JP7809086B2 - Pressure sensor and method for manufacturing the pressure sensor - Google Patents

Description

The present invention relates to a pressure sensor with a simple structure that can be assembled easily and reliably, and a method for manufacturing the pressure sensor.

Various sensors that detect pressure, temperature, etc. are fixed near the object being measured and used to send a detection signal to a measuring device, and are often used either built into the measuring device or attached externally (see Patent Document 1).

This type of sensor is incorporated into a sensor unit that can be installed so that it is exposed to an environment similar to that of the object being measured. The sensor unit is equipped with a terminal block that holds terminals that are electrically connected to the installed sensor, and the sensor's detection signal can be used by connecting a measuring device to these terminals.

JP 2014-98685 A

In such sensor units, the components must be positioned and supported during assembly while also being mechanically and electrically connected so that they function. Therefore, assembling the components by stacking them, for example, is both easy to do and provides excellent positioning accuracy.

However, even if the sensor and terminal block are stacked vertically, the terminals that functionally connect to the sensor are electrically connected by spot welding or soldering to the flat surface, which means that the flat terminals that extend horizontally must be slid horizontally to be positioned and held in place. This means that after various parts in the middle of assembly have been turned sideways to secure the terminals to the terminal block, the parts must then be stacked vertically again and the assembly work resumed, which reduces workability.

The present invention aims to realize a sensor unit that can be assembled by moving the terminals to which the sensor is connected in the vertical direction, and to provide a pressure sensor that includes this sensor unit, as well as a method for manufacturing this sensor unit.

One aspect of the sensor unit invention that solves the above problem is a pressure sensor composed of a sensor unit including a sensor connected to an external device, the sensor unit including a circuit board that is interposed between the sensor and the external device and connected to the sensor; one or both of a connecting member located between the sensor and the circuit board and electrically connected to the sensor and the circuit board, and a terminal member that is electrically connected to the circuit board and electrically connected to the circuit board for electrically connecting the circuit board to the external device; and a terminal block that fixes, positions, and supports the connecting member and/or the terminal member; the circuit board is placed on one or both of the connecting member and the terminal member; the terminal block has a fixing groove that has a depth in the direction in which the circuit boards are stacked and extends at least to the fixing position of one or both of the connecting member and the terminal member; and the fixing portion of one or both of the connecting member and the terminal member is positioned in the fixing groove and is adhered and positioned with an adhesive.

In this way, one aspect of the present invention makes it possible to realize a sensor unit with a simple and easy-to-operate structure in which one or both of the connection members and terminal members that connect the circuit board to the sensor or external device are positioned in a fixing groove in the terminal block that has a depth in the direction in which the circuit boards are stacked, and then bonded and fixed in position with an adhesive. This makes it possible to provide a pressure sensor constructed from this sensor unit and a method for manufacturing a pressure sensor that allows for easy assembly.

FIG. 1 is a vertical cross-sectional view showing a pressure sensor including a pressure sensor unit, which is an example of a sensor unit according to an embodiment of the present invention, and shows a schematic overall configuration thereof. FIG. 2 is a diagram showing an outline of the manufacturing method of the pressure sensor, where (a) is an exploded perspective view from above in which the components are spaced apart in the stacking direction, and (b) is a perspective view from below of one of the components. FIG. 3 is a perspective view showing the main components from one direction. 4A and 4B are diagrams showing one connection terminal attached to the main part of FIG. 3, in which (a) is an elevational front view, (b) is a top view, (c) is a bottom view, and (d) is a plan view showing the lead frame of the three parts. 5A, 5B, 5C, and 5D are diagrams showing a connection terminal different from that shown in FIG. 4, which is attached to the main part of FIG. 3, in which (a) is an elevational front view, (b) is a top view, (c) is a bottom view, and (d) is a side view. 6A and 6B are diagrams showing the state in which the connection terminals are attached to the main components of FIG. 3, with (a) being a longitudinal sectional view and (b) being a top view. 7A and 7B are diagrams for explaining the attachment state of the connection terminals in FIG. 6, where (a) is a perspective view of one connection terminal from one direction and a perspective view of another connection terminal from a different direction, and (b) is a top view of both connection terminals. 8A and 8B are diagrams showing the attachment state of the connection terminals to the main components of FIG. 3 and the circuit board, where (a) is a longitudinal cross-sectional view, (b) is a perspective view, and (c) is an enlarged perspective view of the connection portion between the circuit board and the connection terminal. 9A and 9B are diagrams for explaining the connection state of the connection points in FIG. 8, where FIG. 9A is a vertical cross-sectional view showing the effect of the structure, and FIG. 9B is a vertical cross-sectional view showing a case where the structure is not adopted. 10A and 10B are diagrams showing a first alternative embodiment of this embodiment, where FIG. 10A is a longitudinal sectional view showing a structure equivalent to this embodiment, and FIG. 10B is a longitudinal sectional view showing a structure inferior to this embodiment. FIG. 11 is a diagram showing a second alternative embodiment of the present invention, and is a top view showing a case where a different shape of the connection terminal is adopted. FIG. 11 is a diagram showing a third alternative embodiment of the present invention, and is a top view showing a case where a different shape of the connection terminal is adopted. FIG. 13 is a diagram showing a fourth alternative embodiment of the present invention, and is a vertical cross-sectional view showing a schematic overall configuration thereof. FIG. 14 is a diagram showing a fifth alternative embodiment of the present invention, and is a vertical cross-sectional view showing a schematic overall configuration thereof. FIG. 15 is a vertical cross-sectional view showing a technology prior to the conception of this embodiment.

