Surge protection device

Abstract

The invention relates to a surge protection device, and belongs to the technical field of surge protection. The surge protection device comprises an input piece, an output piece and a contact piece, the input piece and the output piece are separated through the piezoresistor, the contact piece is movably arranged on the input piece, and a hot melting piece is arranged on the input piece; the hot melting piece limits the contact piece to the initial position and enables the input piece and the output piece to be in an open circuit, and after the hot melting piece is melted, the contact piece is reset to the working position, and the input piece and the output piece are electrically connected through the contact piece. According to the surge protection device provided by the invention, the structure for triggering the short circuit of the input piece and the output piece is a mechanical structure, so that the stability of the short circuit between the input piece and the output piece can be ensured no matter how the installation position of the surge protection device is. In addition, the internal resistance of the product is low, the product can still bear large current for a long time after the piezoresistor is short-circuited, and the surge protection effect can be achieved on rear-end equipment.

Description

Technical Field

[0001] This invention belongs to the field of surge protection technology, and specifically relates to a surge protector. Background Technology

[0002] Surge protectors, also known as surge protection devices or SPDs, are mainly used in circuit systems. When a sudden instantaneous overvoltage, i.e., a surge or surge, occurs, the surge protector can quickly conduct and divert the current, discharging the huge overvoltage current to the ground, thereby limiting the voltage across the equipment and protecting the equipment from being burned out.

[0003] According to the patent application number CN200610168473.8, the surge protector is mainly composed of a first conductive electrode element, a second conductive electrode element, and a varistor. The varistor is located between the first conductive electrode element and the second conductive electrode element. A conductive fusible element is provided on the first conductive electrode element. The fusible element melts as the temperature rises in the device, thereby forming a current path between the first and second electrode elements, allowing the current to pass through the fusible element.

[0004] Under normal operation, the input and output terminals are open-circuit, and the varistor can only pass surge current, not power frequency current. When the varistor fails, the power frequency current causes it to heat up, which in turn melts the phase change material, i.e., the conductive fusible element. The molten liquid fills the insulation distance, causing a short circuit between the input and output terminals. At this time, the loop current continues to increase, eventually cutting off the circuit through the upstream fuse.

[0005] However, in the aforementioned short-circuit type SPD, when the varistor is short-circuited, the phase change material is in a molten state. If the installation angle and position differ, the contact surface between the phase change material and the conductive component will change, resulting in varying heat generation. Therefore, the product's heating is unstable. Furthermore, the different contact surfaces cause instability in the internal resistance of this SPD product. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a surge protector with a mechanical structure that triggers a short circuit between the input and output components. Regardless of the orientation of the surge protector, it can ensure the stability of current and voltage after a short circuit between the input and output components, effectively protecting downstream precision equipment.

[0007] The technical solution of the present invention is as follows: This invention provides a surge protector, including an input component, an output component, and a contact component; the input component and the output component are separated by a varistor, the contact component is movably disposed on the input component, and a thermosetting element is disposed on the input component; the thermosetting element limits the contact component to an initial position and opens the circuit between the input component and the output component, and when the thermosetting element melts, the contact component resets to the working position and the input component and the output component are electrically connected through the contact component.

[0008] As an optional feature, the surge protector also includes a reset spring that tends to reset the contact element.

[0009] As an optional solution, the contact element is slidably sleeved on the input element, and the hot melt element is sleeved on the input element and located on one side of the contact element.

[0010] Alternatively, the hot melt component can be ring-shaped.

[0011] As an optional solution, the hot melt component uses a limiting tin ring.

[0012] As an optional solution, the surge protector further includes a housing, with some or all of the input element inserted into the housing and the output element mounted at one end of the housing; or with some or all of the input element inserted into the housing and some or all of the output element inserted into the housing; or with the input element mounted at one end of the housing and some or all of the output element inserted into the housing.

[0013] As an optional solution, the surge protector further includes a housing electrically connected to the output element, the housing having a conductive step configured to abut against and be electrically connected to the reset contact element.

