JP7653953B2 - Pressure Sensors - Google Patents

Description

The present invention relates to a pressure sensor that has a conversion substrate installed inside.

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.

In some pressure sensors, the cable is omitted and the conversion board is placed inside the pressure sensor to solve problems such as the possibility of poor connection due to external shocks or vibrations. However, the conversion board generates heat by itself due to the transformation of the driving 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 transmitted to the conversion board. If these measures are not implemented effectively, problems such as the electronic components in the conversion board exceeding their heat resistance temperature and being damaged will occur.

As a configuration for suppressing heat transfer to the conversion board, FIG. 1 of Patent Document 1 describes a configuration in which an internal space S is provided to suppress the transfer of heat from the semiconductor sensor chip 126 to the conversion board 133, thereby suppressing the effect of heat on the conversion board 133.

International Publication No. WO2022/097437 Patent No. 3987386

In the above configuration described in Patent Document 1, a flexible wire material 132 is used to connect the conversion board 133 and the lead pins 128 on the semiconductor sensor chip 126 side. The flexible wire material 132 is connected to the connection terminals 134 of the conversion board 133 by soldering, which may cause a short circuit due to the occurrence of ion migration (CAF) between the terminals on the surface of the conversion board. In addition, soldering takes time to join the parts, and the space for soldering is narrow, which reduces workability.

The object of the present invention is to provide a pressure sensor that can prevent ion migration and improve workability when joining flexible wire materials.

In order to solve the above problem, the pressure sensor is characterized in that it comprises a pressure detection section having a pressure chamber, a semiconductor sensor chip that detects the pressure of a fluid introduced into the pressure chamber, and lead pins that are connected to the semiconductor sensor chip and form external input/output terminals of the semiconductor sensor chip, a signal transmission section that is adjacent to the pressure detection section and has a board accommodation section, a connector connection section, and a connector housing that defines a partition section between the board accommodation section and the connector connection section, a connection terminal for signal connection with an external circuit, and a signal transmission section that is accommodated in the board accommodation section and is interposed between the lead pins and the connection terminals, a surface-mount metal member is surface-mounted on the signal transmission board, and a flexible connecting material that electrically connects the signal transmission board and the lead pins is connected to the surface-mount metal member by laser welding.

In the above pressure sensor, the signal transfer substrate is a conversion substrate that converts a drive voltage supplied to the semiconductor sensor chip from the external circuit and/or a pressure detection signal detected by the semiconductor sensor chip into an output corresponding to the external circuit, and the signal sending unit may further include a heat-generating component mounted on the conversion substrate.

In the above pressure sensor, the signal intermediary substrate may be a relay substrate that relays the drive voltage supplied to the semiconductor sensor chip from the external circuit and/or the pressure detection signal detected by the semiconductor sensor chip to the external circuit.

In the above pressure sensor, the flexible wire material may be lap welded to the surface mounting metal member, and the flexible wire material may have a conductive member made of stainless steel or nickel.

The pressure sensor may also have the surface-mount metal member made of copper or a copper alloy.

In order to solve the above problem, a pressure sensor is provided that includes a pressure detection section having a pressure chamber, a semiconductor sensor chip that detects the pressure of a fluid introduced into the pressure chamber, and lead pins that are connected to the semiconductor sensor chip and form external input/output terminals of the semiconductor sensor chip, a signal transmission section that is adjacent to the pressure detection section and has a substrate housing section, an upper cover that has the substrate housing section and prevents liquid from entering the substrate housing section, lead wires for signal connection with an external circuit, and a signal transmission board that is housed in the substrate housing section and is interposed between the lead pins and the lead wires, a surface-mount metal member is surface-mounted on the signal transmission board, and a flexible connecting material that electrically connects the signal transmission board and the lead pins is connected to the surface-mount metal member by laser welding.

In the above pressure sensor, the signal transfer substrate is a conversion substrate that converts a drive voltage supplied to the semiconductor sensor chip from the external circuit and/or a pressure detection signal detected by the semiconductor sensor chip into an output corresponding to the external circuit, and the signal sending unit may further include a heat-generating component mounted on the conversion substrate.

In the above pressure sensor, the signal intermediary substrate may be a relay substrate that relays the drive voltage supplied to the semiconductor sensor chip from the external circuit and/or the pressure detection signal detected by the semiconductor sensor chip to the external circuit.