Embodiments of the present invention will be described in detail below with reference to the drawings. Figures 1 to 9 are diagrams illustrating a pressure sensor equipped with a pressure sensor unit, which is an example of a sensor unit according to one embodiment of the present invention, and a method for manufacturing the sensor unit.

In Figures 1 and 2, the pressure sensor 100 is constructed so that the pressure sensor unit 10, assembled by stacking components as described below, is attached to a target location where the pressure characteristics of the external environment are to be measured, and pressure information detected by the pressure sensor chip 11 is output to the connected external device A. The pressure sensor 100 of this embodiment is constructed so that the pressure sensor unit 10, housed in a resin waterproof case 20, can be connected to a pipe to be measured, through which a fluid such as a gas or liquid whose pressure is to be detected is guided, by connecting it with a metal coupling member 30.

The waterproof case 20 is cylindrically shaped to accommodate the pressure sensor unit 10, and the peripheral edge of the cap 28 to which the coupling member 30 is fixed is connected to the opening 20b at one end. This coupling member 30 has an internal thread 30s formed on it so that it can be screwed onto the piping or other object of pressure measurement. Fluid supplied from the piping in the direction of arrow P can be introduced into the pressure chamber PR downstream of the cap 28 via a port 30a that communicates with the internal thread 30s.

The pressure sensor unit 10 comprises a housing 12 fabricated in a short cylindrical shape, the lower axial end face of which is bonded and fixed to a cap 28; a support 13 on which a pressure sensor chip 11 is mounted and positioned so as to be positioned at the center of the inner cylinder of the housing 12; and hermetic glass 14 that is filled around the support 13 within the inner cylinder of the housing 12, sealing it off and securing components that pass through the inner cylinder.

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

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

As a result, the pressure sensor chip 11 functions as a pressure sensor that detects the pressure of the fluid to be detected, which is introduced into the pressure chamber PR from the piping connected to the coupling member 30, as pressure fluctuations in the pressure transmission medium in the liquid-sealed chamber LR via the diaphragm 32.

Here, the pressure sensor chip 11 is electrically connected via bonding wires 11w to lead pins 40, which are connected to multiple lead wires 38 from external device A via a circuit board 50 (described later), to receive power and output a detection signal as pressure information. The liquid-sealed chamber LR between the hermetic glass 14 and the diaphragm 32 within the inner cylinder of the housing 12 is filled with a pressure transmission medium via an oil filling pipe 44. These lead pins 40 and oil filling pipe 44 are aligned at equal intervals on the same circle around the support 13 and are supported insulated from the housing 12 by an insulating material such as the hermetic glass 14. One end of the oil filling pipe 44 is closed after the pressure transmission medium has been filled.

A diaphragm protective cover 34 with multiple communication holes 34a is bonded and fixed to the lower end surface of the housing 12, thereby preventing damage to the diaphragm 32 due to external forces or sudden pressure in the pressure chamber PR. A concave frame 16 is fixed to one end of the hermetic glass 14, and a lid-like shield plate 17 is attached. The frame 16 contains a pressure transmission medium that can flow freely between the pressure sensor chip 11 and the diaphragm 32 via communication holes 17a formed in the shield plate 17, which suppress sudden pressure fluctuations.

The lead pins 40 are arranged on the bottom surface 24b of the resin terminal block 24, which is formed in a short, roughly cylindrical shape with a bottom, and are electrically connected to the pressure sensor chip 11 via bonding wires 11w. Two power terminals, one output signal terminal, and five adjustment terminals used during assembly are arranged on the bottom surface 24b. These lead pins 40 are inserted into insertion holes 24h formed in the bottom surface 24b of the terminal block 24 and fixedly supported by the hermetic glass 14. The terminal block 24 has a roughly cylindrical side wall 24s that is partially flat, and terminal holders 51 and 53, which mount and hold sets of three relay connection terminals 36 (36A-36C) and 37 (37A-37C), described below, are arranged symmetrically about the center of the cylinder.

