Electromagnetic shielding structure
By adopting a shielding frame design with embedded slots and contact shrapnel connections in the electromagnetic shielding structure, the problem of difficult to take into account both electromagnetic shielding and heat dissipation functions in the prior art is solved, and efficient electromagnetic shielding and good heat dissipation performance are achieved, while reducing costs and manufacturing complexity.
Patent Information
- Application Number
- CN202421006484.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-10
- Publication Date
- 2025-02-11
- Estimated Expiration
- 2034-05-10
AI Technical Summary
When designing electromagnetic shielding structures in the prior art, it is difficult to balance factors such as heat dissipation, cost and manufacturability while meeting electromagnetic shielding and heat dissipation functions, resulting in poor product consistency and high cost.
An electromagnetic shielding structure is adopted, including a radiator and a shielding frame. The shielding frame is connected to the radiator through an embedded groove and a contact shrapnel, which not only realizes electromagnetic shielding, but also has good heat dissipation performance, and is simple in structure and low in cost.
This electromagnetic shielding structure can effectively suppress the electromagnetic noise emission generated by high-power DC/DC, meets the electromagnetic compatibility requirements of the vehicle factory, has good heat dissipation performance, and is simple in structure, low cost and simple in manufacturing process.
Smart Images
Figure CN222465185U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electromagnetic shielding, in particular to an electromagnetic shielding structure for a vehicle-mounted high-power DCDC. Background Art
[0002] With the rapid development of automotive electronics, the number and types of on-board electronic devices are increasing, and the electromagnetic environment in the car is becoming increasingly complex. In a complex electromagnetic environment, it is a very important issue that the electronic devices and systems in the car can work normally and are not affected by electromagnetic interference. Among them, the switching power supply system is an important component of the in-vehicle electronic system. It is an interference source and also a susceptible to interference. At present, in high-power non-isolated DC / DC on-board systems, there are strong du / dt and di / dt interference sources near the DC / DC switch MOSFET. The interference source has the characteristics of wide spectrum range, high electromagnetic radiation intensity, and high power consumption. Usually, when designing, it is necessary to use shielding to control the radiated noise of the interference source to meet the standard requirements of the car factory. And because some DC / DC systems have high working power and high requirements for heat dissipation, the application of the shielding solution needs to consider heat dissipation, that is, the shielding body cannot be completely closed, which is contradictory and mutually restrained with the electromagnetic shielding design. In the actual application solution, various factors such as heat dissipation, cost, and manufacturability must be balanced.
[0003] There are two main existing solutions:
[0004] 1. Shielding cover solution. The conventional design of the metal shielding frame 002 and the shielding cover 003 is used to form the main structure of the shielding design, thereby shielding electromagnetic radiation, such as Figure 1 As shown. Specifically, a metal shielding frame 002 and a shielding cover 003 are used to form a complete shielding design body. The shielding cover 003 and the metal heat sink 004 are filled with heat-conducting materials. There is no direct electrical connection, and the electromagnetic shielding effect depends entirely on the metal shielding frame 002 and the shielding cover 003. However, considering the heat dissipation and manufacturing requirements, it is necessary to design a hole on the shielding cover 003, which destroys the electromagnetic shielding effect. Therefore, the size of the hole will form a contradiction between heat dissipation and electromagnetic shielding performance. Moreover, in the above scheme, there are many unstable factors in the material use, manufacturing process, heat dissipation requirements, and structural fixation of the shielding cover 003, which will lead to poor consistency in the product shielding effect and relatively high cost.
[0005] 2. Metal shrapnel solution. Use multiple metal shrapnel 005 to be welded to the main board 001 respectively. The metal shrapnel 005 is arranged in the shape of a shielding frame to act as a shielding frame. The metal heat sink 004 acts as a shielding cover to form the main body of the shielding design, thereby completing the grounding shielding of the radiation source. Figure 2As shown, a plurality of Z-shaped metal springs 005 are welded on the mainboard 001 to form a shielding frame, and the metal heat sink 004 acts as a shielding cover. The metal heat sink 004 contacts the springs and compresses the springs downward, thereby ensuring electrical connection between the metal heat sink 004 and the springs. The defects of this design are: the shrapnel is prone to large deformation during transportation and installation, that is, the deformation is difficult to control; the deformation of the shrapnel will lead to poor contact between it and the metal heat sink 004, which will lead to deterioration of the shielding effect; if the arrangement of the shrapnel on the mainboard 001 deviates from the predetermined position, it may lead to differences in the shielding effect, that is, the product consistency is poor; multiple shrapnel need to be welded and fixed to the mainboard 001 respectively, the manufacturing process is complicated and the cost is high; the Z-shaped metal shrapnel 005 relies on the uppermost plane to electrically contact the metal heat sink 004. If the bending angle of the shrapnel is too large, only the bending part of the Z-shaped metal shrapnel 005 will contact the metal heat sink 004, and the rest of the parts will be separated from the metal heat sink 004, which will reduce the contact effect with the metal heat sink 004; the shrapnel needs to be welded separately, and poor workmanship or vibration can easily cause the shrapnel to fall off, and the manufacturing defect rate is high; the requirements for the shrapnel material are high, and a large number of shrapnel are required to have a good shielding effect, and the cost is high.
