresistor comprises a piezoresistor, a thermal tripping device and an external insulation package. The thermal tripping device comprises a shell, soldering tin and two electrodes, the piezoresistors and the bodies of the thermal tripping device are tightly attached and connected in series, and are connected into a protected circuit in parallel, under normal conditions, the piezoresistors can provide overvoltage protection by leaning on wires, and when the piezoresistors are overloaded or fail, the heating coupling makes the soldering tin in the thermal tripping device melt and disconnect, so that the piezoresistors are tripped from the circuit to avoid ignition. The temperature sensing tripping functional unit of the tripping device is adopted by the patent product, so that the problem that the prior art product cannot bear welding high temperature during assembly, surge pulse impact in a specification range and transient overvoltage conditions which can be tolerated by the piezoresistor to trip in advance is solved, and overvoltage protection failure caused by false tripping is avoided.
Description
Technical Field
The invention relates to the technical field of overvoltage protection of piezoresistors, in particular to a thermal tripping protection type piezoresistor.
Background
The piezoresistors are used in series in the circuit as overvoltage protection elements. When abnormal overvoltage occurs, the voltage-dependent resistor limits the increase of voltage amplitude and absorbs overvoltage energy due to nonlinear characteristics, so that a protection effect is achieved, but when the abnormal overvoltage energy exceeds the load capacity of the voltage-dependent resistor, the voltage-dependent resistor eventually breaks down and short circuits, further fires and burns or even explodes a voltage-dependent resistor body, the whole equipment is burnt and scrapped due to light weight, and serious accident overflow can cause further serious consequences.
To solve this problem, the prior art is that the piezoresistor and the thermal tripping device are connected in series, and the piezoresistor is connected in a circuit to play a role of overvoltage protection, when the overvoltage exceeds the load capacity of the piezoresistor or the piezoresistor fails due to short circuit, the heat of the piezoresistor is conducted to the thermal tripping device to melt the fusible alloy of the tripping button, and the piezoresistor is disconnected from the circuit to prevent fire. Surge Protectors (SPDs) and thermal protection piezoresistors (TMOV) are the primary products of the prior art.
In the technology, the heating of the piezoresistor is conducted to a tripping point only through the electrode, so the tripping point can only adopt low-temperature soldering tin/low-melting point alloy, the tripping point is affected by mechanical tension, the influence of external temperature disturbance or overvoltage in a specification tolerance range is easy to be affected, the piezoresistor is easy to trip by mistake under the condition that the piezoresistor is not overloaded/not failed, and the protective effect of the piezoresistor is lost in advance; because the distance from heat conduction to the tripping point is long, the tripping action is slow when the piezoresistor is overloaded or fails, and the reliability of the thermal protection effect is not high.
The thermal protection piezoresistor is characterized in that a temperature fuse is connected with the piezoresistor in series, the temperature fuse and the piezoresistor body are tightly attached to obtain good thermal coupling, the thermal tripping device is the temperature fuse, the temperature fuse is generally made of low-temperature alloy, and the situation that the temperature fuse is fused by mistake easily occurs when the temperature fuse is welded on a circuit, in-specification overvoltage or other thermal disturbance, so that the piezoresistor is released from the circuit in advance to lose the due overvoltage protection effect.
Disclosure of Invention
The invention aims to provide a thermal tripping protection piezoresistor, which is provided with a thermal tripping device using soldering tin as a temperature sensing tripping functional unit, so that the piezoresistor can perform overvoltage protection on line in a normal state, and the piezoresistor is separated from a circuit when abnormal overvoltage overload or the piezoresistor fails in a short circuit, thereby preventing the piezoresistor from firing and exploding and reducing potential safety hazards.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the utility model provides a thermal trip protection piezoresistor, includes piezoresistor, thermal trip gear and outside insulation encapsulation, its characterized in that: the thermal tripping device comprises an insulating shell, soldering tin and two electrodes, wherein the soldering tin is positioned in the shell and connected with the two electrodes in series, and the two electrodes extend out of the shell; the piezoresistor and the thermal tripping device body are tightly attached and connected in series; the whole device is connected in parallel to a protected loop, and under normal conditions, the piezoresistors can provide overvoltage protection by leaning on wires, and when the piezoresistors are overloaded or fail, the heating coupling causes the soldering tin in the thermal tripping device to be melted and disconnected, and the piezoresistors are tripped from the circuit to avoid ignition.
Preferably, the solder of the thermal tripping device is free to connect with the two electrodes without stress.
Preferably, the soldering tin of the thermal tripping device is high-temperature soldering tin or medium-temperature soldering tin.
Preferably, the solder of the thermal tripping device may be in the form of a solder wire or molten solder.
Preferably, the insulating housing of the thermal tripping device is a ceramic housing, and the cavity of the thermal tripping device is provided with an empty redundant gap besides the solder.
Preferably, the two extraction electrodes are welded on the piezoresistor, which can be in a non-external insulation mode or can be coated or encapsulated by epoxy resin.