Both ends of each lead pin 40 penetrate both sides of the hermetic glass 14 within the inner cylinder of the housing 12, and one end, which faces the liquid-sealed chamber LR, is electrically connected to the pressure sensor chip 11 via a bonding wire 11w. The other ends of the lead pins 40, serving as the power supply terminal and the output signal terminal, are electrically connected to the end surfaces by, for example, spot welding (or molten metal welding) to the terminal pieces 36e of the relay connection terminal 36 held on the side wall 24s of the terminal block 24. The side wall 24s of the terminal block 24 holds a relay connection terminal 37 on the opposite side (facing) of the relay connection terminal 36, to which a lead wire 38 from an external device A is connected, as described below. The terminal pieces 36d, 37d of these relay connection terminals 36, 37 are connected to a circuit board 50, which is placed on top of the relay connection terminal 36, by applying molten solder (conductive connection material) S. That is, relay connection terminal 36 constitutes the connection member, and relay connection terminal 37 constitutes the terminal member. It goes without saying that the conductive connection material is not limited to molten metal such as solder S, and may, for example, be an adhesive containing a conductive material.

The circuit board 50 is located between the pressure sensor chip 11 and external device A and functions as part of the circuit configuration. In this embodiment, it is equipped with an input/output voltage conversion and adjustment circuit that adjusts the different input/output voltages of the pressure sensor chip 11 and external device A, for example, converting the input voltage of external device A from 12V DC or 3.3V DC to the operating voltage of 5V DC for the pressure sensor chip 11. This type of conversion and adjustment circuit is not limited to this embodiment, but can be any conversion and adjustment circuit that can accommodate various drive voltages and pressure detection signal formats, such as voltage output formats for drive/output voltages different from this embodiment, current output formats such as two-wire/three-wire, or digital output formats. Note that these conversion and adjustment circuits are configured by mounting multiple electronic components (not shown).

Here, the terminal block 24 has a terminal block cap 25 attached to the opening side of the cylindrical side wall portion 24s, closing off the installation space SR for the lead pins 40, terminal pieces 36d, 36e, and 37d of the relay connection terminals 36 and 37, and the circuit board 50. Together with the housing 12 to which the support posts 13 of the pressure sensor chip 11 are fixed with hermetic glass 14, the pressure sensor unit 10 is constructed. The housing 12 and the outer periphery of the cap 28 connecting the coupling member 30 are welded from the outside using TIG welding, plasma welding, laser welding, or other welding methods to form an integrated unit with the desired joint strength. The pressure sensor unit 10 is then installed inside the waterproof case 20 and filled with a sealant 26, such as a urethane resin, thereby providing a waterproofing treatment and securing the unit in place. By placing the circuit board 50 within the installation space SR defined by the terminal block 24 and terminal block cap 25, a layer of air with low thermal conductivity can be formed around the circuit board 50, preventing sudden temperature changes from around the pressure sensor or from the piping from being transmitted to the circuit board 50. Furthermore, by arranging the circuit board 50 itself, the components mounted on the circuit board 50, or the connections between the circuit board 50 and the relay connection terminals 36 and 37 so that they do not come into contact with the sealing material 26, it is possible to prevent mechanical stress caused by the contraction and expansion of the sealing material 26 due to changes in ambient temperature from acting on the connecting members, components, and especially their soldered portions.

The pressure sensor unit 10 is assembled by stacking the housing 12, which is secured to the cap 28 connected to the coupling member 30, along with the terminal block 24, circuit board 50, and terminal block cap 25. The terminal block 24 is first mounted on the housing 12, with the relay connection terminals 36 and 37 set in the terminal holders 51 and 53 of the side wall 24s. The ends of the lead pins 40 are then spot-welded to the terminal pieces 36e of the relay connection terminals 36. The circuit board 50 is then placed on the terminal pieces 36d and 37d of the relay connection terminals 36 and 37 and soldered to establish electrical connection. Needless to say, the terminal pieces 36e of the relay connection terminals 36 can be electrically connected to the end faces of the lead pins 40 by soldering, crimping, or other methods other than spot welding. The bottom surface 24b of the terminal block 24 has appropriate insertion holes etc. to allow for assembly, including an insertion hole 24H for the oil filling pipe 44.

