Electromagnetic system

Abstract

The electromagnetic system comprises a circuit board, a change-over switch, a static iron core, a movable iron core, a coil and a coil framework, the circuit board, the change-over switch and the static iron core are sequentially fixed in the base in the length direction of the base, the circuit board and the change-over switch are vertically inserted in the base, and the plane where the circuit board is located is perpendicular to a bottom plate of the base. The base is parallel to the side wall arranged in the width direction of the base; the static iron core is provided with an installation through cavity, the coil framework is arranged in the installation through cavity, at least part of the coil framework extends out of the installation through cavity in the width direction of the base, the part, extending out of the installation through cavity, of the coil framework is matched with the base in a limiting mode, the coil is wound on the coil framework, and the movable iron core is oppositely arranged above the static iron core. And at least part of the movable iron core extends into the through hole of the coil framework through the cavity opening. The electromagnetic system is simple in structure, compact and orderly in layout, small in overall size, fewer in parts, more convenient to install, beneficial to automatic assembly and capable of reducing cost and enhancing use convenience and performance reliability.

Description

TECHNICAL FIELD

[0001] The utility model relates to low voltage electrical apparatus field, concretely relates to a kind of electromagnetic system. BACKGROUND

[0002] Electromagnetic system is the key part in low voltage electrical apparatus, for example contactor, mainly for controlling the opening and closing of contact, to realize the on-off of control circuit.The existing electromagnetic system has the problems of complex structure, unreliable performance, many parts, inconvenient installation, etc. CONTENT OF UTILITY MODEL

[0003] The utility model aims at overcoming at least one defect of prior art, and provides an electromagnetic system.

[0004] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0005] Electromagnetic system, including circuit board, change-over switch, static core, moving core, coil and coil skeleton, coil includes starting winding and holding winding, circuit board is powered for coil through change-over switch, moving core triggers change-over switch to switch to only power supply for holding winding of coil after being attracted with static core, the circuit board, change-over switch and static core are sequentially fixed in the base along the length direction of base, the circuit board and change-over switch are respectively vertically inserted in the base, the plane where the circuit board is and the bottom plate of base are perpendicular, and parallel with the side wall arranged in the width direction of base;The static core is equipped with installation through cavity, the top wall of installation through cavity is equipped with cavity mouth, the coil skeleton is placed in installation through cavity, and the coil skeleton at least partially extends installation through cavity in the width direction of base, the part of coil skeleton extending installation through cavity is limited with base, the coil skeleton has through hole arranged along the height direction of base and penetrating coil skeleton, the coil is wound on coil skeleton, the moving core is oppositely arranged above static core, and the moving core at least partially extends into the through hole of coil skeleton through cavity mouth.

[0006] Optionally, it further includes buffer, the buffer is fixed on the outside of installation through cavity bottom wall of static core, the bottom plate of base is equipped with fixed slot, and the static core is fixed in fixed slot through buffer interference.

[0007] Optionally, the buffer is snap connected between base, the fixed slot is equipped with fixed buckle on the side wall, the top surface of buffer is equipped with fixed buckle matched with fixed buckle, and the fixed buckle is buckled in fixed buckle.

[0008] Optionally, the top surface of fixed buckle is equipped with guide inclined plane, and the bottom surface of buffer is equipped with matched inclined plane matched with fixed buckle and guide inclined plane.

[0009] Optionally, the static iron core is fixed with the buffer through a fixing shaft, the fixing shaft is arranged through the static iron core along the width direction of the base; the electromagnetic system is provided with two buffers, the two buffers are symmetrically arranged on the two sides of the static iron core, and the buffer is provided with a fixing hole matched with the fixing shaft.

[0010] Optionally, a supporting flange for supporting the static iron core is arranged on the side of the buffer facing the static iron core.

[0011] Optionally, the buffer is higher than the bottom wall of the installation through cavity, and a supporting plane for supporting the coil framework is arranged on the top of the buffer.

[0012] Optionally, the static iron core is a square frame structure, surrounds the installation through cavity, and the top edge frame of the static iron core is provided with the cavity opening, so that the top edge frame of the static iron core is divided into two limiting parts located on the two sides of the cavity opening, the limiting part limits the top surface of the coil framework, and the top surface of the coil framework is provided with a limiting boss, the limiting boss and the limiting part are limited and matched in the width direction of the base.

