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 provided with a conversion substrate inside.

Background Art

[0002] Conventionally, in order to conform to various drive voltages and signal formats of pressure detection signals, there is a pressure sensor in which a conversion substrate having a conversion circuit for converting both a drive voltage and a pressure detection signal is externally connected between a control circuit and the pressure sensor.

[0003] In such a pressure sensor, in order to solve problems such as the possibility of connection failure due to external impact or vibration, there is a type in which a cable is omitted and the conversion substrate is disposed inside the pressure sensor. However, the conversion substrate self-heats due to voltage transformation of the drive voltage or the like. Therefore, when the conversion substrate is disposed inside the pressure sensor, it is desirable to efficiently dissipate the heat generated in the conversion substrate and suppress the heat transmitted to the conversion substrate. If these are not effectively implemented, problems such as the electronic components on the conversion substrate exceeding the heat-resistant temperature and being damaged will occur.

[0004] As a configuration for suppressing the heat transmitted to the conversion substrate, FIG. 1 of Patent Document 1 describes that an internal space S is provided to suppress the influence of heat on the conversion substrate 133 in order to suppress the heat transfer from the semiconductor sensor chip 126 side to the conversion substrate 133.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the above configuration described in Patent Document 1, a flexible wiring material 132 is used to connect the conversion substrate 133 and the lead pins 128 on the semiconductor sensor chip 126 side. And since the connection between the flexible wiring material 132 and the connection terminal 134 of the conversion substrate 133 is performed by soldering, there is a risk of causing a short circuit due to the occurrence of ion migration (CAF) between the terminals on the surface of the conversion substrate. Also, soldering takes time for bonding, and furthermore, workability deteriorates because the soldering space is narrow.

[0007] An object of the present invention is to provide a pressure sensor capable of preventing the occurrence of ion migration and improving workability in the bonding of a flexible wiring material.

Means for Solving the Problems

[0008] In order to solve the above problems, the pressure sensor includes 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 intermediate substrate that converts the signal from the external input / output terminal, and a signal transmission unit that outputs the converted signal to an external circuit. A metal member is surface-mounted on the signal intermediate substrate, and a flexible wiring material that electrically connects the signal intermediate substrate and the external input / output terminal is connected to the metal member.

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

[0010] Also, in the above pressure sensor, the flexible wiring material may be lap-welded to the metal member.

[0011] Also, in the above pressure sensor, the flexible wiring material may have a conductive member made of stainless steel or nickel.

[0012] Also, a connection land portion may be formed on the signal intermediate substrate, and the connection land portion and the metal member may be electrically connected by a conductive pattern.

Effects of the Invention

[0013] According to the present invention, in the joining of flexible connection wires, it is possible to provide a pressure sensor that can prevent the occurrence of ion migration and improve workability.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

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

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

[0017] <Term> In the description of this specification and the claims, "one end" and "the other end" indicate "the lower end" and "the upper end" in the drawing.

[0018] <Configuration of Pressure Sensor> The pressure sensor 100 according to an embodiment of the present invention will be described with reference to FIG. 1.

[0019] The pressure sensor 100 is composed of a fluid introduction part 110, a pressure detection part 120, a signal transmission part (main body) 130, and a connection member 140. Hereinafter, each configuration of the pressure sensor 100 will be described in order. Note that the pressure sensor 100 joins and fixes the fluid introduction part 110 and the pressure detection part 120, electrically connects the pressure detection part 120 and the signal transmission part 130, and then integrally assembles the fluid introduction part 110, the pressure detection part 120, and the signal transmission part 130 by the connection member 140.

[0020] <Fluid Introduction Part> The fluid introduction part 110 introduces the fluid to be pressure-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 joint member 111 includes a female screw portion 111a connected to a pipe (not shown) into which the fluid to be pressure-detected is introduced, 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 at the center of the base plate 112. In the present embodiment, the joint member 111 is provided with a female screw portion 111a, but is not limited thereto. For example, it may be provided with a male screw portion, or instead of the joint member 111, a copper connection pipe may be connected.

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

[0023] <Pressure detection unit> The pressure detection unit 120 detects the pressure of the fluid in the pressure chamber 112A, and includes a housing 121 having a through hole, a diaphragm 122 that partitions the above-described pressure chamber 112A and a liquid seal chamber 124A described later, and a protective cover 123 disposed on the pressure chamber 112A side of the diaphragm 122. Further, the pressure detection unit 120 includes a hermetic glass 124 sealed inside the through hole of the housing 121, a liquid seal chamber 124A filled with a sealing oil between a recess on the pressure chamber 112A side of the hermetic glass 124 and the diaphragm 122, and a support column 125 disposed at the center of the hermetic glass 124. Furthermore, the pressure detection unit 120 includes a semiconductor sensor chip 126 supported by the support column 125 and disposed inside the liquid seal chamber 124A, a potential adjustment member 127 disposed around the liquid seal 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 formed of a metallic material such as an Fe—Ni alloy or stainless steel in order to maintain the strength around the hermetic glass 124. The diaphragm 122 and the protective cover 123 are both formed of a metallic material and are both welded at the outer peripheral edge 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 part 110 passes. After the pressure detection part 120 is assembled, the housing 121 is welded from the outside by TIG welding, plasma welding, laser welding or the like at the outer peripheral edge of the base plate 112 of the fluid introduction part 110.

