CN212409941U

CN212409941U - Differential pressure sensor

Info

Publication number: CN212409941U
Application number: CN202021794835.6U
Authority: CN
Inventors: 王小平; 曹万; 王红明; 梁世豪; 张超军; 王晓燕
Original assignee: Wuhan Finemems Inc
Current assignee: Wuhan Finemems Inc
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2021-01-26
Anticipated expiration: 2030-08-25

Abstract

The utility model relates to the technical field of pressure sensors, and discloses a differential pressure sensor, which comprises a detection core body, wherein the detection core body comprises a base body, a circuit board and two pressure sensing chips, the circuit board is adhered to the top of the base body, and the pressure sensing chips are electrically connected to the upper surface of the circuit board; the circuit board is provided with a first through hole concentric with the pressure sensing chip; the lower part of the base body is provided with a first cavity and a second cavity, and vertical second through holes are formed in the first cavity and the second cavity. Set up the pressure sensing chip through the upper surface at the circuit board to through the top seal protection of protection piece with the pressure sensing chip, still be equipped with the second colloid that is equipped with the inside packing of second through-hole that is linked together with first through-hole in first through-hole on the circuit board and the base member and with the bottom seal protection of pressure sensing chip, change the encapsulation position of pressure sensing chip, avoid being corroded, reduce the pressure that produces after being surveyed the medium and freeze simultaneously through the elasticity of protection glue, thereby prolong its life.

Description

Differential pressure sensor

Technical Field

The utility model relates to a pressure sensor technical field specifically is a differential pressure sensor.

Background

The differential pressure sensor DPS is a sensor for measuring the difference between two pressures, and is generally used for measuring the pressure difference between the front and the rear of a certain device or component, and is most typically used for measuring the pressure difference of exhaust gas in the front and the rear channels of an exhaust particulate trap of an automobile engine.

In the prior art, nitrogen oxides (NOx) and particulate matters such as smoke dust and water vapor output by a vehicle engine are easy to crystallize and freeze at low temperature, the chip is damaged by excessive pressure generated when the particles are crystallized and frozen, and meanwhile, the nitrogen oxides form acidic solution when meeting the water vapor, so that the chip and circuits of the sensor are easy to corrode; it is therefore desirable to isolate the sensor pressure sensing die from contaminants, and a differential pressure sensor is proposed to solve the above-mentioned problems.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

The utility model provides a to prior art not enough, the utility model provides a differential pressure sensor possesses advantages such as corrosion-resistant and anti freezing, and differential pressure sensor among the prior art has been solved and has had the easy problem of being corroded and the particle crystallization damage chip that freezes.

(II) technical scheme

In order to achieve the above object, the present invention provides the following technical solutions:

a differential pressure sensor comprises a shell, wherein a detection core body is arranged in the shell, the detection core body comprises a base body, a circuit board and two pressure sensing chips, the circuit board is bonded on the top of the base body, and the pressure sensing chips are electrically connected to the upper surface of the circuit board;

the circuit board is provided with a first through hole concentric with the pressure sensing chip;

a first cavity and a second cavity are formed in the lower portion of the base body, and vertical second through holes are formed in the first cavity and the second cavity;

the second through hole is coaxial with the first through hole, the diameter of the second through hole is larger than that of the first through hole, and first protective glue is filled and sealed in the second through hole and the first through hole.

Preferably, the circuit board is provided with a protection element, the protection element is provided with two encapsulation holes concentric with the pressure sensing chip, and the encapsulation holes are filled with second protective glue.

Preferably, the upper surface of base member is equipped with the constant head tank, constant head tank and circuit board phase-match are used for the location circuit board.

Preferably, the shell is internally provided with a mounting groove matched with the detection core body for mounting the detection core body.

Preferably, the shell is also internally provided with limit grooves which are distributed on the front side and the rear side of the mounting groove; a limiting block is further arranged on the base body; the position of the limiting block corresponds to that of the limiting groove, and the limiting block is matched with the limiting groove in size.

Preferably, the mounting groove is further provided with a second guide pipe and a first guide pipe, the second guide pipe and the first guide pipe are both communicated and connected with an air pipe, and the air pipe is fixedly connected to the lower end of the shell.

Preferably, the second guide pipe is matched with the second cavity and is positioned in the second cavity; the first guide pipe is matched with the first cavity and is positioned in the first cavity.

(III) advantageous effects

Compared with the prior art, the utility model provides a differential pressure sensor possesses following beneficial effect:

1. this differential pressure sensor, through the upper surface at the circuit board set up the pressure sensing chip to seal the protection through the top that the protection piece will sense the pressure chip, still be equipped with the second colloid that the second through-hole inside that is linked together with first through-hole in through the first through-hole on the circuit board and the base member is filled with the bottom of pressure sensing chip and seal the protection, change the encapsulation position of pressure sensing chip, avoid being corroded, the elasticity through the protective rubber simultaneously reduces the pressure that produces after being surveyed the medium and freezing, thereby prolong its life.

