CN117906831A - Pressure sensor - Google Patents

Abstract

The application discloses a pressure sensor, which comprises: the terminal button is fixedly provided with a plurality of contact pins, and the inner side of the lower end of the terminal button protrudes downwards to form a circle of inner surrounding wall; the metal pressure connector is connected to the lower end of the contact pin in a sealing way and forms an installation cavity with the end button, and a pressure leading-in hole is formed in the metal pressure connector; the pressure measuring component is arranged in the mounting cavity and is used for hermetically separating the mounting cavity into an upper cavity and a lower cavity, and comprises a pressure sensitive element positioned in the inner surrounding wall and hermetically fixed at the lower end of the inner surrounding wall; the pressure leading-in hole is communicated with the pressure sensitive element through the lower cavity, one end of the inner side of the contact pin stretches into the upper cavity and is electrically connected with the pressure measuring assembly, and protective gel covering the pressure sensitive element is filled in the upper cavity in a sealing mode. The pressure sensor can omit the surrounding frame and corresponding frame adhering process, so as to reduce the material and process cost.

Description

Pressure sensor

Technical Field

The application relates to the technical field of sensors, in particular to a pressure sensor.

Background

MEMS (microelectromechanical systems) pressure sensors are widely used due to their low cost, easy miniaturization, etc. The pressure measuring component comprises a silicon core body, the middle part of the silicon core body is provided with a film shape, the pressure applied to the silicon film on two sides changes the resistance value of a doped resistor on the silicon film, and a current or voltage signal output by a measuring circuit formed by connecting a plurality of resistors can be further processed by a conditioning circuit and then a measuring result is output to the outside. When a vacuum cavity is arranged on one side of the diaphragm in the silicon chip, the measured pressure is the pressure applied by the other side relative to the vacuum pressure, namely the absolute pressure; when atmospheric pressure is introduced into one side of the diaphragm, the measured pressure is the pressure relative to the atmosphere, namely gauge pressure; when other pressures are respectively introduced to the two sides of the diaphragm, the measured pressure is the difference between the pressures of the two sides, namely the differential pressure. In other pressure sensors, a temperature sensitive element may also be integrated to measure both the pressure and temperature of the medium.

The silicon core needs to be electrically connected with the circuit board through bonding wires (usually gold wires), and the bonding wires are easy to corrode by water vapor in the air or the like or fall off under the mechanical action, so that the pressure sensitive element or the like is generally required to be surrounded by a surrounding frame, and a protective silicone gel or fluorosilicone gel is encapsulated in the surrounding frame to mechanically and chemically protect the bonding wires, and meanwhile, the sensing surface on the side of the silicon core can conduct atmospheric pressure almost without damage. In the framing process, the enclosure is typically adhered to the side of the circuit board by an adhesive. Therefore, the above-mentioned frame attaching process is indispensable. On the other hand, the pressure sensor is connected with external equipment through a plastic terminal button and a metal pin, and sealing glue such as silicone rubber is required to be smeared between the plastic terminal button and the metal pin due to different thermal expansion coefficients so as to ensure sealing.

Disclosure of Invention

In view of the shortcomings of the prior art, the present application provides a pressure sensor that addresses at least one of the shortcomings described above.

A pressure sensor, comprising:

the terminal button is fixedly provided with a plurality of contact pins, and the inner side of the lower end of the terminal button protrudes downwards to form a circle of inner surrounding wall;

The metal pressure connector is connected to the lower end of the contact pin in a sealing way and forms an installation cavity with the end button, and a pressure leading-in hole is formed in the metal pressure connector;

the pressure measuring component is arranged in the mounting cavity and is used for hermetically separating the mounting cavity into an upper cavity and a lower cavity, and comprises a pressure sensitive element positioned in the inner peripheral wall and hermetically fixed at the lower end of the inner peripheral wall; the pressure leading-in hole is communicated with the pressure sensitive element through the lower cavity, one end of the inner side of the contact pin stretches into the upper cavity and is electrically connected with the pressure measuring assembly, and protective gel covering the pressure sensitive element is filled in the upper cavity in a sealing mode.

Preferably, the upper end of the pressure joint forms a cylinder part, the upper end of the cylinder part extends inwards to form a pressing edge, and the pressing edge is pressed downwards on a supporting surface formed by pressing the lower end of the end button on the pressure joint; a sealing gasket is arranged between the end button and the pressing edge and/or the supporting surface.

Preferably, the upper end surface of the pressure leading-in hole is sunken to form a circle of first sealing groove, the first sealing groove is internally provided with a second sealing ring, and the lower end of the base plate tightly presses the second sealing ring in the first sealing groove.

