Pressure Sensor

Abstract

To provide a pressure sensor capable of suppressing the occurrence of ion migration and improving workability in joining of a flexible connection material.SOLUTION: A pressure sensor includes: a pressure detection unit including a pressure detection device configured to detect a pressure of a fluid and an external input / output terminal configured to input and output a signal to and from the pressure detection device; and a signal transmission unit that includes a signal mediation substrate configured to convert the signal from the external input / output terminal and is configured to output the converted signal to an external circuit. A metal member is surface-mounted on the signal medium substrate, and a flexible connection member electrically connecting the signal medium substrate and the external input / output terminal is connected to the metal member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pressure sensor having a conversion substrate provided therein. [Background technology]

[0002] Conventionally, there are pressure sensors in which a conversion board equipped with a conversion circuit that converts both the drive voltage and the pressure detection signal is externally connected between the control circuit and the pressure sensor in order to accommodate various drive voltages and signal formats of the pressure detection signal.

[0003] To solve the problem of poor connection caused by external shocks or vibrations, some pressure sensors omit the cable and place the conversion board inside the pressure sensor. However, the conversion board generates heat due to the transformation of the drive voltage. Therefore, when the conversion board is placed inside the pressure sensor, it is desirable to efficiently dissipate the heat generated in the conversion board and to suppress the heat transfer to the conversion board. If these measures are not implemented effectively, problems such as damage to the electronic components on the conversion board may occur due to temperatures exceeding their heat resistance temperature.

[0004] As a configuration for suppressing heat transfer to the conversion substrate, Figure 1 of Patent Document 1 describes that an internal space S is provided to suppress the heat transfer from the semiconductor sensor chip 126 side to the conversion substrate 133, thereby suppressing the thermal impact on the conversion substrate 133. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. WO2022 / 097437 [Patent Document 2] Patent No. 3987386 Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration described in Patent Document 1, flexible wires 132 are used to connect the conversion board 133 to the lead pins 128 on the semiconductor sensor chip 126. The flexible wires 132 are connected to the connection terminals 134 of the conversion board 133 by soldering, which may cause short circuits due to ion migration (CAF) between the terminals on the surface of the conversion board. Furthermore, soldering takes time to complete the connection, and the limited space for soldering reduces workability.

[0007] An object of the present invention is to provide a pressure sensor that can prevent ion migration from occurring and improve workability when joining flexible connecting wires. [Means for solving the problem]

[0008] In order to solve the above problems, the pressure sensor comprises a pressure detection unit having a pressure detection element that detects the pressure of a fluid and an external input / output terminal that inputs and outputs signals to and from the pressure detection element, and a signal sending unit having a signal intermediate substrate that converts signals from the external input / output terminal and outputs the converted signals to an external circuit, wherein a metal member is surface-mounted on the signal intermediate substrate, and a flexible connecting material that electrically connects the signal intermediate substrate and the external input / output terminal is wired to the metal member.

[0009] In the above pressure sensor, the metal member may be a metal plate.

[0010] In the pressure sensor, the flexible connecting wire may be lap-welded to the metal member.

[0011] In the pressure sensor, the flexible connecting wire may have a conductive member made of stainless steel or nickel.

[0012] Furthermore, a connection land may be formed on the signal transfer board, and the connection land and the metal member may be electrically connected by a conductive pattern. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a pressure sensor that can prevent ion migration from occurring and improve workability when joining flexible connecting wires. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing a pressure sensor according to an embodiment of the present invention. [Figure 2] 2A and 2B are schematic diagrams showing a pressure sensor body according to an embodiment of the present invention, in which FIG. 2A is a perspective view showing the pressure sensor body after being placed on a substrate, and FIG. 2B is a plan view showing the pressure sensor body after being placed on a substrate. [Figure 3] FIG. 3(a) is a cross-sectional view showing a pressure sensor according to another embodiment of the present invention, and FIG. 3(b) is a cross-sectional view showing a pressure sensor according to yet another embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing a pressure sensor according to still another embodiment of the present invention. [Figure 5] FIG. 5(a) is a cross-sectional view showing a pressure sensor having a conversion substrate according to another embodiment of the present invention, and FIG. 5(b) is a cross-sectional view showing a pressure sensor having a relay substrate according to yet another embodiment of the present invention. [Figure 6] FIG. 6(a) is a cross-sectional view showing a pressure sensor having a conversion substrate according to another embodiment of the present invention, and FIG. 6(b) is a cross-sectional view showing a pressure sensor having a relay substrate according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described in detail with reference to Figures 1 to 6. However, the present invention is not limited to this embodiment.

[0016] The pressure sensor 100 according to the embodiment of the present invention includes a heat dissipation means from the conversion board 133 and a heat transfer suppression means to the conversion board 133, thereby effectively dissipating heat generated in the conversion board 133 to the external environment and suppressing heat transfer from the fluid whose pressure is to be detected to the conversion board 133. Here, the heat dissipation means of the conversion board brings the conversion board 133 (including heat-generating components) into indirect thermal contact with the connector housing 131. Therefore, a case where the conversion board 133 is in indirect thermal contact with the connector housing 131 as the heat dissipation means of the conversion board 133 will be described.

[0017] <Terminology> In the description of this specification and the claims, "one end" and "the other end" refer to the "lower end" and "upper end" in the drawings.

[0018] <Pressure sensor configuration> A pressure sensor 100 according to an embodiment of the present invention will be described with reference to FIG.

[0019] The pressure sensor 100 is composed of a fluid introduction section 110, a pressure detection section 120, a signal transmission section (main body) 130, and a connecting member 140. Each component of the pressure sensor 100 will be described below in order. After the fluid introduction section 110 and the pressure detection section 120 are joined and fixed, and the pressure detection section 120 and the signal transmission section 130 are electrically connected, the fluid introduction section 110, the pressure detection section 120, and the signal transmission section 130 are integrally assembled using the connecting member 140.

