Gauge pressure sensor

Abstract

A gauge pressure sensor includes: a main housing; a pressure interface in which a pressure introduction channel is formed is formed in the pressure pipe; the upper cover is downwards connected to the main shell to define a mounting cavity, and at least comprises an upper cover main body; the pressure sensitive element is arranged in the mounting cavity and is sealed at one end of the inner side of the pressure lead-in part; the substrate is arranged in the mounting cavity, generally horizontally extends, and is electrically connected to and surrounds the pressure sensitive element; the cylinder part is used for defining a vent hole and comprises a circle of first flange and a circle of second flange which are respectively formed by extending the upper cover main body towards the upper side and the lower side, and the second flange is downwards attached to the substrate; the dustproof cover is fixed outside the second flange, and a ventilation gap is defined between the dustproof cover and the upper cover; the vent hole is communicated with the environment through the ventilation gap; and the first gel is filled at the bottom of the vent hole and at least covers the pressure sensitive element. According to the gauge pressure sensor, corrosion of moisture and the like in the environment to electronic elements in the sensor can be reduced.

Description

Technical Field

[0001] This application relates to the technical field of pressure sensors, and particularly to a gauge pressure sensor. Background Art

[0002] In existing pressure sensors, especially semiconductor pressure sensors, a frame is provided around the connecting leads between the pressure-sensitive element and its circuit board, and a protective gel is filled in the frame. The frame needs to be pre-bonded to the surface of the circuit board. Finally, the upper cover of the pressure sensor is bonded to its main housing. In these two processes, dispensing with adhesive and long-time curing are required respectively, and in most cases, the curing process needs to be carried out under heating conditions. In addition, after filling in the frame, it is also necessary to discharge air bubbles under negative pressure conditions. This makes the manufacturing efficiency of similar pressure sensors have a large room for improvement.

[0003] On the other hand, for a gauge pressure sensor that needs to introduce ambient pressure as a reference pressure, when introducing ambient pressure, moisture in the environment may enter the sensor interior, causing circuit corrosion.

[0004] The information disclosed in the background part of the present invention is only used to enhance the understanding of the general background of the present invention, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] In view of the deficiencies of the prior art, this application provides a gauge pressure sensor to solve at least one of the above defects.

[0006] To achieve the above object, this application provides the following technical solution: A gauge pressure sensor, comprising:

[0007] A main housing; a pressure interface is provided thereon, and a pressure introduction channel is formed inside.

[0008] An upper cover connected downward to the main housing to enclose an installation cavity, which at least includes an upper cover body;

[0009] A pressure-sensitive element disposed in the installation cavity, which is closed at the inner end of the pressure introduction;

[0010] A substrate disposed in the installation cavity and extending substantially horizontally, which is electrically connected to and surrounds the pressure-sensitive element;

[0011] A cylindrical part defining a ventilation hole, which includes a first flange and a second flange extending respectively from the upper cover body toward the upper and lower sides, and the second flange abuts downward against the substrate;

[0012] A dust cover fixed to the outside of the second flange, which forms a ventilation gap with the upper cover; the ventilation hole is communicated to the environment through the ventilation gap;

[0013] And a first gel filled at the bottom of the ventilation hole, which at least covers the pressure-sensitive element.

[0014] Preferably, the ventilation hole is communicated to the ventilation gap through at least one waterproof and breathable membrane.

[0015] Preferably, the lower end of the first flange is bonded to the substrate by an adhesive.

[0016] Preferably, the lower end of the first flange is recessed inward to form a circular glue groove for accommodating the adhesive, and the circular glue groove is communicated to a first surface formed on the outer end surface of the second flange through at least one glue injection channel arranged in the cylindrical part; the waterproof and breathable membrane includes a first waterproof and breathable membrane bonded to the first surface.

[0017] Preferably, the circumferential width of the lower part of the circular glue groove gradually increases downward.

[0018] Preferably, the first surface is recessed inward to form a glue injection port, and the glue injection port is communicated to the circular glue groove through the glue injection channel.