[0025] The hermetic glass 124 protects the liquid seal chamber 124A in which the semiconductor sensor chip 126 is liquid-sealed from ambient environmental conditions such as moisture, dust, and heat in the air, holds the plurality of lead pins 128, and is provided to insulate the plurality of lead pins 128 from the housing 121. The semiconductor sensor chip 126 is supported on the liquid seal chamber 124A side of the support column 125 disposed at the center of the hermetic glass 124 by an adhesive or the like. In the present embodiment, the support column 125 is formed of an Fe—Ni alloy, but is not limited thereto. For example, it may be formed of other metallic materials such as stainless steel, or may be configured to be directly supported on the flat surface forming the recess of the hermetic glass 124 without providing the support column 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 having a piezoresistive effect (such as single crystal silicon, etc.) inside, a plurality of semiconductor strain gauges formed on the diaphragm, a bridge circuit in which these semiconductor strain gauges are bridge-connected, and an amplifier circuit that processes the output from the bridge circuit, and an integrated circuit such as an arithmetic processing circuit. Further, the semiconductor sensor chip 126 is connected to a plurality of lead pins 128 by bonding wires 126a made of, for example, gold or aluminum, and the plurality of lead pins 128 constitute external input / output terminals of the semiconductor sensor chip 126. Note that the semiconductor sensor chip 126 is not limited to this example, and also includes a form in which the bridge circuit section using strain gauges is separated from the amplifier circuit and the arithmetic processing circuit section.

[0027] The potential adjustment member 127 is provided to place the semiconductor sensor chip 126 in a non-electric field (zero potential) so that circuits inside the chip are not adversely affected by the potential generated between the frame ground and the secondary power supply. The potential adjustment member 127 is disposed between the semiconductor sensor chip 126 and the diaphragm 122 in the liquid seal chamber 124A, is formed of a conductive material such as metal, and is connected to a terminal connected to the zero potential of the semiconductor sensor chip 126.

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

[0029] The oil filling pipe 129 is provided for filling the inside of the liquid seal chamber 124A with encapsulated oil (for example, silicone oil, fluorine-based inert liquid, etc.). Note that after the oil filling, the other end of the oil filling pipe 129 is crushed and blocked as shown in FIG. 1.

[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 from the joint member 111 into the pressure chamber 112A. The pressure of the pressure chamber 112A applied to this diaphragm 122 is transmitted to the semiconductor sensor chip 126 through the encapsulated oil in the liquid seal chamber 124A. Due to this transmitted pressure, the silicon diaphragm of the semiconductor sensor chip 126 deforms, and the pressure is converted into an electrical signal by a bridge circuit using piezoresistive elements, and is output from the integrated circuit of the semiconductor sensor chip 126 to the signal transmission unit 130 through the bonding wire 126a and a plurality of lead pins 128.

[0031] <Signal transmission unit> The signal transmission unit (main body) 130 is for sending the pressure signal detected by the pressure detection unit 120 to the outside, and includes a connector housing 131 for external connection disposed adjacent to the other end side of the pressure detection unit 120, and a flexible connection wire 132 having one end connected to a plurality of lead pins 128. Further, the signal transmission unit 130 includes a conversion board 133 which is a signal mediation board for mediating signals with an external circuit fixed to the connector housing 131 through three connection terminals, and connection terminals 134a to 134c having one end portion penetratingly connected to the conversion board 133. Note that an opening 133f is formed in this conversion board 133 to avoid interference with the oil filling pipe 129.

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

[0033] The conversion substrate 133 includes a conversion circuit (not shown) that converts both the drive voltage and the pressure detection signal in order to correspond to the signal formats of the drive voltage and the pressure detection signal. This conversion circuit steps down the drive voltage (for example, 8V to 36V) of a control circuit (not shown) connected to the outside of the pressure sensor 100 to the drive voltage (for example, 5.0V) of the semiconductor sensor chip 126 through connection terminals 134a to c, and steps up the pressure detection signal (for example, 0.5V to 4.5V) of the pressure sensor 100 to the pressure detection signal (for example, 1V to 5V) of the control circuit through a voltage shift circuit portion (not shown). In this way, by appropriately selecting the conversion substrate 133 provided in the pressure sensor 100 corresponding to the signal formats of the drive voltage and the pressure detection signal, it is possible to absorb the difference between the drive voltage and the pressure detection signal without changing the design of the pressure detection unit 120, particularly the semiconductor sensor chip 126 and the peripheral structure of the liquid seal chamber 124A. By using a conversion substrate that performs the input / output signal conversion process in this way, it is not necessary to prepare semiconductor sensor chips corresponding to various input / output forms, and since it is possible to make changes corresponding to the specifications of the conversion substrate, it is possible to respond to a suitable production method in terms of parts procurement, manufacturing process, cost reduction, etc. Note that even if the input / output form of the pressure sensor does not match the control circuit side, if the control circuit side can perform the input / output conversion process when connected, a circuit with an input / output conversion function on the substrate side is unnecessary.