Preferably, the upper portion of the pressure introduction hole is relatively enlarged to form an enlarged diameter portion.

Preferably, the pressure measuring assembly comprises a substrate and a circuit board adhered to the upper surface of the substrate, and the pressure sensitive element is arranged on the upper surface of the circuit board; the base plate is provided with a through hole for communicating the pressure introduction hole with the pressure sensitive element.

Preferably, one end of the inner side of the pin is electrically connected with a plurality of conductive pads arranged on the circuit board through a flexible electric connector.

Preferably, the flexible electrical connector is a lead, a flexible circuit board, or a conductive spring.

Preferably, the protective gel also covers an inner end of the pin.

Preferably, the lower end of the end button is recessed to form a circle of glue containing groove outside the inner peripheral wall, and sealing adhesive used for sealing and fixing the lower end of the inner peripheral wall and the pressure measuring component is arranged in the glue containing groove.

Preferably, the outer side of the lower end of the end button is recessed to form a circle of glue containing groove positioned on the outer side of the inner surrounding wall, and sealing adhesive used for sealing and fixing the lower end of the inner surrounding wall and the pressure measuring component is arranged in the glue containing groove; meanwhile, the outer contour of the circuit board is positioned in the outer contour of the substrate, the connecting edge area of the circuit board and the substrate is positioned in the glue containing groove, and the sealing adhesive covers the connecting edge area.

Drawings

FIG. 1 is a schematic view of a pressure sensor according to a preferred embodiment of the present invention;

FIG. 2 is a schematic view of a pressure measurement assembly according to a preferred embodiment of the present invention;

reference numerals illustrate: 11a, a first seal groove; 11b, a supporting surface; 11. a first socket part; 12a, a pressure introduction hole; 12b, an expanded diameter portion; 12c, a second seal groove; 12. a joint pipe; 13. a cylinder portion; 14. edge pressing; 1. a pressure joint; 20a, communication holes; 21a, a pressing surface; 21. a second socket joint part; 22. a neck; 23. an external connection part; 24a, a receiving cavity; 24b, a glue receiving groove; 24. an inner peripheral wall; 2. an end button; 31a, through holes; 31. a substrate; 32a, a window; 32b, a connecting edge region; 32. a circuit board; 33. a pressure sensitive element; 34. a bonding wire; 35. other electronic components; 36. a conductive pad; 3. a pressure measurement assembly; 40. a flexible electrical connection; 41. an abutting portion; 42. a core; 4. a contact pin; 5a, a first sealing ring; 5b, a second sealing ring; 5c, a sealing gasket; 6a, sealing adhesive; 6b, protecting the gel;

Detailed Description

The following definitions of terms shall apply throughout this application:

The terms "upper", "lower", "left", "right", "front", "rear", "inner", "outer", "far", "near", and combinations thereof, etc. refer to an azimuth or positional relationship based on that shown in the drawings, or that is conventionally put in place when the product of the present application is used, or that is conventionally understood by those skilled in the art, merely for convenience of describing the present application and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific azimuth, be configured, operated, and used in a specific azimuth, and thus should not be construed as limiting the present application; the terms "horizontal" and "horizontal" refer to directions or planes substantially perpendicular to the directions of gravitational force when the special relationship between the horizontal and the gravitational force is not defined, and "vertical" and "horizontal" refer to two directions perpendicular to the horizontal when the plane is not defined;

The term "and/or" refers to any and all possible combinations of one or more of the listed items;

The terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application can be understood as appropriate by those of ordinary skill in the art;

The term "comprising" is intended to include, but not be limited to, and should be interpreted in the manner commonly used in the patent context;

The terms "about" or "approximately" and the like, when used with a number, may mean the particular number, or alternatively, a range approaching the particular number as understood by those skilled in the art; and if the specification states a component or feature "may", "might", "could", "preferred", "preferably", "best", "particularly", "typically", "optionally", "e.g", "often", "particularly" (or other such words) be included or has a particular characteristic, then that particular component or feature is not necessarily included or has that characteristic, but is optional, i.e., such component or feature may optionally be included in some embodiments, or may be excluded;

The phrases "in one embodiment," "according to one embodiment," "in other embodiments," and the like generally mean that a particular feature, structure, or characteristic described in connection with the phrase may be included in at least one embodiment of the present invention and may be included in more than one embodiment of the present invention (importantly, such phrases do not necessarily refer to the same embodiment); if the specification describes something as "exemplary" or "example," it is to be understood as referring to a non-exclusive example;

The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. The following examples are illustrative only and are not to be construed as limiting the application. In the following description, the same reference numerals are used to designate the same or equivalent elements, and duplicate descriptions are omitted.

