Load switch

Abstract

A load switch relates to the technical field of low-voltage apparatuses. The load switch comprises a housing and a shielding cover sleeved outside the housing. The shielding cover is provided with at least four shielding surfaces, and the at least four shielding surfaces are sequentially connected end to end to form a frame-shaped structure; at least one shielding surface is provided with a slot arranged along the sleeving direction; the shell is provided with a limiting convex rib in a protruding mode, and the limiting convex rib corresponds to the open groove so as to be matched with the open groove in a limiting mode. The shielding cover of the load switch improves the capability of resisting external magnetic field interference of the load switch, improves the reliability of action, reduces the manufacturing difficulty, saves the cost, and is convenient to disassemble and assemble.

Description

Technical Field

[0001] This utility model relates to the field of low-voltage electrical technology, and more specifically, to a load switch. Background Technology

[0002] As a key component of load switches, magnetic shielding covers mainly perform the functions of electric field guidance and insulation protection. By optimizing the electric field distribution, they can effectively suppress partial discharge and block external electromagnetic interference to internal electromagnetic components, thus ensuring the stability of equipment operation.

[0003] In existing technologies, shielding covers mostly adopt a slender cylindrical structure, which is formed by stamping metal sheets and then installed on the outer wall of the switch housing. However, under assembly or mechanical vibration conditions, the shielding cover is prone to radial inward shrinkage deformation, resulting in an abnormally small assembly gap between it and the inner wall of the housing. This, in turn, squeezes the internal rotating mechanism, seriously affecting the mechanical life and operational reliability of the load switch. Furthermore, existing shielding covers mostly use an interference fit method for fixing with shaft holes, which requires special tools for disassembly. This reduces the efficiency of assembly or maintenance during assembly or replacement, and the disassembly process can easily damage the switch housing or magnetic shielding cover. Utility Model Content

[0004] The purpose of this utility model is to provide a load switch whose shielding cover is easy to install and remove and improves the load switch's ability to resist external magnetic field interference, thereby improving the mechanical life and operational reliability of the load switch while reducing manufacturing difficulty.

[0005] The embodiments of this utility model are implemented as follows:

[0006] In one aspect, this utility model provides a load switch, including a housing and a shielding cover sleeved on the outside of the housing; the shielding cover has at least four shielding surfaces, which are connected in sequence to form a frame structure; at least one shielding surface has a slot; the housing is provided with a limiting rib, which is correspondingly provided with the slot to cooperate with the slot for limiting.

[0007] Optionally, both the slot and the limiting rib extend along the sleeve direction; the inner wall of the slot is recessed with an arc-shaped structure, and the side wall of the limiting rib is correspondingly recessed with an arc-shaped protrusion, which can be locked in the arc-shaped structure; or, the inner wall of the slot is protruded with an arc-shaped protrusion, and the side wall of the limiting rib is correspondingly recessed with an arc-shaped structure, which can be locked in the arc-shaped structure.

[0008] Optionally, the slot extends through the shielding surface along the sleeve direction.

[0009] Optionally, at least one end of the slot along the sleeve direction is provided with a disassembly notch, the width of which is greater than the thickness of the limiting rib.

[0010] Optionally, the housing has an armature rotating mechanism, and the housing has a clearance groove at a position corresponding to the rotation axis of the armature rotating mechanism. The clearance groove is located on the side of the housing facing the shield.

[0011] Optionally, a guide portion is provided at the end of the limiting rib along the sleeve direction, and the guide portion has guide slopes on opposite sides along the sleeve direction of the limiting rib.

[0012] Optionally, the end of the guide slope along the sleeve direction is provided with an arc transition surface.

[0013] Optionally, the number of arc-shaped protrusions is at least one pair, and the pair of arc-shaped protrusions are symmetrically distributed around the central axis of the limiting rib, and are respectively located on both sides of the outer wall of the limiting rib along the sleeve direction or on both sides of the inner wall of the slot along the sleeve direction; when the number of arc-shaped protrusions is multiple pairs, the multiple pairs of arc-shaped protrusions are evenly distributed on the side wall of the limiting rib or evenly distributed on the inner wall of the slot.