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

[0035] <Connection member> The connection member 140 includes a caulking plate 141 that caulks and fixes the fluid introduction portion 110, the pressure detection portion 120, and the signal transmission portion 130 by caulking, and an adhesive sheet 142 disposed between the pressure detection portion 120 and the signal transmission portion 130.

[0036] The caulking plate 141 is formed in a cylindrical shape from a metal such as copper. The caulking plate 141 is disposed around the fluid introduction section 110, the pressure detection section 120, and the signal transmission section 130, and is fixed to the fluid introduction section 110 and the signal transmission section 130 by caulking. By this caulking, the adhesive sheet 142 is sandwiched between the pressure detection section 120 and the signal transmission section 130 in order to perform a waterproof and dustproof function. Note that between the adhesive sheet 142 and the housing 121, a non-metallic resin sheet 151 having heat radiation and an adhesive 152 having heat radiation may be sandwiched as means for suppressing heat transfer to the conversion substrate 133. Further, the structure of the caulked portion is not limited to the above method. For example, as shown in FIG. 11 of Patent Document 2, a structure may be adopted in which the fluid introduction section 110 integrally formed so as to accommodate the housing 121 and the connector housing 131 is caulked by the open end on the connector housing 131 side. That is, any structure may be used as long as the adhesive sheet 142 is sandwiched between the housing 121 and the connector housing 131 and compressed and fixed by caulking or the like.

[0037] <Heat dissipation means for the conversion substrate> The conversion substrate 133 includes an other end surface 133b on which various electronic components are mounted and which is separated from the connector housing 131, and one end surface 133a to which connection terminals 134a to 134c and the like are soldered. The heat generating component 133h (for example, a component having a potential difference between input and output terminals and through which a current flows, such as a transistor or a regulator) in the present embodiment is of a lead type and is mounted on the other end surface 133b. Since this conversion substrate 133 self-heats due to transformation of the drive voltage or the like, if no measures are taken against this, there is a risk that the electronic components on the conversion substrate will reach a temperature higher than the heat resistant temperature and be damaged. Therefore, in the present embodiment, various heat dissipation means for the conversion substrate 133 are adopted so that the electronic components of the conversion substrate 133 do not reach a temperature higher than the heat resistant temperature. Thereby, since the heat generated in the conversion substrate 133 can be efficiently dissipated to the external environment, the margin with respect to the heat resistant temperature of the conversion substrate 133 can be improved. Hereinafter, the heat dissipation means of the conversion substrate 133 in the present embodiment will be specifically described.

[0038] <Heat dissipation means of the conversion substrate (lead type heat generating component)> As the heat dissipation means of the conversion substrate 133, a lead type heat generating component 133h is used so as to constitute the heat dissipation path (1) with a broken line in FIG. 1. The lead type heat generating component 133h is provided on the substrate facing surface 131a1 side. Since the periphery of this heat generating component 133h is filled with a heat conductive heat dissipating adhesive 133g, in order to prevent this heat dissipating adhesive 133g from spreading onto the conversion substrate, an adhesive reservoir wall surface 131w is provided to define an adhesive reservoir region 131e between the outer peripheral portion of the connector housing 131. That is, in the present embodiment, the adhesive reservoir region 131e is defined by the adhesive reservoir wall surface 131w and the substrate accommodating portion 131a and the partition portion 131c of the main body 130. The lead type heat generating component 133h is accommodated in this adhesive reservoir region 131e, and only between the adhesive reservoir region 131e and the lead type heat generating component 133h, the heat conductive heat dissipating adhesive 133g is filled. Thereby, in the present embodiment, in order to actively transfer the heat generated in the heat generating component 133h to the heat conductive heat dissipating adhesive 133g surrounding the periphery of the heat generating component 133h, it is possible to dissipate heat more efficiently to the external environment through the connector housing 131.

[0039] Also, as shown in FIGS. 2(a) and 2(b), a notch portion 133k is provided in a portion of the conversion substrate 133 where the heat dissipating adhesive 133g may climb up along the adhesive reservoir wall surface 131w due to surface tension. Thereby, the distance between the conversion substrate 133 and the inner wall of the main body 130 can be widened, and the heat dissipating adhesive 133g that swells and spreads in a direction orthogonal to the direction in which the signal transmission portion 130 and the pressure detection portion 120 are adjacent can be prevented from climbing up along the adhesive reservoir wall surface 131w due to surface tension. Further, by providing the notch portion 133k up to the vicinity of the land portion 133n of the conversion substrate 133, even if the heat dissipating adhesive 133g that overflows in a direction orthogonal to the direction in which the signal transmission portion 130 and the pressure detection portion 120 are adjacent drips onto the substrate, it is possible to prevent the heat dissipating adhesive 133g from adhering to the land portion 133n.

