Pressure sensor device

Abstract

Pressure sensor device, comprising: a housing body (10) with a pressure introduction chamber (31) formed therein; a pressure detection element (32) configured to detect the pressure of a measuring medium introduced into the pressure introduction chamber (31). a wire (33); and a conductor frame (34) which is electrically connected to the pressure detection element (32) via the wire (33), wherein the housing body (10) has a first recessed section (41) and a second recessed section (42) formed therein, wherein the first recessed section (41) faces the pressure introduction chamber (31), wherein the second recessed section (42) is formed in part of a lower section (44) of the first recessed section (41), wherein at least part of the conductor frame (34), the pressure detection element (32) and the wire (33) are arranged within the second recessed section (42), wherein the second recessed section (42) is filled with a first protective element (47), wherein the first recessed section (41) has provided a resin element (48) with a film form in it, wherein the resin element (48) covers an entire surface (47a) of the first protective element (47) and is in close contact with the first protective element (47), wherein the first recessed section (41) is filled with a second protective element (49), and wherein the second protective element (49) is in close contact with the resin element (48).

Description

Technical field

[0001] This disclosure relates to a pressure sensor device comprising a pressure detection element for detecting the pressure of a measuring medium. State of the art

[0002] JP 6 656 336 B1 describes a pressure sensor device with a temperature sensor. This combined pressure sensor device comprises a housing, a pressure sensor module, and a temperature sensor module located within the housing, and a housing in which a pressure inlet passage is formed. The pressure sensor module includes a pressure sensing element, a wire, and a conductor frame. The pressure sensing element detects the pressure of the intake air introduced through the pressure inlet passage. The conductor frame is connected to the pressure sensing element via the wire. Inside the housing, the pressure sensing element, the wire, and the conductor frame are covered with a protective layer of fluoro- or fluorosilicone gel.

[0003] From JP 2005 - 326 338 A, a pressure sensor element consisting of three layers is known, wherein a film-like resin element is located on the outside. US 2006 / 0 137 458 A1 relates to a protective coating for a pressure sensor element consisting of three layers, wherein the middle layer consists of a fluorine-based gel. Summary of the invention: Technical problem

[0004] Depending on the environment in which the pressure sensor is used, a corrosive substance may penetrate the aforementioned protective element. Consequently, in some cases, the pressure sensing element, the wire, and the conductor frame may not be adequately protected. If the corrosive substance penetrates the protective element, causing corrosion in an area between the pressure sensing element and the wire, an area between the wire and the conductor frame, or similar areas, accurate pressure detection becomes difficult. Thus, according to the relevant prior art, the pressure sensor suffers from reduced reliability in some cases, depending on the environment in which it is used.

[0005] This revelation was made to solve the aforementioned problem and has the objective of providing a pressure sensor device capable of further improving reliability. Solution to the problem

[0006] The problem is solved according to the invention by the subject matter of the main claim. The dependent claims relate to further embodiments, and this description explains how the invention can be carried out.

[0007] According to one embodiment of this disclosure, a pressure sensor device is provided comprising: a housing body with a pressure introduction chamber formed therein; a pressure sensing element configured to detect the pressure of a measuring medium introduced into the pressure introduction chamber; a wire; and a conductor frame electrically connected to the pressure sensing element via the wire, wherein the housing body has a first recessed section and a second recessed section formed therein, the first recessed section facing the pressure introduction chamber, the second recessed section being formed in a part of a lower section of the first recessed section, with at least a part of the conductor frame, the pressure sensing element, and the wire being arranged within the second recessed section.wherein the second recessed section is filled with a first protective element, wherein the first recessed section has provided a resin element with a film form in it, wherein the resin element covers an entire surface of the first protective element and is in close contact with the first protective element, wherein the first recessed section is filled with a second protective element and wherein the second protective element is in close contact with the resin element. Advantageous effects of the invention

[0008] According to the present disclosure, the reliability of the pressure sensor device can be further improved. Brief description of the drawings Fig. Figure 1 is a cross-sectional view illustrating a configuration of a pressure sensor device according to a first embodiment of the present disclosure. Fig. Figure 2 is a cross-sectional view to illustrate a configuration of a pressure sensor module of the pressure sensor device according to the first embodiment. Description of the embodiments: First embodiment

[0009] A pressure sensor device according to a first embodiment of this disclosure is described. Fig. Figure 1 is a cross-sectional view illustrating a configuration of the pressure sensor device according to this embodiment. In this embodiment, the pressure sensor device is an intake manifold pressure sensor located on the intake manifold of a vehicle and used in an environment where it is exposed to organic solvents such as gasoline or oils such as engine oil.