[0006] Therefore, in view of the above-mentioned technical problems, it is necessary to make new innovations. Utility Model Content
[0007] The purpose of the utility model is to solve at least one of the deficiencies in the prior art, so an electromagnetic shielding structure is proposed, and the specific scheme is as follows:
[0008] An electromagnetic shielding structure is arranged on the periphery of an electromagnetic interference source on a PCBA, the electromagnetic shielding structure comprises a heat sink and a shielding frame, the heat sink is arranged on a side of the PCBA where the electromagnetic interference source is arranged, the shielding frame is arranged between the heat sink and the PCBA, the shielding frame is arranged around the electromagnetic interference source, the heat sink is provided with an embedding groove corresponding to the shielding frame, the shielding frame is provided with a plurality of contact springs at one end facing the heat sink, the free ends of the contact springs are bent in a direction away from the heat sink, the shielding frame is embedded in the embedding groove at one end facing the heat sink and is connected to the heat sink through the contact springs, and the shielding frame is fixedly connected to the PCBA at one end facing the PCBA.
[0009] Furthermore, the shielding frame is provided with a plurality of outward-turned contact springs and a plurality of inward-turned contact springs at one end facing the heat sink, the free ends of the outward-turned contact springs are bent toward the outer edge of the shielding frame, and the free ends of the inward-turned contact springs are bent toward the inner edge of the shielding frame.
[0010] Furthermore, a plurality of the outward-turned contact springs and a plurality of inward-turned contact springs are alternately distributed along the frame direction of the shielding frame.
[0011] Furthermore, the shielding frame is provided with a plurality of slots at intervals along the frame direction thereof, and the slots penetrate one end of the shielding frame facing the heat sink or one end facing the PCBA.
[0012] Furthermore, the shielding frame is provided with the slots on both sides of the contact spring respectively.
[0013] Furthermore, a folding angle of the contact spring relative to the side wall of the shielding frame is greater than 90°.
[0014] Furthermore, the length of the contact spring is greater than or equal to 1.1d, wherein when the length of the contact spring is d, after the heat sink, the PCBA and the shielding frame are assembled, the contact spring just contacts the heat sink.
[0015] Furthermore, the radial cross-section of the embedding groove is trapezoidal, and the size of the groove opening of the embedding groove is larger than the size of the groove bottom.
[0016] Furthermore, the heat sink is a metal heat sink, a heat dissipation boss is arranged on a side of the heat sink facing the PCBA in an area surrounded by the shielding frame, and a thermal conductive material is arranged between the heat dissipation boss and the PCBA.
[0017] Furthermore, the electromagnetic shielding structure is used for vehicle-mounted DCDC; the contact spring and the shielding frame are integrally formed.
[0018] Compared with the prior art, the electromagnetic shielding structure of the present application has at least one or more of the following beneficial effects:
[0019] This application adopts the electromagnetic shielding structure around the main electromagnetic interference source of the high-power DC / DC, which is also placed in the area where heat dissipation is required. It can effectively suppress the electromagnetic noise emission generated by the DC / DC. After the shielding application, it meets the electromagnetic compatibility requirements of the car factory and has good heat dissipation performance;
[0020] The electromagnetic shielding structure of the present application has both electromagnetic shielding and heat dissipation functions. The structural design scheme not only meets the electromagnetic shielding and heat dissipation functions, but also has the advantages of simple structure, low cost, high stability, etc.