As shown in fig. 1, a preferred embodiment of the present application provides a pressure sensor comprising a housing formed of a button 2 and a pressure tap 1 hermetically connected up and down, the button 2 and the pressure tap 1 enclosing a mounting cavity (not shown). The mounting chamber is sealingly separated by a pressure measuring assembly 3 into an upper chamber (not marked) and a lower chamber (not marked). The pressure measurement assembly 3 includes a pressure sensitive element 33 and other electronic components 35. The pressure joint 1 has a pressure introduction hole 12a at the lower end, and the pressure introduction hole 12a communicates with the lower chamber. One end of the inner side of the plurality of pins 4 is inwards fixed and penetrates through the end button 2 to enter the upper cavity and is electrically connected with the pressure measuring component 3. The upper chamber is filled with a protective gel 6b, and the protective gel 6b at least covers the pressure sensitive element 33. Meanwhile, the protective gel 6b can also cover the lower end of the contact pin 4, so that two steps of adhering a frame and smearing sealant at the contact pin can be omitted at the same time, and the material and process cost is reduced.

The pressure connector 1 is a metal part and may include a first sleeve portion 11 and a connector tube 12 integrally connected up and down, and the pressure inlet hole 12a is disposed in the connector tube 12. The terminal 2 may be a plastic member, and may include a neck 22, where the lower end of the neck 22 extends upward to form an external connection portion 23 for mechanical connection with an external device, and one end of the outer side of the pin 4 extends into the external connection portion 23, and the pin 4 is electrically connected with an external device. The lower peripheral portion of the neck 22 extends downward to form a second socket 21, and the upper end of the second socket 21 forms a pressing surface 21a. The neck 22 extends horizontally and covers the upper side of the upper chamber. The outer wall of the joint pipe 12 can be provided with a second sealing groove 12c, and a first sealing ring 5a is arranged in the second sealing groove 12 c.

The outer side of the upper end of the first sleeve joint part 11 protrudes upwards to form a cylindrical part 13 (preferably circular), and the inner side of the upper end of the first sleeve joint part 11 correspondingly forms a supporting surface 11b. The upper end of the tube portion 13 extends inward to form a pressing edge 14, and the pressing edge 14 presses the end button 2 downward on a supporting surface 11b formed inside the upper end of the first socket portion 11. A sealing gasket 5c is arranged between the lower end supporting surfaces 11b of the second sleeving part 21. In other embodiments, a gasket 5c may be provided between the crimp 14 and the abutment surface 21a to provide a sealed connection between the pressure fitting 1 and the end button 2.

Please refer to fig. 2 in combination. The pressure measuring component 3 may include a substrate 31 and a circuit board 32 attached to the upper surface of the substrate 31. The circuit board 32 may be provided with a window 32a or opening to expose the pressure sensitive element 33 upward to the circuit board 32. The pressure sensor 33 is disposed in the window 32a or the opening, and is adhered to the substrate 31 by a silane primer or the like, and is plugged into an upper end of a through hole 31a disposed in the substrate 31. The lower end of the through hole 31a communicates with the lower chamber. In this way, the pressure medium introduced from the pressure introduction hole 12a is applied to the pressure sensitive element 33 through the pressure introduction hole 12a, the lower chamber, and the through hole 31a in this order. The pressure sensitive element 33 is electrically connected to the circuit board 32 by bond wires 34. Other electronic components 35, such as conditioning components, protective capacitors, etc., are disposed on the upper surface of the circuit board 32. The upper portion of the pressure introduction hole 12a may be relatively enlarged to form an enlarged diameter portion 12b. The upper end surface of the pressure introduction hole 12a is recessed to form a first seal groove 11a, a second seal ring 5b is provided in the first seal groove 11a, and the lower end of the substrate 31 presses the second seal ring 5b into the first seal groove 11a.

The lower inner periphery of the neck 22 projects downwardly to form a ring of inner peripheral walls 24. The lower end of the inner peripheral wall 24 is fixed and sealed to the circuit board 32 by the sealing adhesive 6a. Preferably, a glue receiving groove 24b is formed between the inner wall 24 and the second socket portion 21 to accommodate the sealant 6a. More preferably, the outer contour of the base plate 31 is located in the outer contour of the second socket portion 21, the connecting edge region 32b of the base plate 31 and the circuit board 32 is located in the glue receiving groove 24b, so that the sealing adhesive 6a covers the connecting edge region 32b of the base plate 31 and the circuit board 32 to form better adhesion and sealing with the two, that is, the adhesion strength of the whole end button 2 and the pressure measurement assembly 3 is improved, and meanwhile, the risk that the pressure medium leaks into the accommodating cavity 24a along the inner wall of the second socket portion 21 from the adhesion surface of the base plate 31 and the circuit board 32 and the adhesion surface of the base plate 31 and the inner wall 24 is avoided.