[0014] As an optional solution, the surge protector further includes an input cover and an insulating cover. The input cover is detachably connected to the first end of the housing, and the insulating cover is fitted onto the input component and insulates the input component from the housing.

[0015] As an optional solution, the surge protector further includes two pressure plates sleeved on the input component and a disc spring located between the two pressure plates. An auxiliary step is provided on the input component, and the two pressure plates are located between the insulating cover and the auxiliary step.

[0016] As an optional solution, the output component includes an output cover and an output end, wherein the output cover is detachably connected to the second end of the housing.

[0017] As an optional solution, the conductive step divides the interior of the housing into a first cavity and a second cavity that are interconnected and have opposite openings. The first cavity is a stepped hole that is smaller on the outside and larger on the inside. The contact element is located in the first cavity and is adjacent to the conductive step.

[0018] Alternatively, the input component can be installed through the opening of the first cavity, and the output component can be installed through the opening of the second cavity.

[0019] As an optional feature, the surge protector also includes a pressure plate, which is detachably disposed at one end of the input component and in contact with the varistor.

[0020] As an optional solution, the input component is provided with several copper braided strips around its perimeter.

[0021] As an option, the surge protector also includes an insulating ring configured to separate the varistor from the inner surface of the housing.

[0022] The beneficial effects of this invention are: The surge protector provided by this invention operates with an open circuit between the input and output components during normal operation. The varistor allows surge current to pass through but not power frequency current. When the varistor fails, the fusible link melts due to heat, the contacts reset, and the input and output components become electrically connected. This causes a short circuit and heat between the input and output components, ultimately triggering the upstream fuse to trip and protect the entire electrical circuit. Because the mechanism triggering the short circuit between the input and output components is mechanical, the stability of the short circuit between the input and output components is ensured regardless of the surge protector's installation location, resulting in higher product reliability. Furthermore, the product has low internal resistance, allowing it to withstand large currents for extended periods even after a varistor short circuit, and it also provides surge protection for downstream equipment. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The above and other objects, features, and advantages of the present invention will become clearer through the accompanying drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not intentionally drawn to scale to actual dimensions; the focus is on illustrating the main points of the invention.

[0024] Figure 1 A schematic diagram of the surge protector provided in an embodiment of the present invention. Figure 1 ; Figure 2A schematic diagram of the surge protector provided in an embodiment of the present invention. Figure 2 ; Figure 3 A schematic diagram of the surge protector provided in an embodiment of the present invention. Figure 3 ; Figure 4 for Figure 3 AA section view; Figure 5 A partial (without casing) structural schematic diagram of a surge protector provided in an embodiment of the present invention; Figure 6 A partial structural diagram (without housing, input cover, insulating cover, insulating ring, etc.) of the surge protector provided in an embodiment of the present invention is shown. Figure 7 A partial structural diagram (without housing, input cover, insulating cover, insulating ring, reset spring, etc.) of the surge protector provided in an embodiment of the present invention is shown.

[0025] Icons: 10-Surge protector; 11-Housing; 12-Input component; 13-Output component; 14-Varistor; 15-Contact component; 110-Conductive step; 111-First cavity; 112-Second cavity; 120-Input cover; 121-Insulating cover; 122-Pressure plate; 123-Disc spring; 124-Pressure plate; 125-Copper braided tape; 126-Auxiliary step; 130-Output cover; 131-Output terminal; 140-Insulating ring; 150-Thermofused component; 151-Reset spring. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0030] Please refer to Figures 1-6 As shown, an embodiment of the present invention provides a surge protector 10, which is generally used in conjunction with a fuse and installed in a circuit system. It can discharge instantaneous overvoltage to the ground, limit the voltage across the device, and protect the electrical equipment.

[0031] The surge protector 10 mainly consists of a housing 11, an input component 12, an output component 13, a varistor 14, and a contact component 15. The input component 12, the output component 13, the varistor 14, and the contact component 15 are all installed inside or on the housing 11. The following is a detailed discussion of each component of the surge protector 10.