In the above pressure sensor, the flexible wire material may be lap welded to the surface mounting metal member, and the flexible wire material may have a conductive member made of stainless steel or nickel.

In addition, in the above pressure sensor, the surface mounting metal member may be made of copper or a copper alloy.

The present invention provides a pressure sensor that can prevent ion migration and improve workability when joining flexible wire materials.

FIG. 1 is a cross-sectional view showing a pressure sensor according to an embodiment of the present invention. 2A and 2B are schematic diagrams showing a pressure sensor body according to an embodiment of the present invention, in which FIG. 2A is an oblique 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. 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. FIG. 4 is a cross-sectional view showing a pressure sensor according to yet another embodiment of the present invention. 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. 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.

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.

The pressure sensor 100 according to the embodiment of the present invention is provided with 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 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.

<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.

<Configuration of pressure sensor>
A pressure sensor 100 according to an embodiment of the present invention will be described with reference to FIG.

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 connection 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 by the connection member 140.

<Fluid introduction section>
The fluid introduction portion 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.

The coupling member 111 has a female thread portion 111a that is connected to a pipe (not shown) that introduces the 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 a female thread portion 111a, but is not limited to this, and may have a male thread portion, or may be connected to a copper connection pipe instead of the coupling member 111.

The base plate 112 has a bowl shape that expands radially from one end to the other end with respect to the central axis C of the pressure sensor 100, and forms a pressure chamber 112A between the base plate 112 and the diaphragm 122 described below.

<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 separates the above-mentioned pressure chamber 112A from a liquid-sealed chamber 124A described later, 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 in which sealed oil is filled between the diaphragm 122 and a recess on the pressure chamber 112A side of the hermetic glass 124, and a support 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 arranged inside the liquid-sealed chamber 124A, a potential adjustment member 127 arranged 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.

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 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 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, etc., to the outer periphery of the base plate 112 of the fluid introduction part 110.

The hermetic glass 124 is provided to protect the liquid-sealed chamber 124A in which the semiconductor sensor chip 126 is sealed from ambient environmental conditions such as moisture, dust, and heat in the air, 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 arranged in the center of the hermetic glass 124. Note that in this embodiment, the support 125 is made of an Fe-Ni alloy, but is not limited to this. For example, it may be made of stainless steel or other metal materials, or it may be configured so that the support is directly supported on the flat surface that forms the recess of the hermetic glass 124 without providing the support 125.

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 (such as single crystal silicon) that has a piezoresistance effect inside, a bridge circuit in which the semiconductor strain gauges are bridge-connected, an amplifier circuit that processes 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 the external input/output terminals of the semiconductor sensor chip 126. Note that the semiconductor sensor chip 126 is not limited to this example, and may also include a form in which the bridge circuit section using the strain gauges is separated from the amplifier circuit and the calculation processing circuit section.

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

A number of lead pins 128 and an oil filling pipe 129 are fixed in a penetrating state to the hermetic glass 124 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 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.

The oil filling pipe 129 is provided to fill the interior of the liquid sealing chamber 124A with sealed oil (e.g., silicone oil or a fluorine-based inert liquid). After filling with oil, the other end of the oil filling pipe 129 is crushed and blocked as shown in FIG. 1.

<Operation of 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 the diaphragm 122 is transmitted to the semiconductor sensor chip 126 via the sealed oil in the liquid sealed chamber 124A. The transmitted pressure causes the silicon diaphragm of the semiconductor sensor chip 126 to deform, and the pressure is converted into an electrical signal by a bridge circuit using piezoresistance 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.

<Signal sending section>
The signal sending section (main body) 130 sends out the pressure signal detected by the pressure detection section 120, and includes a connector housing 131 for external connection arranged adjacent to the other end side of the pressure detection section 120, and a flexible connecting wire 132 having one end connected to the multiple lead pins 128. The signal sending section 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 c having one end connected through the conversion board 133. An opening 133f is formed in the conversion board 133 to avoid interference with the oil filling pipe 129.

The connector housing 131 is formed of an insulating resin having a relatively high thermal conductivity, and includes a board accommodating portion 131a having a concave shape on one end, a connector connection portion 131b having a concave shape on the other end and connected to an external connector (not shown), and a partition portion 131c disposed between the board accommodating portion 131a and the connector connection portion 131b. In the internal space S defined by the board 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 material 132, a conversion board 133, and the like are disposed.

