Differential pressure sensor

Abstract

A differential pressure sensor which is easy to manufacture and low in cost comprises a metal main body part, the bottom of which is provided with two interfaces which extend downwards along the longitudinal direction and are separated transversely; the first diaphragm assembly and the second diaphragm assembly are connected to the two connectors in a sealed mode respectively, a first oil filling cavity and a second oil filling cavity are correspondingly defined by the first diaphragm assembly and the second diaphragm assembly and the main body part, and the first diaphragm assembly and the second diaphragm assembly at least comprise metal elastic diaphragms; two ends of the differential pressure connecting channel are respectively communicated to the two oil filling cavities; the differential pressure connecting channel comprises an internal channel; the inner end of the channel is communicated to the second oil filling cavity, and the outer end extends to the second surface of the main body part; the surface channel extends along the outer surface of the main body part, one end of the surface channel is communicated to the outer end of the internal channel, the other end of the surface channel is communicated to the outer end of the channel, and the surface channel is defined by the outer surface of the main body part and the cover plate; the two oil filling cavities and the pressure difference connecting channel are filled with the pressure guiding oil; one side of the pressure sensitive element is exposed in the second oil filling cavity, and the other side of the pressure sensitive element blocks one end of the internal channel.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a differential pressure sensor. Background Art

[0002] A differential pressure sensor is a sensor used to measure the difference in pressure between two locations. CN113029430A discloses a differential pressure sensor mainly used in an EGR (Exhaust Gas Recirculation) system, which introduces pressure to the pressure-sensitive surfaces of the pressure chip on opposite sides through two metal diaphragms and silicone oil. The pressure chip is arranged in the upper wall cavity of one of the pressure introduction ports, and the other pressure introduction port extends to the pressure chip through a transverse connecting channel arranged in a metal sintering seat. Due to the size limitation of the sensor pressure chip, the width of the differential pressure connection channel is usually less than 2 mm, and on the other hand, due to the limitation of the pressure connection and the size of the diaphragm, its transverse dimension exceeds 30 mm, and the aspect ratio is as high as more than 15. The mechanical processing of such a hole with a large aspect ratio is extremely difficult, and the production cost is very high. Summary of the invention

[0003] In view of the deficiencies of the prior art, the present application provides a differential pressure sensor to improve its manufacturability and reduce costs.

[0004] To achieve the above objectives, the present application provides the following technical solution: a differential pressure sensor, comprising:

[0005] The main body is made of metal, and the bottom thereof has two interfaces extending downward in the longitudinal direction and spaced apart in the transverse direction;

[0006] The two diaphragm assemblies, a first diaphragm assembly and a second diaphragm assembly, are respectively sealed and connected to the two interfaces and correspondingly enclose a first oil-filled cavity and a second oil-filled cavity between the main body, and at least include a metal elastic diaphragm for receiving the pressure to be measured and extending laterally;

[0007] The pressure difference connecting channel whose two ends are respectively connected to the two oil filling chambers comprises: an internal channel arranged inside the main body, whose inner end is connected to the first oil filling chamber and whose outer end extends to the first surface of the main body; a channel whose inner end is connected to the second oil filling chamber and whose outer end extends to the second surface of the main body; and a surface channel extending along the outer surface of the main body, whose one end is connected to the outer end of the internal channel and whose other end is connected to the outer end of the channel, and which is surrounded by the outer surface of the main body and the cover plate;

[0008] Pressure-guiding oil, filled in the two oil-filling chambers and the pressure difference connecting channel;

[0009] and a pressure sensitive element having one side exposed to the second oil-filled cavity and the other side blocking one end of the internal passage.

[0010] Preferably, a continuous groove is formed on the outer surface of the main body, and the cover plate closes the groove from the outside and surrounds the groove to form the surface channel.

[0011] Preferably, the outer surface of the main body is provided with a receiving groove for accommodating the cover plate, and the cover plate is sealingly welded to the edge of the receiving groove; the groove is formed by the bottom concave of the receiving groove.

[0012] Preferably, the first surface and the second surface are in the same plane.

[0013] Preferably, the first surface and the second surface are the same side plane.

[0014] The elastic diaphragms of the first diaphragm assembly and the second diaphragm assembly are arranged on the same transverse plane.

[0015] Preferably, the diaphragm assembly also includes a transversely extending annular bottom plate; the upper surface of the annular bottom plate of the second diaphragm assembly is seal-welded to the bottom surface of the main body, and the lower surface of the annular bottom plate of the second diaphragm assembly is seal-welded to the outer edge of the elastic diaphragm.

