Nonlinear compensation adjusting device for bimetallic strip of low-voltage switch thermal magnetic release

Abstract

This invention discloses a bimetallic strip nonlinear compensation and adjustment device for a thermomagnetic trip unit in low-voltage switches, relating to the field of electrical switch technology. It aims to solve the technical problem of bimetallic strip thermomagnetic trip units lacking effective compensation and adjustment mechanisms for nonlinear characteristics and factors such as ambient temperature. This invention achieves basic nonlinear compensation by using an outer arched inclined surface to suppress false tripping under slight overload; it ensures stable conduction by relying on M-shaped contacts and an elastic protection mechanism; it uses a hook-shaped positioning component to achieve mechanical forced reset, avoiding elastic fatigue and position drift, thus improving long-term reliability; it uses a circular arc-shaped fault-tolerant sidewall to prevent false disconnection caused by minor rotation, further enhancing protection stability; and finally, it uses a temperature-adaptive component to achieve full-temperature adaptive compensation, eliminating the interference of ambient temperature on tripping characteristics. The device progressively solves the problems of easy false tripping and insufficient compensation in existing trip units, significantly improving protection accuracy and reliability.

Description

Technical Field

[0001] This invention relates to the field of electrical switch technology, and more specifically, to a bimetallic strip nonlinear compensation adjustment device for a thermomagnetic trip unit used in low-voltage switches. Background Technology

[0002] The thermal-magnetic trip unit is a core protection component of low-voltage switches (such as circuit breakers). It achieves overload protection through the thermal expansion characteristics of a bimetallic strip. With its simple structure and high reliability, it is widely used in low-voltage power distribution systems such as industrial power distribution, building electrical systems, and equipment control. When an overload occurs in the circuit, the heat generated by the overload current causes the bimetallic strip to bend, pushing the tripping mechanism to disconnect the circuit and protect the load equipment and lines. It is a crucial link in ensuring the stable operation of the power distribution system.

[0003] However, existing bimetallic thermal-magnetic trip units commonly suffer from the problem of "thermal tripping malfunction," meaning that the trip unit will unnecessarily trigger tripping when the circuit encounters a slight, brief overload. This malfunction arises from the combined effects of multiple factors: First, the bimetallic strip itself has nonlinear characteristics; its bending amount and temperature rise are not linearly related. When approaching the operating current threshold, even a small temperature rise can cause the bending amount to increase sharply, quickly approaching the tripping position. Second, significant environmental temperature interference occurs. High temperatures in summer and poor ventilation in distribution cabinets can cause the initial temperature of the bimetallic strip to be higher. Combined with the temperature rise caused by a slight overload, this can easily reach the tripping threshold. Third, the influence of transient current surges: the brief surge current generated when a motor starts or the load suddenly increases, although short in duration, can cause the bimetallic strip to rapidly generate a temperature rise "step," which, when combined, triggers malfunctioning tripping.

[0004] Such false tripping caused by minor, transient overloads can lead to unplanned power outages, disrupting production lines and machine rooms, resulting in economic losses and delays. Frequent false tripping exacerbates the aging and damage of equipment such as motors and transformers; increases maintenance costs; and easily leads to safety hazards caused by human error in short-circuiting protection. It also affects the electricity experience for residents and interferes with the stable operation of the power grid and related equipment. Essentially, thermal tripping malfunctions are a functional imbalance caused by the "oversensitivity" of the protection mechanism. Existing bimetallic thermal-magnetic trip units lack effective compensation and adjustment mechanisms for factors such as nonlinear characteristics and ambient temperature, making it impossible to accurately distinguish between "minor, transient overloads" and "continuous overloads," and difficult to balance protection sensitivity and operational reliability. In view of this, we propose a bimetallic nonlinear compensation and adjustment device for thermal-magnetic trip units used in low-voltage switches. Summary of the Invention