[0019] Preferably, the glue injection port surrounds the ventilation hole.

[0020] Preferably, a second surface located below the first surface is formed on the inner periphery of the glue injection port, and the waterproof and breathable membrane further includes a second waterproof and breathable membrane bonded to the second surface.

[0021] The pressure gauge sensor according to any one of the preceding claims, wherein a plurality of buckles are formed on the upper cover body and connected downward to the main housing.

[0022] The pressure gauge sensor according to any one of the preceding claims, wherein the upper cover body extends inward to form a supporting portion that abuts against the substrate. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the pressure gauge sensor of the first embodiment;

[0024] Figure 2 is a partial structural diagram of the pressure gauge sensor of the first embodiment;

[0025] Figure 3 is a partial structural diagram of the pressure gauge sensor of the second embodiment;

[0026] Description of the reference numerals: 111a, surface; 111, the first part; 1120, pressure hole; 1121, axial positioning part; 112a, surface; 112c, glue injection port; 112, the second part; 1131, pressure interface; 1132, axial anti - detachment part; 113, the third part; 114, terminal part; 11, main housing; 121, upper cover body; 122a, annular glue groove; 122b, glue injection channel; 122, flange; 123a, surface; 123b, annular groove; 123c, groove - shaped gap; 123d, surface; 123, flange; 124, supporting part; 125, cylindrical part; 126, connecting flange; 12a, ventilation hole; 12, upper cover; 1, housing; 20, pressure - sensitive element; 40a, surface; 40b, relief part; 40, substrate; 41a, outer end; 41b, inner end; 41, terminal; 42, lead wire; 5, elastic tube; 61, first gel; 62, second gel; 63, bonding glue; 71, dust - proof cover body; 72a, second gap; 72, flange; 73a, first gap; 73, elevation part; 7, dust - proof cover; 8, waterproof and breathable membrane; 9, waterproof and breathable membrane; 112b, accommodation hole; 1221, outer ring part; 1222, inner ring part; 1223, transition part; 15, glue groove; 64, adhesive glue. Detailed implementation manners

[0027] The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are exemplary and are only used to explain the present application, and cannot be construed as a limitation of the present application. In the following description, the same reference numerals are used to represent the same or equivalent elements, and repeated descriptions are omitted.

[0028] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships when the product of the present application is normally placed, or the orientation or positional relationships commonly understood by those skilled in the art. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present application. In addition, the prefixes "first", "second", "third", etc. are only used for the purpose of distinguishing the objects to be modified, and cannot be construed as indicating or implying relative importance.

[0029] In addition, the terms "mounted", "connected", and "coupled" 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, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] It should be further understood that the term "and / or" used in the specification and corresponding claims of this application refers to any combination and all possible combinations of one or more of the listed items.

[0031] As Figure 1 、 Figure 2 shown. The gauge pressure sensor of the first embodiment includes a housing (not marked) that encloses an installation cavity (not marked). The housing includes a main housing 11 with an opening formed on the upper side, and an upper cover 12 covering the opening of the main housing 11. The main housing 11 has at least one pressure interface 1131, and the pressure interface 1131 defines at least a part of a pressure introduction channel. The inner end of the pressure introduction channel communicates with the installation cavity, and the outer end communicates with the pressure medium to be measured. The gauge pressure sensor further includes at least one pressure sensitive element 20 disposed in the installation cavity, which is fixedly closed at the inner end of the pressure introduction channel to obtain the measured pressure of the medium to be measured from the lower side and prevent the medium to be measured from leaking into the installation cavity. The pressure sensitive element 20 can be a semiconductor pressure sensitive element, such as a piezoresistive semiconductor pressure chip or a capacitive semiconductor pressure chip.

