Magnetic latching relay suitable for high temperature working conditions

Abstract

The present invention discloses a magnetic latching relay adapted to high temperature working conditions, wherein a static contact is arranged on a static contact mounting plate, and a moving contact mounting plate is also included, a moving spring lead-out pin is arranged on the moving contact mounting plate, a push piece is movably arranged at the middle end of the moving contact mounting plate, an outer lining spring, a middle lining spring, and a moving spring piece are arranged between the push piece and the moving spring lead-out pin, and a moving contact matching the static contact is arranged on the outer lining spring; the present invention also includes a magnetic steel rotating shaft combination and an electromagnetic drive component, the electromagnetic drive component includes a wire package, an upper yoke and a lower yoke are respectively fixed at both ends of the wire package, an upper bimetallic sheet is welded on the free end of the upper yoke, and a lower bimetallic sheet is welded on the free end of the lower yoke; the free ends of the upper yoke and the lower yoke are matched with the magnetic steel rotating shaft combination, and the magnetic steel rotating shaft combination is matched with the push piece. The magnetic latching relay of the present invention can adapt to high temperature working conditions and overcome the possibility of failure of opening and closing the switch caused by temperature rise.

Description

Technical Field

[0001] The invention relates to the field of intelligent electric meter equipment, and in particular to a magnetic latching relay adapted to high temperature working conditions. Background Art

[0002] Magnetic latching relays are widely used in smart meters. The development direction of magnetic latching relays is miniaturization, low power consumption, and large load capacity. When the meter receives the switch-on and switch-off instructions, it is necessary to output a 100mS amplitude 9V or 12V DC pulse signal to the magnetic latching relay coil. By changing the direction of the pulse signal, the dynamic and static contacts of the relay are attracted and separated. The number of coils is fixed, so the driving relay contact attraction and separation depends on the instantaneous current passing through the coil. Since the coil is wound by enameled copper wire, there is a certain resistance. The commonly used 9V magnetic latching relay coil resistance is about 48Ω at room temperature 23℃, and the 12V magnetic latching relay coil resistance is about 96Ω at room temperature 23℃. However, the resistance of the enameled wire coil will increase with the increase of temperature, and decrease with the decrease of temperature.

[0003] Existing magnetic latching relays have the following defects: the electromagnetic force weakens under high temperature conditions, resulting in an increase in the amplitude of the driving voltage for opening and closing the switch, and in special circumstances, the opening and closing of the switch fails. Summary of the invention

[0004] The object of the present invention is to provide a magnetic latching relay adapted to high temperature working conditions, wherein the magnetic latching relay can adapt to high temperature working conditions and overcome the possibility of failure of opening and closing the switch due to temperature rise.

[0005] To achieve the above object, the scheme of the present invention is: a magnetic latching relay adapted to high temperature working conditions, comprising a static contact mounting plate, on which a static contact is arranged, and a moving contact mounting plate, on which a moving spring lead-out pin is arranged, a push piece is movably arranged at the middle end of the moving contact mounting plate, an outer lining spring, a middle lining spring, and a moving spring piece are arranged between the push piece and the moving spring lead-out pin, and a moving contact matching the static contact is arranged on the outer lining spring;

[0006] It also includes a magnetic steel rotating shaft combination and an electromagnetic drive component, wherein the electromagnetic drive component includes a coil (500), and an upper yoke and a lower yoke are respectively fixed at both ends of the coil (500), an upper bimetallic sheet is welded to the free end of the upper yoke, and a lower bimetallic sheet is welded to the free end of the lower yoke; the free ends of the upper yoke and the lower yoke match the magnetic steel rotating shaft combination, and the magnetic steel rotating shaft combination matches the push sheet.

[0007] Permanent magnetic steel is placed inside the magnetic steel rotating shaft assembly.

[0008] One end of the wire-wrapped enameled wire is welded to the plug pin, and the other end is welded on the plug pin.