[0005] The purpose of this invention is to provide a bimetallic strip nonlinear compensation and adjustment device for a low-voltage switch thermomagnetic trip unit, so as to solve the technical problem that the bimetallic strip thermomagnetic trip unit lacks nonlinear characteristics and has an effective compensation and adjustment mechanism for factors such as ambient temperature.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a bimetallic strip nonlinear compensation adjustment device for a low-voltage switch thermomagnetic trip unit, comprising a thermistor conductive strip made of bimetallic material, wherein a hook-off torsion portion is provided on one side of the thermistor conductive strip, one end of the thermistor conductive strip is provided as an outward arched section, a snap-fit ​​joint extends from one side of the outward arched section, the snap-fit ​​joint is provided as an L-shaped structure protruding in the outward arched direction of the outward arched section, one inclined surface of the snap-fit ​​joint contacts an external contact, and one side of the snap-fit ​​joint extends as an inner pressure section; A protruding block is installed on the outer periphery of the unhooking twisting part. A conductive part is provided at one end of the protruding block. An intermediate contact piece is provided between the conductive part and the inner pressure section. The intermediate contact piece is rotatably connected to the outer shell. The two ends of the intermediate contact piece connect the inner pressure section and the conductive part.

[0007] Preferably, the outer arch section is a curved design facing the direction of the external contact. Under normal operating conditions, the external contact contacts the end of the inclined surface on one side of the snap-fit ​​joint. During the initial stage of the overload bending deformation of the thermal conductive sheet, the external contact moves along the inclined surface on one side of the snap-fit ​​joint.

[0008] Preferably, the intermediate contact piece has an overall M-shaped structure, and the intermediate contact piece consists of a center point and two bent sections. The two bent sections are in contact with the inner pressure section and the conductive part, respectively, and the center point is the rotation point.

[0009] Preferably, a protective mechanism extends from one side of the intermediate contact piece. The protective mechanism includes a pressure-bearing section fixed to a bending section away from the conductive part. An extension section is connected to one side of the pressure-bearing section, and an inner top section is connected to one side of the extension section. The end of the inner top section is rotatably connected to the outer housing.

[0010] Preferably, the inner top section has a curved arch shape, the arched part of the inner top section fits into the snap-fit ​​joint, and both the inner top section and the pressure-bearing section are elastic.

[0011] Preferably, a positioning hook is provided between the internal pressure section and the pressure-receiving section, and the positioning hook is composed of a first hook and a second component.

[0012] Preferably, the first hook is fixed to the pressure section, and the second component is connected to the inner pressure section. Both the first hook and the second component are hook-shaped structures. Under normal operating conditions, the first hook and the second component engage with each other to constrain the position of the thermal conductive sheet and the protection mechanism.

[0013] Preferably, the conductive part includes a fault-tolerant sidewall, the fault-tolerant sidewall being an arc centered on the center point, and a temperature difference adapting component is also provided at one end of the fault-tolerant sidewall. Under overload conditions, the inner pressure section moves along the pressure section and bends against the pressure bending section, causing the temperature difference adapting component to rotate.

[0014] Preferably, the temperature difference adapting component includes a pressure plate, one end of which is rotatably connected to the protrusion, and a temperature difference plate is connected between one side of the pressure plate and the protrusion. The temperature difference plate is made of a material that can deform under the influence of temperature.

[0015] Preferably, the temperature difference sheet has a multi-bend shape.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes the outer arch of the thermistor to engage with the inclined surface of the L-shaped snap-fit ​​joint. During the initial stages of slight overload and minor deformation, the external contacts slide along the inclined surface, maintaining circuit continuity. This effectively avoids unnecessary tripping caused by brief, minor overloads, addressing the "oversensitivity" problem caused by the nonlinear bending of the bimetallic strip at its source. This design can accurately distinguish between slight, brief overloads and continuous overloads, significantly improving operational reliability while ensuring protection sensitivity. It avoids economic losses and accelerated aging caused by unplanned power outages and frequent equipment start-ups and shutdowns, providing more stable overload protection support for low-voltage power distribution systems.

