Pressure sensor

Abstract

To provide a pressure sensor that reduces stress applied to a circuit board mounted therein and achieves a structure ensuring insulating properties, and can thereby measure pressure with high quality.SOLUTION: A pressure sensor 100 has a sensor chip 11 that detects the pressure of a measurement object and is connected to a circuit board 50 mounted inside a case 20. The sensor chip is installed in a liquid-sealed chamber LR to receive the pressure of the measurement object, and the circuit board is installed interposed between the sensor chip and an external device A in an installation space SR that is filled with sealant 26 inside the case and formed in a fluid-tight manner. The pressure sensor comprises a space forming member constituted of a spacer 24 forming an installation space, a lid member 25, and one end face sides of a housing 12, a pillar 13, and hermetic glass 14, and the spacer also constitutes an insulation improvement member that improves insulation resistance to the circuit board. A mounting component 50J of the circuit board is located inside the installation space.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pressure sensor that is liquid-tightly molded with resin. [Background technology]

[0002] 2. Description of the Related Art Various sensors for detecting pressure, temperature, etc. are fixed in the vicinity of a measurement object and are used to send a detection signal to a measuring instrument, etc., and are often used either built into the measuring instrument or attached externally.

[0003] These types of sensors are incorporated into sensor units so that they can be installed in locations exposed to the same environment as the object to be measured. For example, a circuit board may be installed inside the sensor chip when it is necessary to change the electrical characteristics input and output to the sensor chip (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6633597 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the pressure sensor described in Patent Document 1, as shown in FIG. 11, a circuit board 1431 connected to a sensor chip 1121 in a housing 1124 is contained in a case 1135, and the case 1135 is filled with a sealing material 1136 such as a resin material to provide a liquid-tight seal.

[0006] In such a structure, since there is a difference in the linear expansion coefficient of components such as circuit board 1431, case 1135, and sealing material 1136, when a temperature difference occurs inside and outside the object to be measured, a stress corresponding to the temperature difference may occur. This stress may become a load on circuit board 1431 itself and the components mounted on circuit board 1431. In addition, since various electric and electronic components are mounted on circuit board 1431 in such a pressure sensor, it is necessary to ensure insulation around circuit board 1431.

[0007] Therefore, an object of the present invention is to provide a pressure sensor capable of performing high-quality pressure measurements by realizing a structure that reduces the stress applied to an internal circuit board while ensuring insulation. [Means for solving the problem]

[0008] One aspect of the pressure sensor invention that solves the above problems is a pressure sensor in which a sensor for detecting the pressure of the object to be measured is connected to a circuit board that is mounted inside a case, the sensor being installed in a pressure chamber so as to receive the pressure of the object to be measured, the circuit board being installed in an installation space that is formed liquid-tight by filling the case with a sealing material, and the pressure sensor is characterized in that it is provided with a space forming member that forms the installation space and an insulation improving member that improves the insulation resistance between the space forming member and the circuit board, and the mounted components of the circuit board are positioned within the installation space. Effect of the Invention

[0009] According to one aspect of the present invention, the components mounted on the circuit board are positioned within the installation space to avoid contact with the sealing material, and stress loads can be prevented from being applied to the components mounted on the circuit board. In addition, the circuit board in the installation space has improved insulation resistance and is equipped with the components. Therefore, a pressure sensor that can be used with high reliability can be provided. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a diagram showing a pressure sensor according to a first embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Diagram 2] FIG. 2 is a diagram showing a pressure sensor according to a second embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Diagram 3] FIG. 3 is a diagram showing a pressure sensor according to a third embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Figure 4] FIG. 4 is a diagram showing a pressure sensor according to a fourth embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Diagram 5] FIG. 5 is a diagram showing a pressure sensor according to a fifth embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Figure 6] FIG. 6 is a diagram showing a pressure sensor according to a sixth embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Figure 7] FIG. 7 is a diagram showing a pressure sensor according to a seventh embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Figure 8] FIG. 8 is a diagram showing a first alternative embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Figure 9] FIG. 9 is a diagram showing a second alternative embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Figure 10] FIG. 10 is a diagram showing a third alternative embodiment of the present invention, and is a vertical sectional view showing a schematic overall configuration thereof. [Figure 11] FIG. 11 is a diagram showing the prior art of this embodiment, and is a vertical sectional view showing a schematic overall configuration thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a diagram illustrating a pressure sensor according to a first embodiment of the present invention.