[0013] Optionally, the bottom plate of the base is respectively provided with at least two first limiting protrusions and at least two second limiting protrusions, the two first limiting protrusions are oppositely arranged along the length direction of the base, the two second limiting protrusions are oppositely arranged along the width direction of the base, and the coil framework is limited between the two first limiting protrusions and the two second limiting protrusions.

[0014] Optionally, a slot is horizontally arranged on one side of the top of the coil framework, and a wire outlet extending downward is arranged on the side wall of the slot.

[0015] Optionally, a limiting groove is arranged on the top surface of the coil framework.

[0016] Optionally, the bottom plate of the base is respectively provided with two limiting columns, the two limiting columns are oppositely arranged along the width direction of the base, the bottom of the change-over switch is limited between the two limiting columns, the plane where the change-over switch is located is parallel to the side wall arranged in the width direction of the base, the top of the change-over switch is provided with a driving part in the middle, the top of the change-over switch is provided with a top flange protruding outward away from the driving part on the two sides, the top flange is arranged on the limiting column, and the static iron core is switched to keep the winding power supply by pressing the driving part of the change-over switch.

[0017] Optionally, a limiting groove is arranged on the top surface of the limiting column, the top flange of the change-over switch is limited in the limiting groove in the length direction of the base; and / or, the top flange of the change-over switch is fixed on the limiting column through a fixing bolt.

[0018] Optionally, a reinforcing rib is arranged between the outer side of the limiting column and the bottom plate of the base.

[0019] The electromagnetic system of the utility model, vertical circuit board, vertical change-over switch and static core are fixed in base in turn, coil former with coil is installed in static core and cooperates with base limiting, moving core part above static core part extends into coil former, simple structure, compact and orderly layout, small overall volume, less parts, more convenient installation, beneficial to automatic assembly, can reduce cost, enhance use convenience and performance reliability; moreover, replace traditional circuit board and change-over switch and coil former connection, coil former is set separately with circuit board and change-over switch, simplify coil former structure, thereby realize smaller volume, reduce weight.

[0020] Moreover, the buffer on the static core and the fixed groove of the base are tightly matched by extrusion, the buffer plays a buffering and damping role on the static core, preventing the static core from shaking due to the impact of the moving core.

[0021] Moreover, the buffer plays a lower limiting role on the coil former, improving the installation stability of the coil former.

[0022] Moreover, the limiting part of the static core plays a role of upper limiting and horizontal limiting on the coil former, enabling the coil former to be quickly and stably installed in the installation cavity of the static core.

[0023] Moreover, the change-over switch is directly seated on the base in the vertical direction through the limiting column, is positioned through the limiting groove, and is fastened through the fixing bolt, improving the installation stability of the change-over switch and being beneficial to automatic assembly, wherein the automatic equipment can vertically insert and install the change-over switch and then automatically screw the bolt. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the assembly drawing of the electromagnetic system and the base of the utility model;

[0025] Figure 2 is the assembly drawing of the moving and static cores, the buffer and the coil former of the utility model;

[0026] Figure 3 is the exploded view of the moving and static cores, the buffer and the coil former of the utility model;

[0027] Figure 4 is the sectional view of the electromagnetic system and the base of the utility model;

[0028] Figure 5 is another sectional view of the electromagnetic system and the base of the utility model;

[0029] Figure 6 is the structural schematic view of the base of the utility model.

[0030] Circuit board 1; change-over switch 2; fixing bolt 20; top flange 21; static core 3; fixing shaft 30; mounting through cavity 31; cavity opening 32; limiting part 33; dynamic core 4; coil 5; coil skeleton 6; through hole 61; limiting boss 62; insertion slot 63; wire outlet 64; limiting recess 65; buffer 7; fixing clasp 71; matching inclined surface 72; fixing hole 73; supporting flange 74; base 8; fixing slot 81; fixing buckle 82; guide inclined surface 821; first limiting protrusion 83; second limiting protrusion 84; limiting stand 85; limiting slot 86; reinforcing rib 87. DETAILED DESCRIPTION

[0031] The following examples, given in conjunction with the accompanying drawings, further illustrate the specific embodiments of the electromagnetic system of the present application. The electromagnetic system of the present application is not limited to the descriptions of the following examples.