[0009] The static contact is riveted on the static contact mounting plate, the dynamic contact is riveted with the outer lining spring and the inner lining spring and the dynamic spring piece, one end of the push piece is fixed on the magnetic steel shaft assembly, and the other end is provided with a push force slot, and the end of the outer lining spring and the inner lining spring and the dynamic spring piece is arranged in the push force slot. The swing of the magnetic steel shaft assembly drives the static contact and the dynamic contact to contact and separate.

[0010] The upper bimetallic sheet and the lower bimetallic sheet are both bimetallic sheets bent into a U-shaped clip structure, and the clip arm close to the side of the wire package is integrally welded to the yoke iron. The inner layer of the U-shaped clip is set as an active layer, and the outer layer is set as a passive layer, that is, the thermal expansion coefficient of the inner layer is greater than the thermal expansion coefficient of the outer layer. Since the expansion coefficients of the inner layer and the outer layer are different, the expansion coefficient of the inner layer is higher than that of the outer layer after heating, which will cause deformation and bending outward.

[0011] According to the technical solution of the present invention, under normal temperature conditions, there is a non-contact state between the upper bimetallic strip and the magnetic steel shaft assembly, and between the lower bimetallic strip and the pusher strip, that is, a certain gap is provided respectively.

[0012] Under working conditions above 70°C, the upper bimetallic strip bends toward the magnetic steel shaft; the lower bimetallic strip bends toward the pusher strip; this can partially offset the magnetic steel's suction force and offset the increase in the coil drive voltage caused by the temperature.

[0013] The present invention adds two bimetallic strips which are respectively welded on the upper and lower yokes. At room temperature, there is a certain gap between the bimetallic strips and the magnetic steel shaft and the pusher. When the temperature rises to a high temperature of 70°C, the bimetallic strips bend toward the magnetic steel shaft and the pusher to offset a portion of the magnetic steel's suction force. As the temperature rises, the coil resistance increases, the attraction and separation voltages increase accordingly. The bimetallic strips can offset the voltage change caused by the temperature. The upper bimetallic strip reduces the high-temperature switch-on pulse voltage, and the lower bimetallic strip reduces the high-temperature switch-on pulse voltage, which greatly reduces the possibility of failure due to high-temperature switch-on and switch-on voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a contact closed state structure diagram of the magnetic latching relay adapted to high temperature working conditions of the present invention;

[0015] Figure 2 It is a structural diagram of the contact disconnected state of the magnetic latching relay adapted to high temperature working conditions of the present invention;

[0016] Figure 3 This is a structural diagram of the bimetallic strip welded to the yoke in the present invention;

[0017] Figure 4 It is the structural diagram of the bimetallic strip in the present invention;

[0018] Figure 5 It is a cross-sectional structural diagram of the magnetic steel rotating shaft assembly in the present invention;

[0019] Figure 6 It is a schematic diagram of the conversion of the moving and static contacts of the magnetic latching relay adapted to high temperature working conditions from closed to open state of the present invention;

[0020] Figure 7 The present invention is a schematic diagram of the transition from an open state to a closed state of the moving and static contacts of a magnetic latching relay adapted to high temperature working conditions. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is clearly and completely explained below in conjunction with the accompanying drawings. The described embodiments are only a part of the present invention. Based on the key points of the present invention, all other inventions and creations obtained by those skilled in the art without making any creative work are within the scope of protection of the present invention.

[0022] like Figures 1 to 7 As shown, the magnetic latching relay adapted to high temperature working conditions of the present invention comprises a static contact mounting plate 10, on which a static contact 101 is arranged, and also comprises a moving contact mounting plate 20, on which a moving spring lead-out pin 204 is arranged, and a push piece 600 is movably arranged at the middle end of the moving contact mounting plate 20, and an outer lining spring 201, a middle lining spring 202, and a moving spring piece 203 are arranged between the push piece 600 and the moving spring lead-out pin 204, and a moving contact 200 matching the static contact 101 is arranged on the outer lining spring 201;

[0023] It also includes a magnetic steel shaft assembly 300 and an electromagnetic drive component 5, wherein the electromagnetic drive component includes a coil (500), and an upper yoke 501 and a lower yoke 502 are respectively fixed at both ends of the coil (500), an upper bimetallic strip 400 is welded to the free end of the upper yoke 501, and a lower bimetallic strip 401 is welded to the free end of the lower yoke 502; the free ends of the upper yoke 501 and the lower yoke 502 are matched with the magnetic steel shaft assembly 300, and the magnetic steel shaft assembly 300 is matched with the push piece 600.