The series connection of the varistor and the thermal tripping device can be realized in a thermal tripping protection varistor or in a line installation.
Preferably, the packaging form of the external insulation packaging can be a shell packaging, a packaging which is filled with quartz sand and resin or a packaging which is directly coated by an insulation material.
Preferably, a second thermal tripping device is additionally arranged on the other surface of the piezoresistor, the thermal tripping device body is closely attached to the electric piezoresistor body, but is not electrically connected with the piezoresistor, and two electrodes of the second thermal tripping device extend out of an external insulation package during packaging; under normal conditions, the thermal tripping device is in short circuit connection, soldering tin is fused when the piezoresistor is overloaded or fails, the two electrodes are opened, and the two electrodes can be used for detecting the tripping state of the thermal tripping protection piezoresistor by utilizing the state change.
Preferably, the connecting electrode of the piezoresistor and the thermal tripping device is used as a third electrode to extend out of the insulating package, and the change of the point positions of the electrode before and after the soldering tin of the thermal tripping device is fused can be used as a leading-out end for detecting the tripping state of the thermal tripping protection piezoresistor.
Compared with the prior art, the invention has the following advantages:
the thermal tripping protection piezoresistor provided by the invention adopts soldering tin as a temperature sensing tripping functional unit of the tripping device, is cheaper than fusible alloy or low-temperature insurance adopted in the prior art, and particularly adopts high-temperature soldering tin, so that the problem that the product in the prior art cannot bear welding high temperature, overvoltage surge pulse impact within a specification range and transient overvoltage conditions tolerated by the piezoresistor to trip in advance is solved, the piezoresistor can normally provide overvoltage protection by leaning on a line, and the piezoresistor can reliably trip to provide failure protection when overload or failure occurs.
Drawings
FIG. 1 is a schematic perspective view of a thermal trip device and varistor assembly according to one embodiment of the present invention;
FIG. 2 is a schematic view of a rear perspective view of a thermal trip unit and varistor assembly according to one embodiment of the present invention;
FIG. 3 is a schematic view of the overall perspective structure of a housing package according to a first embodiment of the present invention;
fig. 4 is a schematic diagram illustrating a three-dimensional structure of a thermal trip apparatus of the present invention
Fig. 5 is a disassembled perspective view of the thermal trip device of fig. 4
FIG. 6 is a schematic diagram of a front perspective view of a thermal trip unit and varistor assembly in accordance with a second embodiment of the present invention;
FIG. 7 is a schematic view of a rear perspective view of a thermal trip unit and varistor assembly according to a second embodiment of the present invention;
FIG. 8 is a schematic overall perspective view of a band-out enclosure of a second embodiment of the invention;
FIG. 9 is a schematic front perspective view of a thermal trip unit and varistor assembly according to a third embodiment of the present invention;
FIG. 10 is a schematic view of a rear perspective view of a thermal trip unit and varistor assembly according to a third embodiment of the present invention;
FIG. 11 is a schematic overall perspective view of a potting with tape of a third embodiment of the invention;
FIG. 12 is a schematic view of a front perspective view of a thermal trip unit and varistor assembly according to a fourth embodiment of the present invention;
FIG. 13 is a schematic view of a rear perspective view of a thermal trip unit and varistor assembly according to a fourth embodiment of the present invention;
FIG. 14 is a schematic overall perspective view of a potting with housing of a fourth embodiment of the invention;
FIG. 15 is a schematic view of a front perspective view of a thermal trip unit and varistor assembly according to a fifth embodiment of the present invention;
FIG. 16 is a schematic view of a rear perspective view of a thermal trip unit and varistor assembly according to a fifth embodiment of the present invention;
FIG. 17 is a schematic view of the overall perspective structure of a direct external package in accordance with a fifth embodiment of the present invention;
FIG. 18 is a schematic front perspective view of a thermal trip unit and varistor assembly according to a sixth embodiment of the present invention;
FIG. 19 is a schematic view showing a rear perspective view of a thermal trip unit and varistor assembly according to a sixth embodiment of the present invention;
FIG. 20 is a schematic view of the overall perspective structure of a direct external package in accordance with a sixth embodiment of the present invention;
FIG. 21 is a schematic front perspective view of a thermal trip unit and varistor assembly according to a seventh embodiment of the present invention;
FIG. 22 is a schematic rear perspective view of a thermal trip unit and varistor assembly according to a seventh embodiment of the present invention;
FIG. 23 is a schematic view of the overall perspective structure of a direct external package in accordance with a seventh embodiment of the present invention;
wherein: 100. the voltage-sensitive resistor is not externally insulated, the voltage-sensitive resistor is encapsulated by epoxy, the voltage-sensitive lead-out electrode I and the voltage-sensitive lead-out electrode II are respectively arranged; 20. the lead-free solder wire, 200, an alumina porcelain tube, 201, a thermal tripping device, 201a, 202, a first thermal tripping electrode, 202a, a first thermal tripping electrode, 203, a second thermal tripping electrode, 203a, and a second thermal tripping electrode; ABS shell, 301, epoxy resin filler, 302, quartz sand and epoxy resin filler, 303, composite insulation material KF direct packaging.