[0017] 2. This invention employs an M-shaped intermediate contact piece in conjunction with an elastic protection mechanism. The pressure-bearing section adheres to the deformation trajectory of the inner pressure section, absorbing minute displacement deviations and preventing separation or disconnection between the inner pressure section and the intermediate contact piece. The arched inner top section deforms synchronously with the thermistor conductive sheet, providing flexible support and constraint, suppressing fatigue creep caused by long-term operation. The M-shaped structure achieves adaptive rotation with the center point as the fulcrum, and the bent sections at both ends always maintain reliable contact, ensuring stable circuit conduction throughout the entire process. This solves problems such as poor contact, displacement interference, and fatigue failure during deformation, significantly improving the continuous operation stability of the device.

[0018] 3. This invention achieves mechanical engagement and constraint between the thermal conductive sheet and the protection mechanism through a hook-shaped positioning hook. During normal operation, the initial position is locked. After overload is eliminated, the engagement force between the second component and the first hook drives the compressed section and the inner top section to synchronously and accurately reset. This reset method no longer relies solely on the elastic element to recover on its own. Through mechanical positioning, the inner top section is forced to return to a uniform pre-compression state, avoiding fatigue failure and position drift caused by long-term elastic reciprocating motion. This ensures consistent support and constraint effect after each reset, significantly extending the service life of the mechanism and improving long-term operational accuracy and reliability.

[0019] 4. The present invention provides an arc-shaped fault-tolerant sidewall with the rotation center of the middle contact piece as the reference in the conductive part, providing sufficient space for the bending section to move and avoid collision. When the thermistor conductive piece produces a slight displacement deviation, causing the middle contact piece to rotate slightly, the fault-tolerant sidewall can prevent the bending section from directly pushing the conductive part and causing contact breakage, ensuring that the circuit continues to conduct under slight overload. This design further enhances the nonlinear compensation effect, eliminates the risk of disconnection caused by displacement deviation and elastic deformation, and enables the device to maintain stable operation under complex working conditions and after long-term use, thus comprehensively improving the consistency of protection.

[0020] 5. This invention uses multiple curved temperature difference plates to form a temperature difference adaptable component, achieving adaptive adjustment of the lever arm through pure mechanical deformation: at high temperatures, the lever arm contracts to reduce its thrust and suppress premature action of the thermistor; at low temperatures, the lever arm expands to increase its thrust and compensate for insufficient bending. The multiple curved structure improves the compensation amplitude and adjustment accuracy, and can accurately offset the influence of ambient temperature on the tripping characteristics across the entire temperature range. This allows the device to maintain a stable tripping threshold in complex scenarios such as high-temperature cabinets and low-temperature outdoor environments. This design decouples nonlinear compensation and temperature compensation, truly balancing sensitivity and reliability, and comprehensively solving the core problem of the lack of compensation mechanisms in existing trip devices. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall layout structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention under normal operating conditions; Figure 3 This is a schematic diagram of the structure of the thermistor conductive sheet in this invention; Figure 4 This is a schematic diagram of the connection structure between the thermistor conductive sheet and the intermediate contact sheet in this invention; Figure 5 For the present invention Figure 4 Enlarged schematic diagram of the structure at point A; Figure 6 This is a schematic diagram of the connection structure between the protection mechanism and the intermediate contact piece in this invention; Figure 7 For the present invention Figure 2 Enlarged schematic diagram of the structure at point B; Figure 8 This is a schematic diagram of the mating structure between the protrusion and the conductive part in this invention; Figure 9 This is a schematic diagram of the structure of the present invention under slight overload conditions; Figure 10 For the present invention Figure 9 Enlarged schematic diagram of the structure at point C.