In detail, as shown in Figures 3 to 7, the terminal block 24 is designed to attach and hold the relay connection terminals 36, 37 to terminal holders 51, 53 formed on the side wall portion 24s.

The relay connection terminal 36 is formed in a long, elongated shape with end pieces (terminal pieces) on one end and the other end facing each other, i.e., a U-shape. The terminal pieces 36d, 36e extend in parallel to each other, and the flat portion 36f between the terminal pieces 36d, 36e on both ends is positioned parallel to the outer surface of the terminal holding portion 51 of the terminal block 24, with the terminal pieces 36d, 36e extending into the side wall portion 24s. The relay connection terminal 37 is similarly formed in a U-shape with the terminal piece 37d extending into the side wall portion 24s of the terminal block 24 and the flat connection surface 37f aligned parallel to the outer surface of the terminal holding portion 53, while the opposite end of the terminal piece 37d is bent into a bent piece 37e. The core wire C of the lead wire 38 from the external device A is soldered to the connection surface 37f of this relay connection terminal 37, thereby electrically connecting the pressure sensor chip 11 to the external device A via the lead pin 40, relay connection terminals 36 and 37, and circuit board 50.

The terminal holder 51 has multiple inner walls 55 formed on the inside of the side wall 24s of the terminal block 24, facing each other so as to interpose grooves 55g, which are fixing grooves for securing the relay connection terminals 36. The upper surfaces of the inner walls 55 are formed at the same height and are flush with each other. Similarly, the terminal holder 53 has a single inner wall 56 formed on the inside of the side wall 24s of the terminal block 24, facing each other so as to interpose grooves 56g, which are fixing grooves for securing the relay connection terminals 37. A pair of inner walls 57 are formed between the inner walls 55, 56, facing each other so as to interpose grooves 57g, which are formed on the inside of the side wall 24s. In other words, grooves 55g-57g are formed continuously between the side wall 24s and the inner walls 55-57 of the terminal block 24.

The terminal holder 51 is positioned by inserting the terminal piece 36e of each relay connection terminal 36A-36C into the bottom of three slits 55s between the four inner wall portions 55 that face the side wall portion 24s of the terminal block 24. In this state, the flat portion 36f of each relay connection terminal 36A-36C, which is larger than the slits 55s, faces the side wall portion 24s of the inner wall portion 55, and the terminal pieces 36d of each relay connection terminal 36A-36C are folded back at a position on the same plane as the upper surface of the inner wall portion 55. The relay connection terminals 36A-36C each have protrusions (fixing portions) 36h, 36i that extend from the flat portion 36f adjacent to the terminal piece 36e in the planar direction of the flat portion 36f. Additionally, insertion grooves 55h for protrusions 36h and 36i are formed on the bottom surface of groove 55g between side wall portion 24s and side wall 55 of terminal block 24. Protrusions 36h and 36i are inserted into these insertion grooves 55h, maintaining relay connection terminals 36A-36C in an upright position. This structure of terminal holder 51 allows terminal pieces 36e of relay connection terminals 36A-36C to be inserted and assembled from the upper, open end of terminal block 24 so that they fit into grooves 55g and slits 55s; in other words, this structure forms a fixed portion. Note that protrusion 36i is not shown in Figure 2 but is shown in Figure 4.

The relay connection terminal 36 is made up of a set of three relay connection terminals 36A-36C, each with a different shape. Terminal pieces 36d and 36e are each bent perpendicular to the flat surface 36f. Of these, terminal piece 36e is formed so that it extends parallel to the bottom surface 24b of the terminal block 24, with a narrower spacing between them than terminal piece 36d. Specifically, this relay connection terminal 36 is formed so that terminal pieces 36e are connected to lead pins 40, which are arranged at equal intervals on the same circle around the support 13 to correspond to the small pressure sensor chip 11, and so are formed so that they extend parallel to each other with a narrower spacing near the center. Furthermore, terminal piece 36d is connected to a circuit board 50, which can be spaced at any desired interval, and so is formed so that it extends parallel to each other with a wider spacing than terminal piece 36e, making connection easier. As shown in Figure 4(d), the relay connection terminal 36 is formed by punching out a set of three relay connection terminals 36A-36C integrated with a lead frame 36LF, and then bending the terminal pieces 36d and 36e toward the flat portion 36f and the protrusions 36h and 36i, respectively. The slit 55s in the inner wall 55 opens from the groove 55g toward the bottom surface 24b of the terminal block 24. When the terminal fixing adhesive 26g (described below) is injected into the groove 55g to fix the relay connection terminal 36, the rear side of the flat portion 36f (the outer side of the terminal block 24) receives the terminal fixing adhesive 26g, preventing it from leaking toward the bottom surface 24b of the terminal block 24.

