CN216621549U

CN216621549U - Insulating anti-electromagnetic interference structure for pressure sensor

Info

Publication number: CN216621549U
Application number: CN202123075753.3U
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: 2021-12-09
Filing date: 2021-12-09
Publication date: 2022-05-27
Anticipated expiration: 2031-12-09

Abstract

The utility model discloses an insulating anti-electromagnetic interference structure for a pressure sensor, which belongs to the technical field of pressure sensors and comprises a shell, a shielding case, a pressure sensing element, an insulating retainer ring, an electric joint assembly and an FPC (flexible printed circuit) conditioning circuit module, wherein the shell is provided with a body and a bending part, and the body and the bending part form a containing cavity; the shielding cover is arranged in the accommodating cavity; the pressure sensing element is arranged in the shielding cover; the insulating retainer ring is arranged between the pressure sensing element and the shielding case and is respectively connected with the pressure sensing element and the shielding case; the electric connector assembly is arranged in the shielding cover and is pressed by the bending part, and the electric connector assembly is connected with the pressure sensing element; the FPC conditioning circuit module is connected with the pressure sensing element. The utility model achieves the technical effects of reducing the production cost and preventing the pressure sensor from losing efficacy.

Description

Insulating anti-electromagnetic interference structure for pressure sensor

Technical Field

The utility model belongs to the technical field of pressure sensors, and particularly relates to an insulating anti-electromagnetic interference structure for a pressure sensor.

Background

Electronic products must pass EMC experiments, and EMC is defined as comprehensive evaluation of the interference level (EMI) and anti-interference capability (EMS) of the electronic products in terms of electromagnetic fields, and the electronic products must have the capability of preventing the electromagnetic fields generated by the electronic products from interfering other surrounding electronic products and the capability of resisting the electromagnetic fields not generated by the surrounding other electronic products.

At present, in the existing pressure sensor technology, the two aspects of preventing the electromagnetic field generated by the pressure sensor from interfering other surrounding electronic products and resisting the electromagnetic field generated by the pressure sensor from not influencing the pressure sensor by other surrounding electronic products are usually started, the pressure sensor mostly uses a faraday cage principle, namely electrostatic shielding, in the aspect of resisting the electromagnetic interference, the electrostatic shielding is divided into outer shielding and inner shielding, the inner shielding is shielding of a cavity conductor which is grounded, the shielding has the function of solving the problem that the electromagnetic field generated by the pressure sensor interferes other surrounding electronic products, the outer shielding is shielding of a cavity conductor which is not grounded, and the shielding has the function of solving the problem that the pressure sensor is not interfered by the electromagnetic field generated by other surrounding electronic products. The pressure sensor mainly uses the shielding case made of copper material to stop the self-generated interference source in the cylindrical shielding case in a grounding mode, but the copper material is easy to become copper oxide when in air contact, the conductivity of the copper material is reduced, the anti-interference capability is greatly weakened, and the oxidation problem of the processed copper product is solved by the methods of electroplating, oil spraying, paint spraying, passivation, film protection and the like on the surface of the copper material, so that the use cost is increased. And electrodes in the ceramic capacitor thick sheet and the pressure sensing thin sheet are easy to interfere with each other to influence surrounding electronic products, and a layer of conductive material is required to be wrapped on the pressure surface of the ceramic thin sheet to prevent an electromagnetic field generated by a silk-screen electrode at the joint of the ceramic thin sheet and the thick sheet from leaking from the bottom. In order to realize the purpose that the conductive material completely wraps the ceramic capacitor and the sealing problem of the pressed surface of the ceramic sheet cannot be influenced, the conventional pressure sensor is manufactured by adopting a screen printing technology on the pressed surface of the ceramic capacitor sheet to uniformly bond a copper coating on the surface of the ceramic, and then sintering at high temperature, wherein a lower flanging structure is required to be formed by punching a cylindrical copper material on the periphery of the ceramic through a manufacturing punching die, and then the cylindrical copper material is combined with a ceramic bottom surface electrode through the inner wall of a flanging, wherein in order to ensure tight combination, the inner wall of the flanging of the cylindrical copper material on the periphery needs to be coated with metal bonding glue for bonding, and a gluing process is added. As for the external shield, solve itself promptly and not disturbed by the electromagnetic field that other electronic product produced on every side produced, adopt the brass casing that the interference killing feature is strong, in order to satisfy high-voltage insulation's requirement, the most that uses at present is the flexible insulating paper of PI polyimide that insulating ability is extremely strong, because of structure and sealing requirement, insulating paper can not all cover the metal shield cover, can adopt insulating paper parcel at the periphery, lead to having increased the human cost that insulating scroll made the cylindrical structure, the bottom edge adopts high temperature resistant corrosion-resistant and insulating thermoplasticity solid material, use CNC processing or the corresponding cost that has increased of injection molding scheme, in addition also increased the cost of labor of assembling this part. 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, instantaneous overvoltage exceeding normal working voltage is generated by the pressure sensor due to factors such as equipment starting and stopping, power grid impact, faults or lightning stroke in the working process, a conditioning circuit of the pressure sensor is communicated with a shell, a conductive passage is formed between a power supply and the conditioning circuit and between the power supply and the shell, and when the instantaneous overvoltage passes through the conductive passage, the conditioning circuit and a pressure detection component can be punctured to cause the pressure sensor to be prone to failure.