[0010] As in Fig. As shown in Figure 1, the pressure sensor device comprises a housing 11, a housing 20, and a pressure sensor module 30, which is housed in the housing 11. The housing 11 and the housing 20, together with a resin package 35 to be described later, form a housing body 10 of the pressure sensor device. Both the housing 11 and the housing 20 are made of a thermoplastic material. A polybutylene terephthalate resin (PBT resin), a polyphenylene sulfide resin (PPS resin), or a similar material can be used as the thermoplastic resin.

[0011] The housing 11 includes a storage compartment 12 for the pressure sensor module 30 and a port 13 provided on one side of the storage compartment 12. Within the port 13 is an external connection port 14, which is connected to the pressure sensor module 30. The external connection port 14 is to be electrically connected to an external signal processing circuit, such as a vehicle control unit. The housing 11 is integrated with the external connection port 14, the pressure sensor module 30, and the like by overmolding.

[0012] The housing 20 is arranged such that it faces the housing 11 opposite the pressure sensor module 30. A pressure inlet chamber 31 is formed within the housing body 10 between the housing 20 and the pressure sensor module 30.

[0013] The housing 20 comprises a column-shaped section 21, which is inserted into a mounting hole (not shown) located in the intake manifold. Within the column-shaped section 21, a pressure inlet channel 22 is formed for introducing intake air, serving as the measuring medium, into the pressure inlet chamber 31.

[0014] A flange section 23 is formed in the column-shaped section 21, projecting from an outer circumferential side. The flange section 23 is welded or bonded to the housing 11 around its entire circumference. An O-ring 24 is provided on an inner circumferential side with respect to the flange section 23 and on the outer circumferential side with respect to the pressure inlet channel 22. The O-ring 24 is in close contact with both the housing 20 and the resin package 35, which will be described later, thus ensuring an airtight seal between the housing 20 and the pressure sensor module 30. This prevents the intake air introduced into the pressure inlet chamber 31 through the pressure inlet channel 22 from escaping to the outside through a connection between the housing 20 and the pressure sensor module 30.

[0015] A circumferential groove 26 is formed on an outer circumferential surface of the columnar section 21 to accommodate an O-ring 25. When the columnar section 21 is inserted into the mounting opening of the intake manifold, the O-ring 25 ensures an airtight seal between the outer circumferential surface of the columnar section 21 and an inner circumferential surface of the mounting opening.

[0016] Fig. Figure 2 is a cross-sectional view illustrating the configuration of the pressure sensor module of the pressure sensor device according to this embodiment. The upward-downward direction of Fig. 2 is opposite to the upward-downward direction of Fig. 1 inverted. As in Fig. As shown in Figure 2, the pressure sensor module 30 comprises a pressure sensing element 32, a plurality of wires 33, a conductor frame 34 and the resin package 35 for holding the pressure sensing element 32 and the conductor frame 34.

[0017] Each of the multiple wires 33 is a conductive wire made of gold or aluminum. The conductor frame 34 is electrically connected to the pressure sensing element 32 via each wire 33. The conductor frame 34 is embedded in the resin package 35. As in Fig. As shown in Figure 1, an end section 34a of the conductor frame 34 protrudes from the resin package 35. The end section 34a is connected to the external connection terminal 14 by welding or soldering. In this way, the conductor frame 34 is electrically connected to the external connection terminal 14.

