CN217331486U

CN217331486U - High-waterproof high-insulation welded pipe structure pressure sensor

Info

Publication number: CN217331486U
Application number: CN202220715268.3U
Authority: CN
Inventors: 何文超; 吴丛喜
Original assignee: Xiaogan Huagong Gaoli Electron Co Ltd
Current assignee: Xiaogan Huagong Gaoli Electron Co Ltd
Priority date: 2022-03-29
Filing date: 2022-03-29
Publication date: 2022-08-30
Anticipated expiration: 2032-03-29

Abstract

The utility model provides a high waterproof high insulation welded pipe structure pressure sensor, which comprises an outer shell, an inner shell, a metal pipe, an upper end cover and a connecting wire connected with an external circuit, wherein the inner shell is arranged in the outer shell, the bottom of the inner shell is welded with the metal pipe, the metal pipe extends out of the outer shell, an inner shield cover is arranged in the inner shell, a pressure sensing element and a circuit module are sequentially arranged in the inner shield cover from bottom to top, the top of the inner shield cover is sealed by the upper end cover, a contact pin is arranged on the upper end cover, one end of the contact pin is connected with the connecting wire, the other end of the contact pin and the pressure sensing element are both electrically connected with the circuit module, a first through hole is arranged at the bottom of the inner shell, a second through hole is arranged at the bottom of the inner shield cover, the second through hole is just opposite to the first through hole, and the first through hole and the second through hole are both communicated with the metal pipe, the outer shell is filled with pouring sealant, and the inner shell, the inner shield cover and the upper end cover are packaged in the outer shell by the pouring sealant.

Description

High waterproof high insulation welded tube structure pressure sensor

Technical Field

The utility model relates to a pressure sensor technical field especially relates to a high waterproof high insulating welded tube structure pressure sensor.

Background

The voltage output accuracy of the pressure sensor is easily influenced by electromagnetic interference and conductive fluid of the pressure sensor and external electronic products, transient overvoltage exceeding normal working voltage can be generated due to factors such as equipment starting and stopping, power grid impact, faults or lightning stroke in the working process of the pressure sensor, a conditioning circuit of the pressure sensor is communicated with a shell, after a conductive path is formed between a power supply and the conditioning circuit and between the power supply and the shell, when the transient overvoltage passes through the conductive path, the conditioning circuit and a pressure detection component can be punctured, and the pressure sensor is prone to failure. At present, the household appliance industry generally requires that the insulation resistance between an electric connector contact pin and a shell of a product at least reaches 1800V of alternating current, 1S does not have breakdown or 1500V of alternating current for duration, 1min does not have breakdown for duration, in order to meet the requirement, a metal shielding cover structure is mostly arranged inside an existing pressure sensor, the electric connector is pressed by a riveting bending part on the outside, due to the fact that metal shells are adopted, an outer metal shell and an inner shielding cover metal shell are used for avoiding direct conduction, an insulating paper is used for wrapping at a middle gap, the labor cost of manufacturing an insulating paper roll into a cylindrical structure is increased, a bottom edge is made of a high-temperature-resistant, corrosion-resistant and insulating thermoplastic solid material, and the material cost and the labor cost for assembling the parts are correspondingly increased by using CNC machining (computer digital control precision machining) or an injection molding scheme. In addition, the existing pressure sensor has the defects that a leakage gap appears at the riveting connection position of the metal shell and the electric connector, water vapor easily enters, an O-shaped ring needs to be arranged or sealant needs to be applied, and the corresponding material cost and the labor cost are increased.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome manufacturing cost among the current pressure sensor technique high, the problem that pressure sensor easily became invalid provides a high waterproof high insulation welded tube structure pressure sensor, the utility model discloses partial problem among the prior art has been solved at least.

The utility model discloses a realize like this:

the utility model provides a high waterproof high insulation welded tube structure pressure sensor, including shell body, interior casing, tubular metal resonator, upper end cover, the connecting wire that links to each other with external circuit, interior casing is located in the shell body, the bottom of interior casing with the tubular metal resonator welding, the tubular metal resonator stretches out the shell body, be equipped with the internal shield cover in the interior casing, pressure-sensitive element and circuit module are installed from bottom to top in proper order to the inside of internal shield cover, the top of internal shield cover is blocked by the upper end cover, be equipped with the contact pin on the upper end cover, the one end of contact pin links to each other with the connecting wire, the other end of contact pin and the pressure-sensitive element all with circuit module electricity is connected, the bottom of interior casing is seted up first through-hole, the bottom of internal shield cover is seted up the second through-hole, the second through-hole just faces first through-hole, the first through hole and the second through hole are communicated with the metal pipe, pouring sealant is filled in the outer shell, and the inner shell, the inner shield cover and the upper end cover are packaged in the outer shell through the pouring sealant.

