Pressure sensor device

Abstract

A pressure sensor device includes a housing, a pressure detecting element, a wire, and a lead frame, a first recess is formed in the housing to face a pressure introduction chamber, a second recess is formed in a portion of a bottom of the first recess, at least a portion of the lead frame, the pressure detecting element, and the wire are disposed in the second recess, a first protective member is filled in the second recess, a resin member in a film shape is provided in the first recess, the resin member covers an entire surface of the first protective member and is in close contact with the first protective member, a second protective member is filled in the first recess, and the second protective member is in close contact with the resin member.

Description

Technical Field

[0001] This disclosure relates to a pressure sensor device having a pressure sensing element that detects the pressure of a measuring medium. Background Technology

[0002] Patent Document 1 describes a pressure sensor composite temperature sensor device. This pressure sensor composite temperature sensor device includes: a housing; a pressure sensor module and a temperature sensor module included within the housing; and a housing with a pressure introduction path formed therein. The pressure sensor module includes: a pressure sensing element that detects the pressure of intake air introduced through the pressure introduction path; a wire; and a lead frame connected to the pressure sensing element via a cable. Inside the housing, the pressure sensing element, the wire, and the lead frame are covered by a protective member made of fluoropolymer gel or fluorosilicone.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 6656336 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, the operating environment of pressure sensors can cause corrosive substances to penetrate the protective components, thus sometimes failing to adequately protect the pressure sensing element, wires, and lead frame. When corrosive substances penetrate the protective components and cause corrosion at the joints between the pressure sensing element and the wires, and between the wires and the lead frame, accurate pressure detection becomes difficult. Therefore, this has been a technical problem in pressure sensors in the past.

[0008] This disclosure was made to solve the above-mentioned technical problems, and its purpose is to provide a pressure sensor device that can further improve reliability.

[0009] Technical solutions adopted to solve technical problems

[0010] The pressure sensor device disclosed herein includes: a housing having a pressure inlet chamber formed therein; a pressure sensing element for detecting the pressure of a measuring medium introduced into the pressure inlet chamber; a wire; and a lead frame electrically connected to the pressure sensing element via the wire. A first recess and a second recess are formed in the housing, the first recess facing the pressure inlet chamber, and the second recess being formed in a portion of the bottom of the first recess. At least a portion of the lead frame, the pressure sensing element, and the wire are disposed within the second recess. A first protective member is filled in the second recess. A film-like resin member is disposed in the first recess, the resin member covering the entire surface of the first protective member and being in close contact with the first protective member. A second protective member is filled in the first recess, and the second protective member is in close contact with the resin member.

[0011] Invention Effects

[0012] According to this disclosure, the reliability of the pressure sensor device can be further improved. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view showing the structure of the pressure sensor device in Embodiment 1.

[0014] Figure 2 This is a cross-sectional view showing the structure of the pressure sensor module of the pressure sensor device in Embodiment 1. Detailed Implementation

[0015] Implementation Method 1

[0016] The pressure sensor device of Embodiment 1 will be described. Figure 1 This is a cross-sectional view showing the structure of the pressure sensor device according to this embodiment. In this embodiment, an intake pressure sensor is exemplified as the pressure sensor device. The intake pressure sensor is installed in the intake manifold of an automobile and is used in an environment exposed to organic solvents such as gasoline or oils such as engine oil.

[0017] like Figure 1 As shown, the pressure sensor device includes a housing 11, a casing 20, and a pressure sensor module 30 housed within the housing 11. The housing 11 and casing 20, together with the resin encapsulation 35 described later, constitute the casing 10 of the pressure sensor device. Both the housing 11 and casing 20 are formed of thermoplastic resin. Suitable thermoplastic resins include polybutylene terephthalate (PBT resin) and polyethylene terephthalate (PPS resin).

[0018] The housing 11 has a storage section 12 for housing the pressure sensor module 30 and a connector 13 located on the side of the storage section 12. An external connection terminal 14 for connecting to the pressure sensor module 30 is provided inside the connector 13. The external connection terminal 14 is electrically connected to external signal processing circuits such as a vehicle control unit. The housing 11 is integrated with the external connection terminal 14, the pressure sensor module 30, etc., by insert molding.

[0019] The housing 20 is configured to sandwich the pressure sensor module 30 opposite to the outer casing 11. A pressure inlet chamber 31 is formed inside the housing 10 between the housing 20 and the pressure sensor module 30.