[0022] Explanation of the labels in the diagram: 1. Thermistorically conductive sheet; 101. Outer arch section; 102. Snap-fit ​​joint; 103. Inner pressure section; 2. Unhooking torsion part; 3. Protrusion block; 4. Conductive part; 401. Fault-tolerant sidewall; 42. Temperature difference adapting component; 421. Pressure plate; 422. Temperature difference plate; 5. Intermediate contact piece; 501. Center point; 502. Bend joint section; 6. Protection mechanism; 601. Pressure plate; 602. Extension section; 603. Inner top section; 7. Positioning hook; 701. First hook; 702. Second component. Detailed Implementation

[0023] like Figures 1 to 10 As shown, the present invention relates to a bimetallic strip nonlinear compensation adjustment device for a low-voltage switch thermomagnetic trip unit, comprising a thermistor conductive sheet 1 made of bimetallic material, a hook-off torsion part 2 provided on one side of the thermistor conductive sheet 1, an outer arch section 101 at one end of the thermistor conductive sheet 1, a snap-fit ​​joint 102 extending from one side of the outer arch section 101, the snap-fit ​​joint 102 being an L-shaped structure protruding in the outward arch direction of the outer arch section 101, an inclined surface on one side of the snap-fit ​​joint 102 contacting an external contact, and an inner pressure section 103 extending from one side of the snap-fit ​​joint 102.

[0024] The outer arch section 101 is a curved design facing the direction of the external contact. Under normal operating conditions, the external contact contacts the end of the inclined surface on one side of the snap-fit ​​joint 102. When the thermal conductive sheet 1 is in the initial stage of overload bending deformation, the external contact moves along the inclined surface on one side of the snap-fit ​​joint 102. A protruding block 3 is installed on the outer periphery of the unhooking torsion part 2. A conductive part 4 is provided at one end of the protruding block 3. An intermediate contact piece 5 is provided between the conductive part 4 and the inner pressure section 103. The intermediate contact piece 5 is rotatably connected to the outer shell. The two ends of the intermediate contact piece 5 connect the inner pressure section 103 and the conductive part 4.

[0025] Working principle: During normal operation, the external contacts maintain stable contact with the inclined end of the L-shaped snap-fit ​​joint 102 on the thermistor conductive sheet 1, and the circuit is in a conductive state. When the circuit experiences a slight overload, the bimetallic thermistor conductive sheet 1 begins to bend and deform due to heat. Since the outer arch section 101 adopts an arc design facing the external contacts, the outer arch section 101 preferentially generates arc displacement in the initial stage of deformation, driving the snap-fit ​​joint 102 to move synchronously. At this time, the external contacts slide along the inclined surface of the snap-fit ​​joint 102, always maintaining contact and conduction with the inclined surface. It will not disconnect due to the initial slight bending of the thermistor conductive sheet 1. Through the arc guidance of the outer arch section 101 and the cooperation of the inclined surface of the snap-fit ​​joint 102, the circuit is maintained in the initial stage of slight overload and slight deformation, effectively avoiding accidental tripping or disconnection caused by brief and slight overload, and realizing the initial compensation for the nonlinear bending characteristics of the bimetallic sheet.

[0026] Furthermore, during the deformation process, the internal pressure section 103 of the aforementioned thermistor 1 may separate from the intermediate contact piece 5, and under long-term operation, the thermistor 1 is prone to fatigue. In order to ensure the stability of conduction, the above-mentioned thermistor 1 is designed to address this issue.

[0027] The intermediate contact 5 has an overall M-shaped structure. The intermediate contact 5 consists of a center point 501 and two bent sections 502. The two bent sections 502 are in contact with the inner pressure section 103 and the intermediate contact 5, respectively. The center point 501 is the center of rotation. A protective mechanism 6 extends from one side of the intermediate contact 5. The protective mechanism 6 includes a pressure-bearing section 601 fixed to the bent section 502 away from the conductive part 4. An extension section 602 is connected to one side of the pressure-bearing section 601. An inner top section 603 is connected to one side of the extension section 602. The end of the inner top section 603 is rotatably connected to the outer shell. The inner top section 603 has a curved arch shape. The arched part of the inner top section 603 fits with the snap-fit ​​joint 102. Both the inner top section 603 and the pressure-bearing section 601 are elastic. The pressure-bearing section 601 is made of a conductive elastic material. The inclined surface of the pressure-bearing section 601 has the same trajectory as the deformation and stretching movement of the inner pressure section 103, and they remain in contact during the deformation process.