Further, the bottom of interior casing with the bottom threaded connection of shell body, interior casing is the step shaft structure, including little diameter section and big diameter section, little diameter section is equipped with the external screw thread, the bottom of shell body is equipped with the trompil that supplies little diameter section to stretch into, the inner wall of trompil be equipped with external screw thread complex internal thread.

Furthermore, a first sealing ring and a check ring are arranged on the inner bottom surface of the inner shielding cover, the check ring surrounds the first sealing ring, the first sealing ring is in contact with the bottom surface of the pressure sensing element, and the first sealing ring surrounds the second through hole.

Furthermore, an annular groove is formed in the inner bottom surface of the inner shell, a second sealing ring is arranged in the groove, the second sealing ring is in contact with the bottom of the inner shield cover, and the second sealing ring surrounds the first through hole.

Furtherly, the upper end cover is the ladder axle construction, the inner shield top is equipped with the first portion of bending that compresses tightly the upper end cover cascaded surface, interior casing top is equipped with the second portion of bending that compresses tightly first portion of bending, the upper end cover is inside to have seted up accepts circuit module's space, the upper end cover orientation forced induction component's one end edge is equipped with the convex bayonet socket, seted up on forced induction component's the lateral wall with convex bayonet socket joint complex draw-in groove, form a whole behind upper end cover and the forced induction component joint.

Further, the shell body is a plastic shell body or a metal shell body, the inner shell body is a metal inner shell body, and the inner shielding cover is a metal inner shielding cover.

Further, the inside wall of interior casing is equipped with insulating coating.

Furthermore, the inner side wall of the inner shell and the outer side wall of the inner shield are both provided with insulating coatings.

Furthermore, an insulating oxide film is arranged on the inner side wall of the inner shell or the outer side wall of the inner shielding cover.

Furthermore, the contact pin and the welding point of the connecting wire are positioned in pouring sealant, and the pouring sealant covers the lower end of the connecting wire by 0.4-1 cm.

The utility model discloses following beneficial effect has:

1. the utility model provides a pair of high waterproof high insulation welded tube structure pressure sensor low in production cost, waterproof performance is excellent, and dielectric strength is good, at corrosivity, dirty, contain humidity environment such as steam under difficult inefficacy.

2. The utility model provides a high waterproof high insulating welded tube structure pressure sensor shell body can select for use PPE + PA + GF 30%, PBT + GF 30% or plastics such as PA66+ GF 30%, also can adopt the metal preparation, SUS304, SUS316, brass, aluminum alloy, aluminium, carbon steel and so on, because it need not to bear the exogenic action, preferably adopt plastic materials; the inner shell and the metal pipe are connected by brazing, the inner shell is made of metal, SUS304, SUS316, brass, aluminum alloy, aluminum, carbon steel and the like, and the inner shield is made of metal, SUS304, SUS316, brass, aluminum alloy, aluminum, carbon steel and the like; the FPC flexible conditioning circuit module is processed by grounding the inner wall of the inner shield to stop an electromagnetic field generated inside the FPC flexible conditioning circuit module in the metal inner shell, the outer surface of the metal inner shell resists electromagnetic interference generated outside, and high insulation effect can be obtained by adopting three schemes, wherein an insulation coating is arranged on the inner surface of the inner shell, and insulation coatings are arranged on the outer surface of the inner shield and the inner surface of the inner shell simultaneously under the conditions of extremely high requirement and allowable cost to achieve the aim of double insulation When instantaneous large current or large voltage generated in the circuit flows through the FPC flexible conditioning circuit module, the ceramic capacitor pressure sensing element and the inner shield cover through a contact pin and passes through the insulating coating or the insulating oxide film, the circuit is prevented from being continuously conducted due to the insulating property of the coating or the insulating oxide film, and the purpose of resisting high insulating voltage is achieved.