[0012] First Embodiment 1, the pressure sensor 100 is fabricated so that a pressure sensor unit 10 having a pressure sensor chip (sensor) 11 installed therein is attached to a refrigerant pipe in a unit to measure the pressure of the refrigerant in a refrigeration cycle, for example, and pressure information detected by the pressure sensor chip 11 is output to an external device A, which is a control device for controlling the refrigeration cycle. The pressure sensor 100 of this embodiment is constructed so that the pressure sensor unit 10 having a metallic waterproof case 20 formed in a cylindrical shape can be connected, for example, by a metallic joint member 30, to a pipe to be measured through which a fluid such as a gas or liquid whose pressure is to be detected is introduced.

[0013] Here, the waterproof case 20 is fixed by covering one end face of a thick cylindrical metal housing 12 that houses the sensor chip 11 of the pressure sensor unit 10 and welding it, and the peripheral portion of a disk-shaped metal cap 28 to which a joint member 30 is fixed is connected to the other end face of the housing 12 by welding. The joint member 30 is formed with a female thread 30s so that it can be screwed to a pipe or the like for which pressure is to be measured, and a fluid supplied from the pipe in the direction of arrow P is introduced into a pressure chamber PR, which is a space surrounded by the cap 28, the housing 12, and a diaphragm 32 described later, through a port 30a communicating with the female thread 30s. Here, the waterproof case 20, the housing 12, and the cap 28 are integrated with a desired joint strength by welding the outer peripheral portions from the outside by TIG welding, plasma welding, laser welding, or the like.

[0014] The housing 12 is arranged so that the support 13, on one end of which the pressure sensor chip 11 is installed, is located at the center of the inner cylinder, and hermetic glass 14 is formed by filling the space between the inner surface of the housing 12 and the outer surface of the support 13 to ensure a closed state while fixing the members that pass through the interior in a liquid-tight manner.

[0015] In this pressure sensor unit 10, a metal diaphragm 32 is bonded and fixed to the bottom end surface of the housing 12. The diaphragm 32 forms an airtight pressure chamber PR on the cap 28 side, while isolating the installation space of the pressure sensor chip 11 on the support 13 side in the housing 12 from the pressure chamber PR.

[0016] In this pressure sensor unit 10, the installation space for the pressure sensor chip 11, which is formed by the hermetic glass 14 and the diaphragm 32 within the inner tube of the housing 12, is filled with, for example, a predetermined amount of silicone oil (or a fluorine-based inert liquid, etc.) as a pressure transmission medium, so as to function as a liquid-sealed chamber LR.

[0017] As a result, the pressure sensor chip 11 functions as a pressure sensor that detects the pressure of the fluid to be detected, introduced into the pressure chamber PR from the piping connected to the joint member 30, as a pressure fluctuation of the pressure transmission medium in the liquid-sealed chamber LR via the diaphragm 32. That is, the pressure chamber PR in this embodiment is constructed in a structure including a liquid-sealed chamber LR, and is fabricated in a structure that enables the pressure sensor chip 11 to detect the pressure of the fluid to be measured introduced from the joint member 30. Note that the pressure chamber may not include a liquid-sealed chamber, and the pressure of the fluid to be measured may be directly applied to the sensor chip to be measured, and it goes without saying that the measurement target is not limited to liquid, but may be gas such as various gases or mist-like gas containing fine fluid particles.

[0018] Here, the pressure sensor chip 11 is installed so that it is supplied with power by electrically connecting lead pins (sensor connection pin members) 40 connected to a circuit board 50 (described later) via bonding wires 11w, respectively, from a plurality of lead wires (external connection members) 38 from the external device A, and outputs a detection signal as pressure information. In addition, the liquid-sealed chamber LR between the hermetic glass 14 and the diaphragm 32 in the inner cylinder of the housing 12 is filled with a pressure transmission medium via an oil filling pipe 44. These lead pins 40 and the oil filling pipe 44 are aligned at equal intervals in a circle centered on the support 13, and are supported insulated from the housing 12 via an insulator such as the hermetic glass 14. One end of the oil filling pipe 44 is closed after filling with the pressure transmission medium.