[0032] As shown in the drawings, Figure 1 Low-voltage electrical apparatus usually includes an electromagnetic system, and the low-voltage electrical apparatus can be a contactor or a circuit breaker. Taking the contactor as an example, the contactor usually includes a shell, an electromagnetic system installed in the shell, a contact support, and normally open contacts and / or normally closed contacts. Taking the normally open contacts as an example, the normally open contacts include oppositely arranged dynamic contacts and static contacts, and the shell usually includes a base, a base seat, and an upper cover which are sequentially stacked and fixed together. The electromagnetic system includes a circuit board 1, a change-over switch 2, a static core 3, a dynamic core 4, a coil 5, and a coil skeleton 6. The dynamic contacts are installed on the contact support, and the contact support is connected with the dynamic core 4 and is arranged to move synchronously. It should be noted that the working principle of the electromagnetic system is prior art. The coil 5 includes a starting winding and a holding winding, the circuit board 1 supplies power to the coil 5 through the change-over switch 2, and the dynamic core 4 triggers the change-over switch 2 to switch to supply power only to the holding winding of the coil 5 after being attracted to the static core 3, so as to reduce power consumption. When the circuit board 1 receives a voltage signal, the coil 5 is powered on, i.e., the starting winding is powered on or the starting winding and the holding winding are powered on at the same time, to drive the dynamic core 4 to move, so that the dynamic core 4 is attracted to the static core 3, thereby the dynamic core 4 synchronously drives the contact support, so that the dynamic contacts and the static contacts are in contact, i.e., the normally open contacts are closed, and at the same time, the dynamic core 4 gradually presses the change-over switch 2 in the process of being attracted to the static core 3, and after being attracted to the static core 3, the dynamic core 4 triggers the change-over switch 2 to switch to supply power only to the holding winding, without supplying power to the starting winding, so as to reduce the power consumption of the electromagnetic system. When the coil 5 is powered off, the return spring drives the dynamic core 4 to repel the static core 3, so that the dynamic core 4 synchronously drives the contact support, so that the dynamic contacts and the static contacts are separated, i.e., the normally open contacts are opened. The contactor can also be provided with only normally closed contacts, or can be provided with both normally open contacts and normally closed contacts. The normally closed contacts refer to the state that the coil 5 is powered on to open, and the coil 5 is powered off to close. This is prior art, and will not be described here.

[0033] In particular, as shown in the drawings, Figure 1 andFigure 2 As shown, the circuit board 1, the changeover switch 2, and the stationary iron core 3 are sequentially fixed within the base 8 along its length. The circuit board 1 and the changeover switch 2 are vertically inserted into the base 8. The plane of the circuit board 1 is perpendicular to the bottom plate of the base 8 and parallel to the side wall of the base 8 in the width direction. The stationary iron core 3 has a mounting cavity 31, and the top wall of the mounting cavity 31 has an opening 32. The coil frame 6 is placed within the mounting cavity 31, and at least part of the coil frame 6 extends out of the mounting cavity 31 in the width direction of the base 8. The portion of the coil frame 6 extending out of the mounting cavity 31 is fitted with the base 8. The coil frame 6 has a through hole 61 extending through the coil frame 6 along the height direction of the base 8. The coil 5 is wound on the coil frame 6. The moving iron core 4 is positioned above the stationary iron core 3, and at least part of the moving iron core 4 extends into the through hole 61 of the coil frame 6 through the opening 32. It should be noted that the length direction of the base 8 refers to... Figure 4 The width direction of base 8 refers to the vertical direction of the drawing. Figure 4 The left-right direction, the height direction of base 8 refers to Figure 4 Up and down direction.

[0034] In this embodiment of the electromagnetic system, the vertical circuit board 1, the vertical changeover switch 2, and the stationary iron core 3 are sequentially fixed inside the base 8. The coil frame 6, with the coil 5 wound around it, is installed inside the stationary iron core 3 and is positioned in a limiting fit with the base 8. The moving iron core 4, located above the stationary iron core 3, extends into the coil frame 6. The structure is simple, the layout is compact and orderly, the overall size is small, there are fewer parts, installation is more convenient, it is conducive to automated assembly, it can reduce costs, and enhance the convenience of use and the reliability of performance. Moreover, instead of the traditional circuit board 1 and changeover switch 2 being connected to the coil frame 6, the coil frame 6 in this embodiment is set separately from the circuit board 1 and changeover switch 2, simplifying the structure of the coil frame 6, thereby achieving a smaller size and reducing weight.