[0040] And since the lead-type heat-generating component 133h is mounted on the conversion substrate 133 via the lead 133l, physically, the heat-generating part of the heat-generating component 133h is separated from the conversion substrate 133, thereby suppressing the temperature of the electronic components on the conversion substrate 133 from exceeding the heat-resistant 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 closer to the outside air. As a result, the heat-dissipating adhesive 133g filled around the lead-type heat-generating component 133h can more easily 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 substrate 133, heat transfer between the heat-generating component 133h and the conversion substrate 133 can be suppressed.

[0043] <Heat transfer suppression means> Although the fluid to be pressure-detected is introduced into the pressure chamber 112A, depending on the usage conditions of the fluid, a very high-temperature fluid (for example, about 130 (°C)) may be introduced and serve as a heat source. At this time, the heat on the pressure detection unit 120 side (such as the heat of the high-temperature fluid introduced into the pressure chamber 112A) may be transferred to the conversion substrate 133 by heat transfer (heat transfer, heat conduction, and heat radiation (radiation) from one end side to the other end side in FIG. 1), and thus the heat dissipation effect using the heat dissipation means (lead-type heat-generating component) may be offset. Therefore, in the present embodiment, various heat transfer suppression means are adopted so that the heat on the pressure detection unit 120 side (such as the heat of the high-temperature fluid introduced into the pressure chamber 112A) does not transfer to the conversion substrate 133. As a result, in the present embodiment, the heat on the pressure detection unit 120 side can be suppressed from transferring to the conversion substrate 133, so that the heat dissipation effect using the heat dissipation means (lead-type heat-generating component) can be sufficiently achieved. Hereinafter, the heat transfer suppression means for the conversion substrate 133 in the present embodiment will be specifically described.

[0044] <First heat transfer suppression means to the conversion substrate (internal space)> As the first heat transfer suppression means to the conversion substrate 133, the internal space S is used. Specifically, by providing the conversion substrate 133 near the other end of the substrate housing portion 131a, the distance L in the central axis C direction between the conversion substrate 133 and the housing 121 on the pressure detection unit 120 side in the internal space S can be set as large as possible. Thereby, in the present embodiment, since the heat on the pressure detection unit 120 side passes through the internal space S of air with a long heat transfer path and low thermal conductivity, heat transfer to the conversion substrate 133 can be suppressed. However, the conversion substrate 133 and the other end of the substrate housing portion 131a are not in direct contact as described in the next section.

[0045] <Second heat transfer suppression means to the conversion substrate (separation from the main body of the conversion substrate)> As shown in FIG. 1, the conversion substrate 133 is provided at a distance from the other end and the outer periphery of the substrate housing portion 131a so as not to be in direct contact with the connector housing 131. Instead of being directly supported by the connector housing 131, as shown in FIGS. 2(a) and (b), it is supported at three points by three connection terminals 134a to 134c. These three connection terminals 134a to 134c are provided so as to be located on the center side of the conversion substrate 133 where a load is particularly applied when soldering the connection terminals 134a to 134c to the conversion substrate 133. Also, as shown in FIG. 1, the three connection terminals 134a to 134c do not have a linear structure but have a structure with a step 134f, and the conversion substrate 133 can be received at the portion of the step 134f. The position of this step 134f is set to a height that does not contact the connector housing 131 so that, as described above, the conversion substrate 133 is supported at three points when the conversion substrate 133 is housed in the connector housing 131. With such a structure, even when a load is applied during soldering, the conversion substrate 133 is less likely to tilt with respect to the connection terminals 134a to 134c and can be arranged in a well-balanced manner, and the movement of the conversion substrate 133 in the direction of the connector housing 131 (upward direction) is suppressed and it is configured to be firmly supported by the connection terminals 134a to 134c. Further, as shown in FIG. 1, the connection terminals 134a to 134c 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 conversion substrate 133 is fixed to the connector housing 131 with a heat-dissipating adhesive 133g, thereby indirectly fixing the conversion substrate 133 to the connector housing 131. In this way, since the conversion substrate 133 is provided at a distance from the other end of the substrate housing portion 131a so as not to be in direct contact with the connector housing 131, the heat transmitted from the lead-type heat-generating component 133h to the surrounding heat-dissipating adhesive 133g can be suppressed from being transmitted to the conversion substrate 133.

[0046] In addition to the above, since the side portion of the conversion substrate 133 is provided so as to be separated from the outer periphery of the substrate housing portion 131a, it is possible to prevent the stress applied from the connector housing 131 to the conversion substrate 133 caused by the difference in the coefficient of linear expansion due to heat between the conversion substrate 133 and the connector housing 131. Thereby, it is possible to prevent the conversion substrate 133 from being damaged due to the stress applied from the connector housing 131 to the conversion substrate 133 caused by the difference in the coefficient of linear expansion.