The conversion board 133 is provided with a conversion circuit (not shown) that converts both the drive voltage and the pressure detection signal to correspond to the signal system of the drive voltage and the pressure detection signal. This conversion circuit includes a step-down circuit section (not shown) that steps down the drive voltage (e.g., 8 V to 36 V) of the control circuit (not shown) connected to the outside of the pressure sensor 100 via the connection terminals 134a to c to the drive voltage (e.g., 5.0 V) of the semiconductor sensor chip 126, and a voltage shift circuit section (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 provided in the pressure sensor 100 in accordance with the signal system of the drive voltage and the pressure detection signal, the difference between the drive voltage and the pressure detection signal can be absorbed without making design changes to the pressure detection section 120, particularly the semiconductor sensor chip 126, or the peripheral structure of the liquid seal chamber 124A. By using a conversion board that performs input/output signal conversion in this way, there is no need to stock semiconductor sensor chips that correspond to various input/output formats, and because changes can be made by adjusting the specifications of the conversion board, it is possible to accommodate production methods that are 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 process can be performed on the connected control circuit, there is no need for a circuit with input/output conversion function on the board side.

At least three connection terminals 134a-c are provided, one for external output (Vout), one for driving voltage supply (Vcc), and one for ground (GND). In order 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 this conversion board 133, and is electrically connected to metal plate 135 by a conductive pattern. Meanwhile, the other end side of connection terminal 134a penetrates partition portion 131c and extends to connector connection portion 131b. The through hole of partition portion 131c through which connection terminals 134a-c penetrate is sealed with connection terminal fixing adhesive 134g.

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

The crimping plate 141 is formed in a cylindrical shape from a metal such as copper. The crimping plate 141 is arranged 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 crimping. By this crimping, the adhesive sheet 142 is sandwiched between the pressure detection section 120 and the signal transmission section 130 to achieve waterproof and dustproof functions. In addition, a non-metallic resin sheet 151 having thermal radiation properties and an adhesive 152 having thermal radiation properties may be sandwiched between the adhesive sheet 142 and the housing 121 as a means for suppressing heat transfer to the conversion board 133. In addition, the structure of the crimping section is not limited to the above method. For example, as shown in FIG. 11 of Patent Document 2, the fluid introduction section 110 formed as an integral part capable of accommodating the housing 121 and the connector housing 131 may be crimped by the opening end on the connector housing 131 side. In other words, the adhesive sheet 142 is sandwiched between the housing 121 and the connector housing 131 and is fixed by compressing it using a crimp or other method.

<Heat dissipation means for conversion board>
The conversion board 133 has the other end surface 133b on which various electronic components are mounted and which is separated from the connector housing 131, and the one end surface 133a on which the connection terminals 134a-c and the like are soldered. The heat generating component 133h in this embodiment (for example, a component such as a transistor or a regulator, which has a potential difference between input and output terminals and through which a current flows) is of the lead type and is mounted on the other end surface 133b. This conversion board 133 generates heat by itself due to the transformation of the driving voltage, and if no measures are taken against this, the electronic components on the conversion board may reach or exceed their heat resistance temperature and be damaged. Therefore, in this embodiment, various heat dissipation means for the conversion board 133 are adopted so that the electronic components of the conversion board 133 do not reach or exceed their heat resistance temperature. As a result, the heat generated in the conversion board 133 can be efficiently dissipated to the external environment, and the margin for the heat resistance temperature of the conversion board 133 can be improved. The heat dissipation means of the conversion board 133 in this embodiment will be specifically described below.

<Heat dissipation means for conversion board (lead-type heat generating components)>
As a heat dissipation means for the conversion board 133, a lead-type heat generating component 133h is used to form 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. The heat dissipation adhesive 133g having thermal conductivity is filled around the heat generating component 133h, and in order to prevent the heat dissipation adhesive 133g from spreading onto the conversion board, an adhesive reservoir wall surface 131w is provided to define an adhesive reservoir area 131e between the outer periphery of the connector housing 131. That is, in this embodiment, the adhesive reservoir area 131e is defined by the adhesive reservoir wall surface 131w and the board accommodation portion 131a and partition wall portion 131c of the main body 130. A lead-type heat generating component 133h is accommodated in the 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 surrounding the periphery of the heat generating component 133h, so that the heat can be dissipated to the external environment via the connector housing 131 more efficiently.