[0028] The pressure-bearing section 601 is preferably made of phosphor bronze alloy (containing 4-7% Sn, elastic modulus 110-130 GPa, conductivity ≥15% IACS). The pressure-bearing section 601 is provided with a guide slope with an angle of 15-30 degrees to the horizontal direction and a length of 5-10 mm. The end of the inner pressure section 103 moves along the guide slope and maintains elastic contact. The surface roughness of the slope is Ra0.8-1.6 μm to ensure controllable friction coefficient and long-term contact stability.

[0029] Working principle: Under slight overload conditions, the thermal conductive sheet 1 bends due to heat. The deformation of its outer arch section 101 causes the snap-fit ​​joint 102 and the inner pressure section 103 to move synchronously. The inner pressure section 103 first comes into contact with the pressure section 601 made of conductive elastic material in the protection mechanism 6, moves along its inclined trajectory and maintains stable contact. The elastic deformation of the pressure section 601 can absorb the small displacement deviation of the thermal conductive sheet 1, preventing the inner pressure section 103 from separating from the bent section 502 of the intermediate contact piece 5. When there is a normal overload, the inner pressure section 103 will contact the bent section 502, realizing normal disconnection.

[0030] Meanwhile, the inner top section 603 of the protection mechanism 6 is a curved arched elastic structure, and its arch is in contact with the snap-fit ​​joint 102. Under normal conditions, the inner top section 603 is in contact with the snap-fit ​​joint 102 to ensure the positional stability of the thermal conductive sheet 1. When an overload occurs, the inner top section 603 will be stretched by the bent section 502 to match the deformation of the thermal conductive sheet 1. During the overload process, the inner top section 603 moves synchronously and the arch becomes smaller, so that the situation of pressing against the snap-fit ​​joint 102 will not occur, thus maintaining the stability of the initial working state. The M-shaped structure of the middle contact piece 5 takes the center point 501 as the rotation fulcrum, and the bent sections 502 at both ends form reliable contact with the inner pressure section 103 and the conductive part 4, respectively. The elastic guidance of the pressure section 601 and the elastic constraint of the inner top section 603 work together to ensure that the circuit is always conductive during the entire deformation process, effectively avoiding the risk of disconnection caused by the displacement deviation of the inner pressure section 103 or the fatigue of the thermal conductive sheet 1, and improving the operational stability and reliability.

[0031] Furthermore, although the above achieves the reset constraint of the thermistor 1, fatigue may still occur in the inner top section 603. To address this, a positioning hook 7 is provided between the inner pressure section 103 and the pressure-bearing section 601. The positioning hook 7 consists of a first hook 701 and a second component 702. The first hook 701 is fixed to the pressure-bearing section 601, and the second component 702 is connected to the inner pressure section 103. Both the first hook 701 and the second component 702 are hook-shaped structures. Under normal operating conditions, the first hook 701 and the second component 702 engage with each other to constrain the position of the thermistor 1 and the protection mechanism 6.