The terminal holder 53 has slits 53a, 53b formed on its upper and lower surfaces that penetrate the side wall 24s of the terminal block 24, allowing the terminal piece 37d and bent piece 37e of the relay connection terminal 37 to be inserted. Furthermore, the terminal piece 37d and bent piece (intersection) 37e of the terminal holder 53 are positioned so that they contact the upper surface of the inner wall 56 and the bottom surface of the groove 56g after passing through the slits 53a, 53b in the side wall 24s of the terminal block 24 and passing through the inner groove 56g in an intersecting direction. In other words, these configurations form a fixed portion for the relay connection terminal 37.

Due to this structure, the relay connection terminals 37A-37C are all manufactured with the same shape, and the terminal piece 37d and bent piece 37e are bent in the same direction perpendicular to the connection surface 37f so that they contact the upper and lower surfaces of the terminal holding portion 53. Of these, the terminal piece 37d is shaped to be inserted into the side wall portion 24s of the terminal block 24 through the slit 53a to the extent that the circuit board 50 can be placed on it. The relay connection terminals 37 are shaped so that the terminal piece 37d and bent piece 37e are narrower than the wider connection surface 37f, and engagement pieces 37g are formed on both sides of the terminal piece 37d by bending them in the same direction to hook onto the upper surface of the terminal holding portion 53. Note that these engagement pieces 37g may be omitted if the terminal fixing adhesive 26g, described below, is sufficient for fixation.

As a result, the relay connection terminal 36 can be attached to the terminal holder 51 with its long terminal pieces 36d and 36e positioned between the inner wall portions 55 (slits 55s) inside the side wall portions 24s of the terminal block 24, while its protrusions 36h and 36i are inserted into the insertion grooves 55h on the bottom surfaces of the grooves 55g between the side wall portions 24s and the inner wall portions 55 to hold the terminal in place. The terminal can also be attached so that the amount of protrusion of the terminal piece 36e into the terminal block 24 is constant. This configuration positions and supports the terminal piece 36d at the same height as the top surface of the inner wall portions 55, and the terminal piece 36e at the same height as the bottom surface of the slits 55s between the inner wall portions 55. Furthermore, the amount of protrusion of the terminal piece 36e into the terminal block 24 is constant, i.e., the fixed position of the relay connection terminal 36 can be determined. In this way, the positional relationship of the terminal piece 36e with respect to the plane on which the lead pins 40 are arranged, i.e., the position of the end face of the lead pin 40 relative to the extension direction and width direction of the terminal piece 36e, is stabilized, and the height direction of the terminal piece 36e and the end of the lead pin 40 can be stably positioned. This means that when spot welding the end face of the lead pin 40 to the terminal piece 36e, it is necessary to maintain a constant relative positional relationship between the two. Furthermore, the relay connection terminal 37 is attached to the terminal holder 53 so that the terminal piece 37d is positioned and held on the upper surface of the inner wall portion 56 inside the side wall portion 24s of the terminal block 24, i.e., the fixed position of the relay connection terminal 37 can be determined.

As a result, the terminal pieces 36e and bent pieces (fixing portions) 37e of the relay connection terminals 36, 37 can be positioned in grooves 55g, 56g that penetrate the side wall portions 24s of the terminal block 24 and are formed between the inner wall portions 55, 56. The grooves 55g, 56g are deep enough to allow the circuit board 50 to be placed on top of the terminal pieces 36, 37. The relay connection terminals 36, 37 can be positioned and fixed by injecting terminal fixing adhesive 26g into the grooves 55g, 56g. Because the grooves 55g, 56g formed by the inner wall portions 55, 56 are continuous with both sides of the groove 57g between the side wall portions 24s and the inner wall portion 57, the procedure (manufacturing method) can be easily completed by inserting a dispenser into the wide groove 57g and injecting the terminal fixing adhesive 26g (see Figure 6). After this, the relay connection terminals 36, 37 can be electrically connected by spot welding the terminal pieces 36e to the lead pins 40 in a stable position, and the circuit board 50 placed on the terminal pieces 36d, 37d can be electrically connected by soldering in a stable position. The terminal block 24 has a flat surface 29 formed on the inner surface of the arc-shaped side wall 24s facing the inner wall 57. This flat surface 29 engages with the protrusion 25a on the underside of the terminal block cap 25, preventing horizontal displacement and rotation of the terminal block cap 25 when placed on the terminal block 24. By placing the terminal block 24 and the terminal block cap 25 in close contact with each other, leakage of the sealant 26 into the terminal block 24 can be prevented when the sealant 26 is filled around the terminal block 24 and the terminal block cap 25.