[0020] The housing 20 has a cylindrical portion 21 that is inserted into a mounting hole (not shown) formed in the intake manifold. A pressure introduction path 22 is formed inside the cylindrical portion 21, which guides the intake air, which serves as the measuring medium, to the pressure introduction chamber 31.

[0021] A flange 23 protruding outwards is formed on the cylindrical portion 21. The flange 23 is welded or bonded to the housing 11 throughout its entire circumference. An O-ring 24 is provided on the inner circumference of the flange 23 and on the outer circumference of the pressure inlet path 22. The O-ring 24 is in close contact with both the housing 20 and the resin encapsulation 35 (described later) to ensure airtightness between the housing 20 and the pressure sensor module 30. As a result, the intake air guided to the pressure inlet chamber 31 through the pressure inlet path 22 will not leak to the outside from the joint between the housing 20 and the pressure sensor module 30.

[0022] A groove 26 is formed on the outer peripheral surface of the cylindrical portion 21, and the groove 26 extends circumferentially to accommodate the O-ring 25. When the cylindrical portion 21 is inserted into the mounting hole of the intake manifold, the O-ring 25 ensures airtightness between the outer peripheral surface of the cylindrical portion 21 and the inner peripheral surface of the mounting hole.

[0023] Figure 2 This is a cross-sectional view showing the structure of the pressure sensor module of the pressure sensor device in this embodiment. Figure 2 The vertical direction and Figure 1 The up and down directions are reversed. For example... Figure 2 As shown, the pressure sensor module 30 has a pressure sensing element 32, a plurality of wires 33, a lead frame 34, and a resin encapsulation 35 that holds the pressure sensing element 32 and the lead frame 34.

[0024] Multiple wires 33 are made of gold or aluminum. A lead frame 34 is electrically connected to a pressure sensing element 32 via each wire 33. The lead frame 34 is embedded in a resin encapsulation 35. Figure 1As shown, the end 34a of the lead frame 34 protrudes outward from the resin package 35. The end 34a is connected to the external connection terminal 14 by soldering or tin soldering. Thus, the lead frame 34 is electrically connected to the external connection terminal 14.

[0025] As the pressure sensing element 32, a silicon semiconductor element with a diaphragm utilizing the piezoresistive effect and a vacuum chamber can be used. A circuit including a strain gauge resistor is formed in the diaphragm. When the diaphragm deforms due to the pressure of the intake air, the resistance value of the strain gauge resistor changes according to the amount of deformation of the diaphragm. Therefore, the pressure of the intake air can be detected as a change in resistance value. The change in the resistance value of the strain gauge resistor is converted into an electrical signal and amplified. The amplified electrical signal is output via the external connection terminal 14 to a signal processing circuit provided externally to the pressure sensor device.

[0026] In this embodiment, a semiconductor element utilizing the piezoresistive effect can be used as the pressure sensing element 32, but it is not limited to this. The pressure sensing element 32 can also be an element that detects changes in electrostatic capacitance, etc.

[0027] The resin encapsulation 35, together with the housing 11 and the housing 20, constitutes the housing 10 of the pressure sensor device. The resin encapsulation 35 is formed of a thermosetting resin such as epoxy resin.

[0028] A first recess 41 and a second recess 42 are formed in the resin encapsulation 35. The first recess 41 faces the pressure inlet chamber 31. The first recess 41 has a first opening 43 and a first bottom 44. The first recess 41 is formed such that the first opening 43 faces the pressure inlet chamber 31. The second recess 42 is formed on a portion of the first bottom 44 of the first recess 41. The second recess 42 has a second opening 45 and a second bottom 46. The second recess 42 is formed such that the second opening 45 faces the space within the first recess 41. The second bottom 46 is formed to expose a portion of the lead frame 34 embedded in the resin encapsulation 35. The opening of the second opening 45 is smaller than the opening of the first opening 43. That is, the opening area of ​​the second opening 45 is smaller than the opening area of ​​the first opening 43. The first bottom 44 of the first recess 41 is formed in an annular shape to surround the second opening 45 of the second recess 42.

[0029] At least a portion of the lead frame 34, the pressure sensing element 32, and the wire 33 are disposed within the second recess 42. Thus, the connection portion between the pressure sensing element 32 and the wire 33, and the connection portion between the wire 33 and the lead frame 34, are disposed within the second recess 42.