[0020] <Fluid introduction section> The fluid introduction section 110 introduces the fluid whose pressure is to be detected into a pressure chamber 112A described later, and includes a metal joint member 111 and a metal base plate 112 connected to the other end of the joint member 111 by welding or the like.

[0021] The coupling member 111 has a female thread portion 111a that is connected to a pipe (not shown) that introduces a fluid whose pressure is to be detected, and a port 111b that guides the fluid introduced from the pipe to the pressure chamber 112A. The open end of the port 111b is connected by welding or the like to an opening provided in the center of the base plate 112. In this embodiment, the coupling member 111 has the female thread portion 111a, but is not limited to this. For example, the coupling member 111 may have a male thread portion, or a copper connecting pipe may be connected instead of the coupling member 111.

[0022] The base plate 112 has a bowl shape that expands in diameter from one end to the other end in the radial direction relative to the central axis C of the pressure sensor 100, and forms a pressure chamber 112A between itself and a diaphragm 122, which will be described later.

[0023] <Pressure detection section> The pressure detection unit 120 detects the pressure of the fluid in the pressure chamber 112A and includes a housing 121 with a through hole, a diaphragm 122 that separates the pressure chamber 112A from a liquid-sealed chamber 124A described below, and a protective cover 123 that is arranged on the pressure chamber 112A side of the diaphragm 122. The pressure detection unit 120 also includes hermetic glass 124 sealed inside the through hole of the housing 121, liquid-sealed chamber 124A that is filled with sealed oil between the diaphragm 122 and a recess on the pressure chamber 112A side of the hermetic glass 124, and a support post 125 that is arranged in the center of the hermetic glass 124. Furthermore, the pressure detection unit 120 includes a semiconductor sensor chip 126 supported by a support 125 and placed inside the liquid-sealed chamber 124A, a potential adjustment member 127 placed around the liquid-sealed chamber 124A, a plurality of lead pins 128 fixed to the hermetic glass 124, and an oil filling pipe 129 fixed to the hermetic glass 124.

[0024] The housing 121 is made of a metal material such as an Fe-Ni alloy or stainless steel to maintain the strength around the hermetic glass 124. The diaphragm 122 and the protective cover 123 are both made of a metal material and are welded to each other at the outer periphery of the through hole on the pressure chamber 112A side of the housing 121. The protective cover 123 is provided inside the pressure chamber 112A to protect the diaphragm 122, and is provided with a plurality of communication holes 123a through which the fluid introduced from the fluid introduction portion 110 passes. After the pressure detection portion 120 is assembled, the housing 121 is welded from the outside at the outer periphery of the base plate 112 of the fluid introduction portion 110 by TIG welding, plasma welding, laser welding, or the like.

[0025] The hermetic glass 124 is provided to protect the liquid-sealed chamber 124A, in which the semiconductor sensor chip 126 is liquid-sealed, from ambient environmental conditions such as moisture, dust, and heat, to hold the multiple lead pins 128, and to insulate the multiple lead pins 128 from the housing 121. The semiconductor sensor chip 126 is supported by an adhesive or the like on the liquid-sealed chamber 124A side of the support 125, which is located in the center of the hermetic glass 124. Note that, although the support 125 is made of an Fe-Ni alloy in this embodiment, the material is not limited to this. For example, the support 125 may be made of another metal material such as stainless steel, or the support may be directly supported on the flat surface forming the recess of the hermetic glass 124 without the support 125.

[0026] The semiconductor sensor chip 126 in this embodiment is a so-called one-chip type semiconductor sensor chip that includes an internal diaphragm made of a material (e.g., single crystal silicon) having a piezo-resistance effect, a bridge circuit in which a plurality of semiconductor strain gauges are formed on the diaphragm and bridge-connected, an amplifier circuit for processing the output from the bridge circuit, and an integrated circuit such as a calculation processing circuit. The semiconductor sensor chip 126 is connected to a plurality of lead pins 128 by, for example, gold or aluminum bonding wires 126a, and the plurality of lead pins 128 form external input / output terminals for the semiconductor sensor chip 126. The semiconductor sensor chip 126 is not limited to this example, and may also include a chip in which the bridge circuit section using the strain gauges is separated from the amplifier circuit and the calculation processing circuit section.

[0027] The potential adjusting member 127 is provided to place the semiconductor sensor chip 126 in an electric field-free environment (zero potential) and to prevent the circuits in the chip from being adversely affected by the potential generated between the frame earth and the secondary power supply. The potential adjusting member 127 is disposed between the semiconductor sensor chip 126 and the diaphragm 122 in the liquid-sealed chamber 124A, is made of a conductive material such as metal, and is connected to a terminal of the semiconductor sensor chip 126 that is connected to the zero potential.

[0028] A plurality of lead pins 128 and an oil filling pipe 129 are fixed to the hermetic glass 124 by hermetic processing in a penetrating state. In this embodiment, a total of eight lead pins 128 are provided. That is, three lead pins 128 are provided for external output (Vout), drive voltage supply (Vcc), and ground (GND), and five lead pins 128 are provided as terminals for adjusting the semiconductor sensor chip 126. Note that four of the eight lead pins 128 are shown in FIG. 1.

[0029] The oil filling pipe 129 is provided to fill the interior of the liquid-sealed chamber 124A with sealed oil (for example, silicone oil or a fluorine-based inert liquid, etc.). After filling with oil, the other end of the oil filling pipe 129 is crushed and closed as shown in FIG.