In summary, the conventional pressure sensor technology has the technical problems that the production cost is increased and the pressure sensor is easy to fail.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problems that the production cost is increased and the pressure sensor is easy to lose efficacy.

In order to solve the above technical problem, the present invention provides an insulating anti-electromagnetic interference structure for a pressure sensor, the structure comprising: the shell is provided with a body and a bending part, and the body and the bending part form an accommodating cavity; the shielding cover is arranged in the accommodating cavity; the pressure sensing element is arranged in the shielding cover; the insulating retainer ring is arranged between the pressure sensing element and the shielding case and is respectively connected with the pressure sensing element and the shielding case; the electric connector assembly is arranged in the shielding cover and is pressed by the bending part, and the electric connector assembly is connected with the pressure sensing element; the FPC conditioning circuit module is connected with the pressure sensing element; the body is further provided with a groove, the shielding cover is positioned between the groove and the insulating retainer ring, and the groove is annular; the structure further includes: and the second sealing ring is matched with the groove and arranged in the groove.

Further, the structure further includes: the first sealing ring is arranged between the pressure sensing element and the shielding cover, and the first sealing ring is connected with the insulating check ring.

Further, the compression amount of the first sealing ring ranges from 20% to 25%, and the first sealing ring is O-shaped.

Further, the compression amount of the second sealing ring ranges from 20% to 25%, and the second sealing ring is O-shaped.

Further, the structure further includes: and the insulating coating is coated on the shielding case and is positioned between the shielding case and the body.

Further, the insulation resistance of the insulation coating is greater than 100M omega, and the thickness range of the insulation coating is 80um to 100 um.

Furthermore, the insulating retainer ring is made of polytetrafluoroethylene materials, and the outer diameter of the insulating retainer ring is smaller than the inner diameter of the shielding case.

Furthermore, the manufacturing material of the shielding case is a metal material, and the shielding case is connected with the FPC conditioning circuit module.

Further, the structure further includes: the sensing diaphragm is arranged on the pressure sensing element.