[0032] The outer shell 11 mainly serves a supporting function. The shape, size, and structure of the outer shell 11 are not limited and can be set as needed. For example, the outer shell 11 can be cylindrical, prismatic, irregular in shape, etc. In this embodiment, the outer shell 11 is preferably cylindrical. The interior of the outer shell 11 is hollow to form a receiving cavity, which is used to provide a sealed environment for components such as the varistor 14. The shape and size of the receiving cavity can be set as needed.

[0033] The material of the outer casing 11 is not limited; it can be either a conductive material or a non-conductive material. The conductive material can be either a conductive metal or a conductive non-metal. It should be noted that whether the outer casing 11 can conduct electricity depends on its positional relationship and connection with the input component 12 and the output component 13. This point will be discussed in detail later.

[0034] Input component 12 and output component 13 serve as the input terminal and output terminal 131 of surge protector 10, respectively, and are mainly used to connect to the input and output connectors of external lines.

[0035] A portion of the input component 12 is inserted into the receiving cavity of the housing 11, while the other portion is exposed. The exposed portion is used for electrical connection with an external line. The connection method between the input component 12 and the external line is not limited and can refer to existing technology. For example, the exposed portion is provided with a threaded hole, and the input connector is threaded into the threaded hole; or the exposed portion is provided with a socket and a clamping bolt, and the input connector is inserted into the socket and fixed by the clamping bolt. Of course, in some embodiments, the input component 12 is completely inserted into the housing 11, or the input component 12 is completely located outside the housing 11, that is, the input component 12 is connected to one end of the housing 11 but does not extend into the housing 11.

[0036] The shape of the input component 12 is not limited; for example, the input component 12 can be cylindrical, stepped shaft-shaped, prismatic, irregularly shaped, etc. In this embodiment, the input component 12 is generally stepped shaft-shaped, and prismatic in the central region.

[0037] The input component 12 is made of a conductive material, which can be a conductive metal such as copper, silver, or alloy, or a conductive non-metal such as graphite or room temperature semiconductor.

[0038] The input component 12 and the housing 11 can be electrically connected or insulated from each other.

[0039] The output component 13 is mounted on the housing 11. The relative position or connection method between the two is not limited. For example, in some embodiments, a portion of the output component 13 is inserted into the receiving cavity, while another portion is exposed and used to connect to an external line.

[0040] In this embodiment, the output component 13 is completely located outside the housing 11, and is connected to one end of the housing 11. The connection method between the output component 13 and the housing 11 is not limited; it can be integrally formed or detachably connected. Preferably, the output component 13 includes an output cover plate 130 and an output end 131. The output cover plate 130 and the output end 131 are integrally formed, and the output cover plate 130 is detachably connected to one end of the housing 11 via threaded fasteners such as screws or bolts.

[0041] The output component 13 and the housing 11 can be electrically connected or insulated from each other. It should be noted that if the housing 11 is made of a non-conductive material or is made of a conductive material and covered with an insulating layer, both the output component 13 and the input component 12 can directly or indirectly contact the housing 11. If the housing 11 is made of a conductive material, at most one of the input component 12 and the output component 13 can be electrically connected to the housing 11; that is, if the input component 12 is electrically connected to the housing 11, then the output component 13 is insulated from the housing 11; if the output component 13 is electrically connected to the housing 11, then the input component 12 is insulated from the housing 11.

[0042] Varistor 14 is located between input component 12 and output component 13, and is electrically connected to both input component 12 and output component 13. Varistor 14 is made of varistor material and is a relatively mature electrical component. Its structure and principle can refer to existing technologies. For example, the varistor material can be doped metal oxide or silicon carbide, and the metal oxide can be zinc oxide compound, etc. Varistor 14 is a semiconductor device whose resistance changes non-linearly with applied voltage. Its core characteristics are: under normal voltage, its resistance is very high, almost equivalent to an insulator, with only a very weak leakage current passing through, having no impact on the normal operation of the circuit; under overvoltage, when the voltage across its terminals exceeds a specific value, i.e., the varistor voltage, its resistance drops sharply, becoming almost like a conductor, allowing a large current to pass through instantaneously, thereby dissipating the overvoltage energy and protecting the downstream precision circuitry; once the overvoltage disappears and the line voltage returns to normal, the resistance of varistor 14 returns to the high-resistance state, awaiting the next protection action.