[0030] <Operation of the pressure detection unit> The operation of the pressure detection unit 120 will be described. First, the diaphragm 122 is pressed by the fluid introduced into the pressure chamber 112A from the joint member 111. The pressure of the pressure chamber 112A applied to this diaphragm 122 is transmitted to the semiconductor sensor chip 126 via the sealed oil in the liquid-sealed chamber 124A. This transmitted pressure deforms the silicon diaphragm of the semiconductor sensor chip 126, and the pressure is converted into an electrical signal by a bridge circuit using piezo-resistance elements, which is output from the integrated circuit of the semiconductor sensor chip 126 to the signal sending unit 130 via the bonding wires 126a and the multiple lead pins 128.

[0031] <Signal sending section> The signal sending unit (main body) 130 sends the pressure signal detected by the pressure detecting unit 120 to the outside, and includes a connector housing 131 for external connection arranged adjacent to the other end of the pressure detecting unit 120, and a flexible connecting wire 132 having one end connected to the plurality of lead pins 128. The signal sending unit 130 also includes a conversion board 133 which is a signal transfer board for transferring signals to an external circuit fixed to the connector housing 131 via three connection terminals, and the above-mentioned connection terminals 134a to 134c having one end connected to the conversion board 133. An opening 133f is formed in the conversion board 133 to avoid interference with the oil filling pipe 129.

[0032] The connector housing 131 is formed from an insulating resin or the like having a relatively high thermal conductivity, and includes a substrate accommodating portion 131a having a recessed shape on one end, a connector connection portion 131b having a recessed shape on the other end and connected to an external connector (not shown), and a partition wall portion 131c disposed between the substrate accommodating portion 131a and the connector connection portion 131b. A plurality of lead pins 128 and an oil filling pipe 129 extending from the hermetic glass 124, a flexible connecting wire material 132, a conversion substrate 133, etc. are disposed in the internal space S defined by the substrate accommodating portion 131a.

[0033] The conversion board 133 includes a conversion circuit (not shown) that converts both the drive voltage and the pressure detection signal to accommodate the drive voltage and the signal format of the pressure detection signal. This conversion circuit includes a step-down circuit unit (not shown) that steps down the drive voltage (e.g., 8 V to 36 V) of a control circuit (not shown) connected to the outside of the pressure sensor 100 via connection terminals 134a to 134c to the drive voltage (e.g., 5.0 V) of the semiconductor sensor chip 126, and a voltage shift circuit unit (not shown) that boosts the pressure detection signal (e.g., 0.5 V to 4.5 V) of the pressure sensor 100 to the pressure detection signal (e.g., 1 V to 5 V) of the control circuit. In this way, by appropriately selecting the conversion board 133 to be provided within the pressure sensor 100 according to the drive voltage and the signal format of the pressure detection signal, it is possible to absorb differences in the drive voltage and the pressure detection signal without changing the design of the pressure detection unit 120, particularly the semiconductor sensor chip 126, or the peripheral structure of the liquid-sealed chamber 124A. By using a conversion board that performs input / output signal conversion processing in this way, there is no need to stock semiconductor sensor chips that correspond to various input / output formats, and changes can be made by changing the specifications of the conversion board, which allows for a production method that is favorable in terms of parts procurement, manufacturing processes, cost reduction, etc. Furthermore, even if the input / output format of the pressure sensor does not match that of the control circuit, as long as the input / output conversion processing can be performed on the connected control circuit side, there is no need for a circuit with input / output conversion function on the board side.

[0034] At least three connection terminals 134a-c are provided: one for external output (Vout), one for supplying drive voltage (Vcc), and one for ground (GND). To improve assembly, for example, in the case of connection terminal 134a, one end 134d of connection terminal 134a is inserted into a through-hole provided in conversion board 133, and this through-hole is soldered to connect connection terminal 134a to conversion board 133. A land portion 133n is formed at the connection portion of conversion board 133, and is electrically connected to metal plate 135 via a conductive pattern. Meanwhile, the other end of connection terminal 134a penetrates partition wall portion 131c and extends to connector connection portion 131b. The through-holes of partition wall portion 131c through which connection terminals 134a-c penetrate are sealed with connection terminal fixing adhesive 134g.

[0035] <Connection parts> The connecting member 140 includes a crimping plate 141 that connects and fixes the fluid introduction section 110, the pressure detection section 120, and the signal sending section 130 by crimping, and an adhesive sheet 142 that is placed between the pressure detection section 120 and the signal sending section 130.

[0036] The crimping plate 141 is formed into a cylindrical shape from a metal such as copper. The crimping plate 141 is disposed around the fluid introduction portion 110, the pressure detection portion 120, and the signal transmission portion 130, and is fixed to the fluid introduction portion 110 and the signal transmission portion 130 by crimping. This crimping process sandwiches the adhesive sheet 142 between the pressure detection portion 120 and the signal transmission portion 130 to provide waterproof and dustproof functions. Note that a thermally radiative nonmetallic resin sheet 151 and a thermally radiative adhesive 152 may be sandwiched between the adhesive sheet 142 and the housing 121 as a means for suppressing heat transfer to the conversion board 133. The structure of the crimping portion is not limited to the above-described method. For example, as shown in FIG. 11 of Patent Document 2, the fluid introduction portion 110 may be integrally formed so as to accommodate the housing 121 and the connector housing 131, and the open end on the connector housing 131 side may be crimped. That is, any structure may be used as long as adhesive sheet 142 is sandwiched between housing 121 and connector housing 131 and compressed and fixed by caulking or the like.

[0037] <Heat dissipation means for conversion board> The conversion board 133 has an end surface 133b, on which various electronic components are mounted and which is spaced from the connector housing 131, and an end surface 133a, to which the connection terminals 134a-c, etc. are soldered. In this embodiment, the heat-generating component 133h (e.g., a transistor, regulator, or other component having a potential difference between input and output terminals and through which current flows) is a lead type and is mounted on the end surface 133b. The conversion board 133 generates heat due to the transformation of the drive voltage, etc. If no countermeasures are taken, the electronic components on the conversion board may exceed their heat resistance temperature and be damaged. Therefore, in this embodiment, various heat dissipation means for the conversion board 133 are employed to prevent the electronic components of the conversion board 133 from exceeding their heat resistance temperature. This allows heat generated in the conversion board 133 to be efficiently dissipated to the external environment, thereby improving the tolerance for the heat resistance temperature of the conversion board 133. The heat dissipation means for the conversion board 133 in this embodiment will be specifically described below.