Has the advantages that:

the utility model provides an insulating anti-electromagnetic interference structure for a pressure sensor, which is characterized in that a shielding case is arranged in a containing cavity formed by a body and a bent part in a shell, and a pressure sensing element is arranged in the shielding case; an insulation retainer ring is arranged between the pressure sensing element and the shielding case, the insulation retainer ring is respectively connected with the pressure sensing element and the shielding case, an electric connector assembly is arranged inside the shielding case and presses the electric connector assembly through a bent part in the shell, the electric connector assembly is connected with the pressure sensing element, and the FPC conditioning circuit module is connected with the pressure sensing element. The shield cover is arranged between the groove and the insulating retainer ring in the body, the groove is annular, and the second sealing ring is arranged in the groove. Therefore, when instantaneous large current or large voltage is generated in the circuit, the electric joint assembly, the FPC conditioning circuit module and the shell are isolated from each other, and the pressure sensor is not prone to failure after the FPC conditioning circuit module and the pressure sensing element are broken down. Meanwhile, an electromagnetic field generated in the FPC conditioning circuit module can be stopped in the shielding case, electromagnetic interference can be prevented, insulating paper does not need to be wrapped around the shielding case, and an insulating gasket is not needed to be arranged at the bottom of the shielding case, so that the production cost is reduced. And then, the production cost can be reduced, and when instantaneous large current or large voltage is generated in the circuit, the pressure sensor can not be failed due to the breakdown of the FPC conditioning circuit module and the pressure sensing element. Therefore, the technical effects of reducing the production cost and preventing the pressure sensor from losing efficacy are achieved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of an insulating EMI-resistant structure for a pressure sensor according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an electrical contact assembly in an insulated EMI resistant configuration for a pressure sensor according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an FPC conditioning circuit module in an insulating anti-electromagnetic interference structure for a pressure sensor according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a pressure sensing element in an insulated EMI resistant structure for a pressure sensor according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an insulating collar in an insulating anti-EMI structure for a pressure sensor according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a first sealing ring in an insulating anti-EMI structure for a pressure sensor according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a housing in an insulating anti-EMI structure for a pressure sensor according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a second sealing ring in an insulating anti-EMI structure for a pressure sensor according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a shielding case in an insulating EMI-resistant structure for a pressure sensor according to an embodiment of the present invention;

fig. 10 is a schematic diagram of an exploded view of an insulating electromagnetic interference resistant structure for a pressure sensor according to an embodiment of the present invention.

Detailed Description

The utility model discloses an insulating anti-electromagnetic interference structure for a pressure sensor, which is characterized in that a shielding case 8 is arranged in a containing cavity formed by a body and a bent part in a shell 6, and a pressure sensing element 3 is arranged in the shielding case 8; an insulating retainer ring 4 is arranged between a pressure sensing element 3 and a shielding case 8, the insulating retainer ring 4 is respectively connected with the pressure sensing element 3 and the shielding case 8, an electric connector assembly 1 is arranged inside the shielding case 8 and presses the electric connector assembly 1 through a bending part in the shell 6, the electric connector assembly 1 is connected with the pressure sensing element 3, and an FPC conditioning circuit module 2 is connected with the pressure sensing element 3. The shield cover 8 is arranged between the groove in the body and the insulating retainer ring, the groove is annular, and the second sealing ring 7 is arranged in the groove. Therefore, when instantaneous large current or large voltage is generated in the circuit, the electric joint assembly 1, the FPC conditioning circuit module 2 and the shell 6 are isolated from each other, and the pressure sensor is not prone to failure after the FPC conditioning circuit module 2 and the pressure sensing element 3 are broken down. Meanwhile, an electromagnetic field generated in the FPC conditioning circuit module 2 is terminated in the shielding case 8, electromagnetic interference can be prevented, and insulating paper does not need to be wrapped around the shielding case 8 and an insulating gasket is not needed to be arranged at the bottom of the shielding case 8, so that the production cost is reduced. And then, the production cost can be reduced, and when instantaneous large current or large voltage is generated in the circuit, the pressure sensor can not be failed due to the breakdown of the FPC conditioning circuit module 2 and the pressure sensing element 3. Therefore, the technical effects of reducing the production cost and preventing the pressure sensor from losing efficacy are achieved.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention belong to the protection scope of the present invention; the "and/or" keyword referred to in this embodiment represents sum or two cases, in other words, a and/or B mentioned in the embodiment of the present invention represents two cases of a and B, A or B, and describes three states where a and B exist, such as a and/or B, which represents: only A does not include B; only B does not include A; including A and B.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. Spatially relative terms, such as "below," "above," and the like, may be used herein to facilitate describing one element or feature's relationship to another element or feature. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "lower" would then be oriented "upper" other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Also, in embodiments of the utility model where an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used in the embodiments of the present invention are for illustrative purposes only and are not intended to limit the present invention.