These relay connection terminals 36, 37 are plated with M to improve the wettability of molten solder on the soldered terminal pieces 36d, 37d and connection surface 37f, reducing the occurrence of connection failures with the electrode surface 50u of the circuit board 50 (described below) and enabling conductive connection. Plating M is also applied to the area adjacent to the connection surface 37f of the relay connection terminal 37, improving the wettability of the solder and reducing the occurrence of connection failures when soldered to the core wire C of the lead wire 38. Because plating M is applied only to the areas of the relay connection terminals 36, 37 required for soldering and not to other areas, the outflow of molten solder is suppressed. In addition to providing areas with plating M to improve solder wettability, as in this example, the soldering surface may remain as a bare metal surface, with resist or coating applied to areas to restrict solder flow.

As shown in Figure 8, the outer peripheral edge of the circuit board 50, corresponding to the terminal pieces 36d, 37d of the relay connection terminals 36, 37, is recessed inward in a U-shape parallel to the plane of the circuit board 50, forming a connection region recessed electrode surface (recessed wall surface) 50u that opens to both the front and back sides perpendicular to the plane of the circuit board 50. This recessed wall electrode surface 50u extends inward from the outer peripheral edge of the circuit board 50 in a semicircular shape a distance L, allowing molten solder to easily penetrate the entire surface, and its inner surface is plated with plating M, which provides excellent solder wettability. In other words, the recessed wall electrode surface 50u is formed as an oval cutout with a depth L extending from the outer peripheral edge of the circuit board 50 toward the interior of the board. By making the recessed wall surface semicircular, it is expected that stress within the recessed wall surface 50u during fillet formation by solder will be evenly distributed. Uniform stress improves resistance to defects such as poor conductivity due to cracks in soldered joints caused by repeated heating and cooling, or heat cycles, applied to the pressure sensor, resulting in a highly reliable connection. Furthermore, in the manufacturing process for the circuit board 50, it can be manufactured using the same machining tools used to drill mounting holes for mounted components and to cut the exterior shape of the circuit board 50. A rectangular shape requires separate processes and tools, such as cutting with a disk-shaped cutter, so a semicircular shape offers advantages in terms of productivity and quality.

In contrast, the terminal pieces 36d, 37d of the relay connection terminals 36, 37 are formed wider than the recessed wall electrode surface 50u of the circuit board 50 and longer than the depth (distance) L from the outer peripheral edge surface of the recessed wall electrode surface 50u, allowing the circuit board 50 to be placed in a stable position. Furthermore, the terminal block 24 has support pillar-shaped portions 54 formed on the inner surface of the side wall portion 24s that fit into the corner recesses 50r formed at the four corners of the circuit board 50, allowing the circuit board 50 to be positioned. In other words, the terminal pieces 36d, 37d of the relay connection terminals 36, 37 function as support regions that support the vicinity of the recessed wall electrode surface 50u of the circuit board 50. In this embodiment, recessed wall electrode surfaces 50u are formed in the connection areas of both circuit boards 50 that connect to the terminal pieces 36d, 37d of the relay connection terminals 36, 37. However, this is not limited to this; connection may be made on the outer peripheral end surface of the circuit board 50 without forming recessed wall electrode surfaces 50u, or recessed wall electrode surfaces 50u may be formed on only one side. However, forming recessed wall electrode surfaces 50u on both sides is preferable in terms of connection workability and reliability.

As a result, as shown in FIG. 9(a), the circuit board 50 is placed stably on the terminal pieces 36d, 37d of the relay connection terminals 36, 37 and positioned on the support pillars 54 of the terminal block 24. The terminal pieces 36d, 37d are then reliably connected to the recessed wall electrode surface 50u by solder S, which has a larger capacity and a stable shape with a sufficient fillet height than the semicircular recessed wall electrode surface 50u' shown in FIG. 9(b). Because the soldered connection area is on the back side of the circuit board 50, it cannot be directly visually confirmed. However, as in this embodiment, by visually inspecting or image-recognizing the condition of the fillet inside the recessed wall portion 50u, it is possible to determine whether the soldering was performed properly. The circuit board 50 also has an insertion hole 50H through which the oil filler pipe 44 is inserted during assembly.

In this way, in the pressure sensor unit 10 of the pressure sensor 100 of this embodiment, the relay connection terminals 36, 37 are positioned in the grooves 55g, 56g of the terminal holders 51, 53 formed on the side wall portion 24s of the terminal block 24, and the terminals can be fixed using terminal fixing adhesive 26g while the circuit board 50 is placed in the grooves 55g, 56g (manufacturing method).