[0038] <Heat dissipation means for conversion boards (lead-type heat-generating components)> A lead-type heat-generating component 133h is used as a heat dissipation means for the conversion board 133, forming a heat dissipation path indicated by the dashed line (1) in FIG. 1 . The lead-type heat-generating component 133h is provided on the board-facing surface 131a1 side. A heat-dissipating adhesive 133g having thermal conductivity is filled around the heat-generating component 133h. To prevent the heat-dissipating adhesive 133g from spreading onto the conversion board, an adhesive reservoir wall 131w is provided between the heat-generating component 133h and the outer periphery of the connector housing 131, defining an adhesive reservoir region 131e. That is, in this embodiment, the adhesive reservoir region 131e is defined by the adhesive reservoir wall 131w, the board accommodating portion 131a of the main body 130, and the partition wall 131c. A lead-type heat-generating component 133h is accommodated in this adhesive reservoir area 131e, and a heat-dissipating adhesive 133g having thermal conductivity is filled only between the adhesive reservoir area 131e and the lead-type heat-generating component 133h. As a result, in this embodiment, heat generated in the heat-generating component 133h is actively transferred to the heat-dissipating adhesive 133g having thermal conductivity that surrounds the periphery of the heat-generating component 133h, so that the heat can be more efficiently dissipated to the external environment via the connector housing 131.

[0039] 2(a) and 2(b), a cutout 133k is provided in a portion of the conversion substrate 133 where the heat-dissipating adhesive 133g may creep up due to surface tension along the adhesive reservoir wall surface 131w. This increases the distance between the conversion substrate 133 and the inner wall of the main body 130, preventing the heat-dissipating adhesive 133g, which bulges and spreads in a direction perpendicular to the direction in which the signal sending unit 130 and the pressure detection unit 120 are adjacent, from creeping up due to surface tension along the adhesive reservoir wall surface 131w. Furthermore, by providing the cutout 133k up to the vicinity of the land portion 133n of the conversion substrate 133, even if the heat-dissipating adhesive 133g overflows in a direction perpendicular to the direction in which the signal sending unit 130 and the pressure detection unit 120 are adjacent and drips onto the substrate, the heat-dissipating adhesive 133g can be prevented from adhering to the land portion 133n.

[0040] Furthermore, since the lead-type heat-generating component 133h is mounted on the conversion board 133 via the lead 133l, the heat-generating portion of the heat-generating component 133h is physically separated from the conversion board 133, thereby preventing the electronic components of the conversion board 133 from exceeding their heat resistance temperature.

[0041] Here, the lead-type heat generating component 133h is provided on the outer diameter side of the connector housing 131 so as to be close to the outside air. This makes it easier for the heat dissipating adhesive 133g filled around the lead-type heat generating component 133h to dissipate heat to the outside of the connector housing 131.

[0042] Furthermore, by providing a space between the heat-dissipating adhesive 133g filled around the lead-type heat-generating component 133h and the conversion board 133, heat transfer between the heat-generating component 133h and the conversion board 133 can be suppressed.

[0043] <Heat transfer suppression means> A fluid whose pressure is to be detected is introduced into the pressure chamber 112A. Depending on the conditions of use of the fluid, the introduced fluid may be extremely hot (e.g., approximately 130°C), and may become a heat source. In this case, heat from the pressure detection unit 120 (such as the heat of the high-temperature fluid introduced into the pressure chamber 112A) may transfer to the conversion substrate 133 (heat transfer from one end to the other end in FIG. 1, heat conduction, and heat radiation), potentially canceling out the heat dissipation effect of the heat dissipation means (lead-type heat-generating component). Therefore, in this embodiment, various heat transfer suppression means are employed to prevent the heat from the pressure detection unit 120 (such as the heat of the high-temperature fluid introduced into the pressure chamber 112A) from transferring to the conversion substrate 133. As a result, in this embodiment, the heat transfer from the pressure detection unit 120 to the conversion substrate 133 can be suppressed, thereby enabling the heat dissipation effect of the heat dissipation means (lead-type heat-generating component) to be fully achieved. The means for suppressing heat transfer to the conversion substrate 133 in this embodiment will be specifically described below.

[0044] <First Heat Transfer Suppression Means to the Conversion Board (Internal Space)> The internal space S is used as a first means for suppressing heat transfer to the conversion board 133. Specifically, by providing the conversion board 133 near the other end of the board accommodating portion 131a, the distance L in the internal space S in the direction of the central axis C between the conversion board 133 and the housing 121 on the pressure detection unit 120 side can be set as large as possible. As a result, in this embodiment, heat on the pressure detection unit 120 side can be suppressed from being transferred to the conversion board 133 via the internal space S, which has a long heat transfer path and low thermal conductivity and is made of air. However, the conversion board 133 and the other end of the board accommodating portion 131a are not in direct contact with each other, as will be described in the next section.

