JP2020187029A - Pressure detection device - Google Patents

Abstract

To provide a pressure sensor excellent in noise resistance with a small number of components.SOLUTION: A pressure detection device 1 comprises a metal housing having a diaphragm 3a that is deformed under pressure received from a pressure medium, a sensor element 2 for detecting a pressure by detecting the deformation of the diaphragm 3a, and a resin molded member 7 forming a metal plated wire 8 for electrically connecting the sensor element 2 and a connector terminal 5a. A first surface the metal plated wire 8 has, or a surface on the side of the metal housing, and a second surface the metal housing has, or an upper surface of a base member 6, are arranged so as to face with each other at a predetermined interval across an adhesive 9 serving as an insulator.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pressure detector.

In order to respond to the environment of automobiles and improve fuel efficiency, the adoption of hydraulic systems that generate flood control by electric motors and fuel injection systems that apply pressure to fuel to inject it is expanding. These systems are equipped with pressure sensors to detect pressure. Generally, a pressure sensor for detecting oil pressure (hereinafter referred to as a pressure sensor) is housed in a metal housing to ensure strong reliability, and is a measurement target such as hydraulic oil or liquid fuel. It is attached by screw tightening to the metal pipe through which the pressure medium flows. The metal pipe is fixed to a structure having a body GND potential, such as an automobile body or an engine. Therefore, the potential of the metal housing of the pressure sensor becomes the body GND potential as in the metal piping.

The pressure sensor is connected to an electronic control device (ECU: Electrical Control Unit) mounted on the automobile via a harness. If unnecessary electromagnetic waves are present around the harness, the harness acts as an antenna and easily picks up the electromagnetic waves. Then, the electromagnetic wave travels through the harness and flows into the pressure sensor as noise. A detection element that detects pressure in the pressure sensor is arranged between the pressure sensor and the metal housing via an insulating layer. This corresponds to an electrically connected parasitic capacitance having a relatively large capacitance between the detection element and the metal housing. Since the noise flowing from the harness to the pressure sensor is alternating current, the larger the parasitic capacitance, the easier it is for noise to flow from the pressure sensor to the metal housing via the parasitic capacitance. At this time, noise may flow through the processing circuit in the middle, causing the processing circuit to malfunction.

In order to solve the above problems, the technique described in Patent Document 1 is known. In Patent Document 1, a chip capacitor is installed in a pressure sensor, and one electrode of the chip capacitor is electrically connected to the housing, so that noise input to the pressure sensor is transmitted to the housing and the object to be measured via the chip capacitor. The technology to ensure the resistance of the pressure sensor to noise is shown.

Japanese Unexamined Patent Publication No. 2005-257442

In the technique described in Patent Document 1, the substrate and the housing are adhered to each other by a conductive adhesive, so that the chip capacitor mounted on the wiring pattern of the substrate and the housing are electrically connected. Therefore, in order to improve the resistance to electromagnetic noise, it is necessary to add a new chip capacitor, and there is a problem that the number of parts increases accordingly.

The pressure detecting device according to the present invention includes a metal housing having a deformed portion that is deformed by the pressure received from the pressure medium, a detecting element that detects the pressure by detecting the deformation of the deformed portion, and the detecting element and the connector terminal. A resin molded member on which a metal-plated wiring for electrically connecting the two is provided, and the first surface of the metal-plated wiring and the second surface of the metal housing are insulated from each other. They are arranged so as to face each other at predetermined intervals with the body in between.

According to the present invention, it is possible to provide a pressure sensor having excellent noise resistance with a small number of parts.

It is a vertical sectional view which shows the structure of the pressure detection apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the appearance of the resin molding member. It is a figure explaining the capacitor formation using a parasitic capacitance. It is a figure explaining the difference of the circuit operation at the time of noise input when this invention is applied and the case where it is not applied. It is a figure which shows the positional relationship between a metal-plated wiring and a metal housing. It is a figure which shows the example of the EMC test result with respect to the pressure detection apparatus. It is a vertical sectional view which shows the structure of the pressure detection apparatus which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be described.

(First Embodiment)
FIG. 1 is a vertical cross-sectional view showing the configuration of the pressure detecting device 1 according to the first embodiment of the present invention. The pressure detection device 1 is mounted on an automobile and is used, and includes a sensor element 2, a pressure port 3, a connector subassembly 5, a base member 6, a resin molding member 7, and a metal-plated wiring 8.

A rectangular diaphragm 3a that acts as a pressure receiving surface of the pressure medium to be measured is provided on the upper portion of the pressure port 3. The upper surface of the diaphragm 3a, that is, the surface opposite to the pressure receiving surface, is the pedestal surface 3b on which the sensor element 2 is placed. The pressure port 3 introduces a pressure medium such as hydraulic oil or liquid fuel into the pressure receiving surface of the diaphragm 3a. As a result, the diaphragm 3a is deformed according to the pressure of the pressure medium, and distortion is generated. The sensor element 2 detects the amount of deformation, that is, the amount of strain of the diaphragm 3a by measuring the change in the resistance value according to the strain of the diaphragm 3a, and thereby detects the pressure of the pressure medium.