[0014] Optionally, a coil assembly is provided inside the housing, the axial direction of the coil assembly is parallel to the extending direction of the limiting rib, and the limiting rib is located on the outside of the housing near the coil assembly.

[0015] Optionally, the housing includes a main body and a shielding mating part connected to each other; the connection between the main body and the shielding mating part forms a stepped structure, the shielding cover is fitted onto the outer wall of the shielding mating part, the top of the shielding cover is flush with the top of the main body, and the side wall of the shielding cover can abut against the vertical surface of the stepped structure, so that the shielding cover and the main body form a continuous outer contour of equal height along the setting direction.

[0016] Optionally, the shielding cover is a stamped part of magnetically conductive metal.

[0017] The beneficial effects of this utility model include:

[0018] This application provides a load switch, including a housing and a shielding cover fitted outside the housing. The shielding cover has at least four shielding surfaces, which are connected sequentially to form a frame structure. The shielding surfaces can more effectively block electromagnetic interference from electric arcs on the mechanical components, optimize the electric field distribution, and further ensure the stability of equipment operation. At least one shielding surface has a slot, which gives the shielding cover a certain elastic deformation capability. The slot can expand or contract elastically as needed, better adapting to different assembly conditions and minor dimensional changes that may occur during operation. The housing has protruding limiting ribs, which are correspondingly arranged with the slots to cooperate with the slots for limiting, thereby precisely controlling the expansion degree of the shielding cover and ensuring a suitable assembly gap between the shielding cover and the housing. This avoids both excessively small gaps that squeeze the internal rotating mechanism and excessively large gaps that affect the shielding effect, thus improving the overall stability and reliability of the load switch structure. At the same time, the assembly of the load switch is achieved by the snap-fit ​​between the slots and the limiting ribs, which is easier to disassemble and assemble than the hole-shaft fit of the prior art. The shielding cover of the aforementioned load switch improves the load switch's ability to resist external magnetic field interference, enhances the reliability of its operation, reduces manufacturing difficulty, saves costs, and facilitates disassembly and assembly. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 One of the structural schematic diagrams of the load switch provided in the embodiment of this utility model;

[0021] Figure 2 A schematic diagram of the structure of the shielding cover of the load switch provided in this embodiment of the utility model;

[0022] Figure 3 A schematic diagram of the housing of the load switch provided in an embodiment of this utility model;

[0023] Figure 4 This is a magnified view of the details at point A;

[0024] Figure 5 The second schematic diagram of the load switch provided in this embodiment of the utility model.

[0025] Icons: 100-Load switch; 110-Housing; 110a-Main body; 110b-Shielding mating part; 111-Limiting rib; 1111-Arc-shaped protrusion; 1112-Guide part; 1112a-Guide slope; 1112b-Circular transition surface; 112-Alignment groove; 120-Shielding cover; 121-Shielding surface; 122-Slot; 1221-Arc-shaped structure; 1222-Disassembly / assembly notch. Detailed Implementation

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

[0027] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] Please refer to Figure 1This embodiment provides a load switch 100, including a housing 110 and a shield 120 sleeved on the outside of the housing 110; the shield 120 has at least four shielding surfaces 121, which are connected in sequence to form a frame structure; at least one shielding surface 121 has a slot 122; the housing 110 is provided with a limiting rib 111, which is correspondingly provided with the slot 122 to limit and cooperate with the slot 122.

[0031] Specifically, the load switch 100 includes a housing 110 and a shielding cover 120. The shielding cover 120 has at least four shielding surfaces 121, such as... Figure 1 and Figure 2 As shown, the shielding cover 120 includes four shielding surfaces 121, which are connected in sequence to form a frame structure. It can be fitted onto the outer periphery of the housing 110 and affixed to at least a portion of the four outer walls of the housing 110. The shielding cover 120 is a magnetically conductive metal stamping part.

