Pressure sensor

Abstract

To provide a pressure sensor that achieves a structure reducing stress applied to a circuit board mounted therein, and can thereby be used with high reliability.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 and installed 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 in an installation space SR that is filled with sealant 26 inside the case and formed in a fluid-tight manner. The installation space is formed to enable storage of the circuit board inside a cylindrical member 24 having a cylindrical shape, and is accommodated inside the case while being covered with a cylindrical member cap 25 on an opening side of the cylindrical shape.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid-tight molded pressure sensor. [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. 4, 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, when a temperature difference occurs between the inside and outside of the object to be measured, a stress corresponding to the temperature difference occurs because there is a difference in the linear expansion coefficient of components such as circuit board 1431, case 1135, and sealing material 1136. This stress may become a load on circuit board 1431 itself or on the components mounted on circuit board 1431.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a pressure sensor that can be used with high reliability by realizing a structure that reduces the stress applied to an internal circuit board. [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 and the circuit board is installed in a case, the sensor is installed in a pressure chamber so as to receive the pressure of the object to be measured, the circuit board is installed in an installation space formed liquid-tight by filling the case with a sealant, the installation space is formed in a tubular member formed so as to be able to store the circuit board, and the opening side of the tubular member is covered with a lid member and the circuit board is housed in the case. Effect of the Invention

[0009] According to one aspect of the present invention, the circuit board itself and the components mounted on the circuit board are positioned within the installation space to avoid contact with the sealing material, and it is possible to prevent the components mounted on the circuit board from being subjected to stress loads, thereby providing a pressure sensor that can be used with high reliability. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a pressure sensor according to one 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 first alternative 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 second alternative 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 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 one embodiment of the present invention.

[0012] 1, the pressure sensor 100 is assembled by stacking components as described below, attached to a refrigerant pipe in a unit to measure the pressure of the refrigerant in a refrigeration cycle, and fabricated so that pressure information detected by a pressure sensor chip (sensor) 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 housed in a resin waterproof case 20 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 guided.

[0013] Here, the waterproof case 20 is made in a cylindrical shape capable of housing the pressure sensor unit 10, and the periphery of the cap 28 to which the coupling member 30 is fixed is connected to an opening 20b on one end side. This coupling member 30 is formed with a female thread 30s so that it can be screwed to a pipe or the like whose pressure is to be measured, and a fluid supplied from the pipe in the direction of the arrow P is introduced through a port 30a communicating with the female thread 30s into a pressure chamber PR, which is a space surrounded by the cap 28, the housing 12, and a diaphragm 32 described later. Here, various members including the waterproof case 20 and the cylindrical member 24 described later will be described using a cylindrical shape as an example of a cylindrical shape, but it is not necessary to limit these to a cylinder, and it goes without saying that a polygonal cylindrical shape, for example, may be adopted.

[0014] The pressure sensor unit 10 comprises a housing 12 made into a short cylindrical shape and having its lower axial end face joined and fixed to a cap 28, a support 13 on which the pressure sensor chip 11 is mounted and positioned so as to be located at the center of the inner tube of the housing 12, and hermetic glass 14 which is filled around the support 13 within the inner tube of the housing 12 to seal it while fixing members which pass through the inner tube.

[0015] In the pressure sensor unit 10, a metal diaphragm 32 is bonded and fixed to the lower 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 electrically connected to the lead pins (pin members) 40 connected to the multiple lead wires (external connection members) 38 from the external device A via a circuit board 50 described later, via the bonding wires 11w, and is installed so as to be supplied with power and output 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 are arranged on a bottom surface 24b of a resin cylindrical member 24 formed in a short, generally cylindrical shape with a bottom, and 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 inserted into insertion holes 24h formed in the bottom surface 24b of the cylindrical member 24 and fixedly supported by the hermetic glass 14. Here, a part of the generally cylindrical side wall 24s of the cylindrical member 24 is formed in a flat shape at a symmetrical position with respect to the center of the cylinder, and terminal holding parts 51 and 53 for mounting and holding a set of three relay connection terminals (contact members) 36 and 37, which will be described later, are arranged on the flat surface.