[0043] An insulating distance exists between the varistor 14 and the housing 11, or an insulating ring 140 is placed outside the varistor 14. The insulating ring 140 can be made of insulating material and can insulate the varistor 14 from the inner surface of the housing 11.

[0044] To allow surge current to flow smoothly, in this embodiment, a pressure plate 124 can be provided at one end of the input component 12. The pressure plate 124 is made of a conductive material and is capable of conducting electricity. The shape of the pressure plate 124 is not limited, and it can be, for example, a circular plate, a square plate, an elliptical plate, an irregularly shaped plate, etc.

[0045] The pressure plate 124 and the input component 12 can be integrally formed or detachably connected. For example, one side of the pressure plate 124 can be fitted to one end of the input component 12 and the two can be detachably connected by threaded fasteners, while the other side can be tightly fitted to the varistor 14. This arrangement can maximize the contact area and conductive area between the input component 12 and the varistor 14, so that surge current can smoothly pass through the varistor 14 to reach the output component 13.

[0046] Since the input device 12 and the output device 13 are isolated by the varistor 14, the input device 12 and the output device 13 can be in an open circuit state. The open circuit state means that the power frequency current cannot reach the output device 13 from the input device 12, but the surge current can reach the output device 13 through the input device 12 and the varistor 14.

[0047] In this embodiment, the surge protector 10 is a short-circuit type SPD. Therefore, it is necessary to use contact elements 15, etc., to ensure that when the varistor 14 is damaged, the power frequency current can pass between the input terminal and the output terminal 131.

[0048] Specifically, the contact element 15 is movably disposed on the input element 12. The movable connection method between the contact element 15 and the input element 12 is not limited, such as sliding engagement, rotational engagement, etc. In this embodiment, the contact element 15 is slidably sleeved on the input element 12, and the contact element 15 can slide along the axial direction of the input element 12. In other embodiments, the movable connection method can also be: the input element 12 is provided with a sliding groove, and the contact element 15 is provided with a sliding part, the sliding part being slidably embedded in the sliding groove; or one end of the contact element 15 is hinged to the input element 12, and the contact element 15 can rotate around the hinge part, etc.

[0049] Since the contact 15 is slidably fitted onto the input component 12, the contact 15 must be an annular structure, and its shape is not limited, such as a circular annulus or a square annulus. The internal shape of the contact 15 matches that of the input component 12. In some embodiments, if the contact 15 and the input component 12 are not in a slidably fitted relationship, the contact 15 can also be rod-shaped, block-shaped, etc. In addition, the contact 15 generally needs to have a certain rear end to ensure stable contact and conductivity between the contact 15 and the input component 12. In some embodiments, a cylindrical portion can also be provided inside the contact 15, which is fitted onto the input component 12, thereby increasing the contact area between the contact 15 and the input component 12 and making the conductivity more stable. Alternatively, a conductive structure such as a copper braided strip 125 can be provided between the input component 12 and the contact 15.

[0050] In this embodiment, a plurality of copper braided strips 125 are provided around the input component 12. Preferably, the middle part of the input component 12 is prismatic, and copper braided strips 125 are provided on some or all of the faces of the prismatic component. Of course, the copper braided strips 125 may not be used to electrically connect the input component 12 and the contact component 15, but may serve other purposes or may not be provided at all.

[0051] The contact element 15 is made of conductive material, which can be conductive metal material such as copper, iron, alloy, etc., or conductive non-metallic material.

[0052] When the contact 15 slides along the input 12, it has two positions: an initial position and a working position. When the contact 15 is in the initial position, it is electrically connected only to the input 12, or the contact 15 and the input 12 are mutually insulated. In this case, the input 12 and the output 13 are electrically connected only through the varistor 14. Only surge current can pass through the input terminal and the output terminal 131 of the surge protector 10, and power frequency current cannot pass through them. When the contact 15 is in the working position, it is electrically connected to both the input 12 and the output 13, so that the input 12 and the output 13 are electrically connected, that is, the power frequency current can reach the output 13 through the input 12 and the contact 15.