[0024] Permanent magnets are placed inside the magnet shaft assembly 300 .

[0025] One end of the enameled wire of the wire package 500 is welded to the pin 504 , and the other end is welded to the pin 505 .

[0026] The static contact 101 is riveted on the static contact mounting plate 10, the dynamic contact 200 is riveted together with the inner lining spring 202 and the dynamic spring piece 203 of the outer lining spring 201, one end of the push piece 600 is fixed on the magnetic steel shaft assembly 300, and the other end is provided with a push force slot, and the end of the dynamic spring piece 203 of the inner lining spring 202 of the outer lining spring 201 is provided in the push force slot. The swing of the magnetic steel shaft 300 drives the static contact 101 to contact and separate with the dynamic contact 200.

[0027] like Figure 4 It can be seen that the upper bimetallic strip 400 and the lower bimetallic strip 401 are bimetallic strips bent into a U-shaped clip structure, wherein the inner layer is set as an active layer 420 and the outer layer is set as a passive layer 421, that is, the thermal expansion coefficient of the inner layer is greater than the thermal expansion coefficient of the outer layer. Since the expansion coefficients of the inner and outer layers are different, the expansion coefficient of the inner layer is higher than that of the outer layer after heating, which will cause deformation and bending outward. The U-shaped clip is clamped on the upper yoke 501 and the lower yoke 502 respectively, and the clamp arm on the side close to the wire package 500 is integrally welded to the yoke, and the clamp arm on the side away from the wire package is matched with the yoke gap, so that the far side has deformation conditions under high temperature conditions.

[0028] According to the technical solution of the present invention, under normal temperature conditions, the upper bimetallic strip 400 and the magnetic steel shaft assembly 300, and the lower bimetallic strip 401 and the pusher strip 600 are in a non-contact state, that is, a certain gap is provided respectively.

[0029] Under working conditions above 70°C, the upper bimetallic strip 400 bends toward the magnetic steel shaft; the lower bimetallic strip 401 bends toward the pusher strip 600, which can partially offset the magnetic steel's suction force and offset the increase in the coil drive voltage caused by the temperature.

[0030] When the coil (500) flows into the plug pin 504 through the positive pulse signal and flows out through the plug pin 505, the energized coil generates an electromagnetic field, with the N pole at the top and the S pole at the bottom of the electromagnetic field. Due to the principle of like poles repelling each other, when the repulsive force is greater than the permanent magnetic attraction of the magnetic steel shaft assembly 300, the magnetic steel shaft assembly 300 swings and separates, driving the moving spring 203, the middle lining spring 202, and the outer lining spring 201 to move, so that the static contact 101 is separated from the moving contact 200; when The coil (500) flows into the plug pin 505 through the negative pulse signal and flows out through the plug pin 504. The energized coil generates an electromagnetic field, with the S pole at the top and the N pole at the bottom. Due to the principle of like poles repelling each other, when the repulsive force is greater than the permanent magnetic attraction of the magnetic steel shaft assembly 300, the magnetic steel shaft assembly 300 swings and separates, driving the moving spring 203, the middle lining spring 202, and the outer lining spring 201 to move inward, so that the static contact 101 contacts the moving contact 200.

[0031] The coil is the power part of the relay. The coil current is changed by applying a voltage at both ends of the coil, thereby changing the size of the electromagnetic force. The magnetic attraction on the magnetic shaft assembly 300 remains basically unchanged within a temperature range of 70°C, but the coil resistance increases continuously with the increase in temperature. There is a conversion formula Rt=R20[1+(T℃-20℃)×0.04]. The coil resistance usually refers to the resistance at 20°C. Therefore, the coil resistance increases at high temperatures, which reduces the current flowing through the coil at the same voltage, and the electromagnetic force is also reduced. To overcome the permanent magnetic force of the magnetic shaft assembly 300, the coil excitation voltage needs to be increased accordingly.