[0021] The electromagnetic shielding structure of the present application has the advantages of simple process flow and high manufacturability in the product manufacturing process compared with other solutions;
[0022] The electromagnetic shielding structure of the present application can effectively suppress high-frequency noise, so that the high-power DCDC meets the EMC standard requirements of car manufacturers. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a schematic diagram of the explosion structure of a product of a shielding cover solution in the prior art;
[0024] Figure 2 It is a schematic diagram of the explosion structure of a product of a metal shrapnel solution in the prior art;
[0025] Figure 3 A schematic diagram of an exploded structure of an electromagnetic shielding structure provided in an embodiment of the present application;
[0026] Figure 4 A schematic diagram of a structure in which a shielding frame provided in an embodiment of the present application is embedded in a radiator;
[0027] Figure 5 A schematic diagram of the three-dimensional structure of a radiator provided in an embodiment of the present application;
[0028] Figure 6 A schematic cross-sectional view of a heat sink provided in an embodiment of the present application;
[0029] Figure 7 A schematic diagram of the three-dimensional structure of a shielding frame provided in an embodiment of the present application;
[0030] Figure 8 A schematic diagram of the partial structure of the shielding frame provided in an embodiment of the present application.
[0031] Among them, 001-mainboard, 002-metal shielding frame, 003-shielding cover, 004-metal radiator, 005-metal spring, 1-PCBA, 2-radiator, 21-embedded slot, 22-heat dissipation boss, 3-shielding frame, 31-contact spring, 311-outward-turned contact spring, 312-inward-turned contact spring, 32-slot. DETAILED DESCRIPTION
[0032] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.
[0033] Example
[0034] This embodiment provides an electromagnetic shielding structure for a vehicle-mounted high-power DCDC, which is arranged on the periphery of the electromagnetic interference source on PCBA1. The electromagnetic shielding structure includes a heat sink 2 and a shielding frame 3. The heat sink 2 is a metal heat sink, which is a prior art, so its specific structure will not be described in detail here. The heat sink 2 is arranged on the side of the PCBA1 where the electromagnetic interference source is arranged, and the shielding frame 3 is arranged between the heat sink 2 and the PCBA1, and the shielding frame 3 is arranged around the electromagnetic interference source. Figure 3 , Figure 4 or Figure 7 As shown, the figure schematically shows a shielding frame 3 structure in the shape of a notch, but in actual implementation, the shape of the shielding frame 3 is not limited to this shape, and its specific shape can be designed to match the electromagnetic interference source to be shielded, for example, it can also be any other frame shape such as a convex shape, a notch shape, etc.
[0035] The heat sink 2 is provided with an embedding groove 21 corresponding to the shielding frame 3. The shielding frame 3 is provided with a plurality of contact springs 31 at one end facing the heat sink 2. The free ends of the contact springs 31 are bent in the direction away from the heat sink 2. The end of the shielding frame 3 facing the heat sink 2 is embedded in the embedding groove 21 and connected to the heat sink 2 through the contact springs 31. In order to achieve good overlap and product consistency, in a preferred embodiment, the radial cross-section of the embedding groove 21 is preferably trapezoidal, and the notch size of the embedding groove 21 is larger than the bottom size of the groove. For example, the width of the notch of the embedding groove 21 is about 3.4 mm, and the width at the bottom of the groove is 2 mm. Figure 5 and Figure 6 As shown. With such a design, the contact spring 31 of the shielding frame 3 can better elastically contact with the heat sink 2. Of course, the width of the embedded groove 21 is not limited here, and its specific size can be designed according to actual needs. The present application realizes elastic matching connection with the embedded groove 21 on the heat sink 2 by arranging a contact spring 31 on the shielding frame 3. The contact spring 31 will deform when it extends into the embedded groove 21, which can ensure the electrical connection between the contact spring 31 and the heat sink 2, thereby ensuring the electrical contact effect between the shielding frame 3 and the heat sink 2, and then improving the shielding effect. Compared with the Z-shaped metal spring 005 solution in the prior art, the matching mode of the contact spring 31 and the embedded groove 21 is adopted. Even if there is a certain deviation in the bending angle of the contact spring 31, it will not affect the contact effect between the contact spring 31 and the heat sink 2. When the slot width of the embedding slot 21 is designed to be smaller, when the shielding frame 3 is embedded in the embedding slot 21 , the deformation of the contact spring 31 will be greater, and the radio frequency contact impedance will be lower.
[0036] The contact spring 31 is preferably an integrally formed structure of the shielding frame 3. Figure 7 and Figure 8 As shown. With such a design, there is no need to independently set up the shrapnel and the sealing cover, which can effectively reduce the material cost. In addition, there is no need to weld the shrapnel on the PCBA1, which makes the assembly simpler, greatly reduces the cost, and has higher product consistency. In this embodiment, the contact shrapnel 31 and the shielding frame 3 are integrally formed, which has higher strength and is not prone to large deformation. In addition, during the installation of the shielding frame 3, the force direction (pressing the shielding frame 3 downward) avoids the deformation direction of the contact shrapnel 31, thereby reducing the influence of the deformation of the contact shrapnel 31 during the installation process, thereby ensuring the electrical connection effect and shielding effect between the contact shrapnel 31 and the radiator 2.