[0016] Preferably, the cover plate comprises a first portion extending longitudinally, and a lower end of the first portion is integrally connected to the outer edge of the annular bottom plate of the second diaphragm assembly.

[0017] Preferably, the lower end of the main body extends downward to form a sealing flange, and at least a portion of the inner wall of the interface is defined by the inner wall of the sealing flange; the sealing flange is provided with a notch for accommodating the first portion to pass laterally.

[0018] Preferably, the annular bottom plates of the two second diaphragm assemblies are integrally connected to the cover plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A bottom view of a differential pressure sensor device according to a first preferred embodiment;

[0020] Figure 2 The differential pressure sensor device of the first preferred embodiment is Figure 1 A cross-sectional view of AA shown in FIG.

[0021] Figure 3 The differential pressure sensor of the first preferred embodiment is Figure 1 A cross-sectional view of AA shown in FIG.

[0022] Figure 4The differential pressure sensor of the first preferred embodiment is Figure 1 A cross-sectional view of BB shown in ;

[0023] Figure 5 A perspective view of a differential pressure sensor according to a first preferred embodiment;

[0024] Figure 6 is a three-dimensional diagram of the main body of the first preferred embodiment;

[0025] Figure 7 A perspective view of a partial structure of a first preferred embodiment;

[0026] Figure 8 A perspective view of a partial structure of a second preferred embodiment;

[0027] Fig. 9 The differential pressure sensor of the third preferred embodiment is Figure 1 A cross-sectional view of AA shown in FIG.

[0028] Explanation of reference numerals: 200, differential pressure sensor device; 201, sealing flange; 202, terminal; 203, electrical connector; 20, main housing; 301, flange; 30a, sealing groove; 30b, sealing groove; 30, cover; 40, circuit; 50, electrical connector; 60a, interface; 60b, hole; 60, sealing ring; 70, bushing; 100, differential pressure sensor; 101, inner cavity; 102, concave cavity; 103, accommodating cavity; 104, protruding portion; 10a, concave cavity; 10b, storage groove; 10c, upper surface; 10d, upper surface; 10f, upper surface; 10, main body; 11a, interface; 11b, notch; 11, sealing flange; 12, step surface; 14, channel; 15, Channel; 16a, groove; 16b, groove; 16c, bottom groove; 16, side plane; 17a, transverse part; 17b, longitudinal part; 17, surface channel; 18, channel; 19a, first part; 19b, second part; 19c, third part; 19, cover plate; 1a, oil-filled chamber; 1b, oil-filled chamber; 1c, pressure difference connecting channel; 1d, oil-filled hole; 1e, oil-filled hole; 1f, bottom surface; 21, elastic diaphragm; 22, annular bottom plate; 23, pressure ring; 2a, diaphragm assembly; 2b, diaphragm assembly; 32, pin; 33a, via; 33, insulating sealing body; 3, pressure sensitive element; 41, lead; 4, filling body; 5a, cofferdam; 5, plugging piece; 6a, cofferdam; 6, plugging piece. DETAILED DESCRIPTION

[0029] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. The following embodiments are exemplary and are only used to explain the present application, and cannot be interpreted as limiting the present application. In the following description, the same symbols are used to represent the same or equivalent elements, and repeated descriptions are omitted.

[0030] In the description of the present application, it should be understood that the terms "upper", "lower", "inner", "outer", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or the directions or positional relationships in which the products of the present application are usually placed when in use, or the directions or positional relationships usually understood by those skilled in the art, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the equipment or components referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limitations on the present application. In addition, the prepositive terms "first", "second", "third", etc. are only used to distinguish the modified objects, and cannot be understood as indicating or implying relative importance.

[0031] In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] It should be further understood that the term “and / or” used in the specification and corresponding claims of this application refers to any and all possible combinations of one or more of the listed items.