[0032] Existing shielding covers are prone to radial inward shrinkage deformation under assembly or mechanical vibration conditions, resulting in an abnormally small assembly gap between the shielding cover and the inner wall of the housing, which in turn squeezes the internal rotating mechanism. To solve the above problems and improve the reliability and service life of the load switch 100, the shielding cover 120 of this application has at least one shielding surface 121 with a slot 122 arranged along the sleeve direction. Correspondingly, the housing 110 has a limiting rib 111 that is adapted to the shape and position of the slot 122. When the shielding cover 120 is sleeved on the outside of the housing 110, the inner wall of the slot 122 can contact the side wall of the limiting rib 111, so that the shielding cover 120 has a certain elastic deformation capacity and expands outward due to the action of the side wall of the limiting rib 111, which facilitates installation and ensures that a suitable assembly gap is maintained between the shielding cover 120 and the housing 110. This avoids squeezing the internal rotating mechanism due to an excessively small gap and prevents the shielding effect from being affected by an excessively large gap, thereby improving the overall stability and reliability of the load switch 100.

[0033] Preferably, a coil assembly is provided inside the housing 110. The axial direction of the coil assembly is parallel to the extension direction of the limiting rib 111. The limiting rib 111 is located on the outside of the housing 110 near the coil assembly, so as to correspond to the position of the coil assembly. By optimizing the electric field distribution, partial discharge is effectively suppressed, thereby improving the reliability and safety of the load switch 100.

[0034] This limiting and matching method further enhances the stability of the shielding cover 120 after installation, making it less prone to displacement or shaking during operation, thus ensuring the effective realization of its functions such as electric field guidance, insulation protection, and electromagnetic interference blocking. At the same time, it also plays a certain role in positioning the shielding cover 120, facilitating quick and accurate installation of the shielding cover 120 into the correct position during the installation process.

[0035] It should be noted that, in one possible implementation of this application, firstly, as... Figure 2 and Figure 3 As shown, both the slot 122 and the limiting rib 111 extend along the sleeve direction, so that the shield 120 will naturally expand outward under the action of the limiting rib 111 during tooling, and can also guide the assembly of the shield 120; the inner wall of the slot 122 is recessed with an arc-shaped structure 1221, and the side wall of the limiting rib 111 is correspondingly protruded with an arc-shaped protrusion 1111, which can be locked in the arc-shaped structure 1221 to facilitate the limiting of the shield 120 after tooling is completed.

[0036] Of course, besides the above settings, such as Figure 5 As shown, the present application may also provide an arc-shaped protrusion 1111 on the inner wall of the slot 122, and an arc-shaped structure 1221 correspondingly recessed on the side wall of the limiting rib 111, and the arc-shaped protrusion 1111 can be locked in the arc-shaped structure 1221.

[0037] Preferably, the arc-shaped protrusion 1111 has a semi-circular structure, and the depth of the arc-shaped structure 1221 is adapted to the protrusion height of the arc-shaped protrusion 1111. Of course, the protrusion height of the arc-shaped protrusion 1111 can be adjusted according to actual needs to adjust the assembly stability of the shielding cover 120 and the housing 110 and the ease of assembly and disassembly.

[0038] The interlocking of the arc-shaped structure 1221 and the arc-shaped protrusion 1111 makes the connection between the limiting rib 111 and the slot 122 more stable, which can effectively prevent the shielding cover 120 from sliding or displacing unexpectedly, and further improve the stability of the shielding cover 120 after installation.

[0039] In addition, the arc-shaped structure 1221 can make the stress distribution more uniform. When the shield 120 is subjected to external force, such as vibration or electromagnetic force during the operation of the load switch 100, the arc-shaped structure 1221 can evenly distribute the force to the entire contact surface, reduce stress concentration, thereby reducing the risk of damage to the shield 120 and the housing 110 due to excessive local stress and extending the service life of the load switch 100.