[0018] A silicon semiconductor element is used as the pressure sensing element 32. It comprises a vacuum chamber and a diaphragm that utilizes a piezoresistive effect. An electrical circuit, including a measuring resistor, is integrated into the diaphragm. When the diaphragm is deformed by the pressure of the intake air, the resistance of the measuring resistor changes depending on the degree of deformation. In this way, the intake air pressure can be detected as a change in the resistance value. The change in the resistance value of the measuring resistor is converted into an electrical signal for amplification. The amplified electrical signal is output via the external connection terminal 14 to a signal processing circuit located outside the pressure sensor device.

[0019] In this embodiment, a semiconductor element utilizing the piezoresistive effect is used as the pressure sensing element 32, but this disclosure is not limited thereto. The pressure sensing element 32 can be an element that employs a system for detecting a change in capacitance or the like.

[0020] The resin package 35, together with the housing 11 and the housing 20, forms the housing body 10 of the pressure sensor device. The resin package 35 is made of a thermosetting resin, such as an epoxy resin.

[0021] The resin package 35 has a first recessed section 41 and a second recessed section 42 formed within it. The first recessed section 41 faces the pressure introduction chamber 31. The first recessed section 41 comprises a first opening section 43 and a first lower section 44. The first opening section 43 of the first recessed section 41 is formed in the direction of the pressure introduction chamber 31. The second recessed section 42 is formed in a portion of the first lower section 44 of the first recessed section 41. The second recessed section 42 comprises a second opening section 45 and a second lower section 46. In the second recessed section 42, the second opening section 45 is formed in the direction of a space in the first recessed section 41.The second lower section 46 is designed such that a portion of the ladder frame 34, which is buried in the resin package 35, is exposed. The second opening section 45 is designed to be smaller than the first opening section 43. That is, a portion of the second opening section 45 is smaller than a portion of the first opening section 43. The first lower section 44 of the first recessed section 41 is annular in shape, so that it surrounds the second opening section 45 of the second recessed section 42.

[0022] At least a part of the conductor frame 34, the pressure sensing element 32, and the wires 33 are arranged within the second recessed section 42. In this way, a connection section between the pressure sensing element 32 and each wire 33, and a connection section between each wire 33 and the conductor frame 34, are arranged within the second recessed section 42.

[0023] The second recessed section 42 is filled with a first protective element 47. The first protective element 47 fills the entire second recessed section 42. That is, the first protective element 47 extends from the second lower section 46 to the second opening section 45 in a depth direction of the second recessed section 42. A surface 47a of the first protective element 47 is formed in a curved surface shape, e.g., a dome shape, which is convex towards the side of the pressure introduction chamber 31. Viewed from the side of the pressure introduction chamber 31, the shape of an outer edge of the surface 47a corresponds to the shape of the second opening section 45 of the second recessed section 42. The first protective element 47 covers the pressure sensing element 32, the wires 33, and the conductor frame 34 within the second recessed section 42.The first protective element 47 is in close contact with the pressure sensing element 32, the wires 33, and the conductor frame 34. In this way, the pressure sensing element 32, the wires 33, and the conductor frame 34 are protected by the first protective element 47. Furthermore, the first protective element 47 is also in close contact with the resin package 35 of the pressure sensor module 30.

[0024] The first protective element 47 is made of a gel that has electrically insulating properties. A gel has intermediate properties between a solid and a liquid. Accordingly, the first protective element 47 can protect the pressure sensing element 32, the wires 33, and the conductor frame 34, and also transmit the pressure of the measuring medium in the pressure introduction chamber 31 to the pressure sensing element 32.

[0025] In this embodiment, the first protective element 47 is made of a fluorine-based gel. The fluorine-based gel is resistant to organic solvents such as gasoline, oils such as motor oil, and condensate containing corrosive substances such as nitrate ions. In the following description, the organic solvents, oils, and condensate containing corrosive substances are sometimes collectively referred to as "liquid containing corrosive substances." The resistance of the first protective element 47 to the liquid containing corrosive substances can be increased when it is made of a fluorine-based gel.