Wherein, the inner side end of the pin 4 is electrically connected with a plurality of conductive pads 36 arranged on the circuit board 32 through a flexible electrical connector 40. The flexible electrical connector 40 may be a lead, a flexible circuit board, or a conductive spring. When the flexible electrical connector 40 is a conductive spring, an abutting portion 41 may be formed at the lower end of the pin 4, the middle portion of the abutting portion 41 protrudes downward to form a core 42, and the upper end of the conductive spring may be sleeved on the core 42 and pressed upward against the abutting portion 41. In other embodiments, the two ends of the conductive spring may be soldered to the pin 4 and the conductive pad 36, respectively. The pressure sensor 33 may be an absolute chip. In other embodiments, the pressure sensor 33 may be a gauge pressure chip, and at least one communication hole 20a penetrating up and down may be formed on the neck 22 to communicate with the atmosphere, and the protection gel 6b may be filled in the communication hole 20 a.

The scope of the present disclosure is defined not by the detailed description but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims (10)

1. A pressure sensor, comprising:

the terminal button is fixedly provided with a plurality of contact pins, and the inner side of the lower end of the terminal button protrudes downwards to form a circle of inner surrounding wall;

The metal pressure connector is connected to the lower end of the contact pin in a sealing way and forms an installation cavity with the end button, and a pressure leading-in hole is formed in the metal pressure connector;

the pressure measuring component is arranged in the mounting cavity and is used for hermetically separating the mounting cavity into an upper cavity and a lower cavity, and comprises a pressure sensitive element positioned in the inner peripheral wall and hermetically fixed at the lower end of the inner peripheral wall; the pressure leading-in hole is communicated with the pressure sensitive element through the lower cavity, one end of the inner side of the contact pin stretches into the upper cavity and is electrically connected with the pressure measuring assembly, and protective gel covering the pressure sensitive element is filled in the upper cavity in a sealing mode.

2. The pressure sensor of claim 1, wherein the upper end of the pressure joint forms a barrel portion, the upper end of the barrel portion extends inward to form a press edge, and the press edge is pressed downward on a supporting surface formed by pressing the lower end of the end button on the pressure joint; a sealing gasket is arranged between the end button and the pressing edge and/or the supporting surface.

3. The pressure sensor of claim 1, wherein the upper end surface of the pressure introduction hole is recessed to form a circle of first sealing groove, the first sealing groove is internally provided with a second sealing ring, and the lower end of the base plate presses the second sealing ring into the first sealing groove.

4. The pressure sensor of claim 1, wherein the upper portion of the pressure introduction hole is formed into an enlarged diameter portion with respect to the enlarged diameter.

5. The pressure sensor of claim 1, wherein the pressure measurement assembly comprises a substrate and a circuit board bonded to an upper surface of the substrate, the pressure sensitive element being disposed on the upper surface of the circuit board; the base plate is provided with a through hole for communicating the pressure introduction hole with the pressure sensitive element.

6. The pressure sensor of claim 1, wherein the inner end of the pin is electrically connected to a plurality of conductive pads provided on the circuit board by a flexible electrical connection.

7. The pressure sensor of claim 6, wherein the flexible electrical connection is a lead, a flexible circuit board, or a conductive spring.

8. The pressure sensor of any one of claims 1 to 7, wherein the protective gel also covers an inner end of the pin.

9. The pressure sensor of any one of claims 1 to 7, wherein the lower end of the terminal button is recessed outside to form a ring of adhesive receiving groove outside the inner wall, and a sealing adhesive for sealing and fixing the lower end of the inner wall with the pressure measuring component is provided in the adhesive receiving groove.

10. The pressure sensor according to claim 1, wherein the lower end of the end button is recessed to form a circle of glue receiving groove outside the inner wall, and sealing adhesive glue is arranged in the glue receiving groove and used for sealing and fixing the lower end of the inner wall and the pressure measuring component; the outer contour of the circuit board is positioned in the outer contour of the substrate, the connecting edge area of the circuit board and the substrate is positioned in the glue containing groove, and the sealing adhesive covers the connecting edge area.