[0019] Here, the diaphragm 32 is prevented from being damaged by external forces or sudden pressures applied to the pressure chamber PR by a diaphragm protective cover 34 having a plurality of communication holes 34a bonded and fixed to the lower end surface of the housing 12. Also, a concave frame 16 is fixed to one end side of the hermetic glass 14 and a lid-like shield plate 17 is attached to the frame 16, and the frame 16 contains a pressure transmission medium between the pressure sensor chip 11 side and the diaphragm 32 side through the communication holes 17a formed in the shield plate 17 and suppressing sudden pressure fluctuations.

[0020] The lead pins 40 include two power supply terminals, one output signal terminal, and five adjustment terminals used during assembly, and are electrically connected to the pressure sensor chip 11 via bonding wires 11w. These lead pins 40 are fixedly supported by the hermetic glass 14 so as to protrude from one end face side of the housing 12.

[0021] A resin spacer 24 formed in a short, roughly cylindrical shape is fitted into the waterproof case 20 from the opening of one end of the housing 12 to abut against it as a side wall of the space forming member, and a cover member (closing member of the space forming member) 25 is fixed to close the opening of the other end, so that the one end of the housing 12 also functions as a closing member of the space forming member. With this structure, the pressure sensor unit 10 is constructed, which includes an installation space SR for a circuit board 50 to which the lead pins 40 and the lead wires 38 are connected. The waterproof case 20 of the pressure sensor unit 10 is filled with a sealant 26 such as a urethane resin to waterproof the installation space SR for the circuit board 50 and fix it in place, and the circuit board 50 is soldered to the lead pins 40 and the core wires C of the lead wires 38 for positioning and support.

[0022] In this structure, the circuit board 50 is supported in the vertical direction by the soldered lead wires 38 and lead pins 40 and held in the intermediate space of the installation space SR, so that when stress occurs, the lead wires 38 and lead pins 40 are prevented from being slightly deformed and the stress itself is prevented from being applied. Note that the circuit board 50 may be fixed so that a part of its outer peripheral end is supported against the inner surface of the spacer 24 with an adhesive or the like.

[0023] Here, by arranging the circuit board 50 in the installation space SR formed by the housing 12, the spacer 24, and the cover member 25 inside the waterproof case 20, an air layer with low thermal conductivity can be formed around the circuit board 50, and it is possible to prevent temperature changes from around the pressure sensor or from the piping from being suddenly transmitted to the circuit board 50. Also, by arranging the circuit board 50 itself and the mounted components 50J mounted on the circuit board 50 so as not to come into contact with the sealing material 26, it is possible to prevent mechanical stress caused by the contraction and expansion of the sealing material 26 due to changes in the ambient temperature from acting on the connection members, the mounted components 50J, and particularly on their soldered portions.

[0024] Both ends of this lead pin 40 penetrate both sides of the hermetic glass 14 inside the inner tube of the housing 12, and one end on the liquid-sealed chamber LR side is conductively connected to the pressure sensor chip 11 via a bonding wire 11w, while the other end of the lead pin 40 corresponding to the power supply terminal and output signal terminal penetrates through multiple through holes (not shown) in the circuit board 50 in the direction toward the cover member 25 and is conductively connected by soldering or the like.

[0025] In addition, the lead wire 38 that is drawn out so as to be connectable to the external device A passes through the through hole 25h that passes through the cover member 25, and then the core wire C passes through a through hole (not shown) that passes through one part of the circuit board 50 in the direction toward the housing 12, and is soldered or the like for conductive connection. Here, the circuit board 50 is appropriately provided with through holes or the like for assembly work, and for example, an insertion hole (not shown) for the oil filling pipe 44 is also provided. It goes without saying that the connection of the lead pin 40 and the lead wire 38 may be made not only by molten metal such as solder, but also by applying, for example, an adhesive containing a conductive material. In addition to the conductive connection by soldering or conductive adhesive as described above, the conductive connection may be made by welding (for example, spot welding with a laser or the like), and there is no need to limit the welding means in particular.

