Grounding structure of ceramic capacitive pressure sensor

Abstract

The utility model relates to a grounding structure of a ceramic capacitive pressure sensor. The utility model comprises a metal shell which is provided with an annular cavity; the plastic socket comprises a connecting column extending into the annular cavity; the printed circuit board is arranged in the annular cavity; and the grounding insert comprises an annular part and a connecting part, wherein the annular part is respectively propped against the side walls of the annular cavity and the connecting column, and the connecting part extends to the annular part, is partially embedded in the plastic socket and is connected with the printed circuit board. The utility model solves the problems that the ground lug of the ceramic pressure sensor in the prior art is easy to break during assembly and the ground lug is loose and poor in contact after long-time use.

Description

Technical Field

[0001] The utility model relates to the technical field of pressure sensors, in particular to a grounding structure of a ceramic capacitor pressure sensor. Background Art

[0002] A ceramic pressure transducer is a device or apparatus that senses pressure signals and converts them into usable electrical signals according to specific patterns. Depending on the pressure sensing core, ceramic pressure sensors can be categorized as either ceramic resistor pressure sensors (using a ceramic resistor pressure core) or ceramic capacitor pressure sensors (using a ceramic capacitor pressure core).

[0003] Ceramic capacitive pressure sensors, due to their use of a ceramic capacitor pressure core, have a relatively low initial capacitance. However, their "parasitic capacitance," including lead cable capacitance (up to 800pF for a 1-2 meter wire), stray capacitance in the measurement circuit, and capacitance between the sensor plate and surrounding conductors, can be significant. This can lead to the following problems: reduced sensor sensitivity; random variations in capacitance (such as cable capacitance), causing sensor instability and impacting measurement accuracy; and even variations exceeding the capacitance change caused by the measured object, rendering the sensor inoperable.

[0004] In order to solve these problems, ceramic capacitor pressure sensors usually adopt a special structural design to offset the adverse effects of their defects, that is, adding a grounding structure to the sensor circuit.

[0005] The existing grounding between the circuit and the metal housing is achieved through a grounding plate extending outward from the printed circuit board. The grounding plate needs to be clamped between the plastic socket and the metal housing. However, this design has the following drawbacks:

[0006] The grounding sheet is made of copper foil with a thickness of 0.05 to 0.2 mm and a width of 2 to 5 mm. Copper foil of such thickness and area is very fragile and can easily break, fold, or skew during assembly, making grounding impossible.

[0007] The shortcomings of plastic materials during the clamping process are very obvious. After the initial assembly is completed, the external dimensions of the plastic parts are full, but as the product is used for a longer time, the plastic parts may shrink, creep, deform, etc., resulting in poor grounding of the grounding plate, which seriously affects the service life of the product. Summary of the Invention

[0008] To this end, the utility model provides a grounding structure for a ceramic capacitor pressure sensor to solve the problems in the prior art that the grounding piece of the ceramic pressure sensor is easily broken during assembly and the grounding piece becomes loose and has poor contact after long-term use.

[0009] In order to solve the above technical problems, the utility model provides a grounding structure of a ceramic capacitor pressure sensor, comprising:

[0010] A metal shell is provided with an annular cavity;

[0011] A plastic socket including a connecting post extending into the annular cavity;

[0012] A printed circuit board is disposed in the annular cavity;

[0013] The grounding insert comprises an annular portion respectively abutting against the side walls of the annular cavity and the connecting column, and a connecting portion extending from the annular portion, partially embedded in the plastic socket and connected to the printed circuit board.

[0014] In one embodiment of the present invention, a groove is provided at one end of the connecting column relative to the annular cavity, and an installation cavity is provided at the lower part of the annular cavity. A ceramic capacitor pressure core is provided in the installation cavity, and a accommodating cavity for accommodating the printed circuit is formed between the groove and the ceramic capacitor pressure core.

[0015] In one embodiment of the present invention, a sealing groove is provided at the bottom end of the installation cavity, and a sealing member is provided in the sealing groove to abut against the bottom end of the ceramic capacitor pressure core.