[0035] like Figures 2-4 As shown, the electromagnetic system of this embodiment also includes a buffer 7, which is fixed to the outer side of the bottom wall of the mounting cavity 31 of the stationary iron core 3. The base plate of the base 8 is provided with a fixing groove 81, and the stationary iron core 3 is interference-fitted into the fixing groove 81 by the buffer 7. The buffer 7 on the stationary iron core 3 and the fixing groove 81 of the base 8 are pressed tightly against each other, and the buffer 7 plays a role in buffering and shock absorption of the stationary iron core 3, preventing the stationary iron core 3 from shaking due to the impact of the moving iron core 4.

[0036] like Figures 2-4As shown, the buffer 7 is snap connected with the base 8, the side wall of the fixing groove 81 is provided with a fixing buckle 82, the top surface of the buffer 7 is provided with a fixing buckle 71 matched with the fixing buckle 82, and the fixing buckle 82 of the base 8 is buckled in the fixing buckle 71 of the buffer 7, that is, the fixing buckle 82 has an upper limiting effect on the buffer 7. The snap connection between the buffer 7 and the base 8 is convenient for installation and improves the stability of installation. Of course, the fixing buckle 82 and the fixing buckle 71 can also be interference fit, elastic clamping, etc.

[0037] Further, the top surface of the fixing buckle 82 is provided with a guide inclined surface 821, and the bottom surface of the buffer 7 is provided with a matching inclined surface 72 opposite to the fixing buckle 71 and matched with the guide inclined surface 821. The matching inclined surface 72 on the bottom surface of the buffer 7 is matched with the guide inclined surface 821 on the top surface of the fixing buckle 82, so that the buffer 7 can be more easily installed into the fixing groove 81 of the base 8.

[0038] As shown in Figure 2 and Figure 3 The fixing structure between the static iron core 3 and the buffer 7 of the embodiment is shown, the static iron core 3 is fixed with the buffer 7 through a fixing shaft 30, the fixing shaft 30 penetrates the static iron core 3 along the width direction of the base 8; the electromagnetic system is provided with two buffers 7, the two buffers 7 are symmetrically arranged on the two sides of the static iron core 3, the buffer 7 is provided with a fixing hole 73 matched with the fixing shaft 30, and the end of the fixing shaft 30 is inserted into the fixing hole 73. Through the cooperation of the fixing shaft 30 and the fixing hole 73 of the buffer 7, the installation guide effect is achieved, and the buffer 7 and the static iron core 3 are fixed together to ensure the close cooperation and installation with the base 8. The fixing shaft 30 of the embodiment is an independent shaft. Of course, as other embodiments, the fixing shaft 30 can also be integrally arranged with the static iron core 3.

[0039] As shown in Figure 3 The buffer 7 is a straight block structure arranged along the length direction of the base 8, and a supporting flange 74 for supporting the static iron core 3 is protruded on the side of the buffer 7 facing the static iron core 3.

[0040] As shown in Figure 2 and Figure 3 The buffer 7 is higher than the bottom wall of the installation through cavity 31, and the top of the buffer 7 is provided with a supporting plane for supporting the coil skeleton 6. The buffer 7 has a lower limiting effect on the coil skeleton 6, and improves the installation stability of the coil skeleton 6.

[0041] As shown in Figure 2As shown, the static core 3 is a square frame structure, which surrounds the installation through cavity 31. The top wall of the installation through cavity 31 refers to the top edge frame of the static core 3, the bottom wall of the installation through cavity 31 refers to the bottom edge frame of the static core 3, and the top edge frame of the static core 3 is provided with the cavity opening 32, so that the top edge frame of the static core 3 is divided into two limiting portions 33 located on both sides of the cavity opening 32, i.e. the two limiting portions 33 respectively protrude and extend from the top of the two sides of the static core 3 to the inside of the installation through cavity 31 and are spaced apart to form the cavity opening 32. The limiting portion 33 limits the top surface of the coil skeleton 6, and the top surface of the coil skeleton 6 is provided with a limiting boss 62, which is limited and matched with the limiting portion 33 in the width direction of the base 8. The limiting portion 33 of the static core 3 plays a positioning role of upper limiting and horizontal limiting for the coil skeleton 6, so that the coil skeleton 6 can be quickly and stably installed into the installation through cavity 31 of the static core 3.

