CN107093992B

CN107093992B - filter

Info

Publication number: CN107093992B
Application number: CN201710369974.0A
Authority: CN
Inventors: 蒋忠益; 朱建华; 黄寒寒; 陈益芳; 李凯文; 王智会
Original assignee: Shenzhen Zhenhua Ferrite and Ceramic Electronics Co Ltd; China Zhenhua Group Science and Technology Co Ltd
Current assignee: Shenzhen Zhenhua Ferrite and Ceramic Electronics Co Ltd; China Zhenhua Group Science and Technology Co Ltd
Priority date: 2017-05-23
Filing date: 2017-05-23
Publication date: 2023-08-29
Anticipated expiration: 2037-05-23
Also published as: CN107093992A

Abstract

The present invention relates to a filter. A filter includes a housing having an interior cavity, an output terminal disposed at a first end of the housing; the PCB capacitor is formed by a first PCB with copper coated on both sides; the PCB capacitor is arranged in the inner cavity near the first end of the shell and is electrically connected with the output terminal; an input terminal provided at a second end of the housing opposite the first end; a PCB capacitor assembly disposed in the housing interior between the PCB capacitor and the housing second end; the PCB capacitor assembly comprises a second PCB and a plurality of capacitors uniformly distributed on the second PCB around the center line of the second PCB; the PCB capacitor assembly is respectively and electrically connected with the PCB capacitor and the input terminal; an inductor disposed in the housing interior between the PCB capacitive component and the second end of the housing; the inductor is electrically connected with the PCB capacitor component and the output terminal respectively. The PCB capacitor and the capacitor of the PCB capacitor assembly are arranged on the PCB, so that the problem of capacitor cracking caused by stress vibration is avoided, the vibration resistance of the filter is improved, and the reliability of the filter is enhanced.

Description

Filter

Technical Field

The invention relates to the technical field of electromagnetic interference, in particular to a filter.

Background

An electromagnetic interference filter, also known as an "EMI filter", is an electronic circuit device used to suppress electromagnetic interference, particularly noise in a power supply line or a control signal line. Electromagnetic interference filters are typically composed of a network of passive electronic components, including capacitors and inductors, that form an LC circuit. The present capacitor mostly adopts a ceramic wafer through capacitor, and the capacitor can be directly welded inside a shell of the electromagnetic interference filter, so that the capacitor is easy to crack due to the fact that the wafer through capacitor is large in area and thin in thickness and is easy to vibrate due to the stress of the electromagnetic interference filter.

Disclosure of Invention

Based on this, it is necessary to provide a filter with enhanced reliability against vibration and impact forces.

A filter includes a housing; the housing has an inner cavity; further comprises: an output terminal disposed on the first end of the housing; the PCB capacitor is formed by a first PCB with double-sided copper coating; the PCB capacitor is arranged in the inner cavity near the first end of the shell and is electrically connected with the output terminal; an input terminal disposed on a second end of the housing opposite the first end; the PCB capacitor assembly is arranged between the PCB capacitor and the second end of the shell in the inner cavity of the shell; the PCB capacitor assembly comprises a second PCB and a plurality of capacitors uniformly distributed on the second PCB around the central line of the second PCB; the PCB capacitor assembly is electrically connected with the PCB capacitor and the input terminal respectively. The method comprises the steps of carrying out a first treatment on the surface of the The inductor is arranged between the PCB capacitor assembly and the second end of the shell in the inner cavity of the shell; the inductor is electrically connected with the PCB capacitor assembly and the output terminal respectively.

In one embodiment, the magnetic bead is further included; the magnetic beads comprise first magnetic beads and second magnetic beads; the first magnetic beads are connected between the output terminal and the PCB capacitor and are respectively and electrically connected with the output terminal and the PCB capacitor; the second magnetic beads are connected between the PCB capacitor and the PCB capacitor assembly and are respectively and electrically connected with the PCB capacitor and the PCB capacitor assembly.

In one embodiment, the magnetic beads are cylindrical magnetic beads.