[0037] In a preferred embodiment, a plurality of outward-turned contact springs 311 and a plurality of inward-turned contact springs 312 are provided at one end of the shielding frame 3 facing the heat sink 2, and the free ends of the outward-turned contact springs 311 are bent toward the outer edge of the shielding frame 3, and the free ends of the inward-turned contact springs 312 are bent toward the inner edge of the shielding frame 3. That is, the contact springs 31 on the shielding frame 3 are at least partially folded outward, and at least partially folded inward. Such a design can ensure that the forces applied to the shielding frame 3 by each contact spring 31 after deformation cancel each other out, thereby preventing the shielding frame 3 from deviating from the predetermined position and causing poor contact between the contact springs 31 and the heat sink 2. In a further preferred embodiment, a plurality of the outward-turned contact springs 311 and a plurality of the inward-turned contact springs 312 are alternately distributed along the frame direction of the shielding frame 3, such as Figure 7 and Figure 8 Such a design can ensure that when the shielding frame 3 is embedded in the embedding groove 21, the shielding frame 3 is subjected to a more uniform force.
[0038] In a preferred embodiment, the contact springs 31 can be directly distributed continuously along the frame direction of the shield frame 3. The continuous distribution mentioned here should be understood as that the contact springs 31 are not connected to each other, and there may be a certain gap. In other preferred embodiments, there may be a certain interval between some of the adjacent contact springs 31, for example, the interval between some of the adjacent contact springs 31 may be greater than the width of the contact spring 31, such as Figure 7 shown.
[0039] In a preferred embodiment, the shielding frame 3 is provided with a plurality of slots 32 at intervals along the frame direction thereof, and the slots 32 penetrate the end of the shielding frame 3 facing the heat sink 2 or the end facing the PCBA 1. Such a design can offset the elastic strain force of the contact spring 31 when the shielding frame 3 is embedded in the embedding groove 21. In a further preferred embodiment, the shielding frame 3 is provided with the slots 32 on both sides of the contact spring 31, and the slots 32 penetrate the end of the shielding frame 3 facing the heat sink 2, such as Figure 7 It should be noted that two adjacent contact springs 31 that are continuously distributed can be separated by a common slot 32. Providing slots 32 on both sides of the contact spring 31 can reduce the impact on other contact springs 31 when offsetting the elastic strain force of the contact spring 31, and can further improve the electrical connection effect and shielding effect between the shielding frame 3 and the heat sink 2.
[0040] In a preferred embodiment, the folding angle of the contact spring 31 relative to the side wall of the shield frame 3 is greater than 90°. As a result, an acute angle is formed between the contact spring 31 and the side wall of the shield frame 3, which facilitates the deformation of the contact spring 31, thereby facilitating the elastic cooperation between the contact spring 31 and the embedding groove 21. In a further preferred embodiment, the folding angle of the contact spring 31 relative to the side wall of the shield frame 3 is preferably greater than 100°, and more preferably greater than 110°.
[0041] In a preferred embodiment, assuming that the length of the contact spring 31 is d, after the heat sink 2, the PCBA 1 and the shielding frame 3 are assembled, the contact spring 31 just contacts the heat sink 2, and the length of the contact spring 31 is preferably greater than or equal to 1.1d. In a further preferred embodiment, the length of the contact spring 31 is preferably greater than or equal to 1.2d, and more preferably greater than or equal to 1.5d. The longer the length of the contact spring 31, the greater the distance between the free end of the contact spring 31 and the side wall of the shielding frame 3. When the shielding frame 3 is embedded in the embedding groove 21, the deformation of the contact spring 31 is greater, the contact between the shielding frame 3 and the heat sink 2 is better, and the radio frequency impedance is lower. The distance between the free end of the contact spring 31 and the side wall of the shielding frame 3 can be adjusted according to the actual design. For example, the length of the contact spring 31 can be about 2mm, and the distance between the free end of the contact spring 31 and the side wall of the shielding frame 3 is about 1.7mm.
[0042] In a preferred embodiment, the depth of the embedding groove 21 is preferably consistent with the height of the shielding frame 3 .
[0043] In a further embodiment, the shielding frame 3 is fixedly connected to the PCBA 1 at one end thereof facing the PCBA 1. The shielding frame 3 and the PCBA 1 may be fixed by welding or by a card holder, etc. Since welding and card holder fixing are both prior arts, they will not be described in detail here.
[0044] In a preferred embodiment, a heat dissipation boss 22 is provided in the area surrounded by the shielding frame 3 on the side of the heat sink 2 facing the PCBA 1. Figure 4 and Figure 5 As shown. A heat-conducting material is arranged between the heat dissipation boss 22 and the PCBA 1. Such a design can increase the heat dissipation effect of the PCBA 1.