3. The utility model provides a pair of high waterproof high insulating welded tube structure pressure sensor passes through the mode of upper end cap top cavity encapsulating, the internal circuit is wrapped up completely by the casting compound, rely on the high insulating of casting compound and the high waterproof performance after the solidification, saved and set up the process such as O type circle or exert sealant in inner housing and upper end cap joint gap department, saved the required part cost expense to the plug-in connector, the waterproof grade can reach IP69, when having avoided the sensor to use under the humid environment such as corrosivity, dirty, moisture, the risk of the sensor internal circuit short circuit that leads to because of intaking, in addition, because the strong adhesive force of casting compound, can bond with outer housing and inner housing after its solidification, have good mechanical properties, reach the effect of anti-vibration, shock resistance; the sensor has the advantages that the insulation coating and the insulation oxide film structure are adopted inside the sensor, metal parts are isolated from the shell, the purpose of insulation and high voltage resistance is achieved, the overall insulation performance is far higher than the voltage-resistant requirement in the fields of household appliances and the like, the complex structure that insulation paper is arranged on the inner edge of the existing sensor and an insulation gasket is arranged at the bottom of the existing sensor is omitted while the insulation performance is guaranteed, the labor cost for rolling the insulation paper and the processing cost of the insulation gasket are omitted, the insulation coating, the cladding and the like in the prior art are easy to obtain, the sensor has excellent wear-resistant performance, extremely high insulation performance, corrosion resistance, high temperature resistance and the like, metal anodic oxidation or other oxidation treatment processes in the prior art are mature, and convenience is provided for the preparation of the insulation oxide film.

Drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings used in the description of the embodiments or the prior art will be briefly introduced, obviously, the drawings in the description below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic cross-sectional view of a pressure sensor with a high waterproof and high insulating welded pipe structure provided by an embodiment of the present invention;

fig. 2 is a schematic structural view of an outer shell of a pressure sensor with a high waterproof and high insulating welded pipe structure provided by an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a copper pipe welding assembly of a pressure sensor with a high waterproof and high insulation welded pipe structure provided by an embodiment of the present invention;

fig. 4 is a schematic structural view of an inner shield of a pressure sensor with a high waterproof and high insulating welded pipe structure provided in an embodiment of the present invention;

fig. 5 is an external structural schematic diagram of an upper end cap and a contact pin of a high waterproof and high insulating welded pipe structure pressure sensor provided by an embodiment of the present invention;

fig. 6 is a schematic view of an external structure of a pressure sensing element of a pressure sensor with a high waterproof and high insulating welded pipe structure according to an embodiment of the present invention;

fig. 7 is an exploded view of the main structure of the pressure sensor with high waterproof and high insulating welded pipe structure provided by the embodiment of the present invention.

Description of reference numerals: 1. an outer housing; 2. an internal thread; 3. a third accommodating cavity; 4. an inner housing; 5. a groove; 6. a first through hole; 7. a metal tube; 8. an external thread; 9. a second accommodating cavity; 10. a second bending portion; 11. an inner surface of the inner housing; 12. a retainer ring; 13. an inner shield; 14. a second through hole; 15. an outer surface of the inner shield; 16. a first accommodating cavity; 17. a first bending portion; 18. an upper end cover; 19. a convex bayonet; 20. pouring a sealant; 21. inserting a pin; 22. a connecting wire; 23. a circuit module; 24. a pressure sensing element; 25. a card slot; 26. a first seal ring; 27. and a second seal ring.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in 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 of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention; the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, whereby the features defined "first", "second" may explicitly or implicitly include one or more of such features.

As shown in fig. 1-7, an embodiment of the present invention provides a high waterproof high insulation welded pipe structure pressure sensor, which includes an outer shell 1, an inner shell 4, a metal pipe 7, an upper end cover 18, and a connecting wire 22 connected to an external circuit, where the connecting wire 22 is an output signal wire, a 5V power supply wire, and a ground wire, the connecting wire 22 is wrapped with an insulating layer, the inner shell 4 is disposed in the outer shell 1, the bottom of the inner shell 4 is welded to the metal pipe 7, the metal pipe 7 extends out of the outer shell 1, an inner shield 13 is disposed in the inner shell 4, a pressure sensing element 24 and a circuit module 23 are sequentially mounted inside the inner shield 13 from bottom to top, the pressure sensing element 24 is a ceramic capacitor pressure sensing element, the circuit module 23 is an FPC flexible conditioning circuit module, the FPC is a flexible circuit board, the top of the inner shield 13 is blocked by the upper end cover 18, be equipped with contact pin 21 on upper end cover 18, the one end of contact pin 21 with connecting wire 22 links to each other, the other end of contact pin 21 and pressure sensing element 24 all with circuit module 23 electricity is connected, first through-hole 6 has been seted up to the bottom of interior casing 4, second through-hole 14 has been seted up to the bottom of interior shield 13, second through-hole 14 just right first through-hole 6, second through-hole 14 all with tubular metal resonator 7 intercommunication, pack casting glue 20 in shell body 1, casting glue 20 encapsulates interior casing 4, interior shield 13 and upper end cover 18 in the inside of shell body 1, contact pin 21 with connecting wire 22 welding point is located casting glue 20, and casting glue 20 covers connecting wire 22 lower extreme 0.4-1cm, and connecting wire 22 stretches out casting glue 20.