[0045] <Second Means for Suppressing Heat Transfer to the Conversion Board (Separation of the Conversion Board from the Main Body)> As shown in FIG. 1, the conversion board 133 is spaced apart from the other end and outer periphery of the board accommodating portion 131a so as not to come into direct contact with the connector housing 131. Instead of being directly supported by the connector housing 131, the conversion board 133 is supported at three points by three connection terminals 134a-c, as shown in FIGS. 2(a) and 2(b). These three connection terminals 134a-c are positioned toward the center of the conversion board 133, to which a particular load is applied when the connection terminals 134a-c are soldered to the conversion board 133. Also, as shown in FIG. 1, the three connection terminals 134a-c are not linear but have a stepped structure 134f, which allows the conversion board 133 to be supported at the stepped portion 134f. The position of this stepped portion 134f is set at a height such that the conversion board 133 does not come into contact with the connector housing 131 when the conversion board 133 is accommodated in the connector housing 131, so that the conversion board 133 is supported at three points as described above. With this structure, the converter board 133 can be positioned in a balanced manner without tilting relative to the connection terminals 134a-c even when a load is applied during soldering. The converter board 133 is also configured to be prevented from moving (upward) toward the connector housing 131 and firmly supported by the connection terminals 134a-c. Furthermore, as shown in FIG. 1 , the connection terminals 134a-c themselves are fixed to the connector housing 131 with a connection terminal fixing adhesive 134g, and the lead-type heat-generating component 133h mounted on the converter board 133 is fixed to the connector housing 131 with a heat-dissipating adhesive 133g, thereby indirectly fixing the converter board 133 to the connector housing 131. In this way, the converter board 133 is spaced apart from the other end of the board accommodating portion 131a so as not to come into direct contact with the connector housing 131. This prevents heat transferred from the lead-type heat-generating component 133h to the surrounding heat-dissipating adhesive 133g from being transferred to the converter board 133.

[0046] In addition to the above, the conversion board 133 is provided such that its side is spaced apart from the outer periphery of the board accommodating portion 131a, thereby preventing stress from being applied from the connector housing 131 to the conversion board 133 due to the difference in thermal linear expansion coefficients between the conversion board 133 and the connector housing 131. This makes it possible to prevent damage to the conversion board 133 due to stress applied from the connector housing 131 to the conversion board 133 due to the difference in linear expansion coefficients.

[0047] <Third means for suppressing heat transfer to the conversion board (flexible wiring material)> The flexible wire 132 described above is used as a third means for suppressing heat transfer to the conversion board 133. Specifically, the flexible wire 132 is formed, for example, from a flexible printed circuit (FPC), a thin conductive member, a lead wire, or an assembly of lead wires, and connects the lead pins 128 and the metal plate 135 in a curved or bent state in the internal space S. This allows the connection distance between the lead pins 128 and the metal plate 135 to be set relatively large. Furthermore, the flexible wire 132 is thinner and has a smaller cross-sectional area than ordinary wiring materials. As a result, in this embodiment, heat from the semiconductor sensor chip 126 side passes through the flexible wire 132, which has a long heat transfer path, and the cross-sectional area is small, so that heat conduction to the conversion board 133 can be suppressed.

[0048] <Joining flexible wire to metal plate> 2A and 2B are schematic diagrams showing a pressure sensor body according to an embodiment of the present invention, in which Fig. 2A is a perspective view showing the pressure sensor body after being mounted on a substrate, and Fig. 2B is a plan view showing the pressure sensor body after being mounted on a substrate. Note that Fig. 2A shows a part of the connector housing 131 cut away so that the inside of the body can be seen.

[0049] As shown in Figures 2(a) and 2(b), the metal plate 135 is a surface-mount metal component made of copper, phosphor bronze, brass, nickel silver, or other copper alloys, and is preferably plated with tin, gold, or the like. The metal plate 135 is surface-mounted on a conversion board 133, and the flexible connecting wire 132 is connected to the metal plate 135 by welding. Here, because the metal plate 135 is a surface-mount component that does not require a through-hole in the board, the flexible connecting wire 132 and the metal plate 135 can be welded together by other welding methods, such as soldering, as in the case of mounting to the board. Note that, in the case of laser welding, the metal plate 135 is made of a copper alloy, which has high thermal conductivity and is prone to reflecting light, and therefore is not easily workable for laser welding as is. Therefore, the material of the conductive member of the flexible wire material 132 is stainless steel or nickel, which is easy to process for laser welding, and the flexible wire material 132 is placed on the metal plate 135. After that, a laser is irradiated onto the flexible wire material 132 to join (lap weld) the metal plate 135 and the flexible wire material 132.

[0050] In this way, by laser welding the flexible wire material 132 to the metal plate 135, soldering is not required, and ion migration between terminals on the surface of the conversion board 133 can be prevented. Furthermore, the time required to join the flexible wire material 132 and the metal plate 135 can be shortened, enabling joining even in a small work space. Furthermore, lap welding prevents melting of the intermediate layer of the laminated substrate of the conversion board 133 due to laser welding. As described above, the metal plate 135 is made of a metal material with high thermal conductivity, and therefore can partially dissipate heat from the mounted conversion board 133. In this embodiment, the conversion board 133 is a laminated substrate consisting of four layers, but this is not limited thereto and may be a single-layer, single-sided, or double-sided substrate. In addition, although the metal plate 135 is used in this embodiment, this is not limited thereto and jumper wires, jumper pins, etc. may also be used.