In one embodiment, the first PCB board is a multi-layer PCB board.

In one embodiment, the device further comprises a retainer ring; the check ring is arranged in the inner cavity of the shell; the retainer ring is used for fixing devices in the inner cavity of the shell.

In one embodiment, the device further comprises a check ring anti-falling structure; the retaining ring anti-falling structure is used for preventing the retaining ring from falling off.

In one embodiment, the input terminal is provided with external threads, and the second end of the housing is internally provided with internal threads that mate with the external threads.

In one embodiment, the sealing device further comprises sealing glue filled in the inner cavity of the shell.

In one embodiment, the PCB capacitor and the PCB capacitor assembly are both provided with through holes, and the sealant is distributed in the inner cavity through the through holes.

In one embodiment, the filter of any of the above embodiments is a tubular filter.

Above-mentioned filter, among PCB electric capacity and the PCB electric capacity subassembly, the electric capacity all sets up on the PCB board, for traditional electric capacity direct welding at the inside mode of shell, can avoid causing the problem of electric capacity fracture when vibrating because of electromagnetic interference filter atress. Therefore, the anti-vibration capability of the filter is improved, and the reliability of the filter is enhanced.

Drawings

FIG. 1 is a schematic diagram of the internal structure of a filter according to an embodiment;

FIG. 2 is a schematic front view of a filter according to an embodiment;

FIG. 3 is a schematic front view of the A terminal (B terminal) of the filter shown in FIG. 2;

FIG. 4 is a front view of a PCB capacitor in one embodiment;

FIG. 5 is a reverse side view of the PCB capacitor of FIG. 4;

FIG. 6 is a cross-sectional view of a PCB capacitor assembly prior to placement of capacitors thereon in an embodiment;

FIG. 7 is a cross-sectional view of the PCB capacitor assembly of FIG. 6 after placing a capacitor thereon;

fig. 8 is an external view of a PCB capacitor assembly according to an embodiment.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

A filter for suppressing electromagnetic interference in an electronic circuit. As shown in fig. 1, the filter 10 includes a housing 100, an a terminal 600, a B terminal 700, a PCB capacitor 200, a PCB capacitor assembly 300, an inductor 400, and magnetic beads 500. The housing 100 has an interior cavity 101. The a terminal 600 is provided on a first end of the housing 100. The B terminal 700 is provided on a second end of the housing 100 opposite to the first end. The a terminal 600 serves as an output terminal of the filter 10. The B terminal 700 serves as an input terminal of the filter 10. The structures of the a-terminal 600 and the B-terminal 700 are shown with reference to fig. 2 and 3. In the present embodiment, the filter 10 is a tubular filter.

The PCB capacitor 200 is disposed on a first end of the cavity 101 and is electrically connected to the a terminal 600. The PCB capacitor 200 is formed of a first PCB board with copper on both sides. The first PCB is a multi-layer PCB. In this embodiment, the first PCB board is a double-layer board. The front and back structure of the PCB capacitor 200 is shown in fig. 4 and 5.

The inductor 400 is disposed on a second end of the cavity 101 opposite to the first end, and is electrically connected to the B terminal 700. In this embodiment, the filter 10 further includes a high temperature glue 401 wrapped around the outside of the inductor 400.

PCB capacitor assembly 300 is located between PCB capacitor 200 and inductor 400. The PCB capacitor assembly 300 includes a second PCB board and a plurality of capacitors uniformly disposed on the second PCB board around a center line of the second PCB board. The PCB capacitor assembly 300 is electrically connected to the PCB capacitor 200 and the inductor 400, respectively. In this embodiment, the capacitor on the second PCB board is a chip capacitor. The chip capacitor has the advantages of large capacity, small volume and easy chip formation. The capacitance on the second PCB is four. The four capacitors are uniformly distributed on the second PCB around the center line of the second PCB. The internal structure of the PCB capacitor assembly 300 is shown in fig. 6 and 7. Fig. 6 is an internal structural diagram of the PCB capacitor assembly 300 before no capacitors are placed. In the figure, C1, C2, C3, and C4 represent positions for placing the capacitor. Fig. 7 is an internal structural diagram of the PCB capacitor assembly 300 after placing the capacitor. The back of the capacitive element of PCB capacitive assembly 300 is shown in fig. 8.