[0021] One end of the lead pin 40 penetrates the liquid-sealed chamber side of the hermetic glass 14 in the inner cylinder of the housing 12, and the pressure sensor chip 11 is electrically connected to the one end side, which is the liquid-sealed chamber LR side, via a bonding wire 11w. In addition, among the multiple lead pins 40, the terminal piece (connection surface) 36e of the relay connection terminal 36 held on the side wall portion 24s of the cylindrical member 24 extends in a direction intersecting the other end side of the power supply terminal and the output signal terminal, and is electrically connected to the end surface by, for example, spot welding (or molten metal joining) with high quality while appropriately deforming elastically. In addition, the relay connection terminal 37 to which the lead wire 38 from the external device A is connected is held on the opposite (facing) side of the relay connection terminal 36 on the side wall portion 24s of the cylindrical member 24, as described later. A flat circuit board 50 extending in a parallel direction is placed on the terminal pieces (connection surfaces) 36d, 37d of these relay connection terminals 36, 37, and is connected by soldering in which molten solder (conductive connection material) S is applied. It goes without saying that the conductive connection material is not limited to molten metal such as solder S, but may be, for example, an adhesive containing a conductive material. As described above, in addition to the conductive connection using soldering or conductive adhesive, the conductive connection may be achieved by welding (for example, spot welding with a laser, etc.), and there is no need to limit the welding method in particular.

[0022] Here, 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 is 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 voltage different from this embodiment, a current output format such as a two-wire type / three-wire type, or a digital output format. Note that these conversion adjustment circuits are configured by mounting a plurality of electronic components (not shown).

[0023] Here, the cylindrical member 24 has a cylindrical member cap (lid member) 25 attached to the opening side (the other opening end side of the cylindrical member 24) of the cylindrical side wall portion 24s, and an installation space SR is formed for the lead pin 40, the terminal pieces 36d, 36e, 37d of the relay connection terminals 36, 37, and the circuit board 50. The pressure sensor unit 10 is integrated with a desired joint strength by welding the housing 12 and the outer periphery of the cap 28 to which the joint member 30 is connected from the outside by TIG welding, plasma welding, laser welding, or the like. The pressure sensor unit 10, the cylindrical member 24 forming the installation space SR, and the cylindrical member cap 25 are placed inside the waterproof case 20 and filled with a sealant 26 such as a urethane resin, thereby being fixed while being waterproofed. Here, by arranging the circuit board 50 in the installation space SR defined by the cylindrical member 24 and the cylindrical member cap 25, 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, the mounted components mounted on the circuit board 50, or the connection points between the circuit board 50 and the relay connection terminals 36, 37, etc. 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, and in particular on their soldered portions.

[0024] The pressure sensor 100 can be easily and simply assembled with excellent workability by stacking the housing 12, which is fixed to the cap 28 connected to the joint member 30, the cylindrical member 24, the circuit board 50, and the cylindrical member cap 25. After the relay connection terminals 36 and 37 are set in the terminal holding parts 51 and 53 of the side wall part 24s, the cylindrical member 24 is placed on one end side of the housing 12 forming the pressure sensor unit 10, and the end of the lead pin 40 is spot-welded to the terminal piece 36e of the relay connection terminal 36, and then the circuit board 50 is placed on the terminal pieces 36d and 37d of the relay connection terminals 36 and 37 and soldered to establish a conductive connection. It goes without saying that the terminal piece 36e of the relay connection terminal 36 may be conductively connected to the end face of the lead pin 40 by soldering, crimping, or the like, instead of spot welding. In addition, the bottom surface 24b of the cylindrical member 24 is provided with appropriate insertion holes and the like to facilitate assembly, and for example, an insertion hole (not shown) for the oil filling pipe 44 is also provided. By providing the cylindrical member 24 with the insertion holes for the lead pin 40 and the oil filling pipe 44, it is possible to specify the power supply terminal and the output signal terminal to be connected when connecting the terminal piece 36e to the lead pin 40, and prevent connection to an incorrect lead pin 40. In addition, even if the bottom surface 24b is not provided on the cylindrical member 24, a structure may be used in which, for example, steps, irregularities, etc. for engagement are formed at the location of the housing 12 where the cylindrical member 24 is placed, and these steps and irregularities engage with each other to specify the position of the cylindrical member 24 in the circumferential direction relative to the housing 12, i.e., the arrangement direction of the lead pins 40.