[0033] Please refer to Figure 1 to Figure 7The differential pressure sensor 100 of the first embodiment includes a metal main body 10, a diaphragm assembly 2a, and a diaphragm assembly 2b. The bottom of the main body 10 has two interfaces 11a extending downward in the longitudinal direction and separated laterally from front to back. The diaphragm assemblies 2a and 2b are respectively sealed and connected to the two interfaces 11a. The diaphragm assembly 2a and the corresponding one of the interfaces 11a form an oil-filled cavity 1a, and the diaphragm assembly 2b and the corresponding other interface 11a form an oil-filled cavity 1b. The diaphragm assemblies 2a and 2b include at least one laterally extending metal elastic diaphragm 21. The elastic diaphragm 21 of the diaphragm assembly 2a is used to receive a first pressure to be measured, and the elastic diaphragm of the diaphragm assembly 2b is used to receive a second pressure to be measured. The differential pressure sensor device 200 includes the above-mentioned differential pressure sensor 100, and a shell forming a mounting cavity for accommodating the differential pressure sensor 100. The housing may include a main housing 20 and a cover 30, wherein an electrical connector 203 formed on the main housing 20 may be inlaid with a plurality of terminals 202, and a circuit 40 electrically connected to the differential pressure sensor 100 and the terminals 202 is also disposed in the mounting cavity. At least one bushing 70 may be disposed on the cover 30.

[0034] The differential pressure sensor 100 also includes a pressure sensitive element 3, a pressure differential connecting channel 1c, and pressure-conducting oil (not shown) filled in the oil-filling chambers 1a, 1b and the pressure differential connecting channel 1c. The two ends of the pressure differential connecting channel 1c are respectively connected to the two oil-filling chambers 1a, 1b. It can be arranged in the oil-filling chamber 1a. One side of the pressure sensitive element 3 is exposed to the oil-filling chamber 1b, and the first pressure to be measured received by the outer side of the elastic diaphragm 21 of the diaphragm assembly 2a is transmitted to one side of the pressure sensitive element 3 via the pressure-conducting oil in the oil-filling chamber 1a; the other side of the pressure sensitive element 3 is blocked at one end of the pressure differential connecting channel 1c. The second pressure to be measured received by the outer side of the elastic diaphragm 21 of the diaphragm assembly 2b is transmitted to the other side of the pressure sensitive element 3 via the pressure-conducting oil in the oil-filling chamber 1a and the pressure differential connecting channel 1c. Thus, the pressure sensitive element 3 obtains the pressure difference between the first pressure to be measured and the second pressure to be measured. The bottom surface 1f of the main body 10 may be recessed inward to form two concave cavities 102 that constitute a part of the oil filling cavity 1a and the oil filling cavity 1b, respectively, so as to leave necessary longitudinal space for the elastic diaphragm 21 to deform inward. The concave cavity 102 of the oil filling cavity 1a may continue to be recessed inward to form a receiving cavity 103 for receiving the pressure sensitive element 3. A filling body 4 may be provided in the receiving cavity 103 to reduce the filling space of the pressure oil, thereby improving the response of the sensor.

[0035] The differential pressure sensor 100 may include an internal channel (not marked) disposed in the main body 10, a surface channel 17 extending along the outer surface of the main body 10, and a channel 18, which are connected in sequence. The internal channel may include a longitudinally extending channel 14 and a transverse channel 15 extending left and right, the lower end of the channel 14 is closed by the pressure sensitive element 3, and the inner end of the channel 15 may be vertically connected to the upper end of the channel 14. The inner end of the internal channel is connected to the oil filling chamber 1b, and the other end is connected to the first surface of the main body 10; the inner end of the channel 18 is transversely connected to the oil filling chamber 1b, and its outer end extends to the second surface. The first surface and the second surface may be the same side plane 16, and the surface channel 17 extends along the side plane 16 so that the outer end of the channel 18 is connected to the outer end of the channel 15, so that the surface channel 17 can be prevented from crossing multiple surfaces and increasing the difficulty of welding the grooves on the surface of the cover plate 19 and the main body 10.

[0036] The channels 14 and 15 can be obtained by machining, the surface channel 17 can be obtained by the grooves formed on the side plane 16 (which can include the longitudinally extending grooves 16b and the grooves 16a extending transversely in the front and rear directions) and the cover plate 19 (which can correspondingly include the longitudinally extending first part 19a and the front-rear extending second part 19b), and the channel 18 can be obtained by the bottom surface groove 16c formed on the bottom surface 1f of the main body 10 and a bottom plate (not shown). The combination of the groove 16b and the grooves 16a extending transversely in the front and rear directions can be straightened in the middle, or directly replaced by a groove extending obliquely up and down; accordingly, the first part 19a and the second part 19b can also be straightened, or directly replaced by a plate-like part obliquely up and down.