[0026] Here, the circuit board 50 is disposed in an installation space SR in which the housing 12, the support 13, the hermetic glass 14, the spacer 24, and the cover member 25 in the waterproof case 20 constitute space forming members. This circuit board 50 is liquid-tightly housed in the installation space SR formed by the electrically conductive lead pin 40, the housing 12, and the spacer 24 of a desired dimension that ensures a sufficient distance from the waterproof case 20, which has the same potential as the housing 12. That is, since the installation space SR is an air atmosphere, it is difficult to reliably and inexpensively maintain insulation compared to when embedded (molded) with the sealing material 26, but the spacer 24 ensures a sufficient distance from the housing 12 and the waterproof case 20, and also functions as an insulation improving member that improves the insulation resistance of the circuit board 50.

[0027] The circuit board 50 is arranged in series between the pressure sensor chip 11 and the external device A to function as a part of the circuit configuration, and in this embodiment, an input / output voltage conversion adjustment circuit is mounted thereon to adjust different input / output voltages between the pressure sensor chip 11 and the external device A, for example, to convert the input voltage DC12V or DC3.3V of the external device A to the operating voltage DC5V of the pressure sensor chip 11. This type of conversion adjustment circuit is not limited to this embodiment, but may be any conversion adjustment circuit for dealing with various driving voltages and signal formats of pressure detection signals, such as a voltage output format of driving / output voltages different from this embodiment, a current output format such as a two-wire type / three-wire type, or a digital output format. These conversion adjustment circuits are configured by mounting a plurality of electronic components (not shown).

[0028] Thus, in the pressure sensor 100 of this embodiment, the circuit board 50, which is connected in series between the sensor chip 11 and the external device A, is accommodated in the installation space SR in the case 20, which is filled with the sealing material 26 and sealed liquid-tightly. Therefore, in the pressure sensor 100, the circuit board 50 located in the installation space SR formed on one end face side of the housing 12 by the spacer 24 and the lid member 25 can prevent the mechanical load caused by the direct contact of the sealing material 26 made of a molten high-temperature resin during production and the thermal stress caused by the difference in the degree of expansion and contraction due to the difference in the linear expansion coefficient of the constituent materials in response to temperature changes during use from being applied as a stress load to the board itself and the mounted components 50J.

[0029] Furthermore, in this pressure sensor 100, the spacer 24 can ensure a sufficient distance from the housing 12 and the waterproof case 20 in the installation space SR in which the circuit board 50 is installed, thereby improving the insulation resistance of the mounted components 50J on the circuit board 50.

[0030] As a result, the pressure sensor 100 ensures the insulation of the circuit board 50 and can perform high-quality pressure measurement.

[0031] <Second embodiment> 2 is a diagram illustrating a pressure sensor according to a second embodiment of the present invention. Since this embodiment is configured in substantially the same manner as the above-described embodiment, the same components are denoted by the same reference numerals, detailed description is omitted, and only the characteristic parts are described (the same applies to the other embodiments described below).

[0032] 2, in the pressure sensor 100, instead of the spacer 24 of the above embodiment, a resin spacer 124 formed in a cylindrical shape with a bottom is fitted into the waterproof case 20 from one end opening side, with the bottom 124b abutting and fixed to one end face side of the housing 12, and a cover member 25 is fixed to the other end opening side of the spacer 124, thereby constructing a pressure sensor unit 10 having an installation space SR for a circuit board 50 to which the lead pins 40 and lead wires 38 are connected. The spacer 124 is formed in a disk shape having an inner peripheral end face 124i so as to open the penetration portion of the hermetic glass 14 for the lead pins 40, and has a plate bottom 124b that can abut against one end face side of the housing 12.

[0033] Here, in this pressure sensor 100, a step 124a is formed on the inner surface of the cylindrical middle section of the spacer 124, and after assembling the spacer 124 in a state in which the peripheral end of the circuit board 50 is placed on the step 124a, the opposite opening of the housing 12 is covered with the lid member 25 and filled with the sealant 26, thereby making the installation space SR for the circuit board 50 a liquid-tight structure.

[0034] In this pressure sensor 100, the spacer 124 together with the housing 12, the support 13, the hermetic glass 14 and the cover member 25 constitute space-forming members to form the installation space SR within the waterproof case 20, and the circuit board 50 is placed therein, and the side wall portion 124s and the step 124a of the spacer 124 also function as insulation improving members that ensure a sufficient distance between the circuit board 50 and the housing 12 and the waterproof case 20, thereby improving the insulation resistance of the circuit board 50.