[0025] In detail, the cylindrical member 24 is configured so that the relay connection terminals 36, 37 are attached and held in terminal holding portions 51, 53 formed on the side wall portion 24s.

[0026] The relay connection terminal 36 is formed in a long shape with end pieces (terminal pieces) on one end side and the other end side located at both ends facing each other, that is, a U-shape in which a flat portion 36f between the terminal pieces 36d, 36e on both ends extending in a parallel direction of the U-shape is aligned along the outer surface of the terminal holding portion 51 of the cylindrical member 24, and the terminal pieces 36d, 36e are extended into the side wall portion 24s. The relay connection terminal 37 is similarly formed in a U-shape with a bent piece 37e formed by bending the opposite side of the terminal piece 37d while extending the terminal piece 37d into the side wall portion 24s of the cylindrical member 24 and aligning a flat connection surface 37f along the outer surface of the terminal holding portion 53. The core wire C of the lead wire 38 from the external device A is soldered and connected to the connection surface 37f of this relay connection terminal 37, thereby electrically connecting the pressure sensor chip 11 to the external device A via the lead pin 40, the relay connection terminals 36, 37 and the circuit board 50.

[0027] The terminal holding parts 51, 53 can secure a large connection surface by inserting the terminal pieces 36d, 36e, 37d of the relay connection terminals 36, 37 into slits formed in and penetrating the side wall part 24s of the cylindrical member 24, and are attached by fitting the bent piece 37e of the relay connection terminal 37 into a recessed part 53p formed in the outer surface of the side wall part 24s below the terminal holding part 53. A recessed part 51p is also formed in the side wall part 24s of the cylindrical member 24 below the terminal holding part 51 so that the terminal piece 36e of the relay connection terminal 36 is inserted into the slit, and the sealant 26 filled in the waterproof case 20 enters into these recessed parts 51p, 53p, thereby fixing the relay connection terminals 36, 37 to the cylindrical member 24. Alternatively, after the relay connection terminals 36, 37 are attached to the cylindrical member 24, the recesses 51p, 53p may be coated and filled with terminal fixing adhesive 26a (26a is shown in the figure) to fix the terminals.