Referring to fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6, fig. 7, fig. 8, fig. 9 and fig. 10, fig. 1 is a schematic diagram of an insulation structure for a pressure sensor for resisting electromagnetic interference according to an embodiment of the present invention, fig. 2 is a schematic diagram of an electrical connector assembly 1 in an insulation structure for a pressure sensor for resisting electromagnetic interference according to an embodiment of the present invention, fig. 3 is a schematic diagram of an FPC conditioning circuit module 2 in an insulation structure for a pressure sensor for resisting electromagnetic interference according to an embodiment of the present invention, fig. 4 is a schematic diagram of a pressure sensing element 3 in an insulation structure for a pressure sensor for resisting electromagnetic interference according to an embodiment of the present invention, fig. 5 is a schematic diagram of an insulating collar 4 in an insulation structure for a pressure sensor for resisting electromagnetic interference according to an embodiment of the present invention, and fig. 6 is an illustration of a first sealing ring 5 in an insulation structure for a pressure sensor for resisting electromagnetic interference according to an embodiment of the present invention Fig. 7 is a schematic diagram of the housing 6 in the structure for insulation and electromagnetic interference resistance of the pressure sensor according to the embodiment of the present invention, fig. 8 is a schematic diagram of the second sealing ring 7 in the structure for insulation and electromagnetic interference resistance of the pressure sensor according to the embodiment of the present invention, fig. 9 is a schematic diagram of the shielding cover 8 in the structure for insulation and electromagnetic interference resistance of the pressure sensor according to the embodiment of the present invention, and fig. 10 is a schematic diagram of an explosion diagram of the structure for insulation and electromagnetic interference resistance of the pressure sensor according to the embodiment of the present invention. The structure for insulation and electromagnetic interference resistance of the pressure sensor provided by the embodiment of the utility model comprises a shell 6, a shielding case 8, a pressure sensing element 3, an insulation retaining ring 4, an electric connector assembly 1 and an FPC conditioning circuit module 2, wherein the shell 6, the shielding case 8, the pressure sensing element 3, the insulation retaining ring 4, the electric connector assembly 1 and the FPC conditioning circuit module 2 are respectively explained in detail:

for the housing 6, the shield can 8, the pressure sensitive element 3, the insulating collar 4, the electrical connector assembly 1 and the FPC conditioning circuit module 2:

casing 6 is provided with the body and the portion of bending, the body with the portion of bending forms and holds the chamber, as shown in fig. 7, the portion of bending can mean to be located the top opening part to holding the intracavity portion of bending in casing 6, and other parts of being connected with the portion of bending are the body in casing 6 promptly, and the top of body presents for hollow cylindrical structure, and the top of body can be integrated into one piece with the portion of bending, and the intermediate position of body is the hexagon structure, and the below position of body is hollow cylindrical structure. The body still is provided with the recess, shield cover 8 is located the recess with between the insulating retaining ring 4, the recess is the annular. The shielding cover 8 is arranged inside the accommodating cavity; the pressure sensing element 3 is arranged inside the shielding cover 8; insulating retaining ring 4 is installed between pressure sensing element 3 and shield cover 8, insulating retaining ring 4 respectively with pressure sensing element 3 with shield cover 8 is connected, wherein insulating retaining ring 4's preparation material is the PTFE material, insulating retaining ring 4's external diameter is less than shield cover 8's internal diameter. The electric joint component 1 is arranged inside the shielding cover 8, and the electric joint component 1 can be pressed through the bending part, and the electric joint component 1 is connected with the pressure sensing element 3; the FPC conditioning circuit module 2 is connected with the pressure sensing element 3. The structure for insulating and resisting electromagnetic interference of the pressure sensor, provided by the embodiment of the utility model, further comprises an insulating coating and an induction membrane, wherein the insulating coating and the induction membrane are coated on the shielding cover 8, the manufacturing material of the shielding cover is a metal material, so that the shielding cover is a conductor, if the whole shielding cover is manufactured by adopting the metal material, or a metal layer can be arranged on the shielding cover 8, the insulating resistance of the insulating coating is greater than 100M omega, and the thickness range of the insulating coating is 80-100 um. The shield case is connected to the FPC conditioning circuit module 2 (e.g., via a metal layer disposed on the shield case to communicate with the FPC conditioning circuit module 2). The sensing diaphragm is arranged below the pressure sensing element 3.