[0032] By way of example only, the main housing 11 may include a first part 111, a second part 112, and a third part 113. Among them, a terminal portion 114 is provided on the first part 111. The outer end 41a of at least one terminal 41 extends out of the terminal portion 114 from the inside of the installation cavity. The third part 113 includes the above-mentioned pressure interface 1131, which is fixed to the lower side of the first part 111 and together with the first part 111 defines a receiving hole 112b that can accommodate at least a part of the second part 112. Among them, the vertical cross-section of the second part 112 may be generally stepped, and correspondingly, the receiving hole 112b may be a stepped hole. The third part 113 presses the second part 112 upward and fixes it in the receiving hole 112b. Among them, the material of the second part 112 is preferably ceramic or metal, so as to have a more matching thermal expansion coefficient with the semiconductor pressure chip. The second part 112 and the third part 113 are hermetically connected to jointly define a pressure introduction channel. Among them, a pressure hole 1120 penetrating up and down is provided on the third part 113, and the inner cavity of the pressure interface 1131 communicates upward with the lower end of the pressure hole 1120. The pressure-sensitive element 20 is fixedly closed at the upper end of the pressure hole 1120. The inner cavity of the pressure interface 1131 may be further filled with an elastic tube 5 made of an elastic material and penetrating up and down, so that when there is an instantaneous pressure overload or a continuous pressure overload caused by icing of urea solution or the like, a buffer can be formed to protect the pressure-sensitive element 20. Among them, the upper end of the elastic tube 5 may abut inwardly against an axial positioning portion 1121 formed on the second part 112, and the lower end of the elastic tube 5 may abut outwardly against an axial anti-disengagement portion 1132 formed by radially inward extension of the lower end of the pressure interface 1131.

[0033] Among them, the gauge pressure sensor further includes a substrate 40 disposed in the installation cavity and extending generally horizontally. The substrate 40 can be fixed to the surface of the main housing 11. For example, the lower surface of the substrate 40 can be fixed to the upper surface 112a of the second part 112 and the upper surface 111a of the first part 111 by bonding or other suitable means. A relief portion 40b may be provided on the substrate 40 to accommodate the pressure-sensitive element 20. A processing circuit (not shown) is provided on the upper surface of the substrate 40. The processing circuit is electrically connected to the pressure-sensitive element 20 through a lead 42. The pressure-sensitive element 20 is also electrically connected to the inner end 41b of the terminal 41.

[0034] The upper cover 12 includes an upper cover body 121 extending substantially horizontally and a cylindrical portion 125 extending vertically. An air vent 12a extending vertically is defined inside the cylindrical portion 125, which includes a flange 122 and a flange 123 extending from the upper cover body 121 towards the upper and lower sides respectively. The flange 123 abuts against the upper side surface 40a of the substrate 40 downward, so that the substrate 40 separates the inside and outside of the air vent 12a. Among them, at least the pressure-sensitive element 20 and the lead 42 are located inside the air vent 12a. The bottom of the air vent 12a is filled with a first gel 61, and the first gel 61 covers the pressure-sensitive element 20 and / or the lead 42.

[0035] The differential pressure sensor may further include a dust cover 7 fixed outside the flange 123. An air vent gap may be formed between the dust cover 7 and the upper cover 12. The air vent 12a communicates with the environment through the air vent gap, so that the ambient pressure can be applied to the first gel 61 from the inside to the outside through the air vent gap and the air vent 12a in sequence, and the ambient pressure is transmitted to the upper side of the pressure-sensitive element 20 through the first gel 61 as the reference pressure of the pressure-sensitive element 20. Exemplarily, the dust cover 7 includes a dust cover body 71 extending substantially horizontally, and a flange 72 extends downward from the periphery of the dust cover body 71. The flange 72 is buckled on the flange 123, and a horizontal first gap 73a is left between the inner wall of the dust cover body 71 and the upper end face of the flange 123, and a horizontal second gap 72a is left between the flange 72 and the outer wall of the upper cover body 121. A vertical groove-shaped gap 123c is left between the inner side wall of the flange 72 and the inner side wall of the flange 123 (the groove-shaped gap 123c can be formed by at least one vertical groove formed on the outer wall of the flange 123 and the inner side wall of the flange 72). The air vent gap includes the first gap 73a, the groove-shaped gap 123c and the second gap 72a from the inside to the outside in sequence. Among them, at least one elevation portion 73 that supports on the surface 123a may protrude downward from the inner wall of the dust cover body 71, so as to leave the above-mentioned first gap 73a between the dust cover body 71 and the surface 123a.