[0037] The advantage of arranging the pressure difference connection channel 1c in this way is significant, that is, compared with the long thin hole in the front-to-back direction in the prior art, it is only necessary to process a groove on the surface of the main body 10, weld the elastic diaphragm 21 to the bottom surface 1f to obtain the channel 18, and weld the cover plate 19 to the groove to obtain the surface channel 17. Its manufacturability is greatly improved.

[0038] Preferably, the outer surface of the main body 10 is provided with a receiving groove 10b for accommodating the cover plate 19. The cover plate 19 is flush with the edges of the receiving groove 10b and sealed by welding. The groove is formed by the bottom of the receiving groove 10b being concave.

[0039] The surface channel 17 may include a longitudinal portion 17b and a transverse portion 17a extending forward and backward. One end of the transverse portion 17a is connected to the outer end of the channel 15, and the other end is connected to the upper end of the longitudinal portion 17b. The lower end of the longitudinal portion 17b is connected to the outer end of the channel 18 at the transition between the side plane 16 and the bottom surface 1f.

[0040] In some other embodiments, the first surface and the second surface may be the upper surface 10c of the main body 10, that is, the outer ends of the channel 18 and the internal channel may extend to the upper surface 10c of the main body 10, respectively. Accordingly, the channel 18 may be replaced by a longitudinal channel (not marked) processed inside the main body 10, the upper end of the channel 14 may extend upward through the upper surface 10c, and one end of the longitudinal channel is connected to the upper end of the channel 14 through a surface channel provided along the side plane 16. Similarly, the surface channel may be formed by the groove provided on the side plane 16 and the cover plate. More generally, the outer ends of the channel 18 may extend to a first surface (e.g., the side plane 16) of the main body 10, respectively, and the outer ends of the internal channel may extend to a second surface (e.g., the upper surface 10c) of the main body 10. The groove forming the surface channel 17 can extend continuously on the upper surface 10c and the side plane 16, but the groove forming the surface channel 17 needs to correspondingly cross the connecting corner of the upper surface 10c and the side plane 16. It is easy to understand that the first surface and the second surface do not have to be planes, for example, at least one of them can also be a curved surface, and the cover plate 19 only needs to be modified to a matching shape accordingly.

[0041] Among them, the outer edge of the elastic diaphragm 21 can be directly welded to the flat surface of the bottom surface 1f of the main body 10 located in the corresponding interface 11a. However, it is more advantageous that the diaphragm components 2a, 2b can also include a transversely extending annular bottom plate 22. The upper side surface of the annular bottom plate 22 of the diaphragm component 2b is sealed and welded to the bottom surface 1f of the main body 10. The lower side surface of the annular bottom plate 22 of the diaphragm component 2b is sealed and welded to the outer edge of the elastic diaphragm 21. This can facilitate welding. The bottom plate mentioned above can be an annular bottom plate 22. In addition, the lower end of the first part 19a is connected to the outer edge of the annular bottom plate 22 of the diaphragm component 2b. At this time, the oil filling chamber 1a and the oil filling chamber 1b also each include an inner cavity 101 defined by the inner wall of the annular bottom plate 22. At this time, if the inner edge of the lower side surface of the annular bottom plate 22 is sealed and welded to the outer edge of the elastic diaphragm 21, the concave cavity 102 can also be omitted. A cavity 10a for accommodating the annular bottom plate 22 may be formed on the bottom surface 1f, and the lower side surface of the annular bottom plate 22 is preferably flush with the bottom surface 1f.

[0042] More preferably, in order to prevent the elastic diaphragm 21 from being damaged during storage or operation, the diaphragm assembly 2a, 2b may further include a pressure ring 23 which is axially arranged longitudinally and the upper end of which is welded to the edge of the elastic diaphragm 21.

[0043] In order to facilitate the filling of the pressure oil, the differential pressure sensor 100 may further include an oil filling hole 1e for filling the pressure oil into the oil filling chamber 1a, and an oil filling hole 1d for filling the pressure oil into the oil filling chamber 1b. Figure 3As shown, the oil filling hole 1e is arranged longitudinally, and its lower end is directly connected to the oil filling chamber 1a, and its upper end is connected to the upper surface 10f of the main body 10. The upper surface 10f can protrude upward to form a circle of cofferdam 6a around the upper end of the oil filling hole 1e, so as to prevent the pressure oil from leaking and contaminating the sensor when the pressure oil is filled. Similarly, the oil hole 1d can also be arranged longitudinally, and its lower end is directly connected to the oil filling chamber 1b, and its upper end is connected to the upper surface 10d of the main body 10. The upper surface 10d protrudes upward to form a circle of cofferdam 5a around the upper end of the oil filling hole 1d. Among them, after the oil filling operation is completed, the outer ends of the oil filling hole 1d and the oil filling hole 1e are respectively closed by the sealing member 5 and the sealing member 6. For example, the sealing member 5 and the sealing member 6 can be steel balls or other metal parts of suitable shape and size, which may be welded to the main body 10. The upper surface 10f may be defined by a top surface of a protruding portion 104 formed by the main body 10 protruding downward.