[0053] When the contact 15 is in the working position, it can be in direct contact with the output 13 and be electrically connected, or it can be indirectly connected and electrically connected through other structures. Since the input 12 and the output 13 are separated by the varistor 14, if the contact 15 in the working position were to be in direct contact with the output, the contact 15 would have to pass over the varistor 14, which would make the structure of the contact 15 more complex.

[0054] Therefore, in this embodiment, the following schemes can be adopted, but are not limited to: when the output component 13 is electrically connected to the housing 11, the contact component 15 can contact the housing 11 and be electrically connected when the contact component 15 is in the working position. At this time, it should be noted that when the contact component 15 is in the initial position, there is an insulating gap between the contact component 15 and the housing 11 or insulation through an insulating component.

[0055] Furthermore, in order to facilitate contact between the contact 15 in the working position and the housing 11, the following scheme can be adopted, but is not limited to: a conductive step 110 is provided inside the housing 11, the conductive step 110 is located inside the housing 11 and extends inward, and when the contact 15 reaches the working position, the contact ring abuts against the conductive step 110.

[0056] The shape of the conductive step 110 is not limited, such as ring or block, but preferably ring-shaped. This arrangement can increase the contact area between the contact ring and the conductive step 110, so that the power frequency current can pass through smoothly.

[0057] The conductive step 110 divides the accommodating cavity into a first cavity 111 and a second cavity 112. The first cavity 111 and the second cavity 112 are interconnected, and their openings face away from each other. The input component 12 is installed through the opening of the first cavity 111, and the output component 13 is installed through the opening of the second cavity 112. After installation, the center lines of the input component 12 and the output component 13 coincide or are parallel, and are also coincident or parallel to the center line of the outer casing 11. Here, "coincident or parallel" means "completely coincident or completely parallel," or "substantially coincident or substantially parallel." Of course, in some embodiments, it is also possible that the center lines of the input component 12 and the output component 13 do not coincide or are not parallel, and are also not coincident or parallel to the center line of the outer casing 11.

[0058] This design simplifies the assembly of the surge protector 10, allowing the input component 12 and output component 13 to be assembled separately from the bottom and top, while achieving an IP65 protection rating.

[0059] The way the input component 12 is installed inside the housing 11 is not limited. In this embodiment, the following schemes can be adopted, but are not limited to: the surge protector 10 also includes an input cover plate 120 and an insulating cover 121. The input cover plate 120 is sleeved on the input component 12 and is detachably connected to the first end of the housing 11. The insulating cover 121 is sleeved on the input component 12 and insulates the input component 12 from the housing 11.

[0060] The design of the insulating cover 121 is not limited; for example, it can be cylindrical. Preferably, the outer surface of the insulating cover 121 has a stepped shaft-like structure, and the inner surface has a stepped hole-like structure. Of course, the input cover 120 can be made of conductive material or non-conductive material such as plastic. In other embodiments, if the input cover 120 is made of non-conductive material, the insulating cover 121 can be omitted.

[0061] In addition, to avoid the input component 12 from shaking after installation or the gap between it and the varistor 14 due to manufacturing errors, the following solutions can be adopted, but are not limited to: the surge protector 10 also includes two pressure plates 122 and at least one disc spring 123. An auxiliary step 126 is provided on the input component 12. The auxiliary step 126 can be block-shaped or annular. The two pressure plates 122 are respectively located between the insulating cover 121 and the auxiliary step 126. The disc spring 123 is located between the two steps. The disc spring 123 makes the input component 12 tend to move toward the varistor 14, thereby pressing the input component 12 or the pressure plate 124 against the output component 13.