[0032] In order to overcome the above problem, the upper bimetallic strip 400 and the lower bimetallic strip 401 are welded on the upper yoke 501 and the lower yoke 502 respectively. Figure 6 As shown, at room temperature, there is a certain gap between the bimetallic strip and the outer shell of the magnetic steel shaft assembly 300, which does not affect the size of the permanent magnetic force. However, when the temperature rises, due to the inconsistency between the expansion coefficients of the inner and outer layers of the bimetallic strip, the expansion coefficient of the inner layer is higher than that of the outer layer, so that the bimetallic strip bends and deforms toward the magnetic steel shaft assembly 300, which can offset a part of the permanent magnetic force. In this way, the resistance of the coil increases as the temperature rises, and the contact state can be switched from closed to open without increasing the excitation voltage applied to the coil.

[0033] When the moving and static contacts are in the separated state, Figure 7 As shown, at room temperature, there is a certain gap between the bimetallic strip 401 and the pusher strip 600, which does not affect the size of the permanent magnetic force. However, when the temperature rises, the expansion coefficients of the inner and outer layers of the bimetallic strip are inconsistent, and the expansion coefficient of the inner layer is higher than that of the outer layer, so that the bimetallic strip bends and deforms toward the pusher strip 600, which can offset a part of the permanent magnetic force. In this way, the resistance of the coil increases as the temperature rises, and the contact state can be switched from open to closed without increasing the excitation voltage applied to the coil.

[0034] The above descriptions are merely embodiments of the present invention and do not constitute any limitation to the present invention. Any simple modifications, changes and equivalent method variations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A magnetic latching relay adapted to high temperature working conditions, comprising a static contact mounting plate (10), on which a static contact (101) is arranged, and a moving contact mounting plate (20), on which a moving spring lead-out pin (204) is arranged, characterized in that: A push piece (600) is movably provided at the middle end of the moving contact mounting plate (20), an outer lining spring (201), a middle lining spring (202), and a moving spring piece (203) are provided between the push piece (600) and the moving spring lead-out pin (204), and a moving contact (200) matching the static contact (101) is provided on the outer lining spring (201); It also comprises a magnetic steel rotating shaft assembly (300) and an electromagnetic drive assembly (5), wherein the electromagnetic drive assembly comprises a coil (500), an upper yoke (501) and a lower yoke (502) are respectively fixed at two ends of the coil (500), an upper bimetallic sheet (400) is welded to the free end of the upper yoke (501), and a lower bimetallic sheet (401) is welded to the free end of the lower yoke (502); the free ends of the upper yoke (501) and the lower yoke (502) are matched with the magnetic steel rotating shaft assembly (300), and the magnetic steel rotating shaft assembly (300) is matched with the push sheet (600); The upper bimetallic sheet (400) and the lower bimetallic sheet (401) are both bimetallic sheets bent into a U-shaped clamp structure, the clamp arm on the side close to the wire package (500) is integrally welded to the yoke, and the inner layer of the U-shaped clamp is set as an active layer, and the outer layer is set as a passive layer.

2. The magnetic latching relay adapted to high temperature working conditions according to claim 1, characterized in that: The static contact (101) is riveted to the static contact mounting plate (10), the dynamic contact (200) is riveted to the outer lining spring (201) and the inner lining spring (202) and the dynamic spring sheet (203), one end of the push sheet (600) is fixed to the magnetic steel shaft assembly (300), and the other end is provided with a push force slot, and the end of the dynamic spring sheet (203) of the inner lining spring (202) of the outer lining spring (201) is arranged in the push force slot.

3. The magnetic latching relay adapted to high temperature working conditions according to claim 1, characterized in that: Under normal temperature conditions, the upper bimetallic sheet (400) and the magnetic steel rotating shaft assembly (300), and the lower bimetallic sheet (401) and the pushing sheet (600) are in a non-contact state.

4. The magnetic latching relay adapted to high temperature working conditions according to claim 1, characterized in that: Under working conditions above 70°C, the upper bimetallic strip (400) bends towards the direction of the magnetic steel shaft; and the lower bimetallic strip (401) bends towards the direction of the push strip (600).

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