Filter

Abstract

The utility model relates to the field of filters, and discloses a filter, which comprises a metal shell and a circuit board, a stud is arranged on the inner top surface of the metal shell and is used for mounting and fixing the circuit board and the metal shell; two ends of the circuit board are respectively provided with an input lead and an output lead; the circuit board is divided into a first part and a second part by taking the central axis as a boundary; the first part and the second part of the circuit board are respectively provided with mounting holes close to the middle parts, and are combined with the studs of the metal shell through screws. According to the filter, the filter circuit is arranged on the circuit board, and the functional ground wire on the circuit is connected with the metal shell through the stud and the mounting hole, so that reliable grounding is realized, the process and the structure of the product are simple and attractive, the automation degree is high, and the production is convenient.

Description

Technical Field

[0001] The utility model relates to the field of filters, in particular to an electromagnetic compatibility filter with a metal shell. Background Art

[0002] With the continuous development of electronic circuit technology, the power density of switching power supplies is constantly increasing. High efficiency, high reliability, high frequency design and low cost have become the development direction of switching power supplies. The filtering circuit of the switching power supply itself is limited. Accordingly, the demand for EMC filters used with switching power supplies to enable the switching power supply to meet higher EMC performance is also increasing. At the same time, due to the diverse and complex application industries and application environments of switching power supplies, the requirements for EMC filters are also varied. Among them, the demand for EMC filters with higher reliability and better ability to cope with harsh environments with metal casings is particularly important.

[0003] However, the filters currently on the market generally have the problems of low reliability and high production cost. In order to solve the above problems, it is urgent to propose a new filter. Utility Model Content

[0004] In view of this, the utility model provides a filter to solve the problems of low reliability and high production cost of existing filters.

[0005] In order to solve the above problems, the technical solutions provided by the present invention are as follows:

[0006] A filter comprises: a metal shell and a circuit board; two studs spaced apart from each other are provided on the inner top surface of the metal shell; the circuit board is installed in the metal shell, the circuit board comprises a substrate and a filter circuit arranged on the substrate, wherein the filter circuit comprises a first differential mode filter inductor, a second differential mode filter inductor, a first common mode filter capacitor, a second common mode filter capacitor and a ground terminal; the substrate is divided into a first part and a second part by its central axis, the first part and the second part are respectively provided with mounting holes, the positions of the mounting holes correspond to the positions of the studs, the ground terminal is arranged in the mounting holes, the studs are installed in the mounting holes and are tightly connected to the ground terminal; the first differential mode filter inductor and the second differential mode filter inductor are respectively arranged in the first part and the second part, and the first common mode filter capacitor and the second common mode filter capacitor are respectively arranged in the first part and the second part, wherein the mounting hole arranged in the first part is located between the first differential mode filter inductor and the first common mode filter capacitor, and the mounting hole arranged in the second part is located between the second differential mode filter inductor and the second common mode filter capacitor.

[0007] Preferably, the metal shell includes an upper shell and a bottom cover, the upper shell is provided with a cavity, the circuit board is installed in the cavity, the bottom of the cavity is provided with an opening, the bottom cover is arranged at the opening, and the bottom cover and the upper shell are connected by welding at the opening to form a closed metal shell.

[0008] Preferably, the upper shell includes a top plate, two long side plates facing each other front and back, and two short side plates facing each other left and right. The bottoms of the two short side plates are respectively provided with mounting platforms, and the mounting platforms are provided with fixing holes for fixing the filter to the external system.

[0009] Preferably, a support platform for supporting the bottom cover is provided on the inner walls of the two long side panels near the opening.

[0010] Preferably, the two studs are arranged on both sides of the inner top surface of the top plate near the middle portion.

[0011] Preferably, plastic is encapsulated in the metal housing, and the plastic wraps the circuit board.

[0012] Preferably, the filter is further provided with screws, the studs are provided with internal threads, the screws pass through the mounting holes and are screwed with the internal threads of the studs to fix the circuit board on the metal housing.