[0062] The connection method between the output component 13 and the housing 11 is not limited. In this embodiment, the output component 13 includes an output cover plate 130 and an output end 131. The output cover plate 130 is detachably connected to the second end of the housing 11. The detachable connection method between the output cover plate 130 and the housing 11 is not limited, such as connection by threaded fasteners, snap-fit, etc.

[0063] The shape of the input cover 120 is not limited, such as round, square, etc. Preferably, the input cover 120 is round and its diameter is equal to the diameter of the outer shell 11.

[0064] Output terminal 131 is used to connect to the output connector of an external line. The connection method is not limited. For example, output terminal 131 is provided with a threaded post, and the output connector is threadedly engaged with the threaded post. Alternatively, output terminal 131 is provided with a socket and a clamping bolt, and the output connector is inserted into the socket and fixed by the clamping bolt.

[0065] Preferably, the first cavity 111 adopts a stepped hole, which includes a first hole on the outer side and a second hole on the inner side. The diameter of the second hole is larger than the diameter of the first hole. The contact member 15 is located in the second hole, which can increase the distance between the contact member 15 and the inner surface of the outer shell 11, so that the insulation effect between the two is better.

[0066] The input component 12 and the output component 13 are electrically connected by the contact component 15. Since the connection method is mechanical and electrical, the contact area and contact position are relatively fixed, the electrical performance is not affected by the installation position, the connection effect is more stable, and the reliability is higher.

[0067] Since the contact 15 can move along the axial direction of the input 12, when the surge protector 10 is working normally, it is necessary to ensure that the contact 15 remains stationary in the initial position; when the varistor 14 is damaged, it is necessary to ensure that the contact 15 reaches the working position and remains stationary. Therefore, the position of the contact 15 is determined by the thermosetting element 150 and the return spring 151.

[0068] The heat-fused element 150 is disposed on the input element 12 and is used to prevent the contact element 15 from moving from the initial position to the working position. When the temperature exceeds the melting point temperature of the heat-fused element 150, the element can melt, thereby enabling the contact element 15 to move.

[0069] The material of the heat fusible link 150 is not limited. Generally speaking, the melting point of the heat fusible link 150 material cannot be too high or too low. It can be a metallic material such as tin, or a non-metallic material such as plastic or rubber. Preferably, the melting point of the heat fusible link 150 can be set between 110° and 160°. Whether the heat fusible link 150 is conductive or non-conductive does not affect the electrical performance of the surge protector 10. The structure of the heat fusible link 150 is not limited. For example, it can be block-shaped or ring-shaped. In this embodiment, the heat fusible link 150 adopts a limiting tin ring. The limiting tin ring is ring-shaped and sleeved and fixed to the input member 12. The contact member 15 abuts against the limiting tin ring.

[0070] The connection method between the heat-fused component 150 and the input component 12 is not limited. For example, they can be fixed by interference fit, low-temperature welding, or by threaded fasteners. It is necessary to ensure that after the heat-fused component 150 is completely melted, there are no obstacles in front of the contact component 15 until the contact component 15 contacts the conductive step 110.

[0071] After the hot melt component 150 is completely melted, the contact component 15 needs to slide from the initial position to the working position. This action is achieved by the return spring 151. The return spring 151 gives the contact component 15 a tendency to return to its original position. That is, when the limiting solder ring has not melted, the return spring 151 is compressed or stretched, which applies a certain force to the contact component 15, but this force cannot make the contact component 15 push the limiting solder ring to move. When the limiting solder ring melts and fails, the return spring 151 can push the contact component 15 to reach and maintain the working position. The style and installation method of the return spring 151 are not limited, such as compression spring, tension spring, etc. Preferably, the return spring 151 is a compression spring, which is sleeved on the input component 12. One end of the compression spring abuts against the contact component 15, and the other end abuts against the outer shell 11 or other structures, such as the auxiliary step 126, the pressure plate 122, or the insulating cover 121. In other embodiments, the number of reset springs 151 may be multiple, and the multiple reset springs 151 are distributed circumferentially around the input member 12.