2(a) and 2(b), a cutout 133k is provided in a portion of the conversion board 133 where the heat dissipation adhesive 133g may creep up due to surface tension along the adhesive reservoir wall surface 131w. This allows the distance between the conversion board 133 and the inner wall of the main body 130 to be widened, and the heat dissipation adhesive 133g that 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 can be prevented from creeping up due to surface tension along the adhesive reservoir wall surface 131w. In addition, by providing the cutout 133k up to the vicinity of the land portion 133n of the conversion board 133, even if the heat dissipation adhesive 133g that overflows in a direction perpendicular to the direction in which the signal sending unit 130 and the pressure detection unit 120 are adjacent drips onto the board, the heat dissipation adhesive 133g can be prevented from adhering to the land portion 133n.

The lead-type heat-generating component 133h is mounted on the conversion board 133 via the lead 133l, so that 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-resistant temperature.

Here, the lead-type heat generating component 133h is provided on the outer diameter side of the connector housing 131 so that it is closer 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.

Furthermore, by providing a space between the heat dissipation adhesive 133g filled around the lead-type heat generating component 133h and the conversion board 133, it is possible to suppress the transfer of heat between the heat generating component 133h and the conversion board 133.

<Heat transfer suppression means>
A fluid to be subjected to pressure detection is introduced into the pressure chamber 112A, but depending on the conditions of use of the fluid, a very high-temperature fluid (for example, about 130 (°C)) may be introduced and become a heat source. In this case, 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 transfer to the conversion board 133 (heat transfer from one end side to the other end side in FIG. 1, heat conduction, and heat radiation (radiation)), which may cancel out the heat dissipation effect using the heat dissipation means (lead-type heat generating component). Therefore, in this embodiment, various heat transfer suppression means are adopted to prevent the heat on the pressure detection unit 120 side (such as the heat of the high-temperature fluid introduced into the pressure chamber 112A) from transferring to the conversion board 133. As a result, in this embodiment, the heat on the pressure detection unit 120 side can be suppressed from transferring to the conversion board 133, so that the heat dissipation effect using the heat dissipation means (lead-type heat generating component) is sufficiently achieved. The means for suppressing heat transfer to the conversion substrate 133 in this embodiment will be specifically described below.

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

<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 provided apart from the other end and the outer periphery of the board accommodation portion 131a so as not to come into direct contact with the connector housing 131. Instead of the conversion board 133 being directly supported by the connector housing 131, as shown in FIGS. 2(a) and (b), the conversion board 133 is supported at three points by three connection terminals 134a-c. These three connection terminals 134a-c are provided so as to be located toward the center side of the conversion board 133 to which a load is particularly 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 step 134f, and the conversion board 133 can be supported at the step 134f. The position of this step 134f is set at a height that does not come into contact with the connector housing 131 so that the conversion board 133 is supported at three points as described above when the conversion board 133 is accommodated in the connector housing 131. With this structure, the converter board 133 can be arranged in a well-balanced manner without tilting with respect to the connection terminals 134a-c even when a load is applied during soldering, and the converter board 133 is configured to be supported firmly by the connection terminals 134a-c by suppressing movement of the converter board 133 toward the connector housing 131 (upward). Furthermore, as shown in FIG. 1, the connection terminals 134a-c themselves are fixed to the connector housing 131 by the 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 by the heat dissipation adhesive 133g, thereby indirectly fixing the converter board 133 to the connector housing 131. In this way, the converter board 133 is provided away from the other end of the board accommodating portion 131a so as not to come into direct contact with the connector housing 131, and therefore the heat transferred from the lead-type heat generating component 133h to the surrounding heat dissipation adhesive 133g can be suppressed from being transferred to the converter board 133.

In addition to the above, the conversion board 133 is arranged so that its side is spaced away from the outer periphery of the board accommodating portion 131a, which prevents stress from being applied from the connector housing 131 to the conversion board 133 due to the difference in the thermal linear expansion coefficients of 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 the linear expansion coefficients.

<Third Heat Transfer Suppression Means for the Conversion Board (Flexible Wire Material)>
The flexible wire 132 described above is used as a third heat transfer suppression means to the conversion board 133. Specifically, the flexible wire 132 is formed of, for example, a flexible printed circuit board (FPC), a thin plate-shaped conductive member, a lead wire, an assembly of lead wires, etc., and connects between the multiple lead pins 128 and the metal plate 135 in a curved or bent state in the internal space S. Therefore, the connection distance between the multiple lead pins 128 and the metal plate 135 can be set relatively large. In addition, the flexible wire 132 is thinner and has a smaller cross-sectional area than normal wiring materials. As a result, in this embodiment, since the heat on the semiconductor sensor chip 126 side passes through the flexible wire 132 with a long heat transfer path and has a smaller cross-sectional area, it is possible to suppress the heat transfer to the conversion board 133.