[0036] In this way, the differential pressure sensor of this embodiment separates the pressure-sensitive element 20 from other elements and circuits of the processing circuit inside and outside through the flange 122 extending from the upper cover 12, so that the ambient pressure can be directly transmitted to the pressure-sensitive element 20 through the air vent 12a. Since the pressure-sensitive element 20 is protected by the first gel 61, even if there is no strict seal between the flange 122 and the substrate 40, it is very difficult for moisture in the environment to contact other elements and circuits of the processing circuit.

[0037] Among them, in order to suppress the displacement (such as vibration displacement) of the flange 122 relative to the substrate 40, the lower end of the flange 122 can be bonded to the substrate 40 through an adhesive 63. Additionally, the upper cover body 121 extends inward to form a supporting portion 124 that abuts against the surface 40a of the substrate 40, and / or several buckles are formed on the upper cover body 121 and connected downward to the main housing 11.

[0038] Among them, a step can be formed on the upper opening edge of the first part 111, and the peripheral edge of the upper cover body 121 extends downward to form a connecting flange 126. The connecting flange 126 is positioned on the step, and a glue groove 15 is formed between its outer side and the step. The glue groove 15 is filled with an adhesive 64.

[0039] Preferably, in order to enable the adhesive 63 and the adhesive 64 to be injected simultaneously or almost simultaneously, the injection operations of the adhesive 63 and the adhesive 64 can be carried out after the upper cover 12 is assembled to the first part 111. At this time, the lower end of the flange 122 can be recessed inward to form a circular glue groove 122a for accommodating the adhesive 63. The circular glue groove 122a is communicated to a surface 123a formed on the outer end surface of the flange 123 through at least one injection channel 122b provided in the cylindrical portion 125. Preferably, a waterproof and breathable film 8 is also bonded to the surface 123a to further shield the moisture in the environment. Preferably, the surface 123a is recessed inward to form at least one injection port 112c (as Figure 2 shown), and the injection port 112c is communicated to the circular glue groove 122a through at least one of the above injection channels 122b; more preferably, there are two injection channels 122b in total, so that it is convenient to inject glue through one injection port 112c and exhaust air through the other injection channel 122b during injection, so that the adhesive 63 can completely fill the circular glue groove 122a. The lower end of the circular glue groove 122a is closed by the substrate 40. Therefore, after the adhesive 63 is injected into the circular glue groove 122a, the adhesive 63 bonds and fixes the surface 40a of the substrate 40 and the lower end of the flange 122 together.

[0040] In this way, when assembling the differential pressure sensor, the substrate 40 can be first bonded to the surface 112a and the surface 111a, the inner end 41b can be welded to the substrate 40, then the upper cover 12 can be covered, and then the adhesive 63 can be injected from the injection port 112c and the adhesive 64 can be injected into the glue groove 15 almost simultaneously. After that, the adhesive 63 and the adhesive 64 can be cured in the same curing process. Preferably, the components of the adhesive 63 and the adhesive 64 are preferably the same so that they have exactly the same curing temperature and curing duration.

[0041] Please refer to Figure 3。In the second embodiment, the following changes can be made to the gauge pressure sensor: There is only one annular glue injection port 112c in this embodiment, and it surrounds the ventilation hole 12a. A circle of surface 123d that relatively sinks to the lower side of the surface 123a is formed on the inner peripheral edge of the glue injection port 112c. A waterproof and breathable film 9 is adhered to the surface 123d. An annular groove 123b is formed between the surface 123d and the surface 123a. Moisture entering from the outside can be condensed and collected in the annular groove 123b to prevent the condensate from entering the inside of the ventilation hole 12a. At the same time, the annular glue groove 122a can be filled with the bonding glue 63 more quickly during glue injection.