Detailed Description
For further illustration of the various embodiments, the invention is provided with the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments and together with the description, serve to explain the principles of the embodiments. With reference to these matters, one of ordinary skill in the art will understand other possible embodiments and advantages of the present invention. The components in the figures are not drawn to scale and like reference numerals are generally used to designate like components.
Example 1
As shown in fig. 1 to 3, a thermal trip protection varistor includes a varistor, a thermal trip device 201, and an ABS housing 300. The piezoresistor is a piezoresistor 100 without external insulation, and comprises a first pressure-sensitive extraction electrode 102 and a second pressure-sensitive extraction electrode 103, wherein the first pressure-sensitive extraction electrode 102 extends from the surface of the piezoresistor body, and the second pressure-sensitive extraction electrode 103 extends outside the piezoresistor body. As shown in fig. 4 to 5, the thermal tripping device 201 includes an alumina ceramic tube 200, soldering tin, a first thermal tripping electrode 202 and a second thermal tripping electrode 203, wherein the soldering tin is a lead-free solder wire 20, two electrodes (i.e., the first thermal tripping electrode 202 and the second thermal tripping electrode 203) of the thermal tripping device are all welded with the lead-free solder wire 20 to form an electrical connection, the lead-free solder wire 20 is not tensioned and pressed in the alumina ceramic tube 200, and a gap is reserved outside the soldering tin contained in the alumina ceramic tube 200 to facilitate the reliable disconnection of the two thermal tripping electrodes after the melting of the lead-free solder wire 20, and the first thermal tripping electrode 202 and the second thermal tripping electrode 203 extend out of the alumina ceramic tube 200. The body of the non-external insulation piezoresistor 100 and the body of the thermal tripping device 201 are closely attached so as to realize tight thermal coupling and timely fusing of the soldering tin wires, so that the piezoresistor is quickly separated from a circuit, the thermal effect is reduced, and the fire is effectively prevented from overflowing.
Specifically, in this embodiment, the first voltage-sensitive extraction electrode 102 and the first thermal trip electrode 202 are electrically connected by soldering, and the second thermal trip electrode 203 is used as one extraction end of the thermal trip protection piezoresistor, and is separated from the surface of the piezoresistor to be insulated, and the second voltage-sensitive extraction electrode 103 is used as the other extraction end of the thermal trip protection piezoresistor. The non-external insulation piezoresistor 100 and the thermal trip device 201 are packaged in an ABS housing 300 and sealed by an epoxy resin filler 301, and the second voltage-sensitive extraction electrode 103 and the second thermal trip electrode 203 are extended out of the package. The thermal trip protection piezoresistors are connected in series in a protected loop, and normally the non-external insulation piezoresistors 100 can provide overvoltage protection by leaning on wires, and the non-external insulation piezoresistors 100 are overloaded or fail, and the heating coupling causes the lead-free soldering wires 20 in the thermal trip device 201 to be melted and disconnected, so that the non-external insulation piezoresistors 100 are separated from the circuit to avoid ignition.
Example two
As shown in fig. 6 to 8, a thermal trip protection piezoresistor comprises a piezoresistor, a thermal trip device 201 and an ABS housing 300, wherein the piezoresistor is an epoxy encapsulation piezoresistor 101, and has a first pressure-sensitive extraction electrode 102 and a second pressure-sensitive extraction electrode 103, wherein the first pressure-sensitive extraction electrode 102 extends from the surface of the piezoresistor body, and the second pressure-sensitive extraction electrode 103 extends outside the piezoresistor body. As shown in fig. 4 to 5, the thermal tripping device 201 includes an alumina ceramic tube 200, a high-temperature lead-free solder wire 20, a first thermal tripping electrode 202 and a second thermal tripping electrode 203, wherein the two electrodes (i.e., the first thermal tripping electrode 202 and the second thermal tripping electrode 203) of the thermal tripping device are welded with the lead-free solder wire 20 to form an electrical connection, the lead-free solder wire 20 is threaded in the alumina ceramic tube 200 without being tensioned and pressed, a gap is reserved outside the lead-free solder wire 20 accommodated in the alumina ceramic tube 200 so as to facilitate the reliable disconnection of the two thermal tripping electrodes after the lead-free solder wire 20 is melted, and the first thermal tripping electrode 202 and the second thermal tripping electrode 203 extend out of the alumina ceramic tube 200. The body of the epoxy encapsulation piezoresistor 101 and the thermal tripping device 201 are closely attached so as to realize tight thermal coupling, realize timely fusing of the lead-free solder wires 20, and the piezoresistor is quickly separated from the circuit, thereby reducing thermal effect and effectively preventing fire from overflowing.