[0028] The circuit board 50 has an outer peripheral end surface at a location corresponding to the terminal pieces 36d, 37d of the relay connection terminals 36, 37 recessed inward in a U-shape in a direction parallel to the plane of the circuit board 50, and a recessed wall electrode surface (recessed wall surface) 50u of a connection region that opens on both sides perpendicular to the plane of the circuit board 50 is formed. The recessed wall electrode surface 50u is plated with excellent solder wettability on the inner surface by infiltrating a semicircle into the circuit board 50 from the outer peripheral end surface of the circuit board 50, which allows the molten solder to easily penetrate the entire surface (whole surface), and the terminal pieces 36d, 37d of the relay connection terminals 36, 37 are similarly plated to provide high-quality conductive connection. That is, the recessed wall electrode surface 50u is formed as an oval cutout shape from the outer peripheral end surface of the circuit board 50 toward the inside of the board. By making the recessed shape inwardly of the recessed wall surface semicircular, it is expected that the stress inside the recessed wall surface 50u in the formation of a fillet by solder will act evenly. In addition, in the manufacturing process of the circuit board 50, the circuit board 50 can be manufactured using the same processing tools as those used for processing mounting holes for mounted components and for processing the outer shape of the circuit board 50. A rectangular shape requires separate steps and tools, such as processing with a disk-shaped cutter, and a semicircular shape is advantageous in terms of productivity and quality. Here, the recessed wall electrode surface 50u is not limited to the outer peripheral end surface on the opposite side of the circuit board 50, but may be formed at a position that is spaced apart so that soldering can be performed without short circuiting, and may be formed at positions that are evenly or unevenly spaced apart so that connection can be performed at multiple points depending on the convenience of the circuit to be formed. For example, the recessed wall electrode surface 50u may be formed on the outer peripheral end surface on the opposite side of the circuit board 50 located in the radial direction at equal intervals from the center of the support 13 so as to correspond to the lead pin 40. Therefore, in this circuit board 50, the mounting area for mounted components can be secured large without reducing the forming area of ​​the circuit, as in the type in which a circular circuit for connection is formed around a through hole that penetrates as shown in FIG. 4 and pin connection is performed. That is, it is possible to provide a degree of freedom in the layout of the wiring patterns and the arrangement of components on the circuit board without being influenced by the through holes for inserting the lead pins. Also, in this embodiment, the relay connection terminals 36, 37 are arranged to face each other, and by arranging them in this manner, the wiring patterns for power supply and signal transmission to the circuit board 50 can be of approximately uniform length, and the wiring pattern of the circuit board 50 can be simplified.Furthermore, in the soldering operation between the concave wall electrode surface 50u and the terminal pieces 36d, 37d, by making the shape of the connection portion uniform, the heat capacity of the soldering is also approximately uniform, which has the effect of making it possible to perform uniform soldering and improving workability compared to when the connection portion is located at a distance.

[0029] In contrast, the terminal pieces 36d, 37d of the relay connection terminals 36, 37 are formed to be wider than the recessed electrode surface 50u of the circuit board 50 and longer than the depth from the outer peripheral end face of the recessed electrode surface 50u, so that the circuit board 50 can be placed in a stable position. Furthermore, the cylindrical member 24 is designed so that the circuit board 50 can be positioned by fitting support-shaped portions (not shown) into the four corners of the circuit board 50. In other words, the terminal pieces 36d, 37d of the relay connection terminals 36, 37 function as support regions that support the vicinity of the recessed electrode surface 50u of the circuit board 50. In this embodiment, recessed wall electrode surfaces 50u are formed in the connection areas of both circuit boards 50 that are connected to the terminal pieces 36d, 37d of the relay connection terminals 36, 37, but this is not limited to this, and connection may be made at the outer peripheral end surface of the circuit board 50 without forming the recessed wall electrode surface 50u, or the recessed wall electrode surface 50u may be provided on only one of the two sides. However, forming the recessed wall electrode surface 50u on both sides is preferable in terms of connection workability and reliability.

[0030] As a result, the circuit board 50 is placed on the terminal pieces 36d, 37d of the relay connection terminals 36, 37 in a stable position and is held in a stable position in which it is positioned in the positioning shape (not shown) of the cylindrical member 24, and the half oval recessed wall electrode surface 50u is reliably connected to the terminal pieces 36d, 37d by the solder S, which has a larger capacity than the semicircular recessed wall electrode surface and a stable shape with a sufficient fillet height. Since the connection area, which is the soldering point, is on the back side of the circuit board 50, it is not possible to directly visually confirm the connection area. However, as in this embodiment, by managing the state of the fillet inside the recessed wall portion 50u by visual inspection or image recognition, it is possible to determine whether the soldering has been performed normally.

[0031] 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. The installation space SR is formed by covering the cylindrical member cap 25 with the cylindrical member 24 into which the terminal pieces 36d, 37d, 36e of the relay connection terminals 36, 37 which are conductively connected to the recessed wall electrode surface 50u on the outer circumferential end surface of the circuit board 50, the lead pin 40, and the lead wire 38 are inserted and positioned and fixed.