[0044] Please focus on Figure 4 and Figure 5 The lower end of the channel 14 is blocked by the pressure sensitive element 3. The lower end of the oil filling hole 1d is directly connected to the channel 14. In this way, the pressure sensitive element 3 can be bonded with the pin 32 to form a lead 41 and electrically connected to the pin 32. The lower end of the pin 32 extends into the oil filling cavity 1a. For example, the main body 10 can be provided with a longitudinally extending through hole 33a (such as Figure 6 As shown in FIG. 1 , the pin 32 is sealed and insulated by the insulating seal 33 and penetrates the main body 10, so that its upper end extends out of the top of the main body 10 and is electrically connected to the circuit 40. The insulating seal 33 can be a sintered glass. The circuit 40 can be fixed to the top of the main body 10, or to the inner wall of the terminal 202. The inner end of the terminal 202 can be electrically connected to the circuit 40 through an electrical connector 50, and the electrical connector 50 is preferably a flexible electrical connector, such as a flexible board or a conductive spring.

[0045] In some other solutions, preferably, the lower end of the oil filling hole 1d is directly connected to the internal channel instead of being directly connected to the oil filling chamber 1b, but directly connected to the internal channel, for example, the lower end of the oil filling hole 1d can be coaxially connected to the channel 14 downward (the cross-sectional shape and size of the oil filling hole 1d and the channel 14 can be completely the same to facilitate processing). Alternatively, the lower end of the oil filling hole 1d can be directly connected downward to the channel 15 that constitutes a part of the internal channel, wherein the channel 15 can extend transversely in the left-right direction, one end of which is connected to the upper and lower middle parts of the channel 14, and the other end extends through the side plane 16 to connect to the surface channel 17.

[0046] The cover 30 may extend upward to form a circle of flange 301, and the flange 301 is sealedly connected to the sealing groove 30a provided on the periphery of the two holes 60b by the first sealant. Those skilled in the art may also easily connect the main housing 20 and the cover 30 in other ways to obtain a sealed installation cavity. The main housing 20 may extend downward relatively on the inner side of the sealing groove 30a to form a sealing flange 201, and the sealing flange 201 may be supported downward on the step surface 12 formed on the main body 10, and the step surface 12 is separated at the side plane 16. The bottom surface 1f of the main body 10 may extend downward to form a sealing flange 11, and the cross-sectional shape of the sealing flange 11 may be roughly "8" shaped. At least a part of the inner wall of the interface 11a is defined by the inner wall of the sealing flange 11. The sealing flange 11 may be sealedly arranged in the sealing groove 30b formed on the main housing 20 by the second sealant, so that the two interfaces 11a are separated from each other (i.e., not connected). The cover 30 is provided with two longitudinally through holes 60b corresponding to the two interfaces 11a, respectively allowing the medium to be tested with the first pressure and the second pressure to pass through. Preferably, the lower side of the hole 60b can be concave to form an interface 60a allowing the sealing ring 60 to be inserted, and the sealing ring 60 is used to form a seal when connected with the container containing the medium to be tested.

[0047] The sealing flange 11 is provided with a notch 11 b for accommodating the first portion 19 a to pass through laterally, so as to make room for the first portion 19 a to be connected to the annular bottom plate 22 .

[0048] In the above embodiments, the annular bottom plate 22 of the diaphragm assembly 2a can be integrally connected with the first portion 19a and integrally formed, such as by stamping, so as to reduce the manufacturing process and reduce the cost. In addition, the oil filling hole 1d can also be provided on the cover plate 19, and the oil filling hole 1d can be obtained by stamping. In addition, the elastic diaphragms 21 of the diaphragm assembly 2a and the diaphragm assembly 2b are preferably provided on the same transverse plane to reduce interference with the measurement results.