Specifically, in this embodiment, the first voltage-sensitive extraction electrode 102 and the first thermal trip electrode 202 are electrically connected by soldering, and the second thermal trip electrode 203 is used as one extraction terminal of the thermal trip protection piezoresistor, and the second voltage-sensitive extraction electrode 103 is used as the other extraction terminal of the thermal trip protection piezoresistor. The epoxy encapsulated piezoresistor 101 and the thermal trip unit 201 are encapsulated in an ABS housing 300 and sealed with an epoxy fill 301, with the second pressure sensitive lead-out electrode 103 and the second thermal trip electrode 203 extending out of the encapsulation. The thermal trip protection piezoresistor is connected in series to a protected circuit, and normally the epoxy-encapsulated piezoresistor 101 can provide overvoltage protection against wires, and the lead-free solder wire 20 is melted and disconnected by the heat-generating coupling when the epoxy-encapsulated piezoresistor 101 is overloaded or fails, so that the epoxy-encapsulated piezoresistor 101 is separated from the circuit to avoid ignition.
Example III
As shown in fig. 9 to 11, a thermal trip protection varistor includes a varistor, a thermal trip device 201, and an ABS housing 300 and a silica sand and epoxy filler 302 package. The piezoresistor is an epoxy encapsulation piezoresistor 101, and is provided with a first pressure-sensitive extraction electrode 102 and a second pressure-sensitive extraction electrode 103, wherein one end of the first pressure-sensitive extraction electrode 102 extends outside the piezoresistor body, the other end of the first pressure-sensitive extraction electrode extends along the surface of the piezoresistor body, and the second pressure-sensitive extraction electrode 103 extends outside the piezoresistor body and corresponds to one end of the first pressure-sensitive extraction electrode 102. As shown in fig. 4 to 5, the thermal tripping device 201 includes an alumina ceramic tube 200, a high-temperature lead-free solder wire 20, a first thermal tripping electrode 202 and a second thermal tripping electrode 203, wherein the two electrodes (i.e., the first thermal tripping electrode 202 and the second thermal tripping electrode 203) of the thermal tripping device are welded with the lead-free solder wire 20 to form an electrical connection, the lead-free solder wire 20 is threaded in the alumina ceramic tube 200 and is not under tension or pressure, a gap is reserved outside the lead-free solder wire 20 accommodated in the alumina ceramic tube 200 so as to facilitate the reliable disconnection of the two thermal tripping electrodes after the lead-free solder wire 20 is melted, and the first thermal tripping electrode 202 and the second thermal tripping electrode 203 extend out of the alumina ceramic tube 200. The body of the epoxy encapsulation piezoresistor 101 and the thermal tripping device 201 are closely attached so as to realize tight thermal coupling, realize timely fusing of the soldering tin wires, and the piezoresistor is quickly separated from the circuit, thereby reducing the thermal effect and effectively preventing fire from overflowing.
Specifically, in this embodiment, the other end of the first pressure-sensitive extraction electrode 102 is electrically connected to the first thermal trip electrode 202 by soldering, the second thermal trip electrode 203 is used as one extraction end of the thermal trip protection piezoresistor, the second pressure-sensitive extraction electrode 103 is used as the other extraction end of the thermal trip protection piezoresistor, and one end of the first pressure-sensitive extraction electrode 102 is used as the third extraction end of the thermal trip protection piezoresistor. The epoxy encapsulated piezoresistor 101 and the thermal trip device 201 are encapsulated in an ABS housing 300 and a quartz sand and epoxy filler 302, with one end of the first pressure sensitive extraction electrode 102, the second pressure sensitive extraction electrode 103 and the second thermal trip electrode 203 all extending out of the encapsulation. The thermal trip protection piezoresistor is connected in series with the protected loop through the second thermal trip electrode 203 and the second pressure sensitive lead-out electrode 103, and under normal conditions, the piezoresistor can provide overvoltage protection by leaning on a line, and the lead-free solder wire 20 is melted and disconnected by the heating coupling when the epoxy encapsulation piezoresistor 101 is overloaded or fails, so that the epoxy encapsulation piezoresistor 101 is separated from the circuit to avoid ignition. The third lead-out terminal (i.e., the first voltage-sensitive lead-out electrode 102) can be used as a signal terminal to indicate the disconnection state of the thermal tripping device 201 through the potential change of the third lead-out terminal before and after the disconnection of the thermal tripping device 201.
Example IV
As shown in fig. 12 to 14, a thermal trip protection varistor includes a varistor, a thermal trip device 201, and an ABS housing 300 and a silica sand and epoxy filler 302 package. The piezoresistor is an epoxy encapsulation piezoresistor 101, and is provided with a first pressure-sensitive extraction electrode 102 and a second pressure-sensitive extraction electrode 103, wherein the two pressure-sensitive extraction electrodes extend outwards from the body of the piezoresistor and correspond to each other. As shown in fig. 4 to 5, the thermal tripping device 201 includes an alumina ceramic tube 200, a high-temperature lead-free solder wire 20, a first thermal tripping electrode 202 and a second thermal tripping electrode 203, wherein the two electrodes (i.e., the first thermal tripping electrode 202 and the second thermal tripping electrode 203) of the thermal tripping device are welded with the lead-free solder wire 20 to form an electrical connection, the lead-free solder wire 20 is threaded in the alumina ceramic tube 200 and is not under tension or pressure, a gap is reserved outside the lead-free solder wire 20 accommodated in the alumina ceramic tube 200 so as to facilitate the reliable disconnection of the two thermal tripping electrodes after the lead-free solder wire 20 is melted, and the first thermal tripping electrode 202 and the second thermal tripping electrode 203 extend out of the alumina ceramic tube 200. The body of the epoxy encapsulation piezoresistor 101 and the thermal tripping device 201 are closely attached so as to realize tight thermal coupling, realize timely fusing of the soldering tin wires, and the piezoresistor is quickly separated from the circuit, thereby reducing the thermal effect and effectively preventing fire from overflowing.