[0040] Furthermore, such as Figure 3As shown, there is at least one pair of arc-shaped protrusions 1111. Each pair of arc-shaped protrusions 1111 is symmetrically distributed vertically along the central axis of the limiting rib 111, and is located on either side of the outer wall of the limiting rib 111 along the sleeve direction or on either side of the inner wall of the slot 122 along the sleeve direction. This ensures that the limiting force on both sides of the shield 120 is uniform and symmetrical when it is sleeved onto the housing 110, preventing tilting or displacement due to uneven force, thus ensuring a more stable installation on the housing 110 and improving the stability and accuracy of the shield 120 installation. When there are multiple pairs of arc-shaped protrusions 1111, these pairs are evenly distributed on the side walls of the limiting rib 111 or on the inner wall of the slot 122. By providing multiple pairs of arc-shaped protrusions 1111, the shield 120 can be limited and supported at more locations, making the connection between the shield 120 and the housing 110 tighter and more stable.

[0041] Furthermore, the housing 110 includes a main body portion 110a and a shielding mating portion 110b connected to each other; the connection between the main body portion 110a and the shielding mating portion 110b forms a stepped structure, and the shielding cover 120 is fitted onto the outer wall of the shielding mating portion 110b. The top end of the shielding cover 120 is flush with the top end of the main body portion 110a, so that the shielding cover 120 and the main body portion 110a form a continuous outer contour of equal height along the setting direction. With this arrangement, the connection between the main body 110a and the shielding mating part 110b forms a stepped structure, meaning the height of the shielding mating part 110b is less than the height of the main body 110a. This reduces the overall size of the load switch 100, facilitating miniaturization. Furthermore, the sidewall of the shielding cover 120 can be directly abutted against the vertical surface of the stepped structure as needed, allowing the main body 110a and the stepped structure to limit the final installation position of the shielding cover 120 during its installation on the outside of the shielding mating part 110b. In addition, the shielding cover 120 is fitted onto the outside of the shielding mating part 110b. Compared to the prior art where the shielding cover 120 completely covers all four sides of the load switch 100, this application only covers the shielding mating part 110b where the armature rotation mechanism is located, which is easily affected by external magnetic sources. This ensures the load switch 100's ability to resist external magnetic field interference while also reducing manufacturing difficulty and saving manufacturing costs.

[0042] The aforementioned load switch 100 includes a housing 110 and a shielding cover 120 sleeved on the outside of the housing 110. The shielding cover 120 has at least four shielding surfaces 121, which are connected in sequence to form a frame structure. The shielding surfaces 121 can more effectively block electromagnetic interference from electric arcs on the mechanical components, optimize the electric field distribution, and further ensure the stability of equipment operation. At least one shielding surface 121 has a slot 122. The slot 122 allows the shielding cover 120 to have a certain elastic deformation capability. The slot 122 can elastically expand or contract as needed, which can better adapt to different assembly conditions and possible changes during operation. The minor dimensional changes that occur are addressed by the fact that the housing 110 has a protruding limiting rib 111, which corresponds to the slot 122 and engages with it for precise control over the expansion of the shielding cover 120. This ensures a suitable assembly gap between the shielding cover 120 and the housing 110, preventing both excessively small gaps from compressing the internal rotating mechanism and excessively large gaps from affecting the shielding effect. This improves the overall stability and reliability of the load switch 100. Furthermore, the assembly of the load switch 100 is achieved through the snap-fit ​​connection between the slot 122 and the limiting rib 111, which is easier to assemble and disassemble compared to the hole-shaft fit of existing technologies. The shielding cover 120 of the load switch 100 enhances the load switch 100's resistance to external magnetic field interference, improves operational reliability, reduces manufacturing difficulty, saves costs, and facilitates assembly and disassembly.