Specifically, the insulating and electromagnetic interference resistant structure for the pressure sensor provided by the embodiment of the utility model can be particularly applied to a central air conditioning system, and is especially applied to a variable frequency air conditioner. The housing 6 may be referred to as an outer hexagonal housing 6, the shield 8 may be referred to as a cylindrical inner shield 8, and the FPC conditioning circuit module 2 may be referred to as an FPC conditioning circuit. The bending part is arranged at the top of the outer hexagonal shell 6 and is radially bent along the inner side. A groove may be provided in the body, which groove is in the form of a ring, the interior of which groove has a space for accommodating a second sealing ring 7, described below. The cylindrical inner shield 8 is wrapped by the inside of the outer hexagonal housing 6, and the cylindrical inner shield 8 is tightly attached to the bent portion. The outer side and the bottom of the cylindrical inner shield cover 8 are coated with insulating coatings, the insulating resistance of the insulating coatings is larger than 100M omega under 1500V direct current, the thickness of the insulating coatings is 80um to 100um, if the thickness of the insulating coatings is D, D is larger than or equal to 80um and smaller than or equal to 100um, the insulating coatings are nano film layers, namely, the manufacturing materials of the insulating coatings can be glass fibers added into polytetrafluoroethylene powder. The inner wall of the cylindrical inner shielding cover 8 is provided with a metal layer which is contacted with two flexible thin flat plate-shaped pins with copper cladding separated from the FPC conditioning circuit. Pressure-sensitive element 3 is wrapped up in the inside of cylinder internal shield cover 8, and the mutual welding of three copper-clad small circle hole of one end in three contact pin of pressure-sensitive element 3 top and the FPC modulate circuit is equipped with the response diaphragm in the below of pressure-sensitive element 3, and when liquid entered from the below hole of outer hexagon casing 6, the inductive capacitance of pressure-sensitive element 3 can change, and pressure-sensitive element 3 can adopt ceramic material to make and form. Insulating retaining ring 4 sets up between pressure-sensitive element 3 and the 8 bottom inner wall edges of cylinder inner shield cover, and insulating retaining ring 4 is located pressure-sensitive element 3's below, and insulating retaining ring 4 can adopt PTFE preparation to form, and the biggest external diameter of insulating retaining ring 4 slightly is less than the internal diameter of cylinder inner shield cover 8. The electric joint component 1 is matched with the outer hexagonal shell 6, the electric joint component 1 is connected with the bending part, and the electric joint component 1 can be pressed through the bending part. The FPC conditioning circuit is connected with the pressure sensing element 3, three copper-coated small round holes at one end of the FPC conditioning circuit module 2 and three contact pins of the pressure sensing element 3 are welded, the other end of the FPC conditioning circuit module 2 is connected with three contact pins in the electric connector assembly 1, the three contact pins are respectively a power supply voltage input line, a signal output line and a ground wire, and two flexible thin flat plate-shaped pins with copper coatings separated from the FPC conditioning circuit module 2 are in contact with a metal layer. Therefore, a conducting loop is formed by the grounding wire in the electric joint assembly 1, two flexible thin flat plate-shaped pins in the FPC conditioning circuit and the inner wall (namely a metal layer) of the cylindrical inner shield cover 8, so that an electromagnetic field generated by a chip capacitor, a chip resistor, a conditioning chip and the like in the FPC conditioning circuit is stopped on the inner wall of the cylindrical inner shield cover 8, and charges generated by an internal electric field or a magnetic field are introduced into the ground by the grounding wire to play a role in preventing electromagnetic interference. The size of the sensor can be effectively reduced, and the production cost of the sensor is reduced. If the periphery of the circumference of the cylindrical inner shielding cover 8 is not required to be wrapped with insulating paper, and an insulating gasket is not required to be arranged at the bottom of the cylindrical inner shielding cover, the process of rolling the insulating paper in the assembling process is omitted, and the labor cost and the material cost are reduced. The grounding end of the electric joint component 1, the FPC conditioning circuit and the outer hexagonal shell 6 are isolated, so that a series connection conducting loop cannot be formed, instantaneous large current or large voltage cannot be generated in the circuit, and therefore a chip or an electronic element in the FPC conditioning circuit and the pressure sensing element 3 cannot be broken down, and the pressure sensor cannot be prone to failure.