A magnetic bead 500 is disposed on a first end of the inner chamber 101. The magnetic beads 500 include a first magnetic bead 501 and a second magnetic bead 503. The first magnetic bead 501 is connected between the a terminal 600 and the PCB capacitor 200. The first magnetic beads 501 are electrically connected to the a-terminal 600 and the PCB capacitor 200, respectively. The second magnetic bead 503 is connected between the PCB capacitor 200 and the PCB capacitor assembly 300. The second magnetic beads 503 are electrically connected to the PCB capacitor 200 and the PCB capacitor assembly 300, respectively. The magnetic beads 500 serve to suppress high frequency noise and spike interference on the signal line, the power line, and have the ability to absorb electrostatic pulses. The magnetic bead 500 has high resistivity and permeability, which are equivalent to series connection of resistance and inductance, but both the resistance value and the inductance value vary with frequency. The magnetic bead 500 has better high-frequency filtering characteristics than the common inductor, and exhibits resistance at high frequency, so that higher impedance can be maintained in a quite wide frequency range, thereby improving the frequency modulation filtering effect. In this embodiment, the magnetic beads 500 are column-type magnetic beads.

The first end of the a terminal 600 passes through the first magnetic bead 501 and is connected to the PCB capacitor 200. A second end opposite to the first end of the a terminal 600 is exposed to the outside of the first end of the housing 100. In the present embodiment, the structure of the a terminal 600 also has a function of preventing itself from rotating on the housing 100 or from being pulled out. The first end of the B terminal 700 is inserted into the second end of the case 100 and connected to the inductor 400. A second end opposite to the first end of the B terminal 700 is exposed to the outside of the second end of the housing 100. In the present embodiment, the structure of the B terminal 700 also has a function of preventing itself from rotating on the housing 100 or from being pulled out. Specifically, the B terminal 700 is a flat terminal. The flat terminal can prevent the rotation of the terminal.

The first end of the B terminal 700 is provided with external threads and the second end of the housing 100 is provided with internal threads 703 that mate with the external threads of the B terminal 700. Internal threads 703 form a threaded connection with a first end of B terminal 700 for connection with inductor 400 to secure B terminal 700. In other embodiments, the a-terminal 600 may also be provided with external threads (not shown), and the first end of the housing 100 may also be provided with internal threads (not shown) that mate with the external threads of the a-terminal 600. The external threads of the a terminal are threadedly coupled with the internal threads of the first end of the housing 100 to improve the positioning fixability of the a terminal 600.

In the filter 10, the PCB capacitor 200 and the PCB capacitor assembly 300, the capacitors are disposed on the PCB board, and compared with the conventional manner in which the capacitors are directly welded inside the housing, the problem of capacitor cracking caused by the vibration of the filter due to stress can be avoided. Therefore, the anti-vibration capability of the filter is improved, and the reliability of the filter is enhanced. Meanwhile, the PCB capacitor 200 and the PCB capacitor assembly 300 are adopted to replace a ceramic feedthrough capacitor, so that the insertion loss index of the filter in the frequency range of 10KHz-1GHz can reach the level of using the ceramic feedthrough capacitor.

In this embodiment, the filter 10 further includes a retainer 800 and a retainer anti-drop structure 801. The collar seals the first end of the housing 100 to secure the components of the cavity 101. The retaining ring falling off preventing structure 801 is used to prevent the retaining ring 800 from falling off.