Specifically, in this embodiment, the second thermal trip electrode 203 is used as the first lead-out terminal of the thermal trip protection piezoresistor, the second pressure-sensitive lead-out electrode 103 is used as the second lead-out terminal of the thermal trip protection piezoresistor, the first pressure-sensitive lead-out electrode 102 and the first thermal trip electrode 202 are respectively used as the third lead-out terminal and the fourth lead-out terminal of the thermal trip protection piezoresistor, so as to form a reliable electrical connection to connect the epoxy encapsulation piezoresistor 101 and the thermal trip device 201 in series during circuit installation. The epoxy encapsulated piezoresistor 101 and the thermal tripping device 201 are encapsulated in an ABS housing 300 and a quartz sand and epoxy filler 302, and the four terminals (i.e., the first pressure sensitive lead-out electrode 102, the second pressure sensitive lead-out electrode 103, the first thermal tripping electrode 202, the second thermal tripping electrode 203) are all extended out of the encapsulation. The first voltage-sensitive lead-out electrode 102 and the first thermal trip electrode 202 form a reliable electrical connection in series with the epoxy-encapsulated piezoresistor 101 and the thermal trip device 201 when installed, the thermal trip protection piezoresistor is connected in series with a protected circuit through the first lead-out end (i.e. the second thermal trip electrode 203) and the second lead-out end (i.e. the second voltage-sensitive lead-out electrode 103), the piezoresistor can provide overvoltage protection by a line under normal conditions, the lead-free solder wire 20 is melted and disconnected by heat coupling when the epoxy-encapsulated piezoresistor 101 is overloaded or fails, and the epoxy-encapsulated piezoresistor 101 is separated from the circuit to avoid ignition. Meanwhile, the first thermal trip electrode 202 and the second thermal trip electrode 203 of the thermal trip device 201 can be used as signal terminals to indicate the trip state of the thermal trip device 201.
Example five
As shown in fig. 15 to 17, a thermal trip protection varistor includes a varistor, two thermal trip devices having the same configuration, and a composite insulation KF direct package 303. The piezoresistor is an epoxy encapsulation piezoresistor 101, and is provided with a first pressure-sensitive extraction electrode 102 and a second pressure-sensitive extraction electrode 103, wherein the two pressure-sensitive extraction electrodes extend outwards from the piezoresistor body and correspond to each other, and the two thermal tripping devices are respectively and correspondingly arranged on two sides of the epoxy encapsulation piezoresistor 101 body. As shown in fig. 4 to 5, the two thermal tripping devices have the same structure and are composed of an alumina porcelain tube 200, a high-temperature lead-free solder wire 20, a first thermal tripping electrode 202 and a second thermal tripping electrode 203. For convenience of the reader, the two thermal trip devices are respectively labeled as a thermal trip device 201 and a thermal trip device 201a in the drawing, and the thermal trip electrodes of the two thermal trip devices are respectively labeled as a thermal trip electrode one 202, a thermal trip electrode two 203, a thermal trip electrode one 202a and a thermal trip electrode two 203a. Specifically, the first thermal trip electrode and the second thermal trip electrode in each thermal trip device are welded with the lead-free solder wire 20 to form electric connection, the lead-free solder wire 20 is not stressed and pressed when being penetrated in the alumina porcelain tube 200, a gap is reserved outside the lead-free solder wire 20 accommodated in the alumina porcelain tube 200 so as to be beneficial to reliably disconnecting the two thermal trip electrodes after the lead-free solder wire 20 is melted, the first thermal trip electrode 202 and the second thermal trip electrode 203 of the thermal trip device 201 extend out of the alumina porcelain tube 200, and the first thermal trip electrode 202a and the second thermal trip electrode 203a of the thermal trip device 201a with the same structure are led out.