[0030] A first protective member 47 is filled in the second recess 42. The first protective member 47 completely fills the second recess 42. That is, the first protective member 47 fills from the second bottom 46 to the second opening 45 in the depth direction of the second recess 42. The front surface 47a of the first protective member 47 is formed as a curved surface, such as a dome, protruding towards the pressure inlet chamber 31. When viewed from the pressure inlet chamber 31 side, the shape of the outer edge of the front surface 47a is consistent with the shape of the second opening 45 of the second recess 42. The first protective member 47 covers the pressure sensing element 32, the wire 33, and the lead frame 34 in the second recess 42. The first protective member 47 is in close contact with the pressure sensing element 32, the wire 33, and the lead frame 34. Thus, the pressure sensing element 32, the wire 33, and the lead frame 34 are protected by the first protective member 47. In addition, the first protective member 47 is also in close contact with the resin encapsulation 35 of the pressure sensor module 30.

[0031] The first protective member 47 is formed of an electrically insulating gel. The gel has intermediate properties between a solid and a liquid. Therefore, the first protective member 47 can protect the pressure sensing element 32, the wire 33, and the lead frame 34, and can transmit the pressure of the measuring medium in the pressure inlet chamber 31 to the pressure sensing element 32.

[0032] The first protective member 47 in this embodiment is formed of a fluorinated gel. Fluorinated gels are resistant to penetration by organic solvents such as gasoline, oils such as engine oil, and condensate containing corrosive substances such as nitrates. In the following description, organic solvents, oils, and condensate containing corrosive substances are sometimes collectively referred to as "liquids containing corrosive substances". Since the first protective member 47 is formed of a fluorinated gel, its resistance to liquids containing corrosive substances is improved.

[0033] A film-like resin member 48 is provided in the first recess 41. The resin member 48 has a larger profile than the second opening 45 of the second recess 42. The resin member 48 covers the entire front surface 47a of the first protective member 47 and is in close contact with the first protective member 47. When viewed from the pressure inlet chamber 31 side, the resin member 48 covers the pressure sensing element 32, the wire 33, and the lead frame 34. The resin member 48 is opposite to the pressure sensing element 32 in a manner that clamps the first protective member 47. Furthermore, when viewed from the pressure inlet chamber 31 side, the resin member 48 extends over the entire circumference of the first bottom 44, which is formed in an annular shape, and overlaps with the first bottom 44.

[0034] The resin component 48 is formed of a porous material. The resin component 48 has a thickness of approximately 0.3 to 0.4 mm. The resin component 48 possesses flexibility and also the required mechanical strength. The flexibility of the resin component 48 is maintained independently of temperature.

[0035] In this case, if an air layer such as air bubbles is formed between the resin component 48 and the first protective component 47, the air layer will expand or contract due to temperature changes. This expansion or contraction will be transmitted to the pressure sensing element 32 via the first protective component 47. Thus, the expansion or contraction of the air layer becomes an unforeseen error component in pressure detection. Therefore, for accurate pressure detection, it is preferable that no air layer is formed between the resin component 48 and the first protective component 47.

[0036] If the front surface 47a of the first protective member 47 is formed as a concave curved surface, it would be difficult to ensure that the resin member 48 and the first protective member 47 are tightly bonded without air gaps. In contrast, in this embodiment, the front surface 47a of the first protective member 47 is formed as a curved surface protruding towards the pressure inlet chamber 31, thus, it is easy to ensure that the resin member 48 and the first protective member 47 are tightly bonded without air gaps.

[0037] The resin component 48 is formed of a porous material, such as a continuous porous material with a continuous pore structure. Therefore, the resin component 48 is breathable. That is, the resin component 48 allows gases such as air and water vapor to pass through. Thus, when the first protective component 47 is cured into a gel state during the manufacturing process of the pressure sensor device, the increase in internal pressure of the first protective component 47 due to temperature rise can be mitigated. Furthermore, the first protective component 47 can be cured without flattening its shape.

[0038] Furthermore, when the temperature rises during the curing of the first protective member 47, water vapor may sometimes be generated from the first protective member 47. The resin member 48 allows the generated water vapor to pass through, thus preventing the formation of an air layer between the resin member 48 and the first protective member 47.

[0039] The resin component 48 is water-repellent and oil-repellent. Therefore, the resin component 48 can repel liquids containing corrosive substances. As a result, liquids containing corrosive substances can be more reliably prevented from penetrating into the resin component 48.

[0040] In this embodiment, the resin component 48 is formed from polytetrafluoroethylene (PTFE), which is a type of fluorinated resin and is chemically inactive. However, the resin component 48 may also be formed from other fluorinated resins such as tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA).

[0041] A second protective member 49 is filled in the first recess 41. The second protective member 49 covers the entire resin member 48 and is in close contact with the resin member 48. The second protective member 49 faces the pressure inlet chamber 31.