[0072] Of course, in other embodiments, the reset spring 151 can be replaced with other reset structures, such as elastic rubber, or magnets that can attract each other at the corresponding positions of the contact member 15 and the conductive step 110, that is, as long as the contact member 15 has the tendency to reset from the initial position and remain in the working position.

[0073] In addition, sealing elements can be provided at certain locations of the surge protector 10. For example, sealing rings can be provided between the input component 12 and the insulating cover 121, between the insulating cover 121 and the input cover plate 120, between the insulating cover 121 and the outer casing 11, and between the output cover plate 130 and the outer casing 11. The sealing rings are annular, and their setting method can refer to the prior art. For example, a sealing groove can be provided on the input component 12 and other components, and the sealing ring can be embedded in the sealing groove and fit against other adjacent components. This setting can ensure that the accommodating cavity is sealed as a closed space, so that the contact component 15, the varistor 14, etc. are in a sealed environment, preventing rainwater and other substances from entering the accommodating cavity and causing a short circuit.

[0074] The assembly method of the surge protector 10 provided in this embodiment is as follows: The hot melt component 150 is installed on the input component 12, and the contact component 15 is sleeved on the input component 12; Several copper braided strips 125 are sequentially installed on the input component 12; The reset spring 151, pressure plate 122, disc spring 123, pressure plate 122, and insulating cover 121 are sequentially fitted onto the input component 12. During this process, a sealing ring can be installed between the input component 12 and the insulating cover 121. The input component 12 is inserted into the receiving cavity of the housing 11 through the opening of the first cavity 111, and the input cover plate 120 is fixed to the housing 11 by threaded fasteners. During this process, a sealing ring can be installed between the insulating cover 121, the housing 11 and the input cover plate 120. The pressure plate 122 is inserted into the receiving cavity through the opening of the second cavity 112 and fixed to the contact member 15 by threaded fasteners; The insulating ring 140 is placed in the second cavity 112, and the varistor 14 is placed in the insulating ring 140, so that the varistor 14 is in contact with the pressure plate 124. The output cover 130 is fixed to the housing 11 with threaded fasteners.

[0075] The above steps can be added, removed, modified, or their order adjusted as needed. For example, the output component 13 can be assembled first, and then the input component 12 can be assembled; or if the output cover 130 is integrally formed with the outer shell 11, then the corresponding connection and fixing steps are not required; or the hot-melt component 150 can be pre-fixed to the input component 12, so the corresponding steps can be omitted during assembly.

[0076] The surge protector 10 provided in this embodiment operates as follows: The surge protector 10 is located in the electrical circuit. The input component 12 and the output component 13 are electrically connected to the input and output terminals of the electrical circuit, respectively. A fuse may also be installed in the electrical circuit. The fuse may be located upstream of the surge protector 10. When the surge protector 10 is working normally, the thermoplastic component 150 maintains a solid shape, which can restrict the position and movement of the contact component 15. The return spring 151 presses the contact component 15 onto the thermoplastic component 150, making it difficult for the contact component 15 to move. At this time, the input component 12 and the output component 13 are in an open circuit state, and the power frequency current cannot pass through, while the surge current can pass through the input component 12 and the varistor 14 to the output component 13, thus providing surge protection. Under normal voltage, the resistance of varistor 14 is relatively high, resulting in a small current flowing through surge protector 10, which can be considered an open circuit and has no impact on the operation of the electrical circuit. When the electrical circuit is struck by lightning, a momentary overvoltage is generated. The voltage across varistor 14 exceeds the varistor voltage, and the resistance of varistor 14 drops sharply. The surge current can then pass through input component 12, varistor 14, and output component 13, thereby dissipating the energy of the overvoltage and protecting the precision circuit downstream. When the overvoltage disappears, the resistance of varistor 14 returns to a high resistance state, waiting for the next protection action. When the varistor 14 is damaged, for example, after the surge protector 10 is subjected to multiple lightning surges, the varistor 14 is permanently damaged and becomes conductive. At this time, the varistor 14 continuously heats up due to the power frequency current, which affects the temperature of the thermocouple 150. When the temperature of the thermocouple 150 exceeds the melting point of the thermocouple 150, the thermocouple 150 gradually melts, that is, the thermocouple 150 changes from solid to liquid. The resistance preventing the contact 15 from moving disappears, and the reset spring 151 can push the contact 15 to move along the axial direction of the input 12 until the contact 15 abuts against the conductive step 110 and is electrically connected. The input 12 and the output 13 are mechanically and electrically connected through the contact 15, and a short circuit occurs between the input 12 and the output 13. This causes the line current to rise continuously, prompting the upstream fuse to trip and thus protect the entire current circuit. The product is designed with very low internal resistance. Even after the varistor 14 is short-circuited, it can still withstand a large current for a long time and can also provide surge protection for downstream equipment.