<Joining flexible wire material to metal plate>
2A is a schematic diagram showing a pressure sensor body according to an embodiment of the present invention, and FIG 2B is a plan view showing the pressure sensor body after being mounted on a substrate. Note that FIG 2A shows a connector housing 131 with a part cut away so that the inside of the body can be seen.

2(a) and 2(b), the metal plate 135 is a surface-mount metal member, and is made of copper alloys such as copper, phosphor bronze, brass, and nickel silver, and is preferably plated with tin, gold, or the like. The metal plate 135 is surface-mounted on the conversion board 133, and the flexible wire material 132 is connected by welding. Here, since the metal plate 135 is a surface-mount component that does not require a through hole in the board, the flexible wire material 132 and the metal plate 135 may be welded by other welding methods such as soldering, as in the case of mounting on the board. In addition, in the case of laser welding, the metal plate 135 is made of a copper alloy, which has a high thermal conductivity and is prone to reflecting light, and therefore is not easily workable for laser welding as it is. Therefore, the conductive material of the flexible wire material 132 is made of stainless steel or nickel, which has good workability for laser welding, and is placed on the metal plate 135. The flexible wire material 132 is then irradiated with a laser to join the metal plate 135 and the flexible wire material 132 (lap welding).

In this way, by laser welding the flexible wire material 132 to the metal plate 135, soldering is not necessary, and ion migration between the terminals on the surface of the conversion board 133 can be prevented. In addition, the time required to join the flexible wire material 132 and the metal plate 135 can be shortened, and joining can be performed even in a narrow working space. Furthermore, by using overlap welding, melting of the intermediate layer of the conversion board 133, which is a laminated board, due to laser welding can be prevented. As described above, the metal plate 135 is made of a metal material with high thermal conductivity, so it can partially dissipate heat from the mounted conversion board 133. In this embodiment, the conversion board 133 is a laminated board consisting of four layers, but this is not limited to this, and it may be a single-layered one-sided board or a double-sided board. In addition, in this embodiment, the metal plate 135 is used, but this is not limited to this, and jumper wires, jumper pins, etc. may be used.

<Assembly process of the main body>
In the assembly process of the main body 130, first, the three connection terminals 134a-c are inserted into the main body 130. Then, as shown in FIG. 1, the 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 board 133. Next, as shown in FIG. 1, the heat dissipation adhesive 133g is filled into the adhesive reservoir area 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 area 131e, and is not filled to the limit of the fillable volume. Then, the conversion board 133 is inserted into the main body 130. At this time, the metal plate 135 and the lead-type heat generating component 133h are attached to the conversion board 133 in advance, and are inserted into the heat dissipation adhesive 133g filled in the adhesive pool area 131e of the main body 130, since they protrude toward the board-opposing surface 131a1 side. Next, the main body 130 with the conversion board 133 inserted is placed in an oven to heat and harden the heat dissipation adhesive 133g and the connection terminal fixing adhesive 134g. This heating also has the purpose of drying the conversion board 133 to prevent migration due to moisture absorption by the conversion board 133. Then, the connection terminals 134a-c and the lead-type heat generating component 133h are soldered to the conversion board 133. Finally, a solder inspection is performed to confirm whether the soldering is performed properly. If heat dissipation is not performed through the heat dissipation adhesive 133g of the heat generating component 133h, the process of filling the adhesive pool area 131e with the heat dissipation 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.

<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 transmission unit (main body) 130 are assembled as described above. Then, in the pressure detection unit 120, the enclosed oil is filled into the liquid sealed chamber 124A through 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. After that, the multiple 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 material 132 are 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 disposed 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 crimping 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.

Here, if the curved or bent flexible wire material 132 is not used in the pressure sensor 100, the assembly process of the pressure sensor 100 would have required assembling the pressure sensor 100 by stacking it from one end side to the other end side in the direction of the central axis C. Therefore, the degree of freedom of the assembly process is extremely low, making it difficult to shorten the assembly time. However, in this embodiment, the pressure detection unit 120 and the signal transmission unit 130 are connected via the curved or bent flexible wire material 132, which increases the degree of freedom of the assembly process of the pressure sensor 100 and therefore shortens the assembly time.