2. This differential pressure sensor, the diameter of second through-hole with be greater than the diameter of first through-hole, supreme diminishing gradually is down followed to first protective glue, increases effectual pressure sensing area.

Drawings

Fig. 1 is a schematic overall structure diagram of the first embodiment.

Fig. 2 is a schematic diagram of an exploded structure according to an embodiment.

Fig. 3 is a schematic structural diagram of a detection core according to an embodiment.

Fig. 4 is a schematic structural diagram of a circuit board according to a first embodiment.

Fig. 5 is a schematic structural diagram of a circuit board according to a first embodiment.

Fig. 6 is a schematic structural diagram of a substrate according to a first embodiment.

Fig. 7 is a schematic structural diagram of a substrate according to a first embodiment.

FIG. 8 is a schematic view of a substrate of another structure according to one embodiment

Fig. 9 is a schematic diagram of a circuit board with another structure according to the first embodiment.

In the figure: 10 casing, 101 second mounting groove, 102 connecting pipe, 103 mounting groove, 104 spacing groove, 20 upper cover, 30 detection core body, 31 circuit board, 311 first through hole, 312 gold wire bonding part, 313 pressure sensing part, 32 base body, 321 second cavity, 322 first cavity, 323 second through hole, 324 first protective glue, 325 spacing block, 326 detection cavity, 327 through hole, 328 positioning groove, 33 pressure sensing chip, 34 protection piece, 341 second protective glue, 342 packaging hole, 35 chip, 11 electrical connector, 12 air pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1-9, a differential pressure sensor includes a housing 10, a mounting groove 103 is provided in the housing 10, a detecting core 30 is provided in the mounting groove 103, and an upper cover 20, an electrical connector 11 and an air tube 12 are connected to the housing 10; the electric connector 11 is electrically connected with the detection core 30; the upper cover 20 covers the detection core body 30; the air pipe 12 is fixedly connected to the lower portion of the housing 10, and is connected to the second guide pipe 102 and the first guide pipe 101 in the mounting groove 103 in a communicating manner, for feeding the detected gas, detecting the pressure difference by the detecting core 30, and transmitting the signal of the pressure difference through the electrical connector.

As shown in fig. 8-9, for detecting a structure of the detection core 30, the structure includes a base 32, a circuit board 31 and two pressure sensing chip parts 313, the circuit board 31 is adhered on the top of the base 32, the pressure sensing part 313 is located between the surfaces where the circuit board 31 and the base 32 are adhered, the base 32 is provided with a detection cavity 326 vertically arranged corresponding to the position of the pressure sensing part 313, the lower part of the base 32 is provided with the detection cavity 326, the detection cavity 326 is arranged on the periphery of a through hole 327, glue is filled in the through hole 327 to isolate the pressure sensing part 313 from smoke dust and water vapor, so as to avoid easy crystallization and freezing at low temperature, receive pressure and avoid corrosion.

However, since the pressure-sensitive portion 313 is disposed below the circuit board 31, the contact area is large at the time of crystal freezing and detection, resulting in a small effective pressure-sensitive area occupation ratio of the pressure-sensitive portion 313 and being susceptible to temperature and drift, and therefore, another structure has been proposed.

As shown in fig. 1-7, further, the detection core 30 includes a base 32, a circuit board 31 and two pressure-sensing chips 33, the circuit board 31 is adhered on top of the base 32, and the pressure-sensing chips 33 are electrically connected to the upper surface of the circuit board 31;

the circuit board 31 is provided with a first through hole 311 concentric with the pressure sensing chip 33; the lower part of the base body 32 is provided with a first cavity 322 and a second cavity 321, and the second guide pipe 102 is matched with the second cavity 321 and is positioned in the second cavity 321; the first draft tube 101 is matched with the first cavity 322 and is positioned in the first cavity 322; the first cavity 322 and the second cavity 321 are both provided with a vertical second through hole 323; the second through hole 323 is coaxial with the first through hole 311, the diameter sum of the second through hole 323 is larger than that of the first through hole 311, and first protective glue 324 is encapsulated in the second through hole 323 and the first through hole 311, so that the first protective glue 324 is gradually reduced from bottom to top; the pressure is sent to the pressure sensing chip 33 for detection through the second through hole 323, the first through hole and the first protective adhesive 324, and the first protective adhesive 324 is gradually reduced from bottom to top, so that the area of the pressure sensing chip 33 subjected to pressure is finally reduced, the effective pressure sensing area is increased, the detection accuracy is improved, the influence of temperature on the pressure sensing chip is reduced, and in addition, the problems that nitric oxide forms an acidic solution when meeting water vapor, and the chip and the circuit of the sensor are prone to corrosion are also avoided; the pressure-sensitive chip 33 is also more easily produced and assembled by being disposed above the circuit board 31.