[0013] Preferably, the filter circuit further has an input positive terminal, an input negative terminal, an output positive terminal and an output negative terminal respectively arranged on the substrate, the number of grounding terminals is 2, the two grounding terminals are respectively a first grounding terminal and a second grounding terminal, the input positive terminal and the input negative terminal are respectively installed with input wires, the output positive terminal and the output negative terminal are respectively installed with output wires, and the input wires and the output wires are respectively passed through the wire outlet holes arranged at both ends of the metal shell to pass out of the metal shell; one end of the first differential mode filter inductor is connected to the input positive terminal, one end of the second differential mode filter inductor is connected to the input negative terminal, one end of the first common mode filter capacitor is connected to the output positive terminal, the other end of the first common mode filter capacitor is connected to the first ground terminal, one end of the second common mode filter capacitor is connected to the output negative terminal, and the other end of the first common mode filter capacitor is connected to the second ground terminal.

[0014] Preferably, the wire outlet hole is installed with a silicone plug, and the input wire and the output wire pass through the silicone plug respectively.

[0015] Preferably, the four corners of the substrate are all provided with notches for guiding the potting glue into the space formed between the inner top surface of the metal shell and the substrate.

[0016] The utility model has the following beneficial effects:

[0017] (1) The second mounting hole provided in the first portion is located between the first differential-mode filter inductor and the first common-mode filter capacitor, and the second mounting hole provided in the second portion is located between the second differential-mode filter inductor and the second common-mode filter capacitor. In this way, not only the grounding wire connecting the first common-mode filter capacitor and the second common-mode filter capacitor to the ground terminal is designed to be shorter, thereby reducing the impedance of the grounding wire, but also the wiring of the grounding wire can be simplified, thereby reducing the production cost.

[0018] (2) The ground terminal on the circuit board is connected to the metal casing through studs and mounting holes to achieve reliable grounding.

[0019] (3) The filter adopts the circuit board layout method of filtering circuit. The circuit board assembly process is simple, the structure is beautiful, the consistency is good, and the degree of automation is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural diagram of the metal shell electromagnetic compatibility filter of the utility model;

[0021] Figure 2 This is an exploded diagram of the metal shell electromagnetic compatibility filter of the utility model;

[0022] Figure 3 This is a circuit board diagram of the metal shell electromagnetic compatibility filter of the utility model;

[0023] Figure 4 This is a specific schematic diagram of the filter circuit on the substrate of the utility model. DETAILED DESCRIPTION

[0024] In order to make the technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] like Figures 1 to 3 As shown, an electromagnetic compatibility filter provided by the present invention includes a metal housing 1, a circuit board 2, a silicone plug 3 and a wire 4.

[0026] The metal shell 1 consists of an upper shell 11 and a bottom cover 12. The upper shell 11 is provided with a cavity 111 and two studs 112 located in the cavity 111. The bottom of the cavity 111 is provided with an opening 1111. The two studs 112 are arranged on both sides of the inner top surface of the upper shell 11 near the middle part, and the two studs 112 are symmetrically arranged.

[0027] In this embodiment, the upper housing 11 consists of a top plate 113, two long side plates 114 facing each other front and back, and two short side plates 115 facing each other left and right. Two studs 112 are located on either side of the inner top surface of the top plate 115, near the center. Each of the short side plates 115 of the upper housing 11 is provided with a wire outlet hole 116, which is fitted with a silicone plug 3. The input and output wires 41 and 42 of the circuit board 2 located within the cavity 111 of the upper housing 11 extend through the wire outlet holes 116 to connect to the external system.

[0028] A support platform 1141 is provided on the inner wall of the long side plate 114 of the upper shell 11, and the support platform 1141 is close to the opening 1111. There are four support platforms 1141, two on the inner wall of each long side plate 114, which are used to support the bottom cover 12; the bottom cover 12 is provided at the opening 1111 and placed on the support platform 1141. The bottom cover 12 and the metal outer shell 11 are connected by welding at the opening 1111 to form a closed metal shell 1.

[0029] The bottom of the short side plates 115 of the upper shell 11 is respectively provided with an arc-shaped mounting platform 1151, and a fixing hole 1152 is provided on the mounting platform 1151. The mounting platform 1151 and the fixing hole 1152 are used to install and fix the filter on an external system.