<Other embodiments>
Some other embodiments different from the above-mentioned embodiment 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-mentioned embodiment, and the description thereof will be omitted.

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 conversion board 233 is arranged parallel to the central axis C, that is, parallel to the direction in which the signal sending unit 130 is adjacent to the pressure detection unit 120. In addition, the lead type heat generating component 233h has the lead 233l portion bent at a right angle, and the tip of the lead 233l is inserted from the mounting surface 233b to the solder surface 233a through a through hole provided in the conversion board 233, and the through portion is soldered to connect the connection terminal 134a to the conversion board 233. A land portion 233n is formed at the connection portion of this conversion board 233, and is electrically connected to the metal plate 135 by a conductive pattern. In this embodiment, as in the previous embodiment, one side and the other side of the flexible wire 132 are fixed to the multiple lead pins 128 and the surface of the metal plate 135 on the conversion board 233 by laser welding, respectively. This provides the same effect as described above. The same applies to the conversion boards 333 and 433 described below.

As shown in FIG. 3(b), in yet 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, the lead-type heat generating component 333h has the lead 333l bent at a right angle, and the tip 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.

Figure 4 is a cross-sectional view showing a pressure sensor according to yet another embodiment of the present invention. As shown in Figure 4, in this embodiment, the conversion board 433 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, the lead type heat generating component 433h has the lead 433l parallel to the conversion board 433, and a part of the lead 433l is attached to the pattern on the mounting surface 433b of the conversion board 433, for example with a conductive adhesive.

In this way, in another embodiment of the present invention, the conversion boards 233, 333, and 433 are arranged in the direction in which the signal sending unit 130 is adjacent to the pressure detection unit 120, so that the area of the portion facing the adhesive pool area 131e is extremely small compared to the conversion board 133. As a result, even if the lead-type heat generating components 233h, 333h, and 433h are inserted into the adhesive pool area 131e and the heat dissipation 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, the heat dissipation adhesive 133g will not drip onto the conversion boards 233, 333, and 433. In addition, even if the heat dissipation adhesive 133g creeps up due to surface tension, it is possible to prevent the heat dissipation adhesive 133g from dripping onto the conversion boards 233, 333, and 433. Furthermore, even if the heat dissipation 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 to each other, the heat dissipation adhesive 133g can be prevented from adhering to the land portion 233n or 333n.

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

Figure 5(a) shows 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 to exchange signals between the pressure detection unit 120 and the outside, and Figure 5(b) shows a pressure sensor 600 in which a lead wire 611 from the outside is connected to a relay board via a connection terminal 613 to exchange signals between the pressure detection unit 120 and the outside. Note that the same elements as in the above embodiment are given the same numbers and will not be described.

<Signal sending unit according to further another embodiment>
In the embodiment shown in Fig. 5(a), the signal sending unit 530 sends out a pressure signal detected by the pressure detection unit 120 to the outside, and is disposed adjacent to the other end side of the pressure detection unit 120, and includes a lead wire 511 for external connection and a flexible connecting wire 132 having one end connected to a plurality of lead pins 128. The connection terminal 513 is in contact with one end side of the core wire 512 of the lead wire 511 so as to be electrically connected to the lead wire 511 at the other end side, 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 that are electrically connected to each other and fixed. The signal sending unit 530 also includes a conversion board 533 that is a signal transfer board fixed to the upper cover 510 via the connection terminal 513, and a connection terminal 513 whose one end is connected to the conversion board 533 through the connection terminal 513. The portion of the connection terminal 513 that is connected to the conversion board 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 where the lead wire 511 inside the pressure sensor 500 passes through 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 that constitute the signal sending unit 530 are fixed by the waterproof case 515 and the sealant 516 that fills the gap between the waterproof case 515 and the upper cover 510. Note that the conversion board 533 has an opening 533f formed therein to avoid interference with the oil filling pipe 129. Also, similar to the above embodiment, the flexible connecting wire 132 is connected to the metal plate 135 mounted on the conversion board 533 by laser welding or the like. In this way, by connecting to the outside through the lead wires 511, it is possible to provide the pressure sensor 500 with a connection form different from that of a connection through a connector. Note that with the conventional connector type, there is a concern about moisture intrusion from the top surface of the connector, but by filling and sealing the entire portion where the lead wires 511 of the pressure sensor 500 are drawn out to the outside with the sealant 516 as in this embodiment, it is possible to improve the waterproofing of the portion where the lead wires 511 are drawn out to the outside.