[0049] like Figure 8 As shown, in the second embodiment, the annular bottom plate 22 of the diaphragm assembly 2a, 2b can be integrally connected with the first part 19a and integrally formed. This can further reduce the manufacturing process and reduce the cost. Among them, the end of the second part 19b away from the first part 19a is integrally connected to the annular bottom plate 22 of the diaphragm assembly 2a through the third part 19c.

[0050] like Fig. 9As shown, in the third embodiment, the upper end of the oil filling hole 1d can also be enclosed in the cofferdam 6a (sharing the same cofferdam 6a with the upper end of the oil filling hole 1e). This can reduce the manufacturing cost, and the filling operation of the pressure oil into the oil filling chamber 1a and the oil filling chamber 1b can also be carried out simultaneously. The assembly of the sealing member 5 and the sealing member 6 can also be carried out simultaneously or one after another.

[0051] The scope of the disclosure is defined not by the detailed description but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are construed as being included in the disclosure.

Claims

1. A differential pressure sensor (100), characterized in that: include: A metal main body (10) having two interfaces (11a) extending downward in the longitudinal direction and spaced apart in the transverse direction at its bottom; The two diaphragm assemblies (2a, 2b), namely a first diaphragm assembly (2a) and a second diaphragm assembly (2b), are respectively sealed and connected to the two interfaces (11a) and correspondingly enclose a first oil-filled cavity (1a) and a second oil-filled cavity (1b) between the main body (10), and at least comprise a metal elastic diaphragm (21) for receiving a pressure to be measured and extending laterally; A pressure difference connecting channel (1c) whose two ends are respectively connected to the two oil filling chambers (1a, 1b), comprising: an internal channel arranged inside the main body (10), the inner end of which is connected to the first oil filling chamber (1a) and the outer end of which extends to the first surface of the main body (10); a channel (18) whose inner end is connected to the second oil filling chamber (1b) and the outer end of which extends to the second surface of the main body (10); and a surface channel (17) extending along the outer surface of the main body (10), one end of which is connected to the outer end of the internal channel and the other end of which is connected to the outer end of the channel (18), and which is surrounded by the outer surface of the main body (10) and a cover plate (19); Pressure-guiding oil is filled in the two oil-filling chambers (1a, 1b) and the pressure difference connecting channel (1c); and a pressure sensitive element (3) having one side exposed to the second oil-filled cavity (1b) and the other side blocking one end of the internal channel.

2. The differential pressure sensor (100) according to claim 1, characterized in that: A continuous groove is formed on the outer surface of the main body (10), and the cover plate (19) closes the groove from the outside and surrounds the groove to form the surface channel (17).

3. The differential pressure sensor (100) according to claim 2, characterized in that: The outer surface of the main body (10) is provided with a receiving groove (10b) for accommodating the cover plate (19); the cover plate (19) is sealed and welded to the edge of the receiving groove (10b); and the groove is formed by the inward concave bottom of the receiving groove (10b).

4. The differential pressure sensor (100) according to claim 1, characterized in that: The first surface and the second surface are in the same plane.

5. The differential pressure sensor (100) according to claim 1, characterized in that: The first surface and the second surface are in the same side plane (16).

6. The differential pressure sensor (100) according to claim 1, characterized in that: The elastic diaphragms (21) of the first diaphragm assembly (2a) and the second diaphragm assembly (2b) are arranged on the same transverse plane.

7. The differential pressure sensor (100) according to any one of claims 1 to 6, characterized in that: The diaphragm assembly (2a, 2b) also includes a transversely extending annular bottom plate (22); the upper surface of the annular bottom plate (22) of the second diaphragm assembly (2b) is seal-welded to the bottom surface (1f) of the main body (10), and the lower surface of the annular bottom plate (22) of the second diaphragm assembly (2b) is seal-welded to the outer edge of the elastic diaphragm (21).

8. The differential pressure sensor (100) according to claim 7, characterized in that: The cover plate (19) comprises a first portion (19a) extending longitudinally, wherein the lower end of the first portion (19a) is integrally connected to the outer edge of the annular bottom plate (22) of the second diaphragm assembly (2b).

9. The differential pressure sensor (100) according to claim 8, characterized in that: The lower end of the main body (10) extends downward to form a sealing flange (11); at least a portion of the inner wall of the interface (11a) is defined by the inner wall of the sealing flange (11); and the sealing flange (11) is provided with a notch (11b) for accommodating the first portion (19a) to pass horizontally.

10. The differential pressure sensor (100) according to claim 7, characterized in that: The annular bottom plates (22) of the two second diaphragm assemblies (2b) are both integrally connected to the cover plate (19).

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