[0032] Therefore, in pressure sensor 100, circuit board 50 located in installation space SR formed by cylindrical member 24 and cylindrical member cap 25 can prevent mechanical load caused by direct contact of sealing material 26 made of melted high-temperature resin during fabrication, and thermal stress caused by difference in degree of expansion and contraction due to difference in linear expansion coefficient of constituent materials in response to temperature changes during use, from being applied as stress load to the board itself and mounted components. Also, in this pressure sensor 100, sudden temperature changes in response to the installation environment can be mitigated by heat transfer to relay connection terminals 36, 37 without being stopped by lead pins 40 exposed in a small volume in the installation space SR, and it is possible to avoid condensation being induced due to a large temperature difference between only lead pins 40 in a small volume and the inside of the internal space. That is, the pressure sensor of this embodiment is mainly used for measuring the pressure of the refrigerant pipe in the refrigeration cycle, and a temperature difference occurs between the joint member 30, which is the liquid-contacting part that is in a low temperature state due to a sudden drop in the refrigerant temperature, and the installation space SR, but the low temperature of the liquid-contacting part is not easily transmitted to the installation space SR due to the small volume of the lead pin 40, so that the occurrence of significant condensation can be suppressed. Also, in this embodiment, the relay connection terminal 36 is drawn out to the outside of the cylindrical member 24 that forms the installation space SR, and is connected to the circuit board 50 while contacting the sealing material 26 that is in close contact with the case 20 that is in contact with the outside air together with the relay connection terminal 37. With this configuration, the low temperature heat transfer transmitted through the lead pin is hindered by the terminal and the sealing material, and condensation around the circuit board can be suppressed, and the occurrence of short circuits and ion migration caused by condensation can be suppressed.

[0033] This makes it possible to provide a pressure sensor 100 that can be used with high reliability by suppressing the occurrence of short circuits and migration due to condensation.

[0034] As shown in FIG. 2, in the first alternative aspect of the pressure sensor 100 of this embodiment, the cylindrical member 24 in the above-described embodiment is not used, and an installation space SR for accommodating the circuit board 50 is formed by covering the housing 12 with a cylindrical member cap 125 having a lid member integrated therewith.

[0035] This pressure sensor 100 is configured to be conductively connected to a lead pin 40 connected to the sensor chip 11 on a circuit board 50 in the installation space SR without using intermediate connection terminals 36, 37, and to be conductively connected to a lead wire 38 connected to an external device A.

[0036] Specifically, the lead pin 40 and the circuit board 50 are electrically connected by conductive connection at both ends of a flexible wiring member 136 (which may be, for example, a flexible board or a lead wire on which a wiring circuit is formed). The lead pin 40 is connected to one end of the wiring member 136 by spot welding or the like, and the other end of the wiring member 136 is conductively connected to a contact member 138 that penetrates and is soldered to both sides of the circuit board 50.

[0037] The lead wire 38 (core wire C) and the circuit board 50 are electrically connected by conductive connections at both ends of the contact member 126 that penetrates the cylindrical member cap 125, and the core wire C of the lead wire 38 is soldered and connected to one end of the contact member 126 that is located outside the cylindrical member cap 125, while the other end of the contact member 126 that is located inside the cylindrical member cap 125 penetrates both sides of the circuit board 50 and is soldered and connected conductively.

[0038] Here, the pressure sensor 100 of the first alternative embodiment is assembled in a state in which the peripheral edge of the circuit board 50 is placed on the step 125a formed on the inner peripheral surface of the middle stage of the cylindrical member cap 125 with the opening side facing upward, and then is turned upside down and stored in the case 20, and filled with the sealant 26, to create a liquid-tight structure. Also, in this pressure sensor 100, an adhesive 126a is applied to the through-hole 125h of the cylindrical member cap 125 through which the contact member 126 passes, to restrict the sealant 26 from entering the installation space SR. An adhesive 127 is applied to the installation space SR side of the support 13 and the housing 14 to ensure insulation around the lead pin 40.

[0039] In this way, in the first other form of pressure sensor 100, as in the above-described embodiment, the circuit board 50 interposed between the sensor chip 11 and the external device A can be contained within the installation space SR in the case 20 which is liquid-tightly sealed, and it is possible to prevent mechanical loads during manufacture or use, or stress loads such as thermal stress due to temperature changes from being applied.