[0032] Working principle: Under normal operating conditions, the first hook 701 and the second component 702 of the positioning hook 7 are mutually engaged, constraining the position of the thermal conductive sheet 1 and the protection mechanism 6, ensuring the initial contact position of the inner pressure section 103 and the pressure-bearing section 601 is stable. When the circuit overload is eliminated, the temperature of the thermal conductive sheet 1 drops and it begins to reset, driving the second component 702 to move synchronously. During the reset process, the second component 702 and the first hook 701 automatically engage, and the tension of the mechanical engagement pulls the pressure-bearing section 601 to move, thereby driving the inner top section 603 to reset and compress synchronously, so that the inner top section 603 always returns to the initial pre-compression state. This reset process no longer relies solely on the self-recovery of the elastic element, but uses the mechanical positioning of the hook-shaped engagement structure to force the inner top section 603 to return to the same position each time, avoiding positional drift due to long-term elastic reset fatigue, ensuring that the support and constraint of the protection mechanism 6 on the thermal conductive sheet 1 remains stable after reset, effectively solving the elastic fatigue problem of the inner top section 603 and improving the long-term reliability of the mechanism.

[0033] Furthermore, to address the issue of tripping instability caused by differences in the sensitivity of the thermistor 1 under different ambient temperatures, this structure achieves dual compensation through a fault-tolerant sidewall 401 and a temperature-adaptive component 42. Specifically, the conductive part 4 includes a fault-tolerant sidewall 401, which is an arc centered at point 501. A temperature-adaptive component 42 is also provided at one end of the fault-tolerant sidewall 401. Under overload conditions, the inner pressure section 103 moves along the pressure-bearing section 601 and bends against the bending section 502, causing the temperature-adaptive component 42 to rotate.

[0034] The temperature difference adapting component 42 includes a pressure plate 421, one end of which is rotatably connected to the protrusion 3. A temperature difference plate 422 is connected between one side of the pressure plate 421 and the protrusion 3. The temperature difference plate 422 is made of a material that can deform under temperature influence. The temperature difference plate 422 has a multi-bending shape. The multi-bending shape of the temperature difference plate 422 can increase the degree of deformation and further improve the torsion angle of the pressure plate 421.

[0035] An example of a thermocouple 422 is given here: The thermocouple 422 is one or more pieces made of nickel-titanium alloy (NiTi, phase transformation temperature 70°C) or high expansion coefficient alloy (such as Fe-Ni-Cr alloy, with a linear expansion coefficient of 18×10⁻). 6 The multi-layered curved member made of / K contains multiple continuous S-shaped bends, each with a radius of curvature of R2mm to R5mm and a total length of 15-25mm. When the temperature rises from -20℃ to +60℃, the deformation of the temperature difference plate 422 is 0.5-1.2mm. This deformation causes the pressure plate 421 to generate an effective torsion angle of 3-8 degrees through leverage, thereby achieving mechanical compensation for the driving arm of the thermistor conductive plate 1.

[0036] Specific embodiment: When the intermediate contact 5 undergoes a slight rotation around the center point 501, the fault-tolerant sidewall 401 adopts an arc surface design centered on the center point 501, providing space for the bending section 502 to avoid direct push of the conductive part 4 by the slight displacement deviation of the thermal conductive sheet 1, thus preventing circuit malfunction and ensuring stable conduction under slight overload. Secondly, the temperature difference adapting component 42 automatically adjusts the lever arm compensation according to the ambient temperature. In high-temperature environments, the thermal differential plate 422 contracts due to heat, causing the pressure plate 421 to rotate clockwise by 1-3 degrees around its rotational connection point with the protrusion 3. This shortens the force application point of the pressure plate 421 on the bent section 502 by 2-4 mm towards the center point 501, thus shortening the horizontal distance (i.e., the lever arm) between the force application point and the rotation center point 501. Since torque = force × lever arm, with the pushing force generated by the bending of the thermal conductive sheet 1 remaining basically unchanged, the reduction in lever arm leads to a reduction in the actual torque applied to the intermediate contact piece 5, thereby suppressing the trip unit from prematurely actuating due to high temperature. Conversely, in low-temperature environments, the thermal differential plate 422 expands, causing the pressure plate 421 to rotate counterclockwise, increasing the lever arm and increasing the actual torque to compensate for the insufficient pushing torque caused by insufficient bending of the thermal conductive sheet 1 at low temperatures.