[0077] In existing surge protectors using fusible conductive elements, the fusible conductive element melts into a liquid state. Depending on the orientation of the surge protector, the liquid fusible conductive element flows towards the lowest point inside the casing, conforming to the principle of "water flowing downhill." This results in an uncertain and inconsistent contact area between the liquid fusible conductive element and either the first or second conductive electrode element. In practical use, this short-circuit method leads to instability in the current and voltage flowing through the current path due to variations in the contact area between the liquid fusible conductive element and the conductive components, resulting in different cross-sectional areas and volumes of the conductive path containing the fusible conductive element when the surge protector is oriented differently.

[0078] The surge protector 10 described in this application uses a mechanical structure to short-circuit the input element 12 and the output element 13. Specifically, the short circuit between the input element 12 and the output element 13 is achieved through a reset contact 15, which acts as a conductor, preventing current from flowing through the molten fuse 150. After the fuse 150 melts, the contact 15, under the action of the reset spring 151, firmly abuts against the conductive step 110. Regardless of the orientation of the surge protector 10, the contact area and contact stability between the contact 15 and the input element 12 or the output element 13 remain unaffected. The current and voltage passing through the contact 15 are very stable, resulting in better protection for precision equipment requiring downstream protection.

[0079] The above steps can be added, removed, modified, or their order adjusted as needed.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A surge protector, characterized in that, It includes an input component, an output component, and a contact component; the input component and the output component are separated by a varistor, the contact component is movably disposed on the input component, and a thermosetting component is disposed on the input component; The hot melt element confines the contact element to the initial position and opens the circuit between the input element and the output element. When the hot melt element melts, the contact element returns to the working position and the input element and the output element are electrically connected through the contact element.

2. The surge protector according to claim 1, characterized in that, The surge protector also includes a reset spring, which gives the contact a tendency to reset.

3. The surge protector according to claim 1, characterized in that, The contact element is slidably sleeved on the input element, and the hot melt element is sleeved on the input element and located on one side of the contact element.

4. The surge protector according to claim 1, characterized in that, The surge protector also includes a housing electrically connected to the output element, the housing having a conductive step configured to abut against and be electrically connected to the reset contact element.

5. The surge protector according to claim 4, characterized in that, The surge protector also includes an input cover and an insulating cover. The input cover is detachably connected to the first end of the housing, and the insulating cover is fitted onto the input component and insulates the input component from the housing.

6. The surge protector according to claim 5, characterized in that, The surge protector also includes two pressure plates sleeved on the input component and a disc spring located between the two pressure plates. An auxiliary step is provided on the input component, and the two pressure plates are located between the insulating cover and the auxiliary step.

7. The surge protector according to claim 4, characterized in that, The output component includes an output cover and an output end, and the output cover is detachably connected to the second end of the housing.

8. The surge protector according to claim 4, characterized in that, The conductive step divides the interior of the outer shell into a first cavity and a second cavity that are interconnected and have opposite openings. The first cavity is a stepped hole that is smaller on the outside and larger on the inside. The contact element is located in the first cavity and is adjacent to the conductive step.

9. The surge protector according to claim 1, characterized in that, The surge protector also includes a pressure plate, which is detachably disposed at one end of the input component and in contact with the varistor.

10. The surge protector according to claim 1, characterized in that, The input component is surrounded by several copper braided strips.

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