[0026] A film-shaped resin element 48 is provided in the first recessed section 41. The resin element 48 has an outer shape that is larger than that of the second opening section 45 of the second recessed section 42. The resin element 48 covers the entire surface 47a of the first protective element 47 and is in close contact with the first protective element 47. Viewed from the side of the pressure introduction chamber 31, the resin element 48 covers the pressure detection element 32, the wires 33, and the conductor frame 34. The resin element 48 lies opposite the pressure detection element 32 across the first protective element 47. Furthermore, viewed from the side of the pressure introduction chamber 31, the resin element 48 overlaps the first lower section 44, which is formed in an annular shape over its entire circumference.

[0027] The resin element 48 is made of a porous material. It has a thickness of approximately 0.3 mm to 0.4 mm. The resin element 48 is flexible and also possesses the required mechanical strength. Its flexibility is maintained regardless of temperature.

[0028] In this case, if an air layer, such as air bubbles, forms between the resin element 48 and the first protective element 47, a temperature change will cause the air layer to expand or contract, and this expansion or contraction will be transmitted via the first protective element 47 to the pressure sensing element 32. As described above, the expansion or contraction of the air layer is an unintended source of error in pressure sensing. Therefore, to ensure accurate pressure detection, the formation of an air layer between the resin element 48 and the first protective element 47 must be prevented.

[0029] If the surface 47a of the first protective element 47 is formed in a concave curved surface shape, it is difficult to bring the resin element 48 and the first protective element 47 into close contact without an air gap between them. In contrast, in this embodiment, the surface 47a of the first protective element 47 is formed in a curved surface shape that is convex towards the side of the pressure introduction chamber 31, so that the resin element 48 and the first protective element 47 can easily be brought into close contact without an air gap between them.

[0030] The resin element 48 is made of a porous material, for example, a continuous porous material comprising continuous pore structures. Accordingly, the resin element 48 is air-permeable. That is, the resin element 48 allows gases, such as air and water vapor, to pass through it. In this way, when the first protective element 47 is cured into a gel form during the process of manufacturing the pressure sensor device, any increase in the internal pressure of the first protective element 47 associated with the temperature rise can be reduced. Furthermore, the first protective element 47 can be cured without losing its shape.

[0031] Furthermore, when the temperature is increased to cure the first protective element 47, water vapor is generated from the first protective element 47 in some cases. The resin element 48 allows the generated water vapor to pass through, thus preventing the formation of an air layer between the resin element 48 and the first protective element 47.

[0032] Resin element 48 is water-repellent and oil-repellent. Accordingly, resin element 48 can repel liquids containing corrosive substances. This reliably prevents resin element 48 from being attacked by liquids containing corrosive substances.

[0033] In this embodiment, resin element 48 is made of polytetrafluoroethylene (PTFE), which is a type of fluorine-based resin and is chemically inert. However, resin element 48 can also be made of other fluorine-based resins, such as tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA).

[0034] The first recessed section 41 is filled with a second protective element 49. The second protective element 49 covers the entire resin element 48 and is in close contact with the resin element 48. The second protective element 49 faces the pressure introduction chamber 31.

[0035] During the manufacturing process of the pressure sensor device and in the environment where the pressure sensor device is used after it has been installed on a vehicle, there is a possibility that the film-like resin element 48 may tear or be damaged. One function of the second protective element 49 is to protect the resin element 48, preventing it from tearing or being damaged, thus maintaining the function of the resin element 48.

[0036] The second protective element 49 is in close contact not only with the resin element 48, but also with the first protective element 47 and the resin package 35. The resin element 48 is completely covered by the first protective element 47 and the second protective element 49.

[0037] The second protective element 49 is made of a gel. Accordingly, the second protective element 49 can protect the resin element 48 and also transfer the pressure of the measuring medium in the pressure introduction chamber 31 to the resin element 48.

[0038] Similar to the first protective element 47, the second protective element 49 in this embodiment is made of a fluorine-based gel. This increases the resistance of the second protective element 49 to the liquid containing corrosive substances.