[0040] As a second alternative aspect of the pressure sensor 100 of this embodiment, as shown in FIG. 3, without using the cylindrical member cap 25 in the above-described embodiment, a tubular cylindrical member 124 having openings on both ends is placed over the housing 12 to close one end opening, and a lid member 151 is placed over the other end opening to form an installation space SR for accommodating the mounted components of the circuit board 50.

[0041] This pressure sensor 100 is configured so that both the lead pin 40 connected to the sensor chip 11 and the lead wire 38 (core wire C) connected to the external device A are connected to a circuit board 50 (mounted component) in the installation space SR without using relay connection terminals 36, 37.

[0042] Specifically, the lead pin 40 is configured to pass through a through hole 50h1 formed in the circuit board 50 and be soldered directly to the formed circuit for conductive connection, and the lead wire 38 is configured to pass through a through hole 151h formed in the cover member 151, and then pass through a through hole 50h2 similarly formed in the circuit board 50 and be soldered directly to the formed circuit for conductive connection.

[0043] Here, the pressure sensor 100 of the second alternative embodiment is constructed so that a cylindrical spacer member 126 with a bottom is fixed to the housing 12 side within a cylindrical member 124, and the circuit board 50 can be placed and fixed on the opening side of the cylindrical spacer member 126, and the circuit board 50 is positioned and fixed at the middle stage within the installation space SR. The spacer member 126 has an opening 126a formed in a bottom portion 126b so that the lead pins 40 can reach the circuit board 50.

[0044] In this way, the pressure sensor 100 of the second alternative embodiment can also provide the same effects as those of the first alternative embodiment described above.

[0045] In all of these configurations, the entire circuit board is placed in the installation space SR in order to reduce the stress applied to the circuit board. However, this structure is not limited to this, and other parts of the board that have strength may be drawn out of the installation space SR in order to protect the parts of the circuit board that are weak against mechanical stress, i.e., the wiring pattern of the circuit board and the mounting part of the mounted parts on the circuit board (the wiring pattern and the mounted parts are left in the installation space SR). Specifically, although not shown in the figures, a structure can be adopted in which the mounting part of the circuit board, the circuit wiring pattern, etc. are extended from the other parts to penetrate a cylindrical member or a cylindrical member cap, or a slit is formed at the boundary between them to penetrate the other parts, thereby forming a through hole for electrically connecting a lead wire to the circuit board drawn out of the installation space SR. In this circuit board outside the installation space SR, a lead wire connection structure that has sufficient strength even in the space filled with a sealant can be adopted.

[0046] 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]

[0047] 10...Pressure sensor unit 11...Pressure sensor chip 24...Cylindrical member 24s……Side wall part 26...Sealing material 26a……Terminal fixing adhesive 30...Joint member 32...Diaphragm 36, 37...Relay connection terminals 36d, 36e, 37d...Terminal piece 36f……Plane part 37f...Connection surface 38...Lead wire 40...Lead pin 50...Circuit board 50u……Concave wall electrode surface 51, 53...terminal holding part 51p, 53p... hollow 100...Pressure sensor 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, and the circuit board is installed in 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 pressure sensor characterized in that the installation space is formed within a cylindrical member formed to be able to store the circuit board, and the opening side of the cylindrical member is covered with a lid member and the sensor is housed within the case.

2. The pressure sensor described in claim 1, characterized in that the circuit board is installed so as to be interposed between the sensor and an external device, and is conductively connected to the sensor via a pin member passing through one opening end side of the tubular member, and is conductively connected to the external device via an external connection member pulled out to the outside from the other opening end side of the tubular member.

3. 3. The pressure sensor according to claim 2, wherein the circuit board is electrically connected to one or both of the pin members and the external connection members via contact members.

4. 4. The pressure sensor according to claim 3, wherein the contact member has a connection surface extending in a direction intersecting a connection portion of one or both of the pin member and the external connection member.

5. 4. The pressure sensor according to claim 3, wherein the contact member has a connection surface extending in a direction parallel to a connection portion formed in a direction in which the flat shape of the circuit board extends.

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