For this reason, as shown in Figure 15, when the terminal holders 51, 53 formed on the side wall 24s of the terminal block 24 are U-shaped and the relay connection terminals 36, 37 are inserted from the outside, the terminal block 24 must be turned sideways and the terminal fixing adhesive 26a must be injected into the grooves opening on the underside of the terminal holders 51, 53 of the side wall 24s at least twice. In contrast, in this embodiment, the terminal block 24 in an upright position and the relay connection terminals 36, 37 can be fixed simply and quickly by injecting the terminal fixing adhesive 26g once, and the positioning accuracy of the relay connection terminals 36, 37 can also be prevented from decreasing when the terminal block 24 is turned sideways.

As a result, assembly can be easily performed using a simple structure in which the circuit board 50 is simply placed on the terminal block 24 installed above the pressure sensor chip 11 and electrically connected, making it possible to provide a pressure sensor 100 equipped with a pressure sensor unit 10 that is electrically connected with high reliability and quality.

As a first alternative aspect of this embodiment, instead of forming protrusions 36h and 36i on the relay connection terminal 36 mounted on the terminal holder 51 to maintain its position, as shown in FIG. 10(a), the relay connection terminal 36 may be folded back within the groove 55g of the terminal holder 51 and abutted against both wall surfaces to maintain its position while being positioned and fixed with terminal fixing adhesive 26g. However, if microfabrication to bend the relay connection terminal 36 is difficult, adopting the structure of this embodiment is preferable. Furthermore, as shown in FIG. 10(b), similar to the relay connection terminal 37 and the terminal holder 53, the terminal pieces 36d and 36e extending from both sides of the flat portion 36f' of the relay connection terminal 36 may be allowed to pass through the groove 55g of the terminal holder 51 and be positioned and fixed with terminal fixing adhesive 26g. However, with the relay connection terminal 36, the longer terminal piece 36e must pass through two locations on either side of the groove 55g in the terminal holding portion 51, which can make the insertion process complicated, so it is preferable to adopt the structure of this embodiment.

As a second alternative aspect of this embodiment, instead of fabricating relay connection terminals 36 with narrowly spaced terminal pieces 36e to accommodate closely spaced lead pins 40, three relay connection terminals 39 may be fabricated in the same U-shape, each having terminal pieces 39d, 39e that connect to the lead pins 40 and the circuit board 50, and are arranged at equal intervals on the same circle around the support post 13, as shown in FIG. 11 . Specifically, the terminal holder 51 may be fabricated so that the relay connection terminals 39 can be attached with the terminal pieces 39e facing toward the center so as to be connectable to closely spaced lead pins 40, and may have grooves 59g for injecting terminal fixing adhesive 26g. By arranging the relay connection terminals 39 radially to correspond to the lead pins 40, i.e., concentrically with the arrangement of the lead pins 40, the lengths of the terminal pieces 39e of the relay connection terminals 39 can be made uniform, and the three relay connection terminals 39 can be made identical in shape. Furthermore, for example, if the terminal block 24 is formed with terminal holding portions 51 equal to the number of lead pins 40, the number of relay connection terminals 39 for conductive connection between the lead pins 40 and the circuit board 50 can be increased or decreased depending on the circuit configuration of the circuit board 50, making it possible to accommodate a variety of circuit configurations.

As a third alternative to this embodiment, as shown in FIG. 12, the inner wall portions 55, 56 of the terminal holders 51, 53 may be extended outward on both sides, thereby eliminating the need to form the inner wall portion 57 and groove 57g inside the side wall portion 24s of the terminal block 24. In this case, the terminal fixing adhesive 26g that fixes the relay connection terminals 36, 37 needs to be injected at two locations, but the amount injected can be reduced. Furthermore, considering the fluidity of the terminal fixing adhesive 26g, even if the terminal fixing adhesive 26g does not completely fill the grooves 55g, 56g, and 57g, it can be injected primarily into the grooves 55g and 56g, preventing problems such as the terminal fixing adhesive 26g not completely filling or being cut off or overflowing from the grooves.

It goes without saying that the structures of the terminal holders 51, 53 and the relay connection terminals 36, 37 in this embodiment may be interchanged, or one of the structures may be unified and used in common.