The utility model provides a low in production cost, high temperature resistant, corrosion-resistant, highly waterproof, high insulating welded tube structure pressure sensor. What current pressure sensor adopted mostly is that the connecting piece with to the mode of plug-in connection, under moist environment such as extreme abominable steam, dirty, corruption, it causes inside contact pin terminal oxidation corrosion to intake from the connecting piece with the joint gap to the plug-in connection easily, makes circuit signal unstable, influences the signal output precision, and serious can directly lead to the internal circuit short circuit, causes pressure sensor to become invalid. The utility model discloses a mode of 18 top cavity encapsulating of upper end cover, the internal circuit is wrapped up by the casting glue completely, rely on the high insulating and the high waterproof performance after the solidification of casting glue, including casing 4 and upper end cover 18 joint gap department set up procedures such as O type circle or applyed sealed glue, the required part cost expense of plug-in connector has been saved, waterproof grade can reach IP69, avoided the sensor at corrosivity, dirty, when using under the humid environment such as moisture, because of the risk of the sensor internal circuit short circuit that advances water and lead to, furthermore, because the strong adhesive force of casting glue, can bond with shell body 1 and interior casing 4 after its solidification, good mechanical properties has, reach the anti-vibration, the effect of shock resistance.

The bottom of interior casing 4 with the bottom threaded connection of shell body 1, interior casing 4 is the step shaft structure, including little diameter section and big diameter section, little diameter section is equipped with external screw thread 8, the bottom of shell body 1 is equipped with the trompil that supplies little diameter section to stretch into, the inner wall of trompil be equipped with external screw thread 8 complex internal thread 2. The inner bottom surface of the inner shield cover 13 is provided with a first sealing ring 26 and a retainer ring 12, the retainer ring 12 surrounds the first sealing ring 26, the compression amount of the first sealing ring 26 can be controlled by controlling the thickness of the retainer ring 12, the first sealing ring 26 is in contact with the bottom surface of the pressure sensing element 24, and the first sealing ring 26 surrounds the second through hole 14. An annular groove 5 is formed in the inner bottom surface of the inner shell 4, a second sealing ring 27 is arranged in the groove 5, the second sealing ring 27 is in contact with the outer bottom surface of the inner shield 13, and the second sealing ring 27 surrounds the first through hole 6.

Upper end cover 18 is the step shaft structure, inner shield cover 13 top is equipped with the first portion of bending 17 that compresses tightly the 18 ladder faces of upper end cover, 4 tops of interior casing are equipped with the second portion of bending 10 that compresses tightly first portion of bending 17, upper end cover 18 is inside to be seted up and to be acceptd circuit module 23's space, upper end cover 18 orientation forced induction component 24's one end edge is equipped with convex bayonet 19, seted up on forced induction component 24's the lateral wall with convex bayonet 19 joint complex draw-in groove 25, upper end cover 18 forms a whole with forced induction component 24 joint back, can not appear pivoted risk after the riveting of the first portion of bending 17 of inner shield cover 13, the second portion of bending 10 of interior casing 4, when avoiding

interior casing

4 and 1 threaded connection of shell body, the inside rotatory rotation of following of interior casing 4.

The outer shell 1 is a plastic outer shell, the inner shell 4 is a metal inner shell, and the inner shield 13 is a metal inner shield. The outer shell 1 can also be a metal outer shell.

For the purpose of achieving insulation between the inner metal (the inner shell 4 and the inner shield 13) and the outer surface of the whole product, three structural forms can be adopted: firstly, an insulating coating is arranged on the inner side wall (inner surface) of the inner shell 4; secondly, insulating coatings are arranged on the inner side wall (inner surface) of the inner shell 4 and the outer side wall (outer surface) of the inner shield 13, so that a double-layer insulating effect is achieved; thirdly, when the inner side wall of the inner shell 4 or the outer side wall of the inner shield 13 is provided with an insulating oxidation film, when the inner shell 4 or the inner shield 13 is made of aluminum, aluminum alloy or other materials easy to be oxidized, the whole body is oxidized to achieve the purpose of insulation, then the outer side wall (outer surface) of the inner shell 4 or the inner side wall (inner surface) of the inner shield 13 is machined to cut off an oxidation layer, so that the inner surface of the inner shell 4 achieves the insulation effect and the outer surface is conductive to realize the electromagnetic shielding effect or the outer surface of the inner shield 13 achieves the insulation effect and the inner surface is conductive to realize the electromagnetic shielding effect, the FPC flexible conditioning circuit module is connected with the ceramic capacitor pressure sensing element, when instantaneous large current or large voltage generated in a circuit flows through the FPC flexible conditioning circuit module, the ceramic capacitor pressure sensing element and the inner shield through a contact pin, when the insulating coating or the insulating oxide film is passed, the circuit is prevented from being conducted continuously due to the insulating property of the insulating coating or the insulating oxide film, and the purpose of resisting insulating high voltage is achieved.