[0042] As shown in Figure 2 As shown, the top side edge of the coil skeleton 6 is horizontally provided with a slot 63, and the side wall of the slot 63 is provided with a wire outlet 64 extending downward. The enameled wire is wound on the coil skeleton 6 to form the coil 5, and one end of the enameled wire is located in the slot 63 through the wire outlet 64, so that the coil skeleton 6 and the circuit board 1 are connected by the quick plug-in and pull-out connection of the terminal, and the terminal can be at least partially inserted into the slot 63 to realize contact with the coil 5 and realize electrical connection. The terminal can be sheet-shaped or needle-shaped, and the enameled wire extends out of the wire outlet 64 and is wound on the sheet-shaped or needle-shaped terminal, and the terminal is inserted into the slot 63.

[0043] As shown in Figure 2 As shown, the top surface of the coil skeleton 6 is provided with a limiting groove 65, the base is placed on the top surface of the coil skeleton 6, and the bottom surface of the base is provided with a limiting convex which is matched with the limiting groove 65. The limiting groove 65 is matched with the limiting convex to prevent the coil skeleton 6 from shaking up and down. Exemplarily, the limiting groove 65 is provided with four limiting grooves 65 which are distributed in four corners on the top surface of the coil skeleton 6; correspondingly, the limiting convex is provided with four limiting convexes.

[0044] As shown in Figure 6As shown, the horizontal limiting cooperation structure between the coil former 6 and the base 8 in the embodiment, the bottom plate of the base 8 is respectively provided with at least two first limiting protrusions 83 and at least two second limiting protrusions 84 which are upwardly protruded, the two first limiting protrusions 83 are oppositely arranged along the length direction of the base 8, the two second limiting protrusions 84 are oppositely arranged along the width direction of the base 8, and the coil former 6 is limited between the two first limiting protrusions 83 and the two second limiting protrusions 84. During installation, the coil former 6 is first limited by the lower buffer 7 and the upper static core 3 limiting part 33, so that the coil former 6 is tightly fixed with the buffer 7 and the static core 3 by mutual extrusion; and then the coil former 6 is integrally installed into the base 8. The arrangement of the first limiting protrusions 83 and the second limiting protrusions 84 prevents the coil former 6 from horizontally deviating, so as to improve the installation stability of the coil former 6 and ensure that the coil former 6 and the static core 3 are tightly assembled without loosening. Moreover, the coil former 6 is limited in the horizontal direction by the limiting protrusions on the base 8, and the coil former 6 does not need to be provided with a limiting structure, and the coil former 6 only has a simple winding column and a slot 63, so that the structure is simplified.

[0045] Preferably, the first limiting protrusion 83 is a boss structure; and the second limiting protrusion 84 is a column structure.

[0046] Illustratively, the bottom plate of the base 8 is respectively provided with four first limiting protrusions 83 and four second limiting protrusions 84 which are upwardly protruded, and every two first limiting protrusions 83 are oppositely arranged along the length direction of the base 8, and every two second limiting protrusions 84 are oppositely arranged along the width direction of the base 8.