Specifically, the thermal tripping device 201 and the thermal tripping device 201a in this embodiment are correspondingly disposed on the front and back sides of the epoxy encapsulated piezoresistor 101, and the thermal tripping electrodes of the two thermal tripping devices extend outside the piezoresistor body and are correspondingly disposed between the first pressure-sensitive extraction electrode 102 and the second pressure-sensitive extraction electrode 103. The epoxy encapsulation piezoresistor 101 is closely attached to the body of the thermal tripping device 201 so as to realize tight thermal coupling, realize timely fusing of the soldering tin wires of the thermal tripping device 201, and the piezoresistor is quickly separated from a circuit, thereby reducing thermal effect and effectively preventing fire from overflowing. The piezoresistor 101 and the body of the tripping device 201a are closely attached to each other so as to realize tight thermal coupling and timely fusing of the solder wires of the thermal tripping device 201a so as to accurately indicate the tripping state of the thermal tripping protection piezoresistor. The second thermal trip electrode 203 of the thermal trip device 201 is used as one lead-out terminal of the thermal trip protection piezoresistor, the second pressure sensitive lead-out electrode 103 of the piezoresistor 101 is used as the other lead-out terminal of the thermal trip protection piezoresistor, the first pressure sensitive lead-out electrode 102 of the piezoresistor 101 and the first thermal trip electrode 202 of the thermal trip device 201 are respectively used as the third lead-out terminal and the fourth lead-out terminal of the thermal trip protection piezoresistor, so as to form reliable electric connection to connect the piezoresistor 101 and the thermal trip device 201 in series when the circuit is installed, and the first thermal trip electrode 202a and the second thermal trip electrode 203a of the thermal trip device 201a are used as the fifth lead-out terminal and the sixth lead-out terminal of the thermal trip protection piezoresistor. The epoxy-encapsulated piezoresistor 101, the thermal tripping device 201 and the thermal tripping device 201a are directly encapsulated in the composite insulating material KF direct encapsulation 303, and two voltage-sensitive extraction electrodes of the epoxy-encapsulated piezoresistor 101 and four thermal tripping electrodes of the two thermal tripping devices are all protruded out of the encapsulation to form six extraction ends.
Specifically, the first voltage-sensitive extraction electrode 102 of the epoxy-encapsulated piezoresistor 101 and the first thermal trip electrode 202 of the thermal trip device 201 form a reliable electrical connection between the series piezoresistor 101 and the thermal trip device 201 when in installation, the thermal trip protection piezoresistor is connected in series to a protected circuit through the second thermal trip electrode 203 at the extraction end and the second voltage-sensitive extraction electrode 103 at the other extraction end, and under normal conditions, the piezoresistor can provide overvoltage protection by means of wires, and the epoxy-encapsulated piezoresistor 101 is overloaded or is in failure, and the thermal coupling causes the solder wires of the epoxy-encapsulated piezoresistor 101 to be melted and disconnected, so that the piezoresistor 101 is separated from the circuit to avoid ignition. Under normal conditions, the solder wires of the thermal tripping device 201a are intact, and when the piezoresistor 101 is overloaded or fails, the thermal coupling is generated to enable the solder wires to be melted and disconnected, and the first fusing thermal tripping electrode 202a and the second fusing thermal tripping electrode 203a can serve as signal ends to indicate the disconnection state of the thermal tripping device 201, so that the isolation between strong current and weak current is realized, and the thermal tripping device is safer.
Example six
As shown in fig. 18 to 20, a thermal trip protection varistor includes a varistor, two thermal trip devices having the same configuration, and a composite insulation KF direct package 303. The piezoresistor is an epoxy encapsulation piezoresistor 101, and is provided with a first pressure-sensitive extraction electrode 102 and a second pressure-sensitive extraction electrode 103, wherein the first pressure-sensitive extraction electrode 102 extends along the surface of the piezoresistor body, the second pressure-sensitive extraction electrode 103 extends outwards from the piezoresistor body, and two thermal tripping devices are respectively arranged on the front surface and the back surface of the epoxy encapsulation piezoresistor 101 in a staggered manner. As shown in fig. 4 to 5, the two thermal tripping devices have the same structure and are composed of an alumina porcelain tube 200, a high-temperature lead-free solder wire 20, a first thermal tripping electrode 202 and a second thermal tripping electrode 203. For convenience of the reader, the two thermal trip devices are respectively labeled as a thermal trip device 201 and a thermal trip device 201a in the drawing, and the thermal trip electrodes of the two thermal trip devices are respectively labeled as a thermal trip electrode one 202, a thermal trip electrode two 203, a thermal trip electrode one 202a and a thermal trip electrode two 203a. Specifically, the first thermal trip electrode and the second thermal trip electrode in each thermal trip device are welded with the lead-free solder wire 20 to form electric connection, the lead-free solder wire 20 is not stressed and pressed when being penetrated in the alumina porcelain tube 200, a gap is reserved outside the lead-free solder wire 20 accommodated in the alumina porcelain tube 200 so as to be beneficial to reliably disconnecting the two thermal trip electrodes after the lead-free solder wire 20 is melted, the first thermal trip electrode 202 and the second thermal trip electrode 203 extend out of the alumina porcelain tube 200, and the first thermal trip electrode 202a and the second thermal trip electrode 203a of the thermal trip device 201a with the same structure are led out.