[0051] <Main body assembly process> In the process of assembling the main body 130, first, the three connection terminals 134a-c are inserted into the main body 130. Then, as shown in FIG. 1, connection terminal fixing adhesive 134g is applied (filled) around the connection terminals 134a-c so that the inserted connection terminals 134a-c are fixed to the main body 130. However, the thickness of the applied adhesive is determined so that the connection terminal fixing adhesive 134g does not adhere to the conversion substrate 133. Next, as also shown in FIG. 1, heat dissipation adhesive 133g is filled into the adhesive reservoir region 131e of the main body 130. However, the heat dissipation adhesive 133g is filled to about half to 80% of the fillable space volume of the adhesive reservoir region 131e, and is not filled to the limit of the fillable volume. Then, the conversion substrate 133 is inserted into the main body 130. At this time, the metal plate 135 and the lead-type heat-generating component 133h are pre-assembled to the converter board 133 and protrude toward the board-facing surface 131a1. Therefore, they are inserted into the heat-dissipating adhesive 133g filled in the adhesive reservoir area 131e of the main body 130. Next, the main body 130 with the converter board 133 inserted is placed in an oven to heat and harden the heat-dissipating adhesive 133g and the connection terminal fixing adhesive 134g. This heating also serves the purpose of drying the converter board 133 to prevent migration due to moisture absorption by the converter board 133. Then, the connection terminals 134a-c and the lead-type heat-generating component 133h are soldered to the converter board 133. Finally, a soldering inspection is performed to confirm proper soldering. If heat dissipation from the heat-generating component 133h via the heat-dissipating adhesive 133g is not performed, the process of filling the adhesive reservoir area 131e with the heat-dissipating adhesive 133g is omitted. However, even in this case, the heat curing step is necessary, and the connection terminal fixing adhesive 134g is heat cured.

[0052] <Pressure sensor assembly process> Next, the assembly process of the pressure sensor 100 will be described. First, the pressure detection unit 120 and the signal sending unit (main body) 130 are assembled as described above. Then, in the pressure detection unit 120, the liquid-sealed chamber 124A is filled with sealed oil via the oil filling pipe 129, and the oil filling pipe 129 is closed. Furthermore, the fluid introduction unit 110 is fixed to the pressure detection unit 120 by welding or the like. Thereafter, the multiple lead pins 128 of the pressure detection unit 120 and the conversion board 133 of the signal sending unit 130 are arranged in parallel so that they face upward, and one end of the flexible connecting wire 132 is joined to the multiple lead pins 128 and the surface of the metal plate 135 on the conversion board 133 by laser welding, respectively. Furthermore, the pressure detection unit 120 and the signal sending unit 130 are arranged opposite to each other on the same axis via a curved or bent flexible connecting wire 132, and an adhesive sheet 142 is sandwiched between the pressure detection unit 120 and the signal sending unit 130. Finally, one end side and the other end side of the caulking plate 141 are engaged with the base plate 112 of the fluid introduction unit 110 and the connector housing 131 of the signal sending unit 130, respectively, to integrally fix the fluid introduction unit 110, the pressure detection unit 120, and the signal sending unit 130.

[0053] If the pressure sensor 100 does not use the curved or bent flexible connecting wire 132, the assembly process of the pressure sensor 100 requires, for example, stacking from one end to the other end in the direction of the central axis C. This makes it difficult to shorten the assembly time because the degree of freedom in the assembly process is extremely low. However, in this embodiment, the pressure detection unit 120 and the signal transmission unit 130 are connected via the curved or bent flexible connecting wire 132, which increases the degree of freedom in the assembly process of the pressure sensor 100 and thereby shortens the assembly time.

[0054] <Other embodiments> Some other embodiments different from the above-described embodiments will be described with reference to Figures 3(a), (b) and 4. Note that the same reference numerals are used to designate the same components as those in the above-described embodiments, and descriptions thereof will be omitted.

[0055] FIG. 3(a) is a cross-sectional view showing a pressure sensor according to another embodiment of the present invention, and FIG. 3(b) is a cross-sectional view showing a pressure sensor according to yet another embodiment of the present invention. As shown in FIG. 3(a), in this embodiment, the converter substrate 233 is disposed parallel to the central axis C, i.e., parallel to the direction in which the signal sending unit 130 is adjacent to the pressure detection unit 120. The lead-type heat-generating component 233h has a lead 233l bent at a right angle, and its tip is inserted from the mounting surface 233b to the solder surface 233a through a through-hole provided in the converter substrate 233. The through-hole is soldered to connect the connection terminal 134a to the converter substrate 233. A land portion 233n is formed at the connection portion of the converter substrate 233, and is electrically connected to the metal plate 135 via a conductive pattern. In this embodiment, similarly to the above-described embodiment, one end and the other end of the flexible connecting wire material 132 are fixed to the plurality of lead pins 128 and the surface of the metal plate 135 on the conversion substrate 233 by laser welding, respectively. This provides the same effect as described above. The same applies to the conversion substrates 333 and 433 described below.

[0056] 3(b), in still another embodiment, the conversion board 333 is also arranged in a direction parallel to the direction in which the signal sending unit 130 is adjacent to the pressure detection unit 120. Furthermore, in the lead-type heat-generating component 333h, the lead 333l is bent at a right angle, and the tip thereof is further bent into an L-shape. The tip of this L-shaped bent lead 333l is soldered onto the mounting surface 333b of the conversion board 333, and a land portion 333n is formed.

[0057] Fig. 4 is a cross-sectional view showing a pressure sensor according to still another embodiment of the present invention. As shown in Fig. 4, in this embodiment, too, the conversion substrate 433 is arranged in a direction parallel to the direction in which the signal sending unit 130 is adjacent to the pressure detection unit 120. Furthermore, in the lead-type heat-generating component 433h, the leads 433l are parallel to the conversion substrate 433, and a portion of the leads 433l is attached to a pattern on the mounting surface 433b of the conversion substrate 433 with, for example, a conductive adhesive.

[0058] As described above, in another embodiment of the present invention, the conversion substrates 233, 333, and 433 are disposed in the direction in which the signal sending unit 130 is adjacent to the pressure detection unit 120, and therefore the area of ​​the portion facing the adhesive reservoir area 131e is extremely small compared to the conversion substrate 133. As a result, even if the lead-type heat-generating components 233h, 333h, and 433h are inserted into the adhesive reservoir area 131e and the heat-dissipating adhesive 133g spreads while swelling in a direction perpendicular to the direction in which the signal sending unit 130 and the pressure detection unit 120 are adjacent to each other, the heat-dissipating adhesive 133g will not drip onto the conversion substrates 233, 333, and 433. Furthermore, even if the heat-dissipating adhesive 133g creeps up due to surface tension, the heat-dissipating adhesive 133g can be prevented from dripping onto the conversion substrates 233, 333, and 433. Furthermore, even if the heat dissipating adhesive 133g overflows in a direction perpendicular to the direction in which the signal sending section 130 and the pressure detection section 120 are adjacent to each other, the heat dissipating adhesive 133g can be prevented from adhering to the land section 233n or 333n.