[0039] As described above, a protective element for the pressure sensing element 32, the wires 33, and the conductor frame 34 has a laminated structure in which the first protective element 47, the resin element 48, and the second protective element 49 are laminated to the side of the pressure sensing element 32 in the specified order. The resin element 48 is arranged in an intermediate layer between the first protective element 47 and the second protective element 49.

[0040] Both the first protective element 47 and the second protective element 49 are made of a gel. The resin element 48 is formed in a film form. Accordingly, the pressure of the measuring medium in the pressure introduction chamber 31 is transmitted to the pressure sensing element 32 via the second protective element 49, the resin element 48, and the first protective element 47. That is, in this embodiment, the pressure sensing element 32, the wires 33, and the conductor frame 34 can be protected by using the laminated structure of the first protective element 47, the resin element 48, and the second protective element 49 without affecting the detection accuracy of the pressure sensor device.

[0041] It is assumed that in the pressure sensor device with the configuration described above, the liquid containing corrosive substances enters the pressure introduction chamber 31 via the pressure introduction channel 22. This liquid has the potential to penetrate from the surface of the second protective element 49 into the second protective element 49. However, the resin element 48 provided between the second protective element 49 and the first protective element 47 acts as a stopper, preventing the liquid from entering. Accordingly, the penetration of the liquid containing corrosive substances into the first protective element 47 can be suppressed. Thus, according to this embodiment, the pressure sensing element 32, the wires 33, and the conductor frame 34 can be protected from the corrosive substance.

[0042] The resin element 48 prevents the liquid from entering the first protective element 47. In this way, the liquid penetrating the second protective element 49 is absorbed by the second protective element 49. It is possible that a change, such as swelling, will occur in the second protective element 49, which absorbs the liquid, thereby generating a stress. However, the resin element 48, positioned between the second protective element 49 and the first protective element 47, acts as a damping element to suppress the transmission of the stress induced in the second protective element 49 to the first protective element 47. Accordingly, the transmission of the stress caused by the change in the second protective element 49 to the pressure sensing element 32 can be suppressed.

[0043] As described above, the pressure sensor device according to this embodiment comprises the housing 11, the housing 20, the resin package 35, the pressure sensing element 32, the wire 33, and the conductor frame 34. The housing 11, the housing 20, and the resin package 35 correspond to the housing body 10 in which the pressure introduction chamber 31 is formed. The pressure sensing element 32 is configured to detect the pressure of the measuring medium introduced into the pressure introduction chamber 31. The conductor frame 34 is electrically connected to the pressure sensing element 32 via the wire 33. The resin package 35 has a first recessed section 41 and a second recessed section 42. The first recessed section 41 faces the pressure introduction chamber 31. The second recessed section 42 is formed in a portion of the first lower section 44 of the first recessed section 41.At least part of the conductor frame 34, the pressure detection element 32, and the wire 33 are arranged within the second recessed section 42. The second recessed section 42 is filled with the first protective element 47. The first recessed section 41 contains the resin element 48 with a film-like form within it. The resin element 48 covers the entire surface 47a of the first protective element 47 and is in close contact with it. The first recessed section 41 is filled with the second protective element 49. The second protective element 49 is in close contact with the resin element 48.

[0044] In this configuration, the resin element 48 can prevent liquid from entering the first protective element 47, even if the liquid containing corrosive substances penetrates the second protective element 49. Accordingly, the pressure sensing element 32, the wire 33, and the conductor frame 34 can be protected from the corrosive substance. This prevents corrosion at the connection between the pressure sensing element 32 and the wire 33, the connection between the wire 33 and the conductor frame 34, and similar points, thus enabling accurate pressure sensing over extended periods. Therefore, the reliability of the pressure sensor device can be further improved with the configuration described above.

[0045] Furthermore, in the configuration described above, the resin element 48 covers the entire surface 47a of the first protective element 47, thus preventing the liquid penetrating the second protective element 49 from entering the first protective element 47 without passing through the resin element 48. Additionally, in the configuration described above, the resin element 48 is in close contact with the first protective element 47, and the second protective element 49 is in close contact with the resin element 48. Consequently, more accurate pressure sensing can be achieved, and the resin element 48 is prevented from cracking or being damaged.