[0035] In this way, even in the pressure sensor 100 of this embodiment, the spacer 124 can be used to ensure a sufficient distance from the housing 12 and the waterproof case 20 in the installation space SR in which the circuit board 50 is installed, thereby improving the insulation resistance of the mounted component 50J, and thereby achieving the same effects as those of the above-mentioned embodiment.

[0036] <Third embodiment> Next, FIG. 3 is a diagram illustrating a pressure sensor according to a third embodiment of the present invention. In FIG. 3, the pressure sensor 100 is configured in a manner substantially similar to the second embodiment described above, including a spacer 124. In this pressure sensor 100, instead of the core wire C of the lead wire 38, one end of a contact pin (external connection pin member) 126 that passes through the through hole 25h of the cover member 25 passes through a through hole of the circuit board 50 in a direction toward the housing 12 and is electrically connected thereto by soldering or the like, and the core wire C of the lead wire 38 is electrically connected to the other end of the contact pin 126 by soldering or the like.

[0037] For this reason, the lead wire 38 that is pulled out so as to be connectable to the external device A is connected to the contact pin 126 with the coating 38c around the core wire C stripped away up to just before the cover member 25 that forms the installation space SR, and is embedded in the sealing material 26, and the boundary area between the core wire C and the coating 38c, i.e., the end of the coating 38c of the lead wire 38, is liquid-tightly sealed by the sealing material 26.

[0038] Thus, in the pressure sensor 100 of this embodiment, the coating 38c of the lead wire 38 connected to the circuit board 50 is peeled off just before the lid member 25 that forms the installation space SR, and the core wire C of the lead wire 38 is conductively connected by penetrating the lid member 25. Therefore, even if the core wire C of the lead wire 38 is a twisted wire, the space between the coating 38c can be embedded in the sealing material 26 outside the installation space SR, and even if moisture is present around the core wire C, it can be prevented from infiltrating into the circuit board 50.

[0039] As a result, the pressure sensor 100 can achieve the same effects as the above-described embodiment, and the insulation of the circuit board 50 is ensured, enabling high-quality pressure measurement.

[0040] <Fourth embodiment> Next, FIG. 4 is a diagram illustrating a pressure sensor according to a fourth embodiment of the present invention. In FIG. 4, the pressure sensor 100 includes, in addition to the spacer 24 of the above embodiment, The plate 224 (which is not limited to a plate material but may be a flexible sheet material) is a blocking member formed in a disk shape having an inner end surface 224i so as to open the penetration point of the lead pin 40 of the hermetic glass 14 and capable of abutting against one end surface side of the housing 12.

[0041] With this structure, in this pressure sensor 100, the plate 224 is positioned between the circuit board 50 on the side facing the housing 12 etc. within the installation space SR to form a space-forming member, and can also function as an insulation improving member that improves the insulation resistance between the housing 12 and the circuit board 50, thereby ensuring the insulation of the circuit board 50.

[0042] In this way, in the pressure sensor 100 of this embodiment, in addition to being able to obtain the same effects as the above-described embodiments, the plate 224 can improve the insulation resistance between the housing 12 and the like in the installation space SR, thereby ensuring more reliable and high-quality insulation of the mounted components 50J of the circuit board 50.

[0043] <Fifth embodiment> Next, FIG. 5 is a diagram illustrating a pressure sensor according to a fifth embodiment of the present invention. In FIG. 5, instead of the spacer 24 and the cover member 25 of the above-described embodiment, the pressure sensor 100 has a resin spacer 324 formed into a cylindrical shape with a bottom by integrally molding the spacer 24 and the cover member 25, and by turning the spacer 324 upside down and abutting the opening side against the housing 12 and fixing it, it forms a space forming member which, together with the plate 224 of the above-described embodiment, forms the installation space SR for the circuit board 50.

[0044] With this structure, in the pressure sensor 100, the plate 224 and the bottom 324r of the spacer 324 face both sides of the circuit board 50, and the side wall portion 324s of the spacer 324 ensures the separation between the plate 224 and the bottom 324r of the spacer 324, thereby functioning as an insulation improving member that improves the insulation resistance of the circuit board 50.

[0045] In this way, in the pressure sensor 100 of this embodiment, in addition to being able to obtain the same effects as the above-described embodiment, the use of a bottomed cylindrical spacer 324 in which the spacer 24 and the cover member 25 are integrally molded reduces the number of parts and labor required, thereby reducing costs.