[0059] <Further Other Embodiments> Unlike the pressure sensor 100 described above, which connects to the outside using a connector housing 131 having connection terminals 134a-c, the pressure sensor of this embodiment connects to the outside using lead wires that pass through the upper cover and connect directly or indirectly to a conversion board or relay board, which is a signal transfer board, to exchange signals with the outside.

[0060] Fig. 5(a) is a diagram showing a pressure sensor 500 in which a lead wire 511 from the outside is connected to a conversion board 533 via a connection terminal 513, thereby exchanging signals between the pressure detection unit 120 and the outside, and Fig. 5(b) is a diagram showing a pressure sensor 600 in which a lead wire 611 from the outside is connected to a relay board via a connection terminal 613, thereby exchanging signals between the pressure detection unit 120 and the outside. Note that the same elements as those in the above embodiment are given the same numbers, and descriptions thereof will be omitted.

[0061] <Signal sending unit according to still another embodiment> In the embodiment shown in FIG. 5(a), the signal sending unit 530 sends a pressure signal detected by the pressure detection unit 120 to the outside. The signal sending unit 530 is disposed adjacent to the other end of the pressure detection unit 120 and includes a lead wire 511 for external connection and a flexible connecting wire 132, one end of which is connected to a plurality of lead pins 128. The other end of the connection terminal 513 is in contact with one end of the core wire 512 of the lead wire 511 so as to be electrically connected thereto, and is fixed to the lead wire 511 by soldering, ultrasonic welding, crimping, or the like. Signals are exchanged with an external circuit through the lead wire 511 and the connection terminal 513, which are electrically connected and fixed to each other. The signal sending unit 530 also includes a conversion board 533, which is a signal transfer board fixed to the upper cover 510 via the connection terminal 513, and the connection terminal 513, one end of which is connected to the conversion board 533. A terminal adhesive 513g is filled in the portion of the connection terminal 513, which is inserted into the upper cover 510 and connected to the conversion board 533, to fill the gap. By sealing the gap where the lead wire 511 inside the pressure sensor 500 passes with the terminal adhesive 513g, it is possible to prevent moisture from entering the upper cover 510 through the core wire 512 due to breathing inside the upper cover 510. Furthermore, the upper cover 510 and the pressure detection unit 120, which constitute the signal sending unit 530, are fixed by a waterproof case 515 and a sealant 516 that fills the gap between the waterproof case 515 and the upper cover 510. An opening 533f is formed in the conversion board 533 to avoid interference with the oil filling pipe 129. As in the previous embodiment, the flexible connecting wire 132 is connected to a metal plate 135 mounted on the conversion board 533 by laser welding or the like. In this way, by connecting to the outside via the lead wires 511, it is possible to provide a pressure sensor 500 with a connection form different from that of a connection using a connector. Note that with conventional connector types, there is a concern about moisture entering from the top surface of the connector, but by filling and sealing the entire portion of the pressure sensor 500 where the lead wires 511 are drawn out to the outside with a sealant 516 as in this embodiment, it is possible to improve the waterproofness of the portion where the lead wires 511 are drawn out to the outside.

[0062] The upper cover 510 is formed from an insulating resin or the like with a relatively high thermal conductivity, and has a substrate accommodating portion 510a with a concave shape on one end. The internal space S defined by the substrate accommodating portion 510a accommodates a plurality of lead pins 128 and an oil filling pipe 129 extending from the hermetic glass 124, a flexible connecting wire material 132, and a conversion substrate 533. Similar to the previous embodiment, a heat-generating component 533h is mounted on the conversion substrate 533, and a heat-dissipating adhesive 533g is filled around the periphery.

[0063] 5(b), the signal sending unit 630 has the same configuration as the signal sending unit 530, but the relay board 633 does not include a heat-generating component. Instead, the board accommodation section 610a above the relay board 633 has a space 633s. The relay board 633 is a signal transfer board that exchanges signals with the outside via the lead wires 611 and connection terminals 613, which are signal connection means, and relays signals from the pressure detection unit 120. In this way, the pressure detection unit 120 and the signal sending unit 630 are assembled separately and then connected and integrated with the flexible connecting material 132. This eliminates the need for a difficult process, such as directly connecting the lead pins 128 and the core wires 612 of the lead wires 611 in a narrow space, thereby improving workability and productivity.

[0064] <Signal sending unit according to still further embodiments> Fig. 6(a) is a diagram showing a pressure sensor 700 in which a lead wire 711 from the outside is directly connected to a conversion board 733 to exchange signals between the pressure detection unit 120 and the outside, and Fig. 6(b) is a diagram showing a pressure sensor 800 in which a lead wire 811 from the outside is directly connected to a relay board 833 to exchange signals between the pressure detection unit 120 and the outside. Note that the same elements as those in the above embodiment are given the same numbers and their explanations will be omitted.

[0065] As shown in FIG. 6( a), in this embodiment, within the signal transmission unit 730, the core 712 of the lead 711, which serves as a signal connection means, is directly connected to the converter board 733, which serves as a signal transmission board. The other end 712d of the core 712 penetrates the converter board 733, and the penetration portion of the core 712 is soldered to form a land portion 733n. By directly connecting the lead 711 to the converter board 733 in this manner, a connection terminal is not required, thereby reducing the number of components. Furthermore, the number of connection steps at two locations—between the converter board and the connection terminal, and between the connection terminal and the lead—can be halved, thereby shortening the manufacturing process. Furthermore, a sealing adhesive 712g is filled in the gap where the lead 711 is inserted into the upper cover 710, preventing moisture from entering the interior of the upper cover 710 via the core 712 due to the breathing inside the upper cover 710.