[0037] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A nonlinear compensation and adjustment device for a bimetallic strip in a low-voltage switch thermomagnetic trip unit, comprising a thermistor (1) made of bimetallic material, wherein a tripping torsion part (2) is provided on one side of the thermistor (1), characterized in that, One end of the thermal conductive sheet (1) is provided as an outer arch section (101), and a snap-fit ​​joint (102) extends from one side of the outer arch section (101). The snap-fit ​​joint (102) is provided as an L-shaped structure protruding outward from the outer arch section (101). One side of the snap-fit ​​joint (102) is in contact with an external contact point, and one side of the snap-fit ​​joint (102) extends as an inner pressure section (103). A protruding block (3) is installed on the outer periphery of the unhooking twisting part (2). A conductive part (4) is provided at one end of the protruding block (3). An intermediate contact piece (5) is provided between the conductive part (4) and the inner pressure section (103). The intermediate contact piece (5) is rotatably connected to the outer shell. The two ends of the intermediate contact piece (5) connect the inner pressure section (103) and the conductive part (4). The outer arch section (101) is a curved design facing the direction of the external contact. Under normal operating conditions, the external contact is in contact with the end of the inclined side of the snap-fit ​​joint (102). When the thermal conductive sheet (1) is in the initial stage of overload bending deformation, the external contact moves along the inclined side of the snap-fit ​​joint (102). The intermediate contact (5) has an overall M-shaped structure. The intermediate contact (5) consists of a center point (501) and two bent sections (502). The two bent sections (502) are in contact with the inner pressure section (103) and the conductive part (4) respectively. The center point (501) is the center of the rotation point. A protective mechanism (6) extends from one side of the intermediate contact (5). The protective mechanism (6) includes a pressure section (601) fixed to a bending section (502) in the direction away from the conductive part (4). An extension section (602) is connected to one side of the pressure section (601). An inner top section (603) is connected to one side of the extension section (602). The end of the inner top section (603) is rotatably connected to the outer shell. The inner top section (603) is in the shape of a curved arch. The arched part of the inner top section (603) fits into the snap joint (102). Both the inner top section (603) and the pressure section (601) are elastic. A positioning hook (7) is provided between the internal pressure section (103) and the pressure-bearing section (601), and the positioning hook (7) is composed of a first hook (701) and a second component (702).

2. The bimetallic strip nonlinear compensation adjustment device for a low-voltage switch thermomagnetic trip unit according to claim 1, characterized in that, The first hook (701) is fixed to the pressure section (601), and the second component (702) is connected to the internal pressure section (103). The first hook (701) and the second component (702) are hook-shaped structures that can hook each other. Under normal operating conditions, the first hook (701) and the second component (702) hook each other to further constrain the position of the thermal conductive sheet (1) and the protection mechanism (6).

3. The bimetallic strip nonlinear compensation adjustment device for a low-voltage switch thermomagnetic trip unit according to claim 2, characterized in that, The conductive part (4) includes a fault-tolerant sidewall (401), which is an arc centered on the center point (501). A temperature difference adaptor (42) is also provided at one end of the fault-tolerant sidewall (401). Under overload conditions, the internal pressure section (103) moves along the pressure section (601) and bends against the bending section (502) to cause the temperature difference adaptor (42) to rotate.

4. The bimetallic strip nonlinear compensation and adjustment device for a low-voltage switch thermomagnetic trip unit according to claim 3, characterized in that, The temperature difference adapting component (42) includes a pressure plate (421), one end of which is rotatably connected to the protrusion (3), and a temperature difference plate (422) is connected between one side of the pressure plate (421) and the protrusion (3). The temperature difference plate (422) is made of a material that can deform under the influence of temperature.

5. The bimetallic strip nonlinear compensation adjustment device for a low-voltage switch thermomagnetic trip unit according to claim 4, characterized in that, The temperature difference plate (422) has a multi-bend shape.

Images