[0047] <Third heat transfer suppression means (flexible connection wire) for the conversion substrate> The above-described flexible connection wire 132 is used as a third heat transfer suppression means for the conversion substrate 133. Specifically, the flexible connection wire 132 is formed of, for example, a flexible printed circuit board (FPC) having flexibility, a thin plate-shaped conductive member, a single lead wire, an aggregate of lead wires, etc., and in the internal space S, it is curved or bent and connects between the plurality of lead pins 128 and the metal plate 135. Therefore, the connection distance between the plurality of lead pins 128 and the metal plate 135 can be set relatively large. Also, the flexible connection wire 132 is thinner than a normal wiring material and has a smaller cross-sectional area. Thereby, in the present embodiment, since the heat on the semiconductor sensor chip 126 side passes through the flexible connection wire 132 having a long heat transfer path and the cross-sectional area is made small, it is possible to suppress the heat conduction to the conversion substrate 133.

[0048] <Joining of the flexible connection wire to the metal plate> FIG. 2 is a schematic view showing a pressure sensor main body according to an embodiment of the present invention. FIG. 2(a) is a perspective view showing the pressure sensor main body after the substrate is installed, and FIG. 2(b) is a plan view showing the pressure sensor main body after the substrate is installed. Note that FIG. 2(a) shows a part of the connector housing 131 cut away so that the inside of the main body can be seen.

[0049] As shown in FIGS. 2(a) and 2(b), the aforementioned metal plate 135 is a surface-mounting metal member, formed from a copper alloy such as copper, phosphor bronze, brass, or nickel silver, and preferably plated with tin, gold, or the like. The metal plate 135 is surface-mounted on the conversion substrate 133, and the flexible wiring member 132 is connected by welding. Here, since the metal plate 135 is a surface-mounting component that does not require through-holes in the substrate, the welding of the flexible wiring member 132 to the metal plate 135 may be performed by other welding methods such as soldering, similar to when mounting on the substrate. In the case of laser welding, since the metal plate 135 is made of a copper alloy, has a high thermal conductivity, and is easy to reflect light, the workability of laser welding is not good as it is. Therefore, the material of the conductive member of the flexible wiring member 132 is made of stainless steel or nickel, which has good laser welding workability, and after being installed on the metal plate 135, the flexible wiring member 132 is irradiated with a laser to join (overlay weld) the metal plate 135 and the flexible wiring member 132.

[0050] In this way, by laser-welding the flexible wiring member 132 to the metal plate 135, soldering is no longer required, and the occurrence of ion migration between the terminals on the surface of the conversion substrate 133 can be prevented. Also, the joining time between the flexible wiring member 132 and the metal plate 135 can be shortened, and joining is possible even in a narrow working space. Furthermore, by performing overlay welding, melting of the intermediate layer of the conversion substrate 133, which is a laminated substrate by laser welding, can be prevented. And as described above, since the metal plate 135 is a metal material with a high thermal conductivity, it can partially receive heat dissipation from the mounted conversion substrate 133. In this embodiment, the conversion substrate 133 is a four-layer laminated substrate, but it is not limited to this, and it may be a single-layer single-sided substrate or double-sided substrate. Also, in this embodiment, the metal plate 135 is used, but it is not limited to this, and jumper wires, jumper pins, or the like may be used.

[0051] <Assembly process of the main body> In the assembly process of the main body 130, first, three connection terminals 134a to 134c are inserted into the main body 130. Then, as shown in FIG. 1, a connection terminal fixing adhesive 134g is applied (filled) around the connection terminals 134a to 134c so that the inserted connection terminals 134a to 134c are fixed to the main body 130. However, the applied thickness is determined so that the connection terminal fixing adhesive 134g does not adhere to the conversion substrate 133. Next, similarly as shown in FIG. 1, a heat-dissipating adhesive 133g is filled in the adhesive reservoir region 131e of the main body 130. However, the filling of the heat-dissipating adhesive 133g is set to about half to 80% of the fillable space volume of the adhesive reservoir region 131e, and it is not filled up to the limit of the fillable volume. Then, the conversion substrate 133 is inserted into the main body 130. At this time, since the metal plate 135 and the lead-type heat-generating component 133h are previously assembled to the conversion substrate 133 and protrude on the substrate facing surface 131a1 side, they are inserted into the heat-dissipating adhesive 133g filled in the adhesive reservoir region 131e of the main body 130. Next, the main body 130 with the conversion substrate 133 inserted is put into an oven and heated to cure the heat-dissipating adhesive 133g and the connection terminal fixing adhesive 134g. This heating also includes the purpose of drying the conversion substrate 133 to prevent migration due to moisture absorption of the conversion substrate 133. Then, the connection terminals 134a to 134c and the lead-type heat-generating component 133h are soldered to the conversion substrate 133. Finally, a solder inspection is performed to check whether the soldering is proper. Note that if heat dissipation through the heat-dissipating adhesive 133g of the heat-generating component 133h is not performed, the step of filling the heat-dissipating adhesive 133g into the adhesive reservoir region 131e is omitted. However, even in this case, the heat-curing process is necessary, and the connection terminal fixing adhesive 134g is heat-cured.