The upper cover 510 is formed from an insulating resin with a relatively high thermal conductivity, and has a substrate accommodating section 510a with a concave shape on one end. In the internal space S defined by the substrate accommodating section 510a, 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 are arranged. As in the previous embodiment, a heat generating component 533h is mounted on the conversion substrate 533, and the surrounding area is filled with a heat dissipation adhesive 533g.

On the other hand, in the embodiment shown in FIG. 5(b), the signal sending unit 630 has the same configuration as the signal sending unit 530, but the relay board 633 does not have a heat-generating component, and instead the board housing portion 610a at the top of the relay board 633 has a space 633s. The relay board 633 is a signal intermediary board that exchanges signals with the outside via the lead wire 611 and the connection terminal 613, which are signal connection means, and relays the signal from the pressure detection unit 120. In this way, the pressure detection unit 120 and the signal sending unit 630 are assembled separately and connected and integrated with the flexible connecting material 132, so that it is not necessary to go through a difficult process of directly connecting the lead pin 128 and the core wire 612 of the lead wire 611 in a narrow space, thereby improving workability and productivity.

<Signal sending unit according to further embodiment>
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 descriptions thereof will be omitted.

As shown in FIG. 6(a), in this embodiment, in the signal sending section 730, the core wire 712 of the lead wire 711, which is a signal connection means, is directly connected to the conversion board 733, which is a signal transfer board. The other end 712d of the core wire 712 penetrates the conversion board 733, and the through 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 board 733, a connection terminal is not required, and the number of parts can be reduced. In addition, the number of connection steps at two points, the conversion board and the connection terminal, and the connection terminal and the lead wire, can be halved, so that the manufacturing process can be shortened. And, the part where the lead wire 711 is inserted into the upper cover 710 is filled with sealing adhesive 712g so as to fill the gap, and it is possible to prevent moisture from entering the inside of the upper cover 710 through the core wire 712 due to the breathing action inside the upper cover 710.

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 a heat-generating component mounted thereon, and relays the signal from the pressure detection unit 120 to the outside via the lead wire 811, which is a 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 the flexible connecting material 132, thereby eliminating the need for a difficult process of directly connecting the lead pin 128 and the core wire 812 of the lead wire 811 in a narrow space, thereby improving workability and productivity.

<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 processes as those for the pressure sensor 100 will be omitted.

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 wire material 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 opposite each other on the same axis via the curved or bent flexible wire material 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 the sealant 516-816 is filled between the periphery of the upper cover 510-810 and the waterproof case 515-815, and the sealant is held in place until it hardens. This allows the adhesive sheet 142, which is a sealing member, to be clamped and deformed sufficiently to maintain a high sealing performance. In addition, the flanges on the inside of the waterproof cases 515-815 and the base plate 112 are tightly attached to prevent 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.

The above configuration makes it possible to provide a pressure sensor that can prevent ion migration and improve workability when joining flexible wire materials.

100 Pressure sensor 110 Fluid introduction portion 111 Joint member 112 Base plate 120 Pressure detection portion 121 Housing 122 Diaphragm 123 Protective cover 124 Hermetic glass 124A Liquid sealed chamber 125 Support 126 Semiconductor sensor chip 127 Potential adjustment member 128 Lead pin 129 Oil filling pipe 130 Signal sending portion (main body)
131 Connector housing 131a Substrate accommodating portion 131a1 Substrate facing surface 131b Connector connection portion 131c Partition portion 131e Adhesive reservoir area 131w Adhesive reservoir wall surface 132 Flexible connecting wire material 133 Conversion board 133a One end surface 133b Other end surface 133f Opening 133g Heat dissipation adhesive 133h Heat generating component 133k Notch portion 133l Lead 133n Land portion 134a Connection terminal 134b Connection terminal 134c Connection terminal 134d One end portion 134e Other end portion 134f Step 135 Metal plate 140 Connection member 141 Caulking plate 142 Adhesive sheet 151 Resin sheet having thermal radiation properties 152 Adhesive having thermal radiation properties 233 Conversion board 233a Solder surface 233b Mounting surface 233n Land portion 333 Conversion board 333a Solder surface 333b Mounting surface 333n Land portion 433 Conversion board 433a Solder surface 433b Mounting surface 510, 610, 710, 810 Upper cover 510a, 610a, 710a, 810a Board accommodating portion 511, 611, 711, 811 Lead wires 512, 612, 712, 812 Core wires 515, 615, 715, 815 Waterproof case 516, 616, 716, 816 Sealing material 530, 630, 730, 830 Signal sending portion 513 Connection terminal 513g Terminal adhesive 533 Conversion board 533h Heat generating component 533g Heat dissipation adhesive 613 Connection terminal 613g Terminal adhesive 633 Relay board 712g Sealing adhesive 733 Conversion board 733h Heat generating component 733g Heat dissipation adhesive 812g Sealing adhesive 833 Relay board