[0043] For example, in one specific embodiment of this application, such as Figure 1 As shown, Figure 2 As shown, the slot 122 penetrates the shielding surface 121 along the sleeve direction, making the slot 122 a through-hole structure. This design reduces the installation difficulty of the shielding cover 120, improves assembly efficiency, and also facilitates the radial elastic expansion of the shielding cover 120 under the action of the limiting rib 111. Since the slot 122 penetrates the shielding surface 121, it causes the shielding cover 120 to produce uniform elastic deformation, achieving radial expansion; in another specific embodiment of this application, the depth of the slot 122 is less than the width of the shielding surface 121, and the width direction is the sleeve direction of the shielding cover 120.

[0044] Optionally, such as Figure 2 As shown, in order to facilitate the installation and removal of the shielding cover 120, at least one end of the slot 122 along the sleeve direction is provided with a disassembly notch 1222, and the width of the disassembly notch 1222 is greater than the thickness of the limiting rib 111.

[0045] During installation, because the width of the disassembly notch 1222 is greater than the thickness of the limiting rib 111, the limiting rib 111 can more easily enter the slot 122 from the notch, allowing the shielding cover 120 to be more smoothly fitted onto the housing 110. Similarly, during disassembly, a tool can be inserted into the disassembly notch 1222 to pry or lift the shielding cover 120, causing the limiting rib 111 to come out of the slot 122, thereby easily removing the shielding cover 120 from the housing 110 without the need for special tools, improving disassembly and assembly efficiency, and also avoiding damage to the switch housing 110 or the magnetic shielding cover 120 during the disassembly and assembly process.

[0046] In one possible embodiment of this application, the housing 110 has an armature rotating mechanism, such as... Figure 3 As shown, the housing 110 is provided with a clearance groove 112 at a position corresponding to the rotation axis of the armature rotation mechanism. The clearance groove 112 is provided on the side of the housing 110 facing the shield 120.

[0047] Specifically, such as Figure 3 As shown, the housing 110 has a relief groove 112 at a position corresponding to the rotation axis of the armature rotation mechanism. The relief groove 112 ensures that the shielding surface 121 does not directly contact the housing 110, thereby further avoiding the pressure of the shielding cover 120 on the rotation axis of the armature rotation mechanism. This ensures that the shielding cover 120 does not obstruct the normal rotation of the armature rotation mechanism, guarantees the flexibility and reliability of the armature rotation mechanism in the load switch 100, and prevents the shielding cover 120 from squeezing the rotation center of the armature after installation, which could cause product malfunction and enable it to smoothly complete various actions.

[0048] The shape of the clearance groove 112 can be circular, elliptical, polygonal, etc., as long as the clearance groove 112 ensures that the shielding surface 121 and the housing 110 will not directly contact each other, so that the shielding cover 120 will not be pressed against the rotation axis of the armature rotating mechanism.

[0049] For example, the end of the limiting rib 111 along the sleeve direction is provided with a guide portion 1112, and the guide portion 1112 has guide slopes 1112a on opposite sides along the sleeve direction of the limiting rib 111.

[0050] Specifically, such as Figure 3 and Figure 4 As shown, the guide portion 1112 is disposed at the end of the housing 110 along the sleeve direction, and its function is to guide the limiting rib 111 to accurately enter the slot 122. It can make the installation process smoother, reduce the increase in installation time and possible installation errors caused by alignment difficulties, and improve assembly efficiency.

[0051] like Figure 4As shown, the guide portion 1112 has guide slopes 1112a on opposite sides along the sleeve direction of the limiting rib 111, making the guide portion 1112 have an approximately triangular structure. This arrangement makes the width of the guide portion 1112 of the limiting rib 111 gradually increase, so the guide portion 1112 can be inserted into the slot 122 more quickly and easily, avoiding the reduction of assembly efficiency between the shield 120 and the housing 110 due to the width of the limiting rib 111.