In this embodiment, the filter 10 further includes a sealant 900 encapsulated in the cavity 101 of the housing 100. Specifically, the sealant 900 is encapsulated in the electrical filter by a multiple vacuum encapsulation process to ensure the tightness of the filter 10 and to ensure that the filter 10 is free of bubbles. At the same time, the filter 10 is enabled to operate normally at low air pressure. The sealant 900 includes an a/B paste 901 and a G500 paste 903. The G500 glue 903 encapsulates the position where the first end of the B terminal 700 contacts the internal thread, and the retaining ring anti-falling structure 801 is formed by encapsulating the G500 glue 903. The a/B glue 901 encapsulates other parts of the cavity 101 than the part encapsulated by the G500 glue 903. Through holes (not shown) are formed in the PCB capacitor 200 and the PCB capacitor assembly 300, and the sealant 900 penetrates through the through holes to encapsulate the PCB capacitor 200 and the PCB capacitor assembly 300. In this embodiment, the PCB capacitor 200 and the PCB capacitor assembly 300 are integrally encapsulated by the a/B glue 901, so that when the filter is subjected to external stress, the PCB capacitor 200 and the PCB capacitor assembly 300 are not in contact with the housing 100, and the external stress is borne by the PCB board first, thereby achieving the purpose of protecting the capacitor.

Above-mentioned filter adopts PCB board design PCB electric capacity 200 to and form PCB electric capacity subassembly 300 with electric capacity integration on the PCB board, PCB electric capacity 200 and PCB electric capacity subassembly 300 have the through-hole, be convenient for realize the integrative embedment of A/B glue 901. After the PCB capacitor 200 and the PCB capacitor assembly 300 are filled into the tube shell to realize integral encapsulation, the chip capacitor is completely wrapped by the A/B adhesive 901 and is not contacted with the tube shell. Stress generated by warm punching, random vibration, high-frequency vibration, low-frequency vibration, impact and the like is firstly born by the PCB, so that the purpose of protecting the capacitor is achieved. Therefore, the anti-vibration capability of the filter 10 is improved, and the reliability of the filter 10 is enhanced.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1.A filter includes a housing; the housing has an inner cavity; characterized by further comprising:

an output terminal disposed on the first end of the housing;

the PCB capacitor is formed by a first PCB with double-sided copper coating; the PCB capacitor is arranged in the inner cavity near the first end of the shell and is electrically connected with the output terminal;

an input terminal disposed on a second end of the housing opposite the first end;

the PCB capacitor assembly is arranged between the PCB capacitor and the second end of the shell in the inner cavity of the shell; the PCB capacitor assembly comprises a second PCB and a plurality of capacitors uniformly distributed on the second PCB around the central line of the second PCB; the PCB capacitor assembly is respectively and electrically connected with the PCB capacitor and the input terminal;

the inductor is arranged between the PCB capacitor assembly and the second end of the shell in the inner cavity of the shell; the inductor is respectively and electrically connected with the PCB capacitor assembly and the output terminal;

the check ring is arranged in the inner cavity of the shell; the retainer ring is used for fixing a device in the inner cavity of the shell;

the check ring anti-falling structure is used for preventing the check ring from falling off.

2. The filter of claim 1, further comprising magnetic beads; the magnetic beads comprise first magnetic beads and second magnetic beads; the first magnetic beads are connected between the output terminal and the PCB capacitor and are respectively and electrically connected with the output terminal and the PCB capacitor; the second magnetic beads are connected between the PCB capacitor and the PCB capacitor assembly and are respectively and electrically connected with the PCB capacitor and the PCB capacitor assembly.

3. The filter of claim 2, wherein the magnetic beads are cylindrical magnetic beads.

4. The filter of claim 1, wherein the first PCB is a multi-layer PCB.

5. The filter of claim 1, wherein the input terminal is provided with external threads and the second end of the housing is provided with internal threads that mate with the external threads.

6. The filter of claim 1, further comprising a sealant potted in the housing cavity.

7. The filter of claim 6, wherein the PCB capacitor and the PCB capacitor assembly are each provided with a through hole, and the sealant is distributed in the cavity through the through holes.

8. The filter according to any of claims 1-7, which is a tubular filter.