Referring to fig. 1 and 7, the utility model provides a high waterproof high insulating welded tube structure pressure sensor, include: the device comprises an outer shell 1, an inner shell 4, a metal pipe 7, a retainer ring 12, an inner shield 13, a pressure sensing element 24, a first sealing ring 26, a second sealing ring 27, a circuit module 23, an upper end cover 18, a pouring sealant 20, a contact pin 21 and a connecting wire 22; a first accommodating cavity 16 is formed in the inner shield 13, a pressure sensing element 24 and a circuit module 23 are sequentially mounted in the first accommodating cavity 16 from bottom to top, and a second through hole 14 communicated with the first accommodating cavity 16 is formed in the bottom of the inner shield 13; the upper end cover 18 is matched with an opening of the first accommodating cavity 16, a pressure sensing element 24 and a circuit module 23 are packaged in the first accommodating cavity 16, and the internal structure is pressed tightly through the first bending part 17; a pin 21 is arranged at the top of the upper end cover 18, the top end of the pin 21 is welded with the connecting wire 22, and the bottom end of the pin 21 is connected with the circuit module 23; a second accommodating cavity 9 is formed in the inner shell 4, a first bending part 17 of the inner shield 13 is tightly pressed through a second bending part 10, and the inner shield 13 is installed in the second accommodating cavity 9; a third accommodating cavity 3 is arranged in the outer shell 1; pouring a pouring sealant 20 into the third accommodating cavity 3, and encapsulating the inner shell 4, the inner shield cover 13 and the upper end cover 18 in the third accommodating cavity 3; the bottom of the inner shell 4 is provided with a first through hole 6 communicated with a second through hole 14 of the inner shield cover 13.

Furthermore, a check ring 12 is arranged between the inner bottom surface of the inner shielding cover 13 and the pressure sensing element 24; the inner edge of the retainer ring 12 is provided with a first seal ring 26, the first seal ring 26 is in contact with the inner bottom surface of the inner shield 13 and the pressure sensing element 24, and the compression amount of the first seal ring 26 can be controlled by controlling the thickness of the retainer ring 12. The retainer ring 12 is preferably annular, made of polytetrafluoroethylene, the first sealing ring 26 is preferably an O-shaped ring, made of HNBR or EPDM which is corrosion-resistant, tear-resistant, wear-resistant, compression deformation-resistant, high-low temperature-resistant and insulating, and the compression amount of the first sealing ring 26 is 20-25%, so that the first sealing ring has a better sealing effect. When the using environment is medium pressure of 1-2MPa, the check ring structure can be cancelled, a seal ring with an annular structure is adopted, the material of the seal ring is preferably HNBR (hydrogenated nitrile butadiene rubber) or EPDM (ethylene propylene diene monomer) and the like, and the check ring 12 is arranged to prevent the internal seal ring 26 from being extruded under the action of a high-pressure medium to cause leakage.

As shown in fig. 2 and 3, the inner part of the outer shell 1 is provided with the inner thread part 2, the outer part of the inner shell 4 is provided with the outer thread part 8, the inner thread 2 and the outer thread 8 adopt fine threads, because the inner shell 4 and the metal pipe 7 adopt a welding mode, and one end of the whole pressure sensor metal pipe 7 is connected with a client end by brazing, the outer shell 1 has no risk of stress during installation, the acting force generated by a medium does not act on the outer shell 1, the length of the threads is set as short as possible, only a small screwing torque is needed to connect the outer shell 1 and the inner shell 4 together, and the diameter is preferably M20. The threaded connection prevents the potting compound 20 from flowing out of the connection between the outer housing 1 and the inner housing 4. The liquid pouring sealant 20 flows into the gap between the outer shell 1 and the inner shell 4, and after the liquid pouring sealant is solidified, the outer shell 1, the pouring sealant 20 and the inner shell 4 are connected more tightly, so that the outer shell 1 body does not have the possibility of rotating without depending on the locking force of the screw threads.