[0042] Preferably, in order to suppress the displacement of the flange 122 relative to the substrate 40, the flange 122 can also be configured to be axially elastic. For example, the flange 122 can include an outer ring portion 1221 and an inner ring portion 1222 that extend longitudinally. The lower end of the outer ring portion 1221 and the upper end of the inner ring portion 1222 are integrally connected through a transition portion 1223. Among them, the radial outer side of the transition portion 1223 is inclined downward relative to its radial inner side, so that a certain elasticity can be imparted to the flange 122. Among them, the annular glue groove 122a is provided in the inner ring portion 1222.

[0043] In each of the above embodiments, the pressure hole 1120 can also be filled with a second gel 62 to protect the lower side of the pressure-sensitive element 20 from being eroded by the medium to be measured.

[0044] The scope of the present disclosure is not limited by the detailed description, but is limited 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 present disclosure.

Claims

1. A gauge pressure sensor, characterized in that, Comprising: A main housing (11); provided thereon with a pressure interface (1131) having a pressure introduction channel formed therein. An upper cover (12) connected downward to the main housing (11) to enclose an installation cavity, which at least includes an upper cover body (121). A pressure-sensitive element (20) disposed in the installation cavity, which is enclosed at the inner end of the pressure introduction. A substrate (40) disposed in the installation cavity and extending substantially horizontally, which is electrically connected to and surrounds the pressure-sensitive element (20). A cylindrical portion (125) defining a ventilation hole (12a), which includes a first flange (122) and a second flange (123) extending respectively upward and downward from the upper cover body (121) to form a circle, and the second flange (123) abuts downward against the substrate (40). A dust cover (7) fixed outside the second flange (123), which forms a ventilation gap with the upper cover (12); the ventilation hole (12a) communicates with the environment through the ventilation gap. And a first gel (61) filled at the bottom of the ventilation hole (12a), which at least covers the pressure-sensitive element (20).

2. The differential pressure sensor according to claim 1, wherein The ventilation hole (12a) communicates with the ventilation gap through at least one waterproof breathable membrane (8, 9).

3. The manometer sensor according to claim 1, characterized in that The lower end of the first flange (122) is bonded to the substrate (40) by an adhesive (63).

4. The differential pressure sensor according to claim 3, characterized in that The lower end of the first flange (122) is recessed inward to form a circular glue groove (122a) for accommodating the adhesive (63), and the circular glue groove (122a) communicates with a first surface (123a) formed on the outer end surface of the second flange (123) through at least one glue injection channel (122b) provided in the cylindrical portion (125); the waterproof breathable membrane (8, 9) includes a first waterproof breathable membrane (8) bonded to the first surface (123a).

5. The manometer sensor according to claim 4, characterized in that, The circumferential width of the lower part of the circular glue groove (122a) gradually increases downward.

6. The manometer sensor according to claim 4, characterized in that, The first surface (123a) is recessed inward to form a glue injection port (112c), and the glue injection port (112c) communicates with the circular glue groove (122a) through the glue injection channel (122b).

7. The manometer sensor according to claim 6, characterized in that, The glue injection port (112c) surrounds the ventilation hole (12a).

8. The manometer sensor according to claim 7, characterized in that, A second surface (123d) located below the first surface (123a) is formed on the inner periphery of the glue injection port (112c), and the waterproof breathable membrane (8, 9) further includes a second waterproof breathable membrane (9) bonded to the second surface (123d).

9. The differential pressure sensor according to any one of claims 1 to 8, characterized in that, A plurality of buckles are formed on the upper cover body (121) and connected downward to the main housing (11).

10. The differential pressure sensor according to any one of claims 1 to 8, characterized in that, The upper cover body (121) extends inward to form a supporting portion (124) that abuts against the substrate (40).

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