[0046] In the pressure sensor device according to this embodiment, the surface 47a of the first protective element 47 is formed in a curved surface shape that is convex towards the side of the pressure introduction chamber 31. With this configuration, the formation of an air layer between the first protective element 47 and the resin element 48 can be suppressed during the manufacturing process of the pressure sensor device. Accordingly, more accurate pressure sensing can be achieved with the configuration described above.

[0047] In the pressure sensor device according to this embodiment, the resin element 48 is water-repellent and oil-repellent. With this configuration, the resin element 48 can repel liquids containing corrosive substances, thus more reliably suppressing the ingress of these liquids into the first protective element 47.

[0048] In the pressure sensor device according to this embodiment, the resin element 48 is made of a porous material. In this configuration, the water vapor generated in the first protective element 47 can pass through the resin element 48. Accordingly, the increase in the internal pressure of the first protective element 47 can be prevented, and the formation of an air layer between the first protective element 47 and the resin element 48 can be prevented.

[0049] In the pressure sensor device according to this embodiment, the resin element 48 is made of a fluorine-based resin. This configuration increases the resistance of the resin element 48 to the liquid containing corrosive substances.

[0050] In the pressure sensor device according to this embodiment, both the first protective element 47 and the second protective element 49 are made of a fluorine-based gel. This configuration increases the resistance of the first protective element 47 and the second protective element 49 to a liquid containing corrosive substances.

[0051] In the embodiment described above, an intake air pressure sensor arranged on the intake manifold of an internal combustion engine is given as an example of a pressure sensor device, but this disclosure is not limited to this. The pressure sensor device is also suitable for use in detecting the exhaust pressure of the internal combustion engine in an EGR system. Reference symbol list 10 housing bodies, 11 cases, Section 12, Storage Section, 13 connection, 14 external connection ports, 20 cases, 21 column-shaped 22 Pressure inlet channel, 23 Flange section, 24, 25 O-ring, 26 groove section, 30 pressure sensor module, 31 Pressure introduction chamber, 32 pressure detection element, 33 wire, 34 ladder frames, 34a End section, 35 resin packs, 41 first omitted section, 42 second recessed section, 43 first opening section, 44 first lower section (lower section), 45 second opening section, 46 second lower section, 47 first protective element, 47a Surface, 48 resin elements, 49 second protective element

Claims

Pressure sensor device comprising: a housing body (10) with a pressure introduction chamber (31) formed therein; a pressure detection element (32) configured to detect a pressure of a measuring medium introduced into the pressure introduction chamber (31); a wire (33); and a conductor frame (34) which is electrically connected to the pressure sensing element (32) via the wire (33), wherein the housing body (10) has a first recessed section (41) and a second recessed section (42) formed therein, wherein the first recessed section (41) faces the pressure introduction chamber (31), wherein the second recessed section (42) is formed in a part of a lower section (44) of the first recessed section (41), wherein at least a part of the conductor frame (34), the pressure sensing element (32) and the wire (33) are arranged within the second recessed section (42),wherein the second recessed section (42) is filled with a first protective element (47), wherein the first recessed section (41) has provided a resin element (48) with a film form in it, wherein the resin element (48) covers an entire surface (47a) of the first protective element (47) and is in close contact with the first protective element (47), wherein the first recessed section (41) is filled with a second protective element (49), and wherein the second protective element (49) is in close contact with the resin element (48). Pressure sensor device according to claim 1, wherein the surface (47a) of the first protective element (47) is formed into a curved surface shape which is convex towards the side of the pressure introduction chamber (31). Pressure sensor device according to claim 1 or 2, wherein the resin element (48) is water-repellent and oil-repellent. Pressure sensor device according to one of claims 1 to 3, wherein the resin element (48) is made of a porous material. Pressure sensor device according to one of claims 1 to 4, wherein the resin element (48) is made of a fluorine-based resin. Pressure sensor device according to one of claims 1 to 5, wherein both the first protective element (47) and the second protective element (49) are made of a fluorine-based gel.

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