It should be noted that, the outer hexagonal shell 6 can be made of brass material with high mechanical strength, corrosion resistance and good electromagnetic shielding resistance, the thickness of the upper end thin wall of the outer hexagonal shell 6 is 0.8mm (namely, a bending part), and the outer hexagonal shell 6 and the electric joint assembly 1 can form compression connection. Because the compression joint gap is not in the liquid medium such as the refrigerant and is not in the direct action position of the medium such as the refrigerant, the environment sealant can be applied only at the joint gap formed by the inward bending part along the radial direction, the external water vapor can not enter the FPC conditioning circuit module 2 through the sealant, the internal circuit of the FPC conditioning circuit module 2 can be protected, the step of sealing an O-shaped sealing ring on the side surface of the electric connector is not needed, meanwhile, the inward bending part of the outer hexagonal shell 6 along the radial direction is tightly attached to the electric connector assembly 1, the condition that the sealant generates bubbles is reduced, the time of the sealant applying process is shortened, and the cost is reduced. The cylindrical inner shield cover 8 can be made of 316L stainless steel, the 316L stainless steel is more corrosion-resistant than 304 stainless steel, the high-temperature resistance is better, the mechanical strength is high, the wall thickness of the cylindrical inner shield cover 8 can be 0.5mm, an opening for allowing a medium to enter can be further formed in the center of the bottom wall of the cylindrical inner shield cover 8, and the potential safety hazard that the cylindrical inner shield cover 8 is damaged cannot occur under the pressure impact of the medium such as a refrigerant. The outer side (namely, the side close to the body in the shell 6) of the cylindrical inner shield cover 8 is coated with an insulating coating, polytetrafluoroethylene with better corrosion resistance can be adopted as a coating material, the hardness and the wear resistance can be greatly improved after glass fibers are added into polytetrafluoroethylene powder, then a layer of compact nano film layer without pinholes is formed on the outer side of the cylindrical inner shield cover 8 by adopting a chemical vapor deposition process (CVD), the nano film layer has excellent wear resistance, the insulating resistance of the coating is more than 100M omega, and the thickness of the coating is 100 um. Pressure sensing element 3 establishes inside cylinder inner shield cover 8, pressure sensing element 3's below is the response diaphragm, the pressure of medium such as refrigerant can be felt to the response diaphragm, through taking place small distance deformation between inside bipolar plate, change the size of the inside variable capacitance of response diaphragm, the inside reference capacitance of response diaphragm is unchangeable, can measure the ratio between them and produce a series of signals, rethread FPC modulate circuit module 2 comes to handle a series of signals after, just can produce the ratio that changes along with pressure and list voltage signal and export.