C: central axis L: distance in the central axis direction between the conversion board and the housing S: internal space

Claims (12)

a pressure detection unit including a pressure chamber, a semiconductor sensor chip that detects the pressure of a fluid introduced into the pressure chamber, and lead pins that are connected to the semiconductor sensor chip and that constitute external input/output terminals of the semiconductor sensor chip;
a signal sending section adjacent to the pressure detection section, the signal sending section including a board accommodation section, a connector connection section, and a connector housing defining a partition section between the board accommodation section and the connector connection section, a connection terminal for signal connection with an external circuit, and a signal transfer board accommodated in the board accommodation section and interposed between the lead pin and the connection terminal,
A pressure sensor characterized in that a surface-mount metal member is surface-mounted on the signal transfer substrate, and a flexible wire material electrically connecting the signal transfer substrate and the lead pins is connected to the surface-mount metal member by laser welding. the signal intermediate substrate is a conversion substrate that converts a drive voltage supplied from the external circuit to the semiconductor sensor chip and/or a pressure detection signal detected by the semiconductor sensor chip into an output corresponding to the external circuit,
The pressure sensor according to claim 1 , wherein the signal sending section further comprises a heat generating component mounted on the conversion board. The pressure sensor according to claim 1, characterized in that the signal intermediary substrate is a relay substrate that relays a drive voltage supplied to the semiconductor sensor chip from the external circuit and/or a pressure detection signal detected by the semiconductor sensor chip to the external circuit. The pressure sensor according to any one of claims 1 to 3, characterized in that the flexible wire material is lap welded to the surface mounting metal member, and the flexible wire material has a conductive member made of stainless steel or nickel. The pressure sensor according to any one of claims 1 to 3, characterized in that the surface mounting metal member is made of copper or a copper alloy. The pressure sensor according to claim 4, characterized in that the surface mounting metal member is made of copper or a copper alloy. a pressure detection unit including a pressure chamber, a semiconductor sensor chip that detects the pressure of a fluid introduced into the pressure chamber, and lead pins that are connected to the semiconductor sensor chip and that constitute external input/output terminals of the semiconductor sensor chip;
a signal sending section adjacent to the pressure detection section, the signal sending section having a substrate receiving section, an upper cover having the substrate receiving section and preventing liquid from entering the substrate receiving section, lead wires for signal connection with an external circuit, and a signal transfer substrate received in the substrate receiving section and interposed between the lead pins and the lead wires;
Equipped with
A pressure sensor characterized in that a surface-mount metal member is surface-mounted on the signal transfer substrate, and a flexible wire material electrically connecting the signal transfer substrate and the lead pins is connected to the surface-mount metal member by laser welding. the signal intermediate substrate is a conversion substrate that converts a drive voltage supplied from the external circuit to the semiconductor sensor chip and/or a pressure detection signal detected by the semiconductor sensor chip into an output corresponding to the external circuit,
The pressure sensor according to claim 7 , wherein the signal sending section further comprises a heat generating component mounted on the conversion board. The pressure sensor according to claim 7, characterized in that the signal intermediary substrate is a relay substrate that relays the drive voltage supplied to the semiconductor sensor chip from the external circuit and/or the pressure detection signal detected by the semiconductor sensor chip to the external circuit. The pressure sensor according to any one of claims 7 to 9, characterized in that the flexible wire material is lap welded to the surface mounting metal member, and the flexible wire material has a conductive member made of stainless steel or nickel. The pressure sensor according to any one of claims 7 to 9, characterized in that the surface mounting metal member is made of copper or a copper alloy. The pressure sensor according to claim 10, characterized in that the surface mounting metal member is made of copper or a copper alloy.

Images