[0030] The circuit board 2 is positioned within the cavity 111 of the upper housing 11 and secured to the studs 112 with screws through first and second mounting holes 213 and 214 provided on the circuit board 2. The circuit board 2 includes a substrate 21, a filter circuit 22 disposed thereon, and input and output conductors 41 and 42. To protect the circuit board 2, in this embodiment, the upper housing 11 is potted with plastic (not shown), which encapsulates the substrate 21 and filter circuit 22 within the circuit board 2.

[0031] The base plate 21 is divided by its central axis into a first portion 211 and a second portion 212. The first portion 211 is provided with a first mounting hole 213, and the second portion 212 is provided with a second mounting hole 214. The positions of the first mounting hole 213 and the second mounting hole 214 correspond to the positions of the two studs 112, respectively. The two studs 112 are respectively installed in the first mounting hole 213 and the second mounting hole 214. The two studs 112 are each provided with an internal thread. When the circuit board is installed, two screws (not shown) are respectively passed through the first mounting hole 213 and the second mounting hole 214 and screwed into the internal threads of the corresponding studs 112, thereby securing the circuit board 2 to the upper shell 11 of the metal housing 1. In this embodiment, each of the four corners of the base plate 21 is provided with a notch 215 to guide the potting compound into the space formed between the inner top surface of the upper shell 11 of the metal housing 1 and the base plate 21 when potting the circuit board 2.

[0032] refer to Figure 4 The filter circuit 22 includes an input positive terminal Vin+, an input negative terminal Vin-, an output positive terminal Vo+, an output negative terminal Vo-, a ground terminal, a first differential mode filter inductor 221, a second differential mode filter inductor 222, a first common mode filter capacitor 223, and a second common mode filter capacitor 224. There are two ground terminals, namely a first ground terminal GND1 and a second ground terminal GND2. The first ground terminal GND1 is disposed in the first mounting hole 213, and the second ground terminal GND2 is disposed in the second mounting hole 214. When the studs 112 are mounted in the first and second mounting holes 213 and 214, the two studs 112 are tightly connected to the first ground terminal GND1 and the second ground terminal GND2, respectively.

[0033] The first differential-mode filter inductor 221 and the second differential-mode filter inductor 222 are respectively arranged in the first part 211 and the second part 212, and the first common-mode filter capacitor 223 and the second common-mode filter capacitor 224 are respectively arranged in the first part 211 and the second part 212, wherein the first mounting hole 213 arranged in the first part 211 is located between the first differential-mode filter inductor 221 and the first common-mode filter capacitor 223, and the second mounting hole 214 arranged in the second part 212 is located between the second differential-mode filter inductor 222 and the second common-mode filter capacitor 224.

[0034] The wire 4 includes an input wire 41 and an output wire 42. The input wire 41 is installed at the input positive terminal Vin+ and the input negative terminal Vin-, and the output wire 42 is installed at the output positive terminal Vo+ and the output negative terminal Vo-. The input wire 41 and the input wire 42 respectively pass through the wire outlet holes 116 set at both ends of the metal shell 1 and exit the metal shell 1. The distance between the two input wires 41 is smaller than the distance between the two input wires 42.

[0035] One end of the first differential-mode filter inductor 221 is connected to the input positive terminal Vin+, one end of the second differential-mode filter inductor 222 is connected to the input negative terminal Vin-, one end of the first common-mode filter capacitor 223 is connected to the output positive terminal Vo+, the other end of the first common-mode filter capacitor 223 is connected to the first ground terminal GND1, one end of the second common-mode filter capacitor 224 is connected to the output negative terminal Vo-, and the other end of the first common-mode filter capacitor 223 is connected to the second ground terminal GND2.

[0036] The utility model has the following beneficial effects:

[0037] (1) The first mounting hole 213 provided in the first portion 211 is located between the first differential mode filter inductor 221 and the first common mode filter capacitor 223, and the second mounting hole 214 provided in the second portion 212 is located between the second differential mode filter inductor 222 and the second common mode filter capacitor 224. In this way, not only the grounding wire connecting the first common mode filter capacitor 223 and the second common mode filter capacitor 224 to the ground terminal is designed to be shorter, thereby reducing the impedance of the grounding wire, but also the wiring of the grounding wire is simplified, thereby reducing the production cost of the filter.