[0045] This application adopts the electromagnetic shielding structure around the main electromagnetic interference source of the high-power DC / DC, which is also placed in the area where heat dissipation is required. It can effectively suppress the electromagnetic noise emission generated by the DC / DC. After the shielding application, it meets the electromagnetic compatibility requirements of the car factory and has good heat dissipation performance;
[0046] The electromagnetic shielding structure of the present application has both electromagnetic shielding and heat dissipation functions. The structural design scheme not only meets the electromagnetic shielding and heat dissipation functions, but also has the advantages of simple structure, low cost, high stability, etc.
[0047] The electromagnetic shielding structure of the present application has the advantages of simple process flow and high manufacturability in the product manufacturing process compared with other solutions;
[0048] The electromagnetic shielding structure of the present application can effectively suppress high-frequency noise, so that the high-power DCDC meets the EMC standard requirements of car manufacturers.
[0049] In this document, the terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than those listed and may also include additional elements not expressly listed.
[0050] In this document, the directional words such as front, back, top, and bottom are defined by the positions of the components in the drawings and the positions of the components relative to each other, and are only for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the directional words should not limit the scope of protection claimed in this application.
[0051] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.
[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. An electromagnetic shielding structure, which is arranged on the periphery of an electromagnetic interference source on a PCBA (1), characterized in that: The electromagnetic shielding structure comprises a heat sink (2) and a shielding frame (3); the heat sink (2) is arranged on a side of the PCBA (1) on which an electromagnetic interference source is arranged; the shielding frame (3) is arranged between the heat sink (2) and the PCBA (1); the shielding frame (3) is arranged around the electromagnetic interference source; an embedding groove (21) is arranged on the heat sink (2) at a position corresponding to the shielding frame (3); a plurality of contact springs (31) are arranged on one end of the shielding frame (3) facing the heat sink (2); the free ends of the contact springs (31) are bent in a direction away from the heat sink (2); an end of the shielding frame (3) facing the heat sink (2) is embedded in the embedding groove (21) and connected to the heat sink (2) through the contact springs (31); and an end of the shielding frame (3) facing the PCBA (1) is fixedly connected to the PCBA (1).
2. The electromagnetic shielding structure according to claim 1, characterized in that: A plurality of outward-turned contact springs (311) and a plurality of inward-turned contact springs (312) are provided at one end of the shielding frame (3) facing the heat sink (2); the free ends of the outward-turned contact springs (311) are bent toward the outer edge of the shielding frame (3), and the free ends of the inward-turned contact springs (312) are bent toward the inner edge of the shielding frame (3).
3. The electromagnetic shielding structure according to claim 2, characterized in that: A plurality of the outward-turned contact spring sheets (311) and a plurality of inward-turned contact spring sheets (312) are alternately distributed along the frame direction of the shielding frame (3).
4. The electromagnetic shielding structure according to claim 1, characterized in that: The shielding frame (3) is provided with a plurality of slots (32) at intervals along the frame direction thereof, and the slots (32) penetrate one end of the shielding frame (3) facing the heat sink (2) or one end facing the PCBA (1).
5. The electromagnetic shielding structure according to claim 4, characterized in that: The shielding frame (3) is provided with slots (32) on both sides of the contact spring sheet (31).
6. The electromagnetic shielding structure according to claim 1, characterized in that: The folding angle of the contact spring (31) relative to the side wall of the shielding frame (3) is greater than 90°.
7. The electromagnetic shielding structure according to claim 1, characterized in that: The length of the contact spring (31) is greater than or equal to 1.1d, When the length of the contact spring (31) is d, after the heat sink (2), the PCBA (1) and the shielding frame (3) are assembled, the contact spring (31) just contacts the heat sink (2).
8. The electromagnetic shielding structure according to claim 1, characterized in that: The radial cross section of the embedding groove (21) is trapezoidal, and the size of the groove opening of the embedding groove (21) is larger than the size of the groove bottom.
9. The electromagnetic shielding structure according to claim 1, characterized in that: The heat sink (2) is a metal heat sink, and a heat dissipation boss (22) is provided in an area surrounded by the shielding frame (3) on the side of the heat sink (2) facing the PCBA (1), and a heat conductive material is provided between the heat dissipation boss (22) and the PCBA (1).
10. The electromagnetic shielding structure according to claim 1, characterized in that: The electromagnetic shielding structure is used for vehicle-mounted DCDC; the contact spring (31) and the shielding frame (3) are integrally formed.