[0046] Sixth embodiment Next, FIG. 6 is a diagram illustrating a pressure sensor according to a sixth embodiment of the present invention. In FIG. 6, the pressure sensor 100 includes the spacer 324 and the contact pin 126 in the above-described embodiment, and the contact pin 126 passes through a through hole 324h in the bottom 324r of the spacer 324 and is conductively connected to the core wire C of the lead wire 38 together with the circuit board 50.

[0047] Here, in this pressure sensor 100, the circuit board 50 is soldered to the contact pin 126 and the lead pin 40 which are conductively connected to the core wire C of the lead wire 38, and is positioned and supported in the hollow of the installation space SR, but a part of the outer peripheral end portion may be fixed to the inner surface of the spacer 124 with an adhesive or the like so as to assist the support.

[0048] In this way, the pressure sensor 100 of this embodiment can provide the same effects as those of the above-described embodiment.

[0049] Seventh embodiment Next, FIG. 7 is a diagram illustrating a pressure sensor according to a seventh embodiment of the present invention. In FIG. 7, the pressure sensor 100 forms an installation space SR for the circuit board 50 by abutting and fixing the opening side of the side wall portion 324s of the spacer 324 against the housing 12 without having the plate 224 of the above embodiment, and the core wire C of the lead wire 38 is conductively connected to the circuit board 50 without using the contact pin 126 of the above embodiment.

[0050] In addition, in this pressure sensor 100, a resin material is applied to cover the entire surface of the circuit board 50, including the lead pins 40 on both sides thereof, the connection points with the core wires C of the lead wires 38, and the mounted components 50J, and is coated with an insulating coating material (insulation improving member) 424. Furthermore, a resin material is applied to cover the entire surface of one end face of the housing 12 and the support 13, including the penetrating and protruding points of the lead pins 40 on the hermetic glass 14 side, and is coated with an insulating coating material (insulation improving member) 426.

[0051] With this structure, in the pressure sensor 100, both sides of the circuit board 50 are covered with an insulating coating material 424 to ensure improved insulation, and the housing 12 side is also covered with an insulating coating material 426 to ensure improved insulation.

[0052] In this manner, in the pressure sensor 100 of this embodiment, the circuit board 50 itself and the housing 12 side are covered with insulating coating materials (coating materials) 424, 426, ensuring insulation at the connection points with the lead pin 40 and the core wire C of the lead wire 38, enabling reliable and high-quality pressure measurements to be performed.

[0053] <Other forms of the first type> 8, in the pressure sensor 100 according to the first alternative aspect of the above-described embodiment, a resin material is applied to the exposed portion from the cylindrical shape within the inner peripheral end surface 124i of the bottom portion 124b of the spacer 124 in the above-described second embodiment to the gap between the bottom portion 124b and the hermetic glass 14, to be coated with an insulating coating material (insulation improving member) 524. This improves the insulation resistance of the penetrating and protruding portion of the lead pin 40 on the hermetic glass 14 side, thereby ensuring insulation between the lead pin 40 and the housing 12, and between the housing 12 and the circuit board 50.

[0054] <Second other form> As shown in FIG. 9, in a second alternative aspect of the pressure sensor 100 of the above-described embodiment, a roughly cylindrical metal waterproof case 620 is attached instead of the waterproof case 20 in the above-described embodiment, and a sealant 26 is filled on the outside of a cover member 625 (described below) on the open end side of the waterproof case 620 to ensure liquid-tightness.

[0055] In addition, in the pressure sensor 100, instead of the above-mentioned spacer 124, a resin spacer 624 formed in a cylindrical shape with a short side wall and a bottom, omitting one end opening side, is fixed to one end face of the housing 12 with its bottom 624b abutting at the position (height) of the step 124a, and a circuit board 50 to which the lead pin 40 and the lead wire 38 are connected is fixed to the other end opening end 624a of the spacer 624.

[0056] The waterproof case 620 has locking portions 620t formed as dimples or ribs projecting inward so that a desired space can be formed above the circuit board 50, and is supported by a cover member 625 having an outer diameter slightly smaller than that of the housing 12 engaging with the locking portions 620t. Therefore, the installation space SR for installing the circuit board 50 is ensured without relying on the spacer 124.