[0047] As Figure 5 and Figure 6As shown, the mounting structure between the change-over switch 2 and the base 8 of the present embodiment, the bottom plate of the base 8 is respectively provided with two limiting columns 85 upwardly protruding, the two limiting columns 85 are oppositely arranged along the width direction of the base 8, the bottom of the change-over switch 2 is limited between the two limiting columns 85, the plane where the change-over switch 2 is located is parallel to the side wall of the base 8 arranged in the width direction, that is, the length direction of the change-over switch 2 is arranged along the width direction of the base 8, the height direction of the change-over switch 2 is arranged along the height direction of the base 8, and the width (thickness) direction of the change-over switch 2 is arranged along the length direction of the base 8, the middle of the top of the change-over switch 2 is provided with a driving part, the two sides of the top of the change-over switch 2 are provided with top flanges 21 protruding outwardly away from the driving part, the top flanges 21 of the change-over switch 2 are lapped on the limiting columns 85, and the moving iron core 4 switches the signal of the change-over switch 2 by pressing down the driving part of the change-over switch 2. The change-over switch 2 is convenient to install and replace. When the coil 5 is energized, the moving iron core 4 is driven to move, the moving iron core 4 is attracted to the static iron core 3, the moving iron core 4 synchronously drives the contact support to move, the moving iron core 4 presses down the driving part of the change-over switch 2 to make the change-over switch 2 switch the signal, and the power supply from the starting winding to the coil 5 is switched to the power supply only to the holding winding, thereby reducing the power consumption of the electromagnetic system.

[0048] Further, the top surface of the limiting column 85 is provided with a limiting groove 86, the top flange 21 of the change-over switch 2 is limited in the limiting groove 86 in the length direction of the base 8; and the top flange 21 of the change-over switch 2 is fixed on the limiting column 85 by the fixing bolt 20. The change-over switch 2 is directly seated on the base 8 in the vertical direction of the limiting column 85, is positioned by the limiting groove 86, and is fastened by the fixing bolt 20, thereby improving the installation stability of the change-over switch 2 and being beneficial to automatic assembly, that is, the change-over switch is vertically inserted and assembled by the automatic equipment, and then the bolt is automatically screwed. Of course, the fixing of the change-over switch 2 can also use the limiting buckle and the pressing sheet. The limiting and fixing structure between the change-over switch 2 and the base 8 of the present embodiment can be the limiting groove 86 matched with the top flange 21, or the fixing bolt 20 can be arranged to fix the top flange 21 on the limiting column 85, or the limiting groove 86 and the fixing bolt 20 are arranged at the same time.

[0049] Preferably, the outer side of the limiting column 85 and the bottom plate of the base 8 are provided with a reinforcing rib 87 to reinforce the limiting column 85 and prevent the limiting column 85 from deforming. Of course, the reinforcing rib 87 can also be connected between the outer side of the limiting column 85 and the side wall of the base 8.

[0050] It should be noted that in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings or the orientation or positional relationship commonly used in use, and are only for the convenience of description, and do not indicate that the device or element referred to must have a particular orientation, so it cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation in description, and cannot be understood as indicating relative importance.

[0051] The above is a further detailed description of the present application in combination with specific preferred embodiments, and the specific implementation of the present application cannot be limited to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, which should be considered as falling within the scope of protection of the present application.

Claims

1. An electromagnetic system comprising a circuit board (1), a changeover switch (2), a stationary iron core (3), a moving iron core (4), a coil (5), and a coil frame (6), wherein the coil (5) comprises a starting winding and a holding winding, the circuit board (1) supplies power to the coil (5) via the changeover switch (2), and the moving iron core (4), after engaging with the stationary iron core (3), triggers the changeover switch (2) to switch to supply power only to the holding winding of the coil (5), characterized in that: The circuit board (1), the changeover switch (2), and the stationary iron core (3) are sequentially fixed inside the base (8) along the length of the base (8). The circuit board (1) and the changeover switch (2) are vertically inserted into the base (8). The plane of the circuit board (1) is perpendicular to the bottom plate of the base (8) and parallel to the side wall of the base (8) in the width direction. The stationary iron core (3) is provided with a mounting cavity (31). The top wall of the mounting cavity (31) is provided with an opening (32). The coil frame (6) is placed inside the mounting cavity (31), and the coil... The coil frame (6) extends at least partially out of the mounting cavity (31) in the width direction of the base (8). The portion of the coil frame (6) extending out of the mounting cavity (31) is matched with the base (8). The coil frame (6) has a through hole (61) that extends through the coil frame (6) along the height direction of the base (8). The coil (5) is wound on the coil frame (6). The moving iron core (4) is positioned above the stationary iron core (3), and the moving iron core (4) extends at least partially into the through hole (61) of the coil frame (6) through the cavity (32).