[0016] In one embodiment of the present utility model, an annular step is provided at the bottom end of the annular cavity, the connecting column is against the annular step, an opening is provided at one end of the annular cavity opposite to the annular step and a flange is provided at the opening, an annular recess is provided at the outer end of the connecting column, and the flange is against the lower end surface of the annular recess.

[0017] In one embodiment of the present utility model, the connecting portion includes a first section that is respectively abutted against the flange and the lower end surface of the annular recess, a second section embedded in the plastic socket, and a third section welded to the printed circuit board, and the first section, the second section and the third section are connected in sequence.

[0018] The above technical solution of the utility model has the following advantages compared with the prior art:

[0019] The grounding structure of a ceramic capacitor pressure sensor described in the utility model is characterized by arranging a grounding insert having an annular portion between the cylindrical surface where the plastic socket contacts the metal shell. The entire annular portion of the grounding insert can contact the surface of the annular cavity of the metal shell. The printed circuit board and the metal insert are welded together by the connecting portion, thereby achieving grounding between the printed circuit board and the metal shell. The design of embedding the grounding insert and the plastic socket as one body avoids the problem that the traditional grounding plate is easy to break, fold or loose during assembly and use, and solves the problem in the prior art that the grounding plate is easy to break during assembly and the grounding plate becomes loose and has poor contact after long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0021] Figure 1 It is a schematic diagram of the overall structure of the grounding structure of the ceramic capacitor pressure sensor of the present invention.

[0022] Figure 2 yes Figure 1 A partial enlarged schematic diagram.

[0023] Description of the accompanying drawings:

[0024] 1. Metal housing; 11. Annular cavity; 111. Annular step; 112. Flanged edge; 12. Mounting cavity; 13. Ceramic capacitor pressure core; 14. Sealing groove; 15. Sealing element;

[0025] 2. Plastic socket; 21. Connecting column; 211. Groove; 212. Annular notch;

[0026] 3. Printed circuit boards;

[0027] 4. Grounding insert; 41. Ring portion; 42. Connecting portion; 421. First section; 422. Second section; 423. Third section. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0029] In the present invention, if there is a description of directions (up, down, left, right, front and back), it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0030] In this utility model, "several" means one or more, "multiple" means more than two, "greater than," "less than," "exceeds," etc. are understood to exclude the number itself; "above," "below," "within," etc. are understood to include the number itself. In the description of this utility model, the use of "first" or "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0031] In this utility model, unless otherwise expressly defined, terms such as "disposed," "installed," and "connected" should be interpreted broadly. For example, they may refer to direct connection or indirect connection through an intermediate medium; fixed connection or detachable connection or integral molding; mechanical connection or electrical connection or mutual communication; and internal connection between two components or interaction between two components. Those skilled in the art can reasonably determine the specific meanings of these terms in this utility model based on the specific content of the technical solution.

[0032] Reference Figure 1 、 Figure 2 As shown, the grounding structure of a ceramic capacitor pressure sensor of the present invention includes:

[0033] The metal shell 1 is provided with an annular cavity 11;

[0034] The plastic socket 2 includes a connecting column 21 extending into the annular cavity 11;

[0035] The printed circuit board 3 is arranged in the annular cavity 11;

[0036] The grounding insert 4 includes an annular portion 41 that abuts against the side walls of the annular cavity 11 and the connecting column 21 , and a connecting portion 42 that extends from the annular portion 41 , is partially embedded in the plastic socket 2 , and is connected to the printed circuit board 3 .

[0037] In one embodiment, the annular cavity 11 and the connecting column 21 are both cylindrical. It can be understood that the annular portion 41 is circular.

[0038] In one embodiment, a groove 211 is provided at one end of the connecting column 21 relative to the annular cavity 11, and an installation cavity 12 is provided at the lower part of the annular cavity 11. A ceramic capacitor pressure core 13 is provided in the installation cavity 12, and a receiving cavity for accommodating the printed circuit is formed between the groove 211 and the ceramic capacitor pressure core 13.