The pressure sensing element 24 is a ceramic capacitance pressure sensing element, preferably made of 96% ceramic material, and has excellent characteristics of strong corrosion resistance, impact resistance, high elasticity and the like, and the extremely high thermal stability of the ceramic capacitance enables the working range to be-40 ℃ to 135 ℃, when the ceramic capacitance pressure sensor works, the pressure directly acts on the sensing diaphragm of the ceramic capacitance pressure sensing element, and the capacitance change between the base electrode and the diaphragm electrode is in proportion to the pressure. When the pressure is recovered, the performance of the pressure sensing diaphragm is not influenced, and the defect that the traditional pressure sensing diaphragm is invalid due to low-range overload is overcome;

the circuit module 23 is an FPC flexible conditioning circuit module, the base material of the FPC flexible conditioning circuit module is organic polymer material PI polyimide with better bending resistance, the temperature resistance is more than 400 ℃, the temperature range of long-term use is-200 ℃ to 300 ℃, the bending strength of the polyimide reinforced by graphite and glass fiber can reach 345MPa, so that the FPC flexible conditioning circuit module has excellent mechanical property, and in addition, the material property has high insulating property;

the inner shield 13 is preferably made of a metal material having electromagnetic shielding resistance, and the inner shield 13 made of SUS304, SUS316, brass, aluminum alloy, aluminum, carbon steel, or the like can meet the requirements;

the inner housing 4 is preferably made of a metal material, and the inner housing 4 made of SUS304, SUS316, brass, an aluminum alloy, aluminum, carbon steel, or the like can suffice;

the outer shell 1 can be made of high-temperature-resistant and corrosion-resistant PPE + PA + GF 30%, PBT + GF 30%, PA66+ GF 30% and other plastics, or can be made of metal such as SUS304, SUS316, brass, aluminum alloy, aluminum, carbon steel and the like;

for the purpose of achieving insulation between the internal metal (inner shield 13 and inner housing 4) and the overall outer surface of the product, three possibilities are now provided in this embodiment:

the first scheme is as follows: an insulating coating is formed between the inner shield 13 and the inner housing 4. When the insulating coating is arranged on the outer surface of the inner shield cover 13, the requirement on the surface roughness of a wrapping structure of a riveting cutter (a riveting insert) is extremely high, when the roughness cannot be achieved, and the wrapping structure has sharp corners or transition unevenness, the coating on the outer surface of the inner shield cover is easily damaged, the requirement on the processing precision of the riveting cutter (the riveting insert) and the like is high, and the insulating coating is preferably arranged on the inner surface of the inner shell 4. Scheme II: under the conditions of cost allowance and higher insulation requirement, the double insulation function can be simultaneously arranged on the outer surface of the inner shielding cover 13 and the inner surface of the inner shell 4; the polytetrafluoroethylene with excellent corrosion resistance is preferably selected as the coating material, the hardness and the wear resistance are greatly improved after the glass fiber is added into the polytetrafluoroethylene powder, then a compact nano film layer without pinholes is formed on the metal shell by adopting a chemical vapor deposition process (CVD), the wear resistance of the coating is excellent, the insulation resistance is larger than 100 MOmega, and the thickness is 20-100 um. The third scheme is that an insulating oxide film is formed between the inner shield cover 13 and the outer shell 1, because the anodic oxide film of aluminum is a high-resistance insulating film, the breakdown voltage of the insulating film is greater than 30V/um, the specially prepared high-insulation film even reaches 200V/um, when the inner shell 4 or the inner shield cover 13 is aluminum, aluminum alloy or other materials easy to oxidize, the oxidation treatment is carried out through the whole body, the thickness of the oxide film is controlled, the oxide film is used for achieving the insulation purpose, then the oxide film is machined and cut on the outer surface of the inner shell 4 or the inner surface of the inner shield cover 13, the inner surface of the inner shell 4 achieves the insulation effect, the outer surface of the inner shield cover is conductive, the electromagnetic shielding effect is achieved, or the outer surface of the inner shield cover 13 achieves the insulation purpose, and the inner surface of the inner shield cover is conductive, and the electromagnetic shielding effect is achieved.

The upper end cover 18 is made of PEE + PA + GF 30%, PBT + GF 30% or PA66+ GF 30% and other plastics, the three materials are all resistant to corrosion and high temperature, and 30% of glass fiber is added to the three materials to achieve excellent mechanical performance;

the contact pin 21 is plated with tin on the surface of phosphor copper with good welding performance and good conductivity, preferably, the contact pin 21 and the upper end cover 18 are in an integrated plastic sealing structure;

the pouring sealant 20 is epoxy resin, organic resin, room temperature vulcanized silica gel, polyamide or polyurethane hot melt adhesive and the like;

the connecting wires 22 are output signal wires, 5V power supply wires, and ground wires.