Further, the circuit board 31 is provided with a protection element 34, the protection element 34 is provided with two encapsulation holes 342 concentric with the pressure sensing chip 33, and the encapsulation holes 342 are filled with a second protective adhesive 341; the second protective paste 341 and the protection member 34 form a sealed space to protect the pressure sensing chip 33 from corrosion from the outside, and the connection between the two can be more stable for the pressure sensing chip 33.

Furthermore, a gold wire bonding part 312 is arranged on the circuit board 31, and the gold wire bonding part 312 is connected with the pressure sensing chip 33 through a gold wire; the circuit board 31 may be connected to the electrical connector 11 by aluminum wire bonding, soldering or laser welding;

further, a mounting groove 103 matched with the detection core 30 is formed in the shell 10 and used for mounting the detection core 30, and limiting grooves 104 distributed on the front side and the rear side of the mounting groove 103 are also formed in the shell 10; a limiting block 325 is also arranged on the base body 32; the position of the limiting block 325 corresponds to that of the limiting groove 104, and the size of the limiting block is matched with that of the limiting groove; the upper surface of the base body 32 is provided with a positioning groove 328, and the positioning groove 328 is matched with the circuit board 31 and used for positioning the circuit board 31; the base 32 and the circuit board 31 are connected more stably, the base 32 is mounted in the housing 10 more stably, and the assembly in production is facilitated.

When in use:

(1) the measured fluid enters the first cavity 322 and the second cavity 321 through the air tube 12, the pressure of the measured fluid acts on the second protective adhesive 341, the pressure sensing chip 33 detects the pressure, and the second protective adhesive 341 and the first protective adhesive 324 encapsulate and protect the pressure sensing chip 33 to avoid corrosion.

In summary, the pressure sensing chip 33 is disposed on the upper surface of the circuit board 31, the top of the pressure sensing chip 33 is sealed and protected by the protection member 34, the bottom of the pressure sensing chip 33 is sealed and protected by the second colloid 324 filled in the first through hole 311 on the circuit board 31 and the second through hole 323 arranged in the base 32 and communicated with the first through hole 311, the packaging position of the pressure sensing chip 33 is changed to avoid corrosion, and meanwhile, the pressure generated after the detected medium is frozen is reduced by the elasticity of the protection colloid, so that the service life of the pressure sensing chip is prolonged, and the problems that the differential pressure sensor in the prior art is easy to corrode and the chip is damaged by freezing of particle crystals are solved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A differential pressure sensor, comprising a housing (10), a detection core (30) arranged in the housing (10), characterized in that: the detection core body (30) comprises a base body (32), a circuit board (31) and two pressure sensing chips (33), the circuit board (31) is adhered to the top of the base body (32), and the pressure sensing chips (33) are electrically connected to the upper surface of the circuit board (31);

the circuit board (31) is provided with a first through hole (311) which is concentric with the pressure sensing chip (33);

a first cavity (322) and a second cavity (321) are formed in the lower portion of the base body (32), and vertical second through holes (323) are formed in the first cavity (322) and the second cavity (321);

the second through hole (323) and the first through hole (311) are coaxial, the diameter sum of the second through hole (323) is larger than that of the first through hole (311), and first protective glue (324) is encapsulated in the second through hole (323) and the first through hole (311).

2. A differential pressure sensor as recited in claim 1, wherein: the circuit board (31) is provided with a protection part (34), the protection part (34) is provided with two packaging holes (342) which are concentric with the pressure sensing chip (33), and a second protective adhesive (341) is encapsulated in the packaging holes (342).

3. A differential pressure sensor as recited in claim 1, wherein: the upper surface of base member (32) is equipped with constant head tank (328), constant head tank (328) and circuit board (31) phase-match for location circuit board (31).

4. A differential pressure sensor as recited in claim 1, wherein: the shell (10) is internally provided with a mounting groove (103) matched with the detection core body (30) for mounting the detection core body (30).

5. A differential pressure sensor as claimed in claim 4, wherein: limiting grooves (104) distributed on the front side and the rear side of the mounting groove (103) are further formed in the shell (10); a limiting block (325) is further arranged on the base body (32); the position of the limiting block (325) corresponds to that of the limiting groove (104), and the size of the limiting block is matched with that of the limiting groove.

6. A differential pressure sensor as claimed in claim 4, wherein: the mounting groove (103) is also provided with a second guide pipe (102) and a first guide pipe (101), the second guide pipe (102) and the first guide pipe (101) are both communicated and connected with an air pipe (12), and the air pipe (12) is fixedly connected to the lower end of the shell (10).

7. A differential pressure sensor as recited in claim 6, wherein: the second guide pipe (102) is matched with the second cavity (321) and is positioned in the second cavity (321); the first draft tube (101) is matched with the first cavity (322) and is positioned in the first cavity (322).