[0052] <Assembly Process of Pressure Sensor> Next, the assembly process of the pressure sensor 100 will be described. First, the pressure detection unit 120 and the signal transmission unit (main body) 130 are assembled as described above. Then, in the pressure detection unit 120, the sealed oil is filled into the liquid seal chamber 124A through the oil filling pipe 129, and the oil filling pipe 129 is closed. Further, the fluid introduction unit 110 is fixed to the pressure detection unit 120 by welding or the like. After that, a plurality of lead pins 128 of the pressure detection unit 120 and the conversion board 133 of the signal transmission unit 130 are arranged in parallel so as to face upward, and one side and the other side of the flexible connection member 132 are respectively joined to the surfaces of the plurality of lead pins 128 and the metal plate 135 on the conversion board 133 by laser welding. Further, the pressure detection unit 120 and the signal transmission unit 130 are arranged to face each other on the same axis via the curved or bent flexible connection member 132, and an adhesive sheet 142 is sandwiched between the pressure detection unit 120 and the signal transmission 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 transmission unit 130 respectively, and the fluid introduction unit 110, the pressure detection unit 120, and the signal transmission unit 130 are integrally fixed.

[0053] Here, in the pressure sensor 100, when the curved or bent flexible connection member 132 is not adopted, the assembly process of the pressure sensor 100 needs to be assembled, for example, stacked from one end side to the other end side in the direction of the central axis C. Therefore, since the degree of freedom of the assembly process is extremely low, it has been difficult to shorten the assembly time. However, in the present embodiment, by connecting between the pressure detection unit 120 and the signal transmission unit 130 via the curved or bent flexible connection member 132, the degree of freedom of the assembly process of the pressure sensor 100 can be increased, so that the assembly time can be shortened.

[0054] <Other Embodiments> Some other embodiments different from the above-described embodiments will be described with reference to FIGS. 3(a), (b) and 4. The same components as those in the above-described embodiments are denoted by the same reference numerals, and the description 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 still another embodiment of the present invention. As shown in FIG. 3(a), in the present embodiment, the conversion substrate 233 is arranged parallel to the central axis C, that is, in a direction parallel to the direction in which the signal transmission unit 130 is adjacent to the pressure detection unit 120. Further, in the lead type heating component 233h, the lead 233l portion is bent at a right angle, and its tip is inserted into a through hole provided in the conversion substrate 233 from the mounting surface 233b to the solder surface 233a, and this through portion is soldered to connect the connection terminal 134a to the conversion substrate 233. A land portion 233n is formed at the connection portion of the conversion substrate 233 and is electrically connected by the metal plate 135 and the conductive pattern. Also in the present embodiment, as in the above-described embodiment, one and the other of the flexible connection wires 132 are fixed by laser welding on the surfaces of the plurality of lead pins 128 and the metal plate 135 on the conversion substrate 233, respectively. Thereby, the same effect as described above can be obtained. The same applies to the conversion substrates 333 and 433 described later.

[0056] As shown in FIG. 3(b), also in still another embodiment, the conversion substrate 333 is arranged in a direction parallel to the direction in which the signal transmission unit 130 is adjacent to the pressure detection unit 120. Further, in the lead type heating component 333h, the lead 333l is bent at a right angle, and further, its tip is bent in an L shape. The tip of the lead 333l bent in the L shape is soldered on the mounting surface 333b of the conversion substrate 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, also in this embodiment, the conversion substrate 433 is arranged in a direction parallel to the direction in which the signal transmission unit 130 is adjacent to the pressure detection unit 120. Further, in the lead-type heating component 433h, the lead 433l is parallel to the conversion substrate 433, and a part of the lead 433l is attached to a pattern on the mounting surface 433b of the conversion substrate 433 with, for example, a conductive adhesive or the like.

[0058] Thus, in other embodiments of the present invention, since the conversion substrates 233, 333, 433 are arranged in the direction in which the signal transmission unit 130 is adjacent to the pressure detection unit 120, the area of the portion facing the adhesive reservoir region 131e is extremely small compared to the conversion substrate 133. Thereby, the lead-type heating components 233h, 333h, 433h are respectively inserted into the adhesive reservoir region 131e, and even if the heat-dissipating adhesive 133g swells and spreads in a direction orthogonal to the direction in which the signal transmission unit 130 and the pressure detection unit 120 are adjacent, the heat-dissipating adhesive 133g does not drip onto the conversion substrates 233, 333, 433. Further, even if the heat-dissipating adhesive 133g crawls up due to surface tension, it is possible to prevent the heat-dissipating adhesive 133g from dripping onto the conversion substrates 233, 333, 433. Furthermore, even if the heat-dissipating adhesive 133g overflows in a direction orthogonal to the direction in which the signal transmission unit 130 and the pressure detection unit 120 are adjacent, it is possible to prevent the heat-dissipating adhesive 133g from adhering to the land portions 233n or 333n.