The top of the upper end cover 18 is provided with three pins 21 which are integrally injection-molded with the upper end cover 18, the pins 21 are exposed out of the surface of the upper end cover 18 by 3-5mm, and before being welded with a connecting wire 22, batch calibration and detection functions can be realized by the contact conduction of a special spring type plug connector and the upper ends of the three pins 21. The upper end cover 18 is buckled and pressed on the FPC flexible conditioning circuit module 23, so that the bottom end of the contact pin 21 is connected with the FPC flexible conditioning circuit module in a welding mode. Referring to fig. 5 and 6, convex bayonet 19 is opened to upper end cover 18 side, draw-in groove 25 with convex bayonet 19 mutual matching is seted up to ceramic capacitor pressure sensing element 24 side, use upper end cover 18 when encapsulating ceramic capacitor pressure sensing element 24 and FPC flexible conditioning circuit module 23 in inner shield cover 13's first holding chamber 16, upper end cover 18 and ceramic capacitor pressure sensing element 24 form a whole, pivoted risk can not appear after the riveting of the second bending portion 10 of inner housing 4, when having avoided follow-up top square structure through upper end cover 18 or interior casing 4 upper edge location screw thread, interior casing 4 is inside to follow rotatory when interior casing 4 assembles into shell body 1 and rotates.

After the calibration and the detection are completed, the top end of the contact pin 21 and the connecting wire 22 wrapped with the insulating layer are subjected to lead-free tin soldering, the inner shell 4 is installed in the outer shell 1 through the matching effect of the external thread 8 and the internal thread 2, the pouring sealant 20 is injected into the third accommodating cavity 3 from the upper end of the outer shell 1, and the pouring sealant 20 is made of epoxy resin. The potting adhesive 20 completely submerges the soldering points of the pins 21 and the connecting wires 22, covers the lower end of the connecting wires 22 by 0.4-1cm, and flows into the side wall gap between the outer shell 1 and the inner shell 4 through the action of gravity. After the pouring sealant 20 is cured, the internal circuit structure of the pressure sensor is completely wrapped by the pouring sealant 20 with excellent insulation resistance and waterproof performance, the waterproof grade can reach IP69, and the risk of short circuit of the internal circuit of the sensor caused by water inflow in humid environments such as corrosion, dirt, water vapor and the like is avoided. In addition, due to the strong adhesive force of the pouring sealant 20, the pouring sealant can be bonded with the outer shell 1 and the inner shell 4 after being cured, so that the pouring sealant has excellent mechanical properties and achieves the purposes of vibration resistance and impact resistance.

Because the curing period of the pouring sealant 20 is long, enough curing period needs to be left when pouring in batches, and under the dual evaluation of time cost and material cost, polyamide or polyurethane hot melt adhesive can also be used as the pouring sealant 20, and the process period is shortened by a low-pressure injection molding technology.

When the pressure sensor with the high-waterproof high-insulation welded pipe structure meets instantaneous large current or large voltage generated in a circuit in use, the current or the voltage flows through the FPC flexible conditioning circuit module 23, the ceramic capacitor pressure sensing element 24 and the inner shield cover 13 through the contact pin 21, when the current or the voltage reaches an insulation coating, the circuit is prevented from being continuously conducted due to the insulation property of the coating, the purpose of high insulation voltage resistance is achieved between the contact pin and a shell (the whole outer part of a product comprises a plastic shell, the lower part of the inner shell and three outer surfaces of a metal pipe), and the overall insulation performance of the pressure sensor is far higher than the voltage resistance requirement that the alternating current 1800V acts for 1s or the alternating current 1500V acts for 1min without breakdown in the fields of commercial air conditioning household appliances and the like. The utility model relates to a high waterproof high insulating welded tube structure pressure sensor has cancelled the inside loaded down with trivial details structure that sets up insulating paper and bottom edge and set up insulating washer that sets up of current pressure sensor, has saved the cost of labor of insulating paper system of rolling up and insulating washer's processing cost, has also saved the part cost to the plug-in connector of being connected with the contact pin.