Specifically, the first thermal trip electrode 202 of the thermal trip device 201 is connected to the first pressure-sensitive lead-out electrode 102 along the varistor body, the first thermal trip electrode 203 of the thermal trip device 201 extends out of the varistor body, and the first thermal trip electrode 202a and the second thermal trip electrode 203a of the thermal trip device 201a extend out of the varistor body. The piezoresistor 101 is closely attached to the body of the thermal tripping device 201 so as to realize tight thermal coupling, realize timely fusing of the soldering tin wires of the piezoresistor, quickly separate from the circuit, reduce thermal effect and effectively prevent fire from overflowing. The piezoresistor 101 and the body of the thermal tripping device 201a are closely attached to realize tight thermal coupling and timely fusing of the solder wires thereof so as to accurately indicate the tripping state of the thermal tripping protection piezoresistor. The first pressure-sensitive extraction electrode 102 of the piezoresistor and the first thermal trip electrode 202 of the thermal trip device 201 are electrically connected by soldering, the second thermal trip electrode 203 of the thermal trip device 201 is used as one extraction end of the thermal trip protection piezoresistor, the second pressure-sensitive extraction electrode 103 of the piezoresistor 101 is used as the other extraction end of the thermal trip protection piezoresistor, and the first thermal trip electrode 202a and the second thermal trip electrode 203a of the thermal trip device 201a are used as the extraction ends three and four of the thermal trip protection piezoresistor. The piezoresistor 101, the thermal tripping device 201 and the thermal tripping device 201a are packaged in a composite insulating material KF direct package 303, and the pressure-sensitive extraction electrode two 103, the thermal tripping electrode two 203, the thermal tripping electrode one 202a and the thermal tripping electrode two 203a are all extended out of the package.
Specifically, the thermal trip protection piezoresistor is connected in series to the protected circuit through the second thermal trip electrode 203 at the leading-out end and the second pressure-sensitive leading-out electrode 103 at the other leading-out end, and under normal conditions, the piezoresistor can provide overvoltage protection by a line, and the epoxy encapsulation piezoresistor 101 is overloaded or is in failure, and the heating coupling causes the solder wire to be melted and disconnected, so that the epoxy encapsulation piezoresistor 101 is separated from the circuit to avoid ignition. Under normal conditions, the solder wires of the thermal tripping device 201a are intact, and when the piezoresistor 101 is overloaded or fails, the thermal coupling is generated to enable the solder wires to be melted and disconnected, and the first thermal tripping electrode 202a and the second thermal tripping electrode 203a which are fused can serve as signal ends to indicate the tripping state of the thermal tripping protection piezoresistor, so that the isolation between strong current and weak current is realized, and the thermal tripping protection piezoresistor is safer.
Preferably, the external insulation packaging form of the thermal tripping protection piezoresistor can be a shell packaging, a quartz sand packaging filled in the shell, a quartz sand and epoxy resin material packaging filled in the shell or an insulation material direct coating packaging.
Example seven
As shown in fig. 21 to 23, a thermal trip protection varistor includes a varistor, two thermal trip devices having the same configuration, and a composite insulation KF direct package 303. The piezoresistor is an external insulation-free piezoresistor 100, and comprises a first pressure-sensitive extraction electrode 102 and a second pressure-sensitive extraction electrode 103, wherein the first pressure-sensitive extraction electrode 102 extends along the surface of the body of the piezoresistor, the second pressure-sensitive extraction electrode 103 extends outwards from the body of the piezoresistor, and two thermal tripping devices are respectively arranged on the front surface and the back surface of the piezoresistor. As shown in fig. 4 to 5, the two thermal tripping devices have the same structure and are composed of an alumina ceramic tube 200, a high-temperature lead-free solder wire 20, a first thermal tripping electrode 202 and a second thermal tripping electrode 203, and in order to facilitate the reader to distinguish the two thermal tripping devices, the two thermal tripping devices are respectively marked as a thermal tripping device 201 and a thermal tripping device 201a in the drawing, and the thermal tripping electrodes of the two thermal tripping devices are respectively marked as a first thermal tripping electrode 202, a second thermal tripping electrode 203, a first thermal tripping electrode 202a and a second thermal tripping electrode 203a. Specifically, the first thermal trip electrode and the second thermal trip electrode of each thermal trip device are welded with the lead-free solder wire 20 to form electric connection, the lead-free solder wire 20 is not stressed and pressed when being penetrated in the alumina porcelain tube 200, a gap is reserved outside the lead-free solder wire 20 accommodated in the alumina porcelain tube 200 so as to be beneficial to reliably disconnecting the two thermal trip electrodes after the lead-free solder wire 20 is melted, the first thermal trip electrode 202 and the second thermal trip electrode 203 extend out of the alumina porcelain tube 200, and the first thermal trip electrode 202a and the second thermal trip electrode 203a of the thermal trip device 201a with the same structure are led out.