[0059] <Still Another Embodiment> Unlike the pressure sensor 100 described above that makes an external connection using the connector housing 131 having the connection terminals 134a to 134c, in the pressure sensor of this embodiment, the external connection is made by inserting an upper cover and using a lead wire that directly or indirectly communicates signals with an external device by directly or indirectly connecting to a conversion substrate or a relay substrate that is a signal intermediary substrate.

[0060] FIG. 5(a) is a diagram showing a pressure sensor 500 in which an external lead wire 511 is connected to a conversion substrate 533 via a connection terminal 513 to exchange signals between the pressure detection unit 120 and the outside, and FIG. 5(b) is a diagram showing a pressure sensor 600 in which an external lead wire 611 is connected to a relay substrate via a connection terminal 613 to exchange signals between the pressure detection unit 120 and the outside. Note that the same elements as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0061] <Signal transmission unit according to still another embodiment> In the embodiment shown in FIG. 5(a), the signal transmission unit 530 transmits the pressure signal detected by the pressure detection unit 120 to the outside. It is arranged adjacent to the other end side of the pressure detection unit 120 and includes an external connection lead wire 511 and a flexible connection member 132 having one end connected to a plurality of lead pins 128. The connection terminal 513 contacts the other end side so as to be electrically connected to one end side of the core wire 512 of the lead wire 511, and is fixed to the lead wire 511 by soldering, ultrasonic welding, caulking, or the like. Through the lead wire 511 and the connection terminal 513 that are electrically connected and fixed to each other, signal exchange with an external circuit is performed. Further, the signal transmission unit 530 includes a conversion substrate 533 that is a signal medium substrate fixed to the upper cover 510 via the connection terminal 513, and a connection terminal 513 having one end portion penetratingly connected to the conversion substrate 533. The portion of the connection terminal 513 penetratingly connected to the conversion substrate 533 and inserted into the upper cover 510 is filled with a terminal adhesive 513g so as to fill the gap. In this way, by sealing the gap in the portion through which the lead wire 511 inside the pressure sensor 500 passes with the terminal adhesive 513g, it is possible to prevent moisture from entering the inside of the upper cover 510 through the core wire 512 due to the breathing action inside the upper cover 510. Furthermore, the upper cover 510 and the pressure detection unit 120 constituting the signal transmission unit 530 are fixed by a waterproof case 515 and a sealing material 516 filled in the gap between the waterproof case 515 and the upper cover 510. Note that an opening 533f is formed in the conversion substrate 533 to avoid interference with the oil filling pipe 129. Also, similar to the above-described embodiment, the flexible connection member 132 is connected to a metal plate 135 mounted on the conversion substrate 533 by laser welding or the like. In this way, by connecting to the outside with the lead wire 511, it is possible to provide the pressure sensor 500 with a connection form different from that by a connector. Note that in the conventional connector type, there is a concern about moisture intrusion from the upper surface of the connector, but by filling and sealing the entire portion where the lead wire 511 of the pressure sensor 500 is drawn out to the outside with the sealing material 516 as in this embodiment, the waterproof property of the portion where the lead wire 511 is drawn out to the outside can be improved.

[0062] The upper cover 510 is formed of an insulating resin or the like having a relatively high thermal conductivity, and has a substrate accommodating portion 510a having a concave shape on one end side. In the internal space S defined by the substrate accommodating portion 510a, a plurality of lead pins 128 and an oil filling pipe 129 extending from the hermetic glass 124, a flexible connection member 132, a conversion substrate 533, and the like are arranged. A heat generating component 533h is mounted on the conversion substrate 533 as in the above embodiment, and a heat dissipation adhesive 533g is filled around it.

[0063] On the other hand, in the embodiment shown in FIG. 5(b), the signal transmission unit 630 has the same configuration as the signal transmission unit 530. However, the relay substrate 633 does not include a heat generating component. Instead, the substrate accommodating portion 610a above the relay substrate 633 has a space 633s. The relay substrate 633 is a signal intermediate substrate that exchanges signals with the outside through lead wires 611 and connection terminals 613, which are signal connection means, and relays the signal from the pressure detection unit 120. In this way, by separately assembling the pressure detection unit 120 and the signal transmission unit 630 and connecting and integrating them with the flexible connection member 132, it is possible to improve workability and productivity because it is not necessary to go through a difficult process such as directly connecting the core wire 612 of the lead pin 128 and the lead wire 611 in a narrow space.

[0064] <Furthermore, a signal transmission unit according to a further embodiment> FIG. 6(a) is a diagram showing a pressure sensor 700 that directly connects a lead wire 711 from the outside to a conversion substrate 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 that directly connects a lead wire 811 from the outside to a relay substrate 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 denoted by the same reference numerals, and the description thereof is omitted.