The pressure sensor with the high-waterproof and high-insulation welded pipe structure can be particularly applied to a central air-conditioning system, and is especially applied to a variable frequency air conditioner. When refrigerant pressure acts on ceramic capacitor pressure sensing element 24, the response diaphragm response pressure of ceramic capacitor pressure sensing element 24 below, through taking place small distance deformation between inside bipolar plate, change the size of the inside variable capacitance of response diaphragm, and the inside reference capacitance of response diaphragm is unchangeable, utilize the characteristics of these two electric capacities, measure the ratio between them, the PIN needle and the FPC flexible conditioning circuit module 23 one end of ceramic capacitor pressure sensing element 24 upper end are connected, the signal conditioning through FPC flexible conditioning circuit module 23 produces the proportion voltage signal output signal along with pressure change. The output signal is connected with the lower end of the contact pin 21 through a small copper-clad circular hole in the FPC flexible conditioning circuit module 23 and is transmitted out through the connecting wire 22. The inner side wall of the inner shield cover 13 is in contact with two flexible thin flat plate-shaped pins with copper cladding separated from the FPC flexible conditioning circuit module 23, and charges generated by an electric field or a magnetic field are introduced to the ground through a grounding wire, so that the electromagnetic interference is prevented.

Details not described in this specification are within the skill of the art that are well known to those skilled in the art.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a high waterproof high insulating welded tube structure pressure sensor which characterized in that: comprises an outer shell, an inner shell, a metal pipe, an upper end cover and a connecting wire connected with an external circuit, wherein the inner shell is arranged in the outer shell, the bottom of the inner shell is welded with the metal pipe, the metal pipe extends out of the outer shell, an inner shield is arranged in the inner shell, a pressure sensing element and a circuit module are sequentially arranged in the inner shield from bottom to top, the top of the inner shield is sealed by the upper end cover, a contact pin is arranged on the upper end cover, one end of the contact pin is connected with the connecting wire, the other end of the contact pin and the pressure sensing element are electrically connected with the circuit module, a first through hole is arranged at the bottom of the inner shell, a second through hole is arranged at the bottom of the inner shield, the second through hole is just opposite to the first through hole, and the first through hole and the second through hole are both communicated with the metal pipe, the outer casing is filled with pouring sealant, and the pouring sealant encapsulates the inner casing, the inner shield cover and the upper end cover in the outer casing.

2. The high waterproof high insulation welded pipe structure pressure sensor according to claim 1, characterized in that: the bottom of interior casing with the bottom threaded connection of shell body, interior casing is the step shaft structure, including little diameter section and big diameter section, little diameter section is equipped with the external screw thread, the bottom of shell body is equipped with the trompil that supplies little diameter section to stretch into, the inner wall of trompil be equipped with external screw thread complex internal thread.

3. The high waterproof high insulating welded tube structure pressure sensor of claim 1, characterized in that: the inner bottom surface of the inner shield cover is provided with a first sealing ring and a check ring, the check ring surrounds the first sealing ring, the first sealing ring is in contact with the bottom surface of the pressure sensing element, and the first sealing ring surrounds the second through hole.

4. The high waterproof high insulating welded tube structure pressure sensor of claim 1, characterized in that: an annular groove is formed in the inner bottom surface of the inner shell, a second sealing ring is arranged in the groove and is in contact with the bottom of the inner shield cover, and the second sealing ring is arranged around the first through hole.

5. The high waterproof high insulating welded tube structure pressure sensor of claim 1, characterized in that: the upper end cover is the step shaft structure, the inner shield top is equipped with the first portion of bending that compresses tightly the upper end cover ladder face, interior casing top is equipped with the second portion of bending that compresses tightly first portion of bending, the inside accomodation of having seted up of upper end cover the space of circuit module, the upper end cover orientation forced induction component's one end edge is equipped with the convex bayonet socket, seted up on forced induction component's the lateral wall with convex bayonet socket joint complex draw-in groove, form a whole behind upper end cover and the forced induction component joint.

6. The high waterproof high insulation welded pipe structure pressure sensor according to claim 1, characterized in that: the outer shell is a plastic outer shell or a metal outer shell, the inner shell is a metal inner shell, and the inner shielding cover is a metal inner shielding cover.

7. The high waterproof high insulation welded pipe structure pressure sensor according to claim 6, characterized in that: the inside wall of interior casing is equipped with insulating coating.

8. The high waterproof high insulating welded tube structure pressure sensor of claim 6, characterized in that: the inside wall of interior casing and the lateral wall of internal shield cover all is equipped with insulating coating.

9. The high waterproof high insulating welded tube structure pressure sensor of claim 6, characterized in that: and an insulating oxide film is arranged on the inner side wall of the inner shell or the outer side wall of the inner shielding cover.

10. The high waterproof high insulating welded tube structure pressure sensor of claim 1, characterized in that: the contact pin and the connecting wire welding point are located in pouring sealant, and the pouring sealant covers the lower end of the connecting wire by 0.4-1 cm.