[0039] In one embodiment, a sealing groove 14 is provided at the bottom end of the installation cavity 12 , and a sealing member 15 is provided in the sealing groove 14 to abut against the bottom end of the ceramic capacitor pressure core 13 .

[0040] In one embodiment, an annular step 111 is provided at the bottom end of the annular cavity 11, and the connecting column 21 is abutted against the annular step 111. An opening is provided at one end of the annular cavity 11 opposite to the annular step 111, and a flange 112 is provided at the opening. An annular recess 212 is provided at the outer end of the connecting column 21, and the flange 112 is abutted against the lower end surface of the annular recess 212.

[0041] In one embodiment, the connecting portion 42 includes a first section 421 that respectively abuts against the flange 112 and the lower end surface of the annular recess 212, a second section 422 embedded in the plastic socket 2, and a third section 423 welded to the printed circuit board 3, and the first section 421, the second section 422 and the third section 423 are connected in sequence.

[0042] By placing a (metal copper) grounding insert 4 with an annular portion 41 between the contacting cylindrical surfaces of the plastic socket 2 and the metal housing 1, the entire annular portion 41 of the grounding insert 4 can contact the surface of the annular cavity 11 of the metal housing 1, increasing the contact area. The printed circuit board 3 and the metal insert are welded together via the connecting portion 42, thereby achieving grounding between the printed circuit board 3 and the metal housing 1. The integrated design of the grounding insert 4 and the plastic socket 2 avoids the problem of traditional grounding plates being easily broken, folded, or loosened during assembly and use, solving the problem of grounding plates in the prior art being easily broken during assembly and loosened and poor contact after long-term use.

[0043] The grounding insert 4 comprises an annular portion 41 and an extension portion, making the entire structure more solid and stable. The annular portion 41 is in close contact with the annular cavity 11 of the metal housing 1, ensuring the stability of the grounding connection under vibration or external force.

[0044] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to examples, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A grounding structure for a ceramic capacitor pressure sensor, characterized in that: include: A metal housing (1) is provided with an annular cavity (11); A plastic socket (2) comprising a connecting post (21) extending into the annular cavity (11); A printed circuit board (3) is arranged in the annular cavity (11); The grounding insert (4) comprises an annular portion (41) respectively abutting against the side walls of the annular cavity (11) and the connecting column (21), and a connecting portion (42) extending from the annular portion (41), partially embedded in the plastic socket (2) and connected to the printed circuit board (3).

2. The grounding structure of a ceramic capacitor pressure sensor according to claim 1, characterized in that: A groove (211) is provided at one end of the connecting column (21) relative to the annular cavity (11); a mounting cavity (12) is provided at the lower portion of the annular cavity (11); a ceramic capacitor pressure core (13) is provided in the mounting cavity (12); and a receiving cavity for receiving the printed circuit is formed between the groove (211) and the ceramic capacitor pressure core (13).

3. The grounding structure of a ceramic capacitor pressure sensor according to claim 2, characterized in that: A sealing groove (14) is provided at the bottom end of the installation cavity (12), and a sealing member (15) is provided in the sealing groove (14) and abuts against the bottom end of the ceramic capacitor pressure core (13).

4. The grounding structure of a ceramic capacitor pressure sensor according to claim 1, characterized in that: An annular step (111) is provided at the bottom end of the annular cavity (11), the connecting column (21) abuts against the annular step (111), an opening is provided at one end of the annular cavity (111) opposite to the annular step (111), and a flange (112) is provided at the opening, an annular recess (212) is provided at the outer end of the connecting column (21), and the flange (112) abuts against the lower end surface of the annular recess (212).

5. The grounding structure of a ceramic capacitor pressure sensor according to claim 4, characterized in that: The connecting portion (42) comprises a first section (421) respectively abutting against the flange (112) and the lower end surface of the annular recess (212), a second section (422) embedded in the plastic socket (2), and a third section (423) connected to the printed circuit board (3) by welding, wherein the first section (421), the second section (422), and the third section (423) are connected in sequence.

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