[0042] During the manufacturing process of the pressure sensor device and in the usage environment of the pressure sensor after installation in a vehicle, damage or breakage may occur in the membrane-like resin component 48. One of the functions of the second protective component 49 is to protect the resin component 48 from damage or breakage and to maintain the function of the resin component 48.

[0043] The second protective member 49 is not only in close contact with the resin member 48, but also with the first protective member 47 and the resin encapsulation member 35. The entire periphery of the resin member 48 is covered by the first protective member 47 and the second protective member 49.

[0044] The second protective member 49 is formed of gel. Therefore, the second protective member 49 can protect the resin member 48 and can transmit the pressure of the measuring medium in the pressure introduction chamber 31 to the resin member 48.

[0045] The second protective member 49 in this embodiment is also formed of a fluorinated gel, just like the first protective member 47. This improves the resistance of the second protective member 49 to liquids containing corrosive substances.

[0046] Thus, the protective member that protects the pressure sensing element 32, the wire 33, and the lead frame 34 has a stacked structure in which a first protective member 47, a resin member 48, and a second protective member 49 are sequentially stacked from the pressure sensing element 32 side. The resin member 48 is located in the intermediate layer between the first protective member 47 and the second protective member 49.

[0047] Both the first protective member 47 and the second protective member 49 are formed of gel. The resin member 48 is formed as a film. Therefore, the pressure of the measuring medium in the pressure inlet chamber 31 is transmitted to the pressure sensing element 32 via the second protective member 49, the resin member 48, and the first protective member 47. That is, in this embodiment, the pressure sensing element 32, the wire 33, and the lead frame 34 can be protected by the stacked structure of the first protective member 47, the resin member 48, and the second protective member 49 without sacrificing the detection accuracy of the pressure sensor device.

[0048] In the pressure sensor device with the structure described above, a liquid containing corrosive substances enters the pressure inlet chamber 31 via the pressure inlet path 22. The liquid may permeate from the front of the second protective member 49 into its interior. However, the resin member 48 disposed between the second protective member 49 and the first protective member 47 functions as a barrier to prevent liquid intrusion. Therefore, the permeation of the liquid containing corrosive substances into the first protective member 47 can be suppressed. Thus, according to this embodiment, the pressure sensing element 32, the wire 33, and the lead frame 34 can be protected from corrosive substances.

[0049] Liquid penetration into the first protective member 47 is prevented by the resin member 48. Thus, liquid that has permeated into the interior of the second protective member 49 is absorbed by the second protective member 49. Swelling or other deterioration may occur in the second protective member 49 after absorbing the liquid, potentially generating stress. However, the resin member 48, disposed between the second protective member 49 and the first protective member 47, functions as a buffer to suppress the transmission of stress generated in the second protective member 49 to the first protective member 47. Therefore, the transmission of stress caused by deterioration of the second protective member 49 to the pressure sensing element 32 can be suppressed.

[0050] As described above, the pressure sensor device of this embodiment includes: a housing 11, which serves as a housing 10 having a pressure inlet chamber 31 formed therein; a housing 20 and a resin encapsulation 35; a pressure sensing element 32; a wire 33; and a lead frame 34. The pressure sensing element 32 is configured to detect the pressure of a measuring medium introduced into the pressure inlet chamber 31. The lead frame 34 is electrically connected to the pressure sensing element 32 via the wire 33. A first recess 41 and a second recess 42 are formed in the resin encapsulation 35. The first recess 41 faces the pressure inlet chamber 31. The second recess 42 is formed in a portion of the first bottom 44 of the first recess 41. At least a portion of the lead frame 34, the pressure sensing element 32, and the wire 33 are disposed within the second recess 42. A first protective member 47 is filled in the second recess 42. A film-like resin member 48 is provided in the first recess 41. The resin member 48 covers the entire front surface 47a of the first protective member 47 and is in close contact with the first protective member 47. A second protective member 49 is filled in the first recess 41. The second protective member 49 is in close contact with the resin member 48.

[0051] According to the structure described above, even if a liquid containing corrosive substances penetrates the second protective member 49, the resin member 48 can prevent the liquid from seeping into the first protective member 47. Therefore, the pressure sensing element 32, the wire 33, and the lead frame 34 can be protected from corrosive substances. Consequently, since corrosion can be suppressed at the joints between the pressure sensing element 32 and the wire 33, and at the joints between the wire 33 and the lead frame 34, accurate pressure sensing can be performed over a long period. Therefore, according to the structure described above, the reliability of the pressure sensor device can be further improved.