It is worth mentioning that the substrate of the FPC conditioning circuit module 2 may be organic polymer PI polyimide, which has a high temperature resistance of more than 400 ℃, and a long-term use temperature range of-200 ℃ to 300 ℃, so that the substrate of the FPC conditioning circuit module 2 has high insulation performance. The organic polymer material PI polyimide flexible material has good bending resistance, and the bending strength of the polyimide reinforced by graphite and glass fiber can reach 345 MPa. Three copper-clad round holes at one end of the FPC conditioning circuit module 2 are connected with three contact pins of the ceramic capacitor, the other end of the FPC conditioning circuit module 2 is connected with three tinned contact pins in the electric joint component 1, and the three wires are respectively a power voltage input wire, a signal wire and a grounding wire. When the pressure of the medium changes, the distance between the polar plates of the sensing membrane acting on the pressure sensing element 3 changes slightly, so that the variable capacitance changes, and the specific voltage signal which changes along with the pressure can be generated and output by amplifying the variable capacitance through the conditioning chip of the FPC conditioning circuit module 2. The external grounding wire, two flexible thin flat plate pins in the FPC conditioning circuit and the inner wall of the cylindrical inner shielding cover 8 form a conducting loop, so that an electromagnetic field generated by a chip capacitor, a chip resistor, a conditioning chip and the like in the FPC conditioning circuit is stopped at the inner wall of the cylindrical inner shielding cover 8. Then the electric charge generated by the internal electric field or magnetic field is introduced into the ground by the grounding wire, so that the electromagnetic interference is prevented, and the insulating paper does not need to be wrapped around the shielding cover 8 and an insulating gasket does not need to be arranged on the bottom of the shielding cover 8, so that the production cost is reduced.

The structure for insulating and resisting electromagnetic interference of the pressure sensor, provided by the embodiment of the utility model, further comprises a first sealing ring 5, an insulating coating coated on the shielding case 8, a metal layer coated on the shielding case 8 and an induction membrane, wherein the first sealing ring 5 is arranged between the pressure sensing element 3 and the shielding case 8, the first sealing ring 5 is connected with the insulating retainer ring 4, the compression amount range of the first sealing ring 5 is 20-25%, and the first sealing ring 5 is in an O shape. And a second sealing ring 7 matched with the groove is arranged in the groove, the compression amount range of the second sealing ring 7 is 20-25%, and the second sealing ring 7 is in an O shape. Under 1500V direct current voltage, coat in the insulation resistance of the insulating coating of shield cover 8 is greater than 100M omega, the thickness range of insulating coating is 80um to 100 um. And the metal layer coated on the shielding cover 8 is connected with the FPC conditioning circuit module 2. The sensing diaphragm is arranged below the pressure sensing element 3.

Specifically, the first sealing ring 5 is disposed below the pressure sensing element 3, the first sealing ring 5 may be made of an insulating HNBR (i.e., hydrogenated nitrile rubber) with corrosion resistance, tear resistance, wear resistance, compression deformation resistance, and high and low temperature resistance, and the compression amount of the first sealing ring 5 is 20% to 25%, so that the first sealing ring 5 has a better sealing effect. Insulating retaining ring 4 sets up in the outward flange of first sealing washer 5, adopts the polytetrafluoroethylene material that corrosion resistance is excellent, insulating properties is good, and the polytetrafluoroethylene material of adoption can prevent that the internal seal circle from taking place "to extrude" phenomenon and leading to revealing under the high pressure medium effect, can play insulating and sealed dual function. The second sealing ring 7 is arranged at the bottom of the outer side of the cylindrical inner shielding cover 8, the second sealing ring 7 is embedded into the groove which is annular, so that the second sealing ring 7 can prevent a medium from leaking through a gap between the cylindrical inner shielding cover 8 and the outer hexagonal shell 6, the second sealing ring 7 is made of an anticorrosive HNBR (high temperature and low temperature resistant HNBR), wear resistance, compression deformation resistance, high temperature and low temperature resistance and insulation HNBR, the compression amount of the second sealing ring 7 is between 20% and 25%, and the second sealing ring 7 has a better sealing effect.