[0066] The configuration of the signal sending unit 830 of the embodiment shown in Fig. 6(b) is the same as that of the embodiment shown in Fig. 6(a). However, the signal transfer board of this embodiment is a relay board 833, which does not have any heat-generating components mounted thereon and relays signals from the pressure detection unit 120 to the outside via lead wires 811, which are signal connection means. In this way, the pressure detection unit 120 and the signal sending unit 830 are assembled separately and then connected and integrated with flexible connecting material 132, thereby eliminating the need for a difficult process such as directly connecting the lead pins 128 to the core wires 812 of the lead wires 811 in a narrow space, thereby improving workability and productivity.

[0067] <Pressure sensor assembly process> Next, a description will be given of the assembly process of the pressure sensors 500 to 800. Note that a description of the same steps as those for the pressure sensor 100 will be omitted.

[0068] The multiple lead pins 128 of the pressure detection unit 120 and the signal transfer board (conversion board or signal relay board) of the signal transmission units 530-830 are arranged in parallel so that they face upward, and one side and the other side of the flexible connecting wire 132 are joined by laser welding to the multiple lead pins 128 and the surface of the metal plate 135 on the signal transfer board. Furthermore, the pressure detection unit 120 and the signal transmission units 530-830 are arranged facing each other on the same axis via the curved or bent flexible connecting wire 132, and an adhesive sheet 142 is sandwiched between the pressure detection unit 120 and the signal transmission units 530-830. Then, the waterproof case 515-815 is attached from the pressure detection unit 120 side, and a sealant 516-816 is filled between the periphery of the upper cover 510-810 and the waterproof case 515-815, and this state is maintained until the sealant hardens. This allows the adhesive sheet 142, which is a sealing member, to be sandwiched and deformed sufficiently, maintaining a high sealing performance. Also, the flanges on the inside of the waterproof cases 515-815 and the base plate 112 are tightly attached to each other, preventing the sealing material 516-816 from leaking from the bottom. As a result, the fluid introduction section 110, the pressure detection section 120, and the signal transmission sections 530-830 are fixed together.

[0069] According to the above-described configuration, it is possible to provide a pressure sensor that can prevent ion migration from occurring and improve workability when joining flexible connecting wires. [Explanation of symbols]

[0070] 100 Pressure Sensor 110 Fluid introduction section 111 Joint members 112 base plate 120 Pressure detection unit 121 Housing 122 diaphragm 123 Protective Cover 124 Hermetic Glass 124A Liquid sealing chamber 125 Post 126 Semiconductor sensor chip 127 Potential adjustment material 128 lead pin 129 Oil filling pipe 130 Signal sending unit (main body) 131 Connector housing 131a Substrate storage section 131a1 Substrate facing surface 131b Connector connection part 131c Bulkhead 131e Adhesive pool area 131w Adhesive pool wall 132 Flexible Wire Connection Material 133 Conversion board 133a One end face 133b Other end face 133f opening 133g heat dissipating adhesive 133h Heat generating parts 133k Notch 133l Lead 133n Land Department 134a connection terminal 134b connection terminal 134c connection terminal 134d One end 134e Other end 134th floor step 135 Metal Plate 140 Connecting member 141 Caulking plate 142 adhesive sheet 151 Thermally radiating resin sheet 152 Thermally radiating adhesive 233 Conversion board 233a Solder surface 233b Mounting surface 233n Land Department 333 conversion board 333a Solder surface 333b Mounting surface 333n Land Department 433 conversion board 433a Solder surface 433b Mounting surface 510,610,710,810 Upper cover 510a, 610a, 710a, 810a Substrate accommodation section 511,611,711,811 lead wire 512,612,712,812 core wire 515,615,715,815 Waterproof Case 516,616,716,816 Encapsulants 530,630,730,830 Signal sending section 513 Connection terminal 513g Terminal Adhesive 533 conversion board 533h Heat generating parts 533g heat dissipation adhesive 613 Connection terminal 613g Terminal Adhesive 633 Relay board 712g sealing adhesive 733 Conversion Board 733h Heat generating parts 733g heat dissipation adhesive 812g sealing adhesive 833 Relay board C center axis L: Distance between the converter board and the housing in the direction of the central axis S interior space

Claims

1. a pressure detection unit including a pressure detection element for detecting the pressure of a fluid and an external input / output terminal for inputting and outputting signals to and from the pressure detection element; a signal transmission unit having a signal intermediate substrate that converts a signal from the external input / output terminal and that outputs the converted signal to an external circuit, A pressure sensor characterized in that a metal member is surface-mounted on the signal transfer substrate, and a flexible connecting material that electrically connects the signal transfer substrate and the external input / output terminal is connected to the metal member.

2. 2. The pressure sensor according to claim 1, wherein the metal member is a metal plate.

3. 3. The pressure sensor according to claim 1, wherein the flexible connecting wire is lap-welded to the metal member.

4. 4. The pressure sensor according to claim 3, wherein the flexible connecting wire has a conductive member made of stainless steel or nickel.

5. 3. The pressure sensor according to claim 1, wherein a connection land portion is formed on the signal transfer substrate, and the connection land portion and the metal member are electrically connected by a conductive pattern.

6. 4. The pressure sensor according to claim 3, wherein a connection land portion is formed on the signal transfer substrate, and the connection land portion and the metal member are electrically connected by a conductive pattern.

7. 5. The pressure sensor according to claim 4, wherein a connection land portion is formed on the signal transfer substrate, and the connection land portion and the metal member are electrically connected by a conductive pattern.

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