The pressure port 3 and the base member 6 are both made of metal such as SUS, and are joined to each other by welding or the like. A resin molding member 7 is fixed on the base member 6 by an adhesive 9. Hereinafter, the combination of the pressure port 3 and the base member 6 is referred to as a “metal housing”. It should be noted that there is no problem in using a metal housing in which the pressure port 3 and the base member 6 are integrally formed, instead of joining the pressure port 3 and the base member 6 to form a metal housing.

The connector subassembly 5 has a connector terminal 5a. A harness (not shown) is connected to the connector terminal 5a. The pressure detection device 1 outputs the pressure detection result to the ECU by being connected to the ECU of the automobile via this harness. The connector subassembly 5 is integrally molded with a cover 10 for shielding the sensor element 2 and the like from the outside.

The resin molding member 7 is a resin structure in which the metal-plated wiring 8 is formed. In the pressure detection device 1 of the present embodiment, the resin molded member 7 eliminates the need for a metal member such as a lead frame that has been conventionally used. The resin molding member 7 is formed with an insertion portion 7c (see FIG. 2) for inserting the connector terminal 5a. A metal-plated wiring 8 is arranged on the inner wall of the insertion portion 7c. A bonding portion 8a (see FIG. 2) connected to the sensor element 2 by wire bonding using the wire 11 is provided on the other end side of the metal-plated wiring 8. For the wire 11, for example, aluminum (Al) or gold (Au) is used. By inserting the connector terminal 5a into the insertion portion 7c of the resin molding member 7 and enclosing it with the conductive paste 5b, the sensor element 2 can be inserted through the wire 11, the metal-plated wiring 8, the conductive paste 5b, the connector terminal 5a, and the harness. It is electrically connected to the ECU.

When assembling the pressure detection device 1, the resin molding member 7 on which the metal-plated wiring 8 is formed is fixed on the base member 6 with an adhesive 9, and the sensor element 2 and the bonding portion 8a of the metal-plated wiring 8 are wired. Connect with 11. Then, in order to protect the sensor element 2 from foreign matter and the like, the silicone gel 12 is potted on the surface of the sensor element 2. Then, after applying the conductive paste 5b into the insertion portion 7c of the resin molding member 7, the connector terminal 5a is inserted into the insertion portion 7c and fixed. In this state, the connector subassembly 5 and the metal housing are integrated by joining the cover 10 and the base member 6 by welding or the like. As a result, the pressure detection device 1 is configured.

The sensor element 2 is a pressure detection element having a one-chip structure in which a strain detection element and a processing circuit are integrally formed on a silicon substrate. Therefore, a circuit board for laying out the processing circuit is unnecessary. The output signal generated by the sensor element 2 with respect to the pressure received by the diaphragm 3a passes through the wire 11, the metal-plated wiring 8, and the connector terminal 5a, and is transmitted to the ECU by the harness.

Next, the detailed shapes of the resin molding member 7 and the metal-plated wiring 8 will be described with reference to FIG. FIG. 2 is a diagram showing the appearance of the resin molded member 7 on which the metal-plated wiring 8 is formed. In FIG. 2, the figure on the left side is a projection drawing of the resin molding member 7, and the figure on the right side is a plan view.

As shown in FIG. 2, the resin molding member 7 is formed with an insertion portion 7c. On the inner wall of the insertion portion 7c, one end side of the metal-plated wiring 8 is arranged as a connector contact portion 8b. The figure on the right side of FIG. 2 shows that the connector contact portion 8b is arranged on the inner wall on the right side in the drawing in the insertion portion 7c, but if the connector terminal 5a can be reliably contacted, the connector contact portion 8b is inserted. The connector contact portion 8b can be arranged on the inner wall at an arbitrary position in the portion 7c. A bonding portion 8a for connecting to the sensor element 2 by wire bonding is provided on the other end side of the metal-plated wiring 8.

When the connector terminal 5a is inserted into the insertion portion 7c while the conductive paste 5b is applied into the insertion portion 7c including the connector contact portion 8b, the connector terminal 5a contacts the connector contact portion 8b via the conductive paste 5b. To do. As a result, it is possible to secure an electrical connection between the connector terminal 5a and the metal-plated wiring 8.