The utility model provides an insulating anti-electromagnetic interference structure for a pressure sensor, which is characterized in that a shielding case 8 is arranged in a containing cavity formed by a body and a bent part in a shell 6, and a pressure sensing element 3 is arranged in the shielding case 8; an insulating retainer ring 4 is arranged between a pressure sensing element 3 and a shielding case 8, the insulating retainer ring 4 is respectively connected with the pressure sensing element 3 and the shielding case 8, an electric connector assembly 1 is arranged inside the shielding case 8 and presses the electric connector assembly 1 through a bending part in the shell 6, the electric connector assembly 1 is connected with the pressure sensing element 3, and an FPC conditioning circuit module 2 is connected with the pressure sensing element 3. The shield cover 8 is arranged between the groove in the body and the insulating retainer ring, the groove is annular, and the second sealing ring 7 is arranged in the groove. Therefore, when instantaneous large current or large voltage is generated in the circuit, the electric joint assembly 1, the FPC conditioning circuit module 2 and the shell 6 are isolated from each other, and the pressure sensor is not prone to failure after the FPC conditioning circuit module 2 and the pressure sensing element 3 are broken down. Meanwhile, an electromagnetic field generated in the FPC conditioning circuit module 2 is terminated in the shielding case 8, electromagnetic interference can be prevented, and insulating paper does not need to be wrapped around the shielding case 8 and an insulating gasket is not needed to be arranged at the bottom of the shielding case 8, so that the production cost is reduced. And then, the production cost can be reduced, and when instantaneous large current or large voltage is generated in the circuit, the pressure sensor can not be failed due to the breakdown of the FPC conditioning circuit module 2 and the pressure sensing element 3. Therefore, the technical effects of reducing the production cost and preventing the pressure sensor from losing efficacy are achieved.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims

1. An insulating anti-electromagnetic interference structure for a pressure sensor, the structure comprising: the shell is provided with a body and a bending part, and the body and the bending part form an accommodating cavity; the shielding cover is arranged in the accommodating cavity; the pressure sensing element is arranged in the shielding cover; the insulating retainer ring is arranged between the pressure sensing element and the shielding case and is respectively connected with the pressure sensing element and the shielding case; the electric connector assembly is arranged in the shielding cover and is pressed by the bending part, and the electric connector assembly is connected with the pressure sensing element; the FPC conditioning circuit module is connected with the pressure sensing element; the body is further provided with a groove, the shielding cover is positioned between the groove and the insulating retainer ring, and the groove is annular; the structure further includes: and the second sealing ring is matched with the groove and arranged in the groove.

2. The insulating anti-electromagnetic interference structure for a pressure sensor of claim 1, further comprising:

the first sealing ring is arranged between the pressure sensing element and the shielding cover, and the first sealing ring is connected with the insulating check ring.

3. The insulating anti-electromagnetic interference structure for a pressure sensor according to claim 2, characterized in that:

the compression amount range of the first sealing ring is 20% -25%, and the first sealing ring is O-shaped.

4. The insulating anti-electromagnetic interference structure for a pressure sensor according to claim 1, characterized in that:

the compression amount range of the second sealing ring is 20% -25%, and the second sealing ring is O-shaped.

5. The insulating anti-electromagnetic interference structure for a pressure sensor of claim 1, further comprising:

and the insulating coating is coated on the shielding case and is positioned between the shielding case and the body.

6. The insulating anti-electromagnetic interference structure for a pressure sensor according to claim 1, characterized in that:

the insulation resistance of insulating coating is greater than 100M omega, the thickness range of insulating coating is 80um to 100 um.

7. The insulating anti-electromagnetic interference structure for a pressure sensor according to claim 1, characterized in that:

the insulating retainer ring is made of polytetrafluoroethylene materials, and the outer diameter of the insulating retainer ring is smaller than the inner diameter of the shielding case.

8. The insulating anti-electromagnetic interference structure for a pressure sensor according to claim 1, characterized in that:

the manufacturing material of the shielding cover is a metal material, and the shielding cover is connected with the FPC conditioning circuit module.

9. The insulating anti-electromagnetic interference structure for a pressure sensor of claim 1, further comprising:

the sensing diaphragm is arranged on the pressure sensing element.