For example, as a fourth alternative embodiment of this embodiment, as shown in FIG. 13, instead of using the relay connection terminal 37 as a terminal member, the lead wire 38 may be used as the terminal member, passing through the terminal block 25 and electrically connected to the circuit board 50 by soldering or the like. In this fourth alternative embodiment, the lead wire 38 is electrically connected to the circuit board 50 in advance, and the terminal piece 36e of the relay connection terminal 36 is spot welded to the lead pin 40. The circuit board 50 to which the lead wire 38 is connected is then placed on the terminal piece 36d of the relay connection terminal 36, and the placement portion is soldered and then covered with the terminal block cap 25 to complete the assembly. After this assembly process, the sealant 26 is filled between the waterproof case 20 and the terminal block 24 and terminal block cap 25.

In addition, as a fifth alternative aspect of this embodiment, as shown in Figure 14, the relay connection terminal 37 may be left as is, and the lead pin 40 may be used as the connecting member and directly soldered to the circuit board 50 for electrical connection without using the relay connection terminal 36 of the connecting member.

The scope of the present invention is not limited to the exemplary embodiments shown and described, but also includes all embodiments that achieve equivalent effects to the object of the present invention. Furthermore, the scope of the present invention is not limited to the combination of inventive features specified in each claim, but can be defined by any desired combination of all the respective disclosed specific features.

10... Pressure sensor unit 11... Pressure sensor chip 20... Waterproof case 24... Terminal block 24b... Bottom surface portion 24s... Side wall portion 25... Terminal block cap 26... Sealing material 26a, 26g... Terminal fixing adhesive 29... Planar portion 30... Joint member 36, 36A to 36C, 37, 37A to 37C, 39... Relay connection terminal 36d, 36e, 37d, 39d, 39e... Terminal piece 36f... Planar portion 36h, 36i... Projection piece 37e... Bend Piece 37f... connection surface 37g... engaging piece 38... lead wire 40... lead pin 50... circuit board 50r... angular recess 50u... recessed wall electrode surface 51, 53... terminal holding portion 53a, 53b... slit 54... pillar-shaped portion 55 to 57... inner wall portion 55g to 57g, 59g... groove 55h... insertion groove 55s... slit 100... pressure sensor A... external device L... recess distance LR... liquid-sealed chamber M... plating S... conductive connecting material SR... installation space

Claims (6)

A pressure sensor configured by a sensor unit including a sensor connected to an external device,
a circuit board that is disposed between the sensor and the external device and is connected to the sensor; one or both of a connection member that is located between the sensor and the circuit board and is conductively connected to the sensor and the circuit board, and a terminal member that is conductively connected to the circuit board and is used to conductively connect the circuit board to the external device; and a terminal block that fixes, positions, and supports the connection member and/or the terminal member;
the circuit board is placed on one or both of the connection members and the terminal members;
The terminal block has a fixing groove formed therein that has a depth in the direction in which the circuit boards are stacked and that extends at least to the fixing positions of one or both of the connecting member and the terminal member, and the fixing portions of one or both of the connecting member and the terminal member are positioned in the fixing groove and are bonded and positioned with an adhesive. The pressure sensor described in claim 1, characterized in that it comprises a side wall portion that forms the outer surface of the terminal block and an inner wall portion that is positioned facing the inside of the side wall portion and forms the fixing groove. The pressure sensor described in claim 1, characterized in that the fixing groove is formed in a continuous shape so as to include at least the fixing points of one or both of the connecting member and the terminal member. The pressure sensor described in claim 1, characterized in that one or both of the connection member and the terminal member have a fixing portion that extends in a direction overlapping the circuit board and is positioned within the fixing groove, and is fixed to the terminal block. The pressure sensor described in claim 1, characterized in that one or both of the connecting member and the terminal member are fixed to the terminal block with their intersecting portions, which extend in a direction intersecting the depth direction of the fixing groove, positioned within the fixing groove. A method for manufacturing a pressure sensor configured by a sensor unit including a sensor connected to an external device, comprising:
The sensor unit includes a circuit board that is disposed between the sensor and the external device and is connected to the sensor; one or both of a connection member that is located between the sensor and the circuit board and is conductively connected to the sensor and the circuit board, and a terminal member that is conductively connected to the circuit board and is used to conductively connect the circuit board to the external device; and a terminal block that fixes, positions, and supports one or both of the connection member and the terminal member,
the circuit board is placed on one or both of the connection member and the terminal member;
the terminal block has a fixing groove formed therein, the fixing groove having a depth in the direction in which the circuit boards are stacked and extending at least to a fixing position of one or both of the connection member and the terminal member;
The terminal block has:
A method for manufacturing a pressure sensor, characterized in that the fixing portions of one or both of the connecting member and the terminal member are positioned in the fixing groove, adhesive is injected into the fixing groove to position, adhere and fix them, and then the circuit boards are stacked and held together to assemble.