[0052] Furthermore, in this structure, the resin member 48 covers the entire front surface 47a of the first protective member 47, thus preventing liquid that has penetrated the second protective member 49 from seeping into the first protective member 47 without passing through the resin member 48. Moreover, in this structure, the resin member 48 is in close contact with the first protective member 47, and the second protective member 49 is in close contact with the resin member 48, thus enabling more accurate pressure detection and preventing damage or breakage to the resin member 48.

[0053] In the pressure sensor device of this embodiment, the front surface 47a of the first protective member 47 is formed as a curved surface protruding towards the pressure inlet chamber 31. According to this structure, during the manufacturing process of the pressure sensor device, the formation of an air layer between the first protective member 47 and the resin member 48 can be suppressed. Therefore, according to this structure, more accurate pressure detection can be performed.

[0054] In the pressure sensor device of this embodiment, the resin component 48 is both water-repellent and oil-repellent. Due to this structure, the resin component 48, which contains corrosive substances, can be repelled, thus more reliably preventing liquid from seeping into the first protective component 47.

[0055] In the pressure sensor device of this embodiment, the resin member 48 is formed of a porous material. According to this structure, water vapor generated in the first protective member 47 can permeate through the resin member 48. Therefore, it is possible to prevent the internal pressure of the first protective member 47 from rising or to prevent the formation of an air layer between the first protective member 47 and the resin member 48.

[0056] In the pressure sensor device of this embodiment, the resin component 48 is formed of a fluorinated resin. This structure improves the resistance of the resin component 48 to liquids containing corrosive substances.

[0057] In the pressure sensor device of this embodiment, both the first protective member 47 and the second protective member 49 are formed of fluorinated gel. This structure improves the resistance of both the first protective member 47 and the second protective member 49 to liquids containing corrosive substances.

[0058] Furthermore, while the embodiment described above uses an intake pressure sensor mounted on the intake manifold of an internal combustion engine as an example of a pressure sensor device, it is not limited to this. The pressure sensor device can also be used to detect the exhaust pressure of an internal combustion engine in an ERG system.

[0059] (Symbol Explanation)

[0060] 10 Housing; 11 Outer shell; 12 Reception section; 13 Connector; 14 External connection terminal; 20 Housing; 21 Cylindrical section; 22 Pressure introduction path; 23 Flange; 24, 25 O-rings; 26 Groove; 30 Pressure sensor module; 31 Pressure introduction chamber; 32 Pressure detection element; 33 Wire; 34 Lead frame; 34a End; 35 Resin encapsulation; 41 First recess; 42 Second recess; 43 First opening; 44 First bottom (bottom); 45 Second opening; 46 Second bottom; 47 First protective member; 47a Front; 48 Resin member; 49 Second protective member.

Claims

1. A pressure sensor device, characterized in that, include: A housing having a pressure inlet chamber formed inside; A pressure sensing element that detects the pressure of the measuring medium introduced into the pressure inlet chamber; electric wire; as well as A lead frame, which is electrically connected to the pressure sensing element via the wire. The housing has a first recess and a second recess. The first recess faces the pressure inlet chamber. The second recess is formed on a portion of the bottom of the first recess. At least a portion of the lead frame, the pressure sensing element, and the wire are disposed within the second recess. The second recess is filled with a first protective component. A film-like resin component is provided in the first recess. The resin component covers the entire surface of the first protective component and is in close contact with it. A second protective component is filled into the first recess. The second protective component is in close contact with the resin component.

2. The pressure sensor device as described in claim 1, characterized in that, The surface of the first protective member is formed as a curved surface that protrudes toward the pressure inlet chamber.

3. The pressure sensor device as described in claim 1, characterized in that, The resin component is water-repellent and oil-repellent.

4. The pressure sensor device as described in claim 2, characterized in that, The resin component is water-repellent and oil-repellent.

5. The pressure sensor device according to any one of claims 1 to 4, characterized in that, The resin component is formed of a porous material.

6. The pressure sensor device as described in any one of claims 1 to 4, characterized in that, The resin component is formed from a fluorinated resin.

7. The pressure sensor device as described in claim 5, characterized in that, The resin component is formed from a fluorinated resin.

8. The pressure sensor device according to any one of claims 1 to 4 and claim 7, characterized in that, Both the first protective component and the second protective component are formed of fluorinated gel.

9. The pressure sensor device as described in claim 5, characterized in that, Both the first protective component and the second protective component are formed of fluorinated gel.

10. The pressure sensor device as claimed in claim 6, characterized in that, Both the first protective component and the second protective component are formed of fluorinated gel.

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