[0052] Optionally, such as Figure 4 As shown, the guide slope 1112a has a rounded transition surface 1112b at its end along the sleeve direction. Compared with the sharp end, the rounded transition surface 1112b has no sharp edges, which can prevent scratches on the surface of the slot 122 or other related components during the sleeve process, protect the surface quality of the parts, prevent damage or performance degradation of the parts due to surface scratches, and extend the service life of the shield 120.

[0053] The above description is merely an optional embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

[0054] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.

Claims

1. A load switch, characterized in that, The device includes a housing (110) and a shield (120) fitted over the housing (110); the shield (120) has at least four shielding surfaces (121), which are connected in sequence to form a frame structure; at least one of the shielding surfaces (121) has a slot (122); the housing (110) has a protruding limiting rib (111), which is correspondingly provided with the slot (122) to limit and cooperate with the slot (122).

2. The load switch according to claim 1, characterized in that, Both the slot (122) and the limiting rib (111) extend along the sleeve direction; the inner wall of the slot (122) is recessed with an arc-shaped structure (1221), and the side wall of the limiting rib (111) is correspondingly recessed with an arc-shaped protrusion (1111), which can be locked in the arc-shaped structure (1221); or, the inner wall of the slot (122) is recessed with an arc-shaped protrusion (1111), and the side wall of the limiting rib (111) is correspondingly recessed with an arc-shaped structure (1221), which can be locked in the arc-shaped structure (1221).

3. The load switch according to claim 1, characterized in that, The slot (122) penetrates the shielding surface (121) along the sleeve direction.

4. The load switch according to claim 1, characterized in that, At least one end of the slot (122) along the sleeve direction is provided with a disassembly notch (1222), the width of which is greater than the thickness of the limiting rib (111).

5. The load switch according to claim 1, characterized in that, The housing (110) has an armature rotating mechanism inside. The housing (110) has a clearance groove (112) at a position corresponding to the rotation axis of the armature rotating mechanism. The clearance groove (112) is located on the side of the housing (110) facing the shield (120).

6. The load switch according to claim 4, characterized in that, The limiting rib (111) has a guide portion (1112) at its end along the sleeve direction, and the guide portion (1112) has guide slopes (1112a) on opposite sides along the sleeve direction of the limiting rib (111).

7. The load switch according to claim 6, characterized in that, The guide slope (1112a) has an arc transition surface (1112b) at its end along the sleeve direction.

8. The load switch according to claim 2, characterized in that, The number of the arc-shaped protrusions (1111) is at least one pair. The pair of arc-shaped protrusions (1111) are symmetrically distributed around the central axis of the limiting rib (111) and are respectively located on both sides of the outer wall of the limiting rib (111) along the sleeve direction or on both sides of the inner wall of the slot (122) along the sleeve direction. When the number of the arc-shaped protrusions (1111) is multiple pairs, the multiple pairs of arc-shaped protrusions (1111) are evenly distributed on the side wall of the limiting rib (111) or evenly distributed on the inner wall of the slot (122).

9. The load switch according to claim 1, characterized in that, A coil assembly is provided inside the housing (110). The axial direction of the coil assembly is parallel to the extension direction of the limiting rib (111). The limiting rib (111) is located on the outside of the housing (110) near the coil assembly.

10. The load switch according to claim 1, characterized in that, The housing (110) includes a main body (110a) and a shielding mating part (110b) connected to each other. An armature rotating mechanism is provided in the shielding mating part (110b). A stepped structure is formed at the connection between the main body (110a) and the shielding mating part (110b). The shielding cover (120) is fitted on the outer wall of the shielding mating part (110b). The top of the shielding cover (120) is flush with the top of the main body (110a), and the side wall of the shielding cover (120) can abut against the vertical surface of the stepped structure, so that the shielding cover (120) and the main body (110a) form a continuous outer contour of equal height along the setting direction.

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