[0038] (2) The grounding terminal on the circuit board is connected to the metal housing through the two studs 112 and the first and second mounting holes 213 and 214, thereby achieving reliable grounding.

[0039] (3) The filter adopts the circuit board layout method of filtering circuit. The circuit board assembly process is simple, the structure is beautiful, the consistency is good, and the degree of automation is high.

[0040] The description of the above embodiments is only used to help understand the concept of the present invention and is not intended to limit the present invention. For ordinary technicians in this technical field, any modifications, equivalent replacements, improvements, etc. made without departing from the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A filter, characterized in that: include: A metal shell, wherein the inner top surface of the metal shell is provided with two studs spaced apart from each other; A circuit board, the circuit board is installed in the metal housing, the circuit board includes a substrate and a filter circuit arranged on the substrate, wherein the filter circuit includes a first differential mode filter inductor, a second differential mode filter inductor, a first common mode filter capacitor, a second common mode filter capacitor and a ground terminal; The base plate is divided into a first part and a second part by its central axis, the first part and the second part are respectively provided with mounting holes, the positions of the mounting holes correspond to the positions of the studs, the grounding end is provided in the mounting holes, the studs are installed in the mounting holes and the studs are tightly connected to the grounding end; The first differential mode filter inductor and the second differential mode filter inductor are respectively arranged in the first part and the second part, and the first common mode filter capacitor and the second common mode filter capacitor are respectively arranged in the first part and the second part, wherein the mounting hole arranged in the first part is located between the first differential mode filter inductor and the first common mode filter capacitor, and the mounting hole arranged in the second part is located between the second differential mode filter inductor and the second common mode filter capacitor.

2. The filter according to claim 1, characterized in that: The metal shell includes an upper shell and a bottom cover, the upper shell is provided with a cavity, the circuit board is installed in the cavity, the bottom of the cavity is provided with an opening, the bottom cover is arranged at the opening, and the bottom cover and the upper shell are connected by welding at the opening to form a closed metal shell.

3. The filter according to claim 2, characterized in that: The upper shell includes a top plate, two long side plates opposite to each other in front and back, and two short side plates opposite to each other in left and right. The bottoms of the two short side plates are respectively provided with mounting platforms, and the mounting platforms are provided with fixing holes for fixing the filter to an external system.

4. The filter according to claim 3, characterized in that: The inner walls of the two long side plates are provided with a support platform for supporting the bottom cover at a position close to the opening.

5. The filter according to claim 3, characterized in that: The two studs are arranged on both sides of the inner top surface of the top plate near the middle portion.

6. The filter according to claim 2, characterized in that: Plastic is encapsulated in the metal shell, and the plastic wraps the circuit board.

7. The filter according to claim 1, characterized in that: A screw is also provided, the stud is provided with an internal thread, the screw passes through the mounting hole and is screwed with the internal thread of the stud to fix the circuit board on the metal shell.

8. The filter according to claim 1, characterized in that: The filter circuit also has an input positive terminal, an input negative terminal, an output positive terminal and an output negative terminal respectively arranged on the substrate, the number of the grounding terminals is 2, the two grounding terminals are respectively a first grounding terminal and a second grounding terminal, the input positive terminal and the input negative terminal are respectively installed with input wires, the output positive terminal and the output negative terminal are respectively installed with output wires, and the input wires and the output wires are respectively passed through the outlet holes arranged at both ends of the metal shell and out of the metal shell; One end of the first differential mode filter inductor is connected to the input positive end, one end of the second differential mode filter inductor is connected to the input negative end, one end of the first common mode filter capacitor is connected to the output positive end, the other end of the first common mode filter capacitor is connected to the first ground end, one end of the second common mode filter capacitor is connected to the output negative end, and the other end of the first common mode filter capacitor is connected to the second ground end.

9. The filter according to claim 8, characterized in that: The outlet hole is provided with a silicone plug, and the input wire and the output wire pass through the silicone plug respectively.

10. The filter according to claim 2, characterized in that: The four corners of the substrate are all provided with notches for guiding the potting glue into the space formed between the inner top surface of the metal shell and the substrate.

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