Specifically, in this embodiment, the body of the thermal tripping device 201 and the non-external insulation piezoresistor 100 are closely attached to each other, so as to realize tight thermal coupling, realize timely fusing of the solder wires thereof, and the piezoresistor is quickly separated from the circuit, thereby reducing thermal effect and effectively preventing fire from overflowing. The varistor 100 and the body of the thermal trip device 201a are closely attached to each other so as to achieve tight thermal coupling and timely fusing of the solder wires thereof, so as to accurately indicate the trip state of the thermal trip protection varistor. The first pressure-sensitive extraction electrode 102 of the non-external insulation piezoresistor 100 and the first heat-release electrode 202 of the heat-release device 201 are electrically connected by soldering, the second heat-release electrode 203 of the heat-release device 201 is used as one extraction end of the heat-release protection piezoresistor, the second pressure-sensitive extraction electrode 103 of the piezoresistor 100 is used as the other extraction end of the heat-release protection piezoresistor, the first heat-release electrode 202a and the second heat-release electrode 203a of the heat-release device 201a are used as the third extraction end and the fourth extraction end of the heat-release protection piezoresistor, and the second heat-release electrode 203, the first heat-release electrode 202a and the second heat-release electrode 203a are required to leave the body of the non-external insulation piezoresistor 100 to be insulated. The piezoresistor 100, the thermal tripping device 201 and the thermal tripping device 201a are packaged in a composite insulating material KF direct package 303, and the pressure-sensitive extraction electrode two 103, the thermal tripping electrode two 203, the thermal tripping electrode one 202a and the thermal tripping electrode two 203a are all extended out of the package.
Specifically, the thermal trip protection piezoresistor is connected in series to the protected loop through the second thermal trip electrode 203 at the leading-out end and the second pressure sensitive leading-out electrode 103 at the other leading-out end, and under normal conditions, the piezoresistor can provide overvoltage protection by a line, and no overload or heating coupling of the external insulation piezoresistor 100 occurs when in failure, so that the soldering wire of the external insulation piezoresistor is melted and disconnected, and no external insulation piezoresistor 100 is separated from the circuit to avoid ignition. Under normal conditions, the solder wires of the thermal tripping device 201a are intact, and the solder wires are fused and disconnected without heating coupling when the external insulation piezoresistor 100 is overloaded or fails, so that the first thermal tripping electrode 202a and the second thermal tripping electrode 203a can be used as signal ends for indicating the tripping state of the thermal tripping protection piezoresistor, thereby realizing the isolation of strong current and weak current and being safer.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. The utility model provides a thermal trip protection piezoresistor, includes piezoresistor, thermal trip gear and outside insulation encapsulation, its characterized in that: the thermal tripping device comprises an insulating shell, soldering tin and two electrodes, wherein the soldering tin is positioned in the shell and connected with the two electrodes in series, and the two electrodes extend out of the shell; the piezoresistor and the thermal tripping device body are tightly attached and connected in series; the whole device is connected in parallel to a protected loop, and under normal conditions, the piezoresistors can provide overvoltage protection by leaning on wires, and when the piezoresistors are overloaded or fail, the heating coupling causes the soldering tin in the thermal tripping device to be melted and disconnected, and the piezoresistors are tripped from the circuit to avoid ignition.
2. The thermal trip protection varistor of claim 1, wherein: the soldering tin of the thermal tripping device is freely connected with the two electrodes, and no stress exists.
3. The thermal trip protection varistor of claim 2, wherein: the soldering tin of the thermal tripping device is high-temperature soldering tin or medium-temperature soldering tin.
4. A thermal trip protection varistor as defined in claim 3, wherein: the solder of the thermal trip device may be in the form of a solder wire or molten solder.
5. The thermal trip protection varistor of claim 1, wherein: the insulating shell of the thermal tripping device is a ceramic shell, and the cavity of the thermal tripping device is provided with an empty redundant gap besides soldering tin.
6. The thermal trip protection varistor of claim 1, wherein: the piezoresistor is welded with two extraction electrodes, which can be in a non-external insulation mode or can be coated or encapsulated by epoxy resin.
7. A thermal trip protection varistor as defined in claim 1, wherein: the series connection of the piezoresistors and the thermal tripping device can be realized in the thermal tripping protection piezoresistors or in the line installation.
8. The thermal trip protection varistor of claim 1, wherein: the packaging form of the external insulation packaging can be a shell packaging, a packaging in which quartz sand and resin are filled in the shell or a packaging in which insulating materials are directly coated.
9. The thermal trip protection varistor of claim 1, wherein: the other side of the piezoresistor is additionally provided with a second thermal tripping device, the thermal tripping device body is closely attached to the piezoresistor body, but is not electrically connected with the piezoresistor, and two electrodes of the second thermal tripping device extend out of the external insulation package during packaging, and can be used for detecting the tripping state of the thermal tripping protection piezoresistor.
10. The thermal trip protection varistor of claim 1, wherein: and the connecting electrode of the piezoresistor and the thermal tripping device is used as a third electrode to extend out of the insulating package and can be used as a leading-out end for detecting the tripping state of the thermal tripping protection piezoresistor.
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| CN202310035631.6A CN116052971A (en) | 2023-01-10 | 2023-01-10 | Thermal tripping protection piezoresistor |
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| CN202310035631.6A CN116052971A (en) | 2023-01-10 | 2023-01-10 | Thermal tripping protection piezoresistor |
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