2. The electromagnetic system according to claim 1, characterized in that: It also includes a buffer (7), which is fixed on the outer side of the bottom wall of the mounting cavity (31) of the stationary iron core (3). The base plate of the base (8) is provided with a fixing groove (81), and the stationary iron core (3) is interference-fixed in the fixing groove (81) by the buffer (7).

3. The electromagnetic system according to claim 2, characterized in that: The buffer (7) is snapped together with the base (8). The side wall of the fixing groove (81) is provided with a fixing buckle (82). The top surface of the buffer (7) is provided with a fixing slot (71) that cooperates with the fixing buckle (82). The fixing buckle (82) is fastened in the fixing slot (71).

4. The electromagnetic system according to claim 3, characterized in that: The top surface of the fixing buckle (82) is provided with a guide slope (821), and the bottom surface of the buffer (7) is provided with a mating slope (72) that is opposite to the fixing buckle (71) and cooperates with the guide slope (821).

5. The electromagnetic system according to claim 2, characterized in that: The stationary iron core (3) is fixed to the buffer (7) by a fixed shaft (30), and the fixed shaft (30) is set through the stationary iron core (3) along the width direction of the base (8); the electromagnetic system is provided with two buffers (7), which are symmetrically arranged on both sides of the stationary iron core (3), and the buffers (7) are provided with fixing holes (73) that cooperate with the fixed shaft (30).

6. The electromagnetic system according to claim 2, characterized in that: The buffer (7) has a support flange (74) protruding on the side facing the stationary iron core (3) for supporting the stationary iron core (3).

7. The electromagnetic system according to claim 2, characterized in that: The buffer (7) is higher than the bottom wall of the mounting cavity (31), and the top of the buffer (7) is provided with a support plane for supporting the coil frame (6).

8. The electromagnetic system according to claim 1 or 7, characterized in that: The stationary iron core (3) is a square frame structure that surrounds the mounting cavity (31). The top edge of the stationary iron core (3) is provided with the cavity opening (32), which divides the top edge of the stationary iron core (3) into two limiting parts (33) located on both sides of the cavity opening (32). The limiting part (33) limits the top surface of the coil frame (6), and the top surface of the coil frame (6) is provided with a limiting boss (62). The limiting boss (62) and the limiting part (33) are in a limiting fit in the width direction of the base (8).

9. The electromagnetic system according to claim 1, characterized in that: The base plate of the base (8) is provided with at least two first limiting protrusions (83) and at least two second limiting protrusions (84) that protrude upwards respectively. The two first limiting protrusions (83) are arranged opposite each other at intervals along the length direction of the base (8), and the two second limiting protrusions (84) are arranged opposite each other at intervals along the width direction of the base (8). The coil frame (6) is located between the two first limiting protrusions (83) and the two second limiting protrusions (84).

10. The electromagnetic system according to claim 1, characterized in that: The top side of the coil frame (6) is provided with a slot (63) and the side wall of the slot (63) is provided with a downwardly extending outlet (64).

11. The electromagnetic system according to claim 1, characterized in that: The top surface of the coil frame (6) is provided with a limiting groove (65).

12. The electromagnetic system according to claim 1, characterized in that: The base plate of the base (8) has two limiting columns (85) that protrude upwards. The two limiting columns (85) are arranged opposite each other at intervals along the width direction of the base (8). The bottom of the changeover switch (2) is limited between the two limiting columns (85). The plane of the changeover switch (2) is parallel to the side wall of the base (8) in the width direction. The top center of the changeover switch (2) has a driving part. The top two sides of the changeover switch (2) have top flanges (21) that protrude outwards away from the driving part. The top flanges (21) rest on the limiting columns (85). The moving iron core (4) switches the changeover switch (2) to keep the winding powered by pressing down the driving part of the changeover switch (2).

13. The electromagnetic system according to claim 12, characterized in that: The top surface of the limiting column (85) is provided with a limiting groove (86), and the top flange (21) of the changeover switch (2) is located in the limiting groove (86) at the upper limit of the length direction of the base (8); and / or, the top flange (21) of the changeover switch (2) is fixed to the limiting column (85) by a fixing bolt (20).

14. The electromagnetic system according to claim 12, characterized in that: A reinforcing rib (87) is provided between the outer side of the limiting column (85) and the bottom plate of the base (8).

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