[0065] As shown in Fig. 6(a), in this embodiment, within the signal transmission unit 730, the core wire 712 of the lead wire 711, which is the signal connection means, is directly connected to the conversion substrate 733, which is the signal medium substrate. The other end 712d of the core wire 712 penetrates the conversion substrate 733, and the penetrated portion of the core wire 712 is soldered to form a land portion 733n. In this way, by directly connecting the lead wire 711 to the conversion substrate 733, connection terminals are not required, and the number of components can be reduced. Also, since the two connection processes of the conversion substrate and the connection terminal, and the connection terminal and the lead wire can be halved, the manufacturing process can be shortened. And, the portion where the lead wire 711 is inserted into the upper cover 710 is filled with a sealing adhesive 712g to fill the gap, and moisture intrusion into the upper cover 710 through the core wire 712 due to the breathing action inside the upper cover 710 can be prevented.

[0066] The configuration of the signal transmission 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 medium substrate of this embodiment is the relay substrate 833, no heat-generating components are mounted, and it relays the signal from the pressure detection unit 120 to the outside through the lead wire 811, which is the signal connection means. In this way, by separately assembling the pressure detection unit 120 and the signal transmission unit 830 and connecting and integrating them with the flexible wiring material 132, difficult processes such as directly connecting the lead pin 128 and the core wire 812 of the lead wire 811 in a narrow space can be avoided, so that workability can be improved and productivity can be enhanced.

[0067] <Assembly process of the pressure sensor> Next, the assembly process of the pressure sensors 500 to 800 will be described. Note that the processes similar to those of the aforementioned pressure sensor 100 will be omitted from the description.

[0068] Arrange the plurality of lead pins 128 of the pressure detection unit 120 and the signal medium substrates (conversion substrates or signal relay substrates) of the signal transmission units 530 to 830 in parallel so that they face upward, and laser-weld one side and the other side of the flexible connection material 132 onto the surfaces of the plurality of lead pins 128 and the metal plate 135 on the signal medium substrate, respectively. Further, arrange the pressure detection unit 120 and the signal transmission units 530 to 830 to face each other on the same axis via the curved or bent flexible connection material 132, and sandwich the adhesive sheet 142 between the pressure detection unit 120 and the signal transmission units 530 to 830. Then, attach the waterproof cases 515 to 815 from the pressure detection unit 120 side, fill the sealing materials 516 to 816 between the peripheries of the upper covers 510 to 810 and the waterproof cases 515 to 815, and maintain the holding state until the sealing materials are cured. As a result, the adhesive sheet 142, which is a sealing member, can be sandwiched and sufficiently deformed to maintain a high sealing property. Also, the flange portion inside the waterproof cases 515 to 815 and the base plate 112 can be brought into close contact with each other to prevent the sealing materials 516 to 816 from leaking from the bottom. As described above, the fluid introduction unit 110, the pressure detection unit 120, and the signal transmission units 530 to 830 are integrally fixed.

[0069] According to the configuration as described above, it is possible to provide a pressure sensor that can prevent the occurrence of ion migration and improve workability in the joining of the flexible connection material.

Description of Reference Numerals

[0070] 100 Pressure sensor 110 Fluid introduction unit 111 Joint member 112 Base plate 120 Pressure detection unit 121 Housing 122 Diaphragm 123 Protection cover 124 Hermetic glass 124A Liquid seal chamber 125 Support pillar 126 Semiconductor sensor chip 127 Potential adjustment member 128 lead pins 129 oil filling pipe 130 signal transmission section (main body) 131 connector housing 131a board housing section 131a1 board facing surface 131b connector connection section 131c partition section 131e adhesive reservoir area 131w adhesive reservoir wall surface 132 flexible connecting wire 133 conversion board 133a one end face 133b other end face 133f opening 133g heat conductive adhesive 133h heat generating component 133k notch 133l lead 133n land section 134a connection terminal 134b connection terminal 134c connection terminal 134d one end part 134e other end part 134f step 135 metal plate 140 connection member 141 caulking plate 142 adhesive sheet 151 resin sheet with heat radiation property 152 adhesive with heat radiation property 233 conversion board 233a solder surface 233b mounting surface 233n land section 333 conversion board 333a solder surface 333b mounting surface 333n land section 433 conversion board 433a solder surface 433b mounting surface Upper covers 510, 610, 710, 810 Substrate housing parts 510a, 610a, 710a, 810a Lead wires 511, 611, 711, 811 Core wires 512, 612, 712, 812 Waterproof cases 515, 615, 715, 815 Sealing materials 516, 616, 716, 816 Signal output parts 530, 630, 730, 830 Connection terminals 513 Terminal adhesives 513g Conversion substrates 533 Heat generating components 533h Heat dissipation adhesives 533g Connection terminals 613 Terminal adhesives 613g Relay substrates 633 Sealing adhesives 712g Conversion substrates 733 Heat generating components 733h Heat dissipation adhesives 733g Sealing adhesives 812g Relay substrates 833 Central axis C Distance L in the central axis direction between the conversion substrate and the housing Internal space S

Claims

1. a pressure detection unit including a pressure detection element for detecting a 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 section having a signal intermediate substrate for converting a signal from the external input / output terminal and for outputting 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 material 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 board, 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 board, 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 board, and the connection land portion and the metal member are electrically connected by a conductive pattern.

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