[0057] <Third other form> 10, the pressure sensor 100 according to the third alternative aspect of the above embodiment does not use the spacer 24 or the like in the above embodiment, and instead includes a housing 712 formed in a generally cylindrical shape with a bottom by integrally forming a cylindrical side wall portion 712s similar to the spacer 24 on the outer periphery of a cylindrical base portion 712b having a thickness similar to that of the housing 12, instead of the housing 12. As in the above embodiment, the housing 712 has the hermetic glass 14 formed integrally in the base portion 712b together with the support posts 13, and a cover member 725 is fixed to cover the open end of the side wall portion 712s so as to close it, thereby forming an installation space SR for accommodating the circuit board 50 on which the mounting components 50J are mounted.

[0058] In this pressure sensor 100, instead of the above-mentioned spacer 124, a resin spacer 724 formed in a cylindrical shape with a short side wall and a bottom, omitting one end opening side, is fixed at the position (height) of the step 124a with its bottom 724b abutting against one end face side of the base portion 712b of the housing 712, and a circuit board 50 to which the lead pins 40 and lead wires 38 are connected to the other end opening side of the spacer 724 is positioned and fixed in the middle of the installation space SR.

[0059] The pressure sensor 100 also includes a waterproof case 720 formed in a roughly cylindrical shape that encloses the entire outer side of the cover member 725 as well as the lateral outer side of the housing 712 in the pressure sensor unit 10, and the waterproof case 720 has one end opening 720a fixed to the peripheral portion of the cap 28 to which the coupling member 30 is fixed, and a sealant 726 is filled in from the other end opening side to provide a liquid-tight seal all the way to the outer circumferential surface side of the housing 712.

[0060] The scope of the present invention is not limited to the exemplary embodiments shown and described, but includes all embodiments that achieve equivalent effects to the object of the present invention. Moreover, the scope of the present invention is not limited to the combination of inventive features specified in each claim, but may be defined by any desired combination of each and every particular feature disclosed. [Explanation of symbols]

[0061] 10...Pressure sensor unit 11...Pressure sensor chip 12, 712...Housing 20, 620, 720...Waterproof case 24, 124, 324, 524, 624, 724...Spacers 25, 325, 625, 725....Cover parts 26, 226, 626, 726...Sealing material 30...Joint member 38...Lead wire 40...Lead pin 50...Circuit board 50J...Mounted parts 100...Pressure sensor 126……Contact pin 224...Plate 424, 426, 524...insulating coating material 620t……locking part A……External device C...Core wire SR……Installation space

Claims

1. A pressure sensor in which a sensor for detecting a pressure to be measured is connected to a circuit board that is installed inside a case, the sensor is installed in a pressure chamber to receive a pressure to be measured, and the circuit board is installed in an installation space formed liquid-tight by filling a sealant in the case, A space forming member that forms the installation space, and an insulation improving member that improves insulation resistance between the space forming member and the circuit board, A pressure sensor, characterized in that the mounted components of the circuit board are positioned within the installation space.

2. 2. The pressure sensor according to claim 1, wherein the insulation improving member is constituted by a part of the space forming member, and improves insulation resistance by setting a desired separation distance between the space forming member and the circuit board.

3. The pressure sensor according to claim 1, characterized in that the insulation improving member is composed of at least one of a plate material, a sheet material, or a coating material made of an insulating material and arranged between the space forming member and the circuit board to improve insulation resistance.

4. the installation space is surrounded and formed by the space forming member, the space forming member being configured by a side wall portion forming a cylindrical shape capable of storing the circuit board, and a pair of closing members positioned on both ends of the cylindrical shape and closing an opening, the side wall portion functions as a spacer for improving insulation resistance by setting a desired distance between the pair of blocking members and the circuit board, The pressure sensor according to claim 1 , wherein the side wall portion and the pair of closing members constitute the space forming member and the insulation improving member.

5. One of the closing members is integrally formed with the side wall portion into a cylindrical shape having a bottom, and the other closing member functions as a lid member for the cylindrical shape, The pressure sensor of claim 4 , wherein the sidewall supports at least a portion of a peripheral edge of the circuit board.

6. the circuit board is disposed between the sensor and an external device, the sensor is electrically connected to the circuit board via a sensor connection pin member that penetrates the space forming member, The pressure sensor according to claim 1, characterized in that an external connection member that is pulled out to the outside and connected to the external device is conductively connected to the circuit board via an external connection pin member that penetrates the space forming member.

Images