Further, the resin molding member 7 is provided with an insertion guide 7b for positioning when the connector terminal 5a is inserted into the insertion portion 7c. The position and shape of the insertion guide 7b are formed so as to correspond to the position and shape of a protrusion (not shown) provided on the connector subassembly 5. If the insertion guide 7b does not exist, the position and orientation of the connector terminal 5a may shift when the connector terminal 5a is inserted into the insertion portion 7c, and the connector terminal 5a may not be accurately contacted with the connector contact portion 8b. Therefore, in the present embodiment, by providing the insertion guide 7b in the resin molding member 7, when the connector subassembly 5 is assembled, the insertion guide 7b is fitted with the protrusion of the connector subassembly 5 to form the connector terminal 5a. Positioning is done. In the state of being positioned in this way, the connector terminal 5a is inserted into the insertion portion 7c.

Further, the resin molding member 7 is provided with a mounting portion 7a on which electronic components such as chip capacitors are mounted. The connector terminal 5a is press-molded into a shape that does not interfere with the electronic components mounted on the mounting portion 7a when inserted into the inserting portion 7c so as not to interfere with the mounting of the electronic components on the mounting portion 7a. ing. After mounting the necessary electronic components, the mounting portion 7a is potted with the silicone gel 12 in the same manner as the sensor element 2 to protect the surface (see FIG. 1).

Next, the capacitor formation using the parasitic capacitance, which is a feature of the present embodiment, will be described below with reference to FIGS. 3 and 4.

FIG. 3 is a partially enlarged view of the pressure port 3 on which the sensor element 2 is mounted. As shown in FIG. 3, the sensor element 2 is bonded onto the pressure port 3 via a bonding agent 4. As described above, the sensor element 2 has a one-chip configuration in which the strain detection element and the processing circuit are integrally formed. The adhesive 4 is an insulator such as an inorganic adhesive, and is applied with a thickness extremely thin compared to the area of the sensor element 2. Therefore, on the circuit including the sensor element 2, the joint portion between the sensor element 2 and the pressure port 3 sandwiching the bonding agent 4 acts as a parasitic capacitance Cic having a relatively large capacitance.

FIG. 4 is a diagram illustrating the action of the parasitic capacitance Cic. FIG. 4A shows a schematic circuit diagram when the noise countermeasures of the present embodiment are not taken, and FIG. 4B shows a circuit schematic diagram when the noise countermeasures of the present embodiment are taken. There is. The IC and the protection circuit shown in these schematic circuit diagrams show a circuit composed of electronic components mounted on the mounting portion 7a of the sensor element 2 and the resin molding member 7.

In the case of FIG. 4A in which noise countermeasures have not been implemented, when noise is input from the wiring connected to the IC via the protection circuit, the noise is a parasitic capacitance provided between the IC and the metal housing. It flows through the CiC into the metal housing of the body GND potential. At that time, noise may pass through the IC, that is, the processing circuit of the sensor element 2, causing the processing circuit to malfunction, and the output of the sensor element 2 may become abnormal.

On the other hand, in the case of FIG. 4B in which noise countermeasures are taken, a capacitance Ct that acts as a noise path is formed between the metal-plated wiring 8 and the metal housing, as will be described later. Therefore, the input noise flows into the metal housing of the body GND potential through the capacitance Ct without passing through the IC. As a result, it is possible to avoid a malfunction of the processing circuit due to noise and prevent an output abnormality of the sensor element 2.

In general, if parasitic components such as inductance and resistance are ignored in a capacitor, the impedance becomes smaller as the capacitance is larger at the same frequency, and AC current becomes easier to flow. That is, assuming that the capacitance of the capacitor is C [F], the impedance Z [Ω] of the capacitor is expressed by the following equation (1).
Z = 1 / (ωC) ・ ・ ・ (1)

In the above equation (1), ω [rad / s] represents the angular frequency of the AC current flowing through the capacitor, which is expressed by the following equation (2) using the frequency f [Hz] of the AC current. To.
ω = 2 × π × f ・ ・ ・ (2)

As described above, if the AC current has the same frequency, the impedance Z becomes smaller as the capacitance C is larger, and the AC current becomes easier to flow. Therefore, it can be seen that by making the value of the capacitance Ct larger than the parasitic capacitance Cic, the noise flowing into the processing circuit can be suppressed and the noise immunity of the sensor element 2 can be improved.

In the present embodiment, by arranging the resin molding member 7 which is an insulator between the metal-plated wiring 8 and the metal housing, a parasitic capacitance is generated between the metal-plated wiring 8 and the metal housing, and this parasitic capacitance is generated. By using the capacitance as the above capacitance Ct, the noise immunity of the sensor element 2 is improved. This point will be described in detail below with reference to FIG.

FIG. 5 is a diagram showing a positional relationship between the metal-plated wiring 8 and the metal housing. In FIG. 5, in order to make it easy to understand the positional relationship between the metal-plated wiring 8 and the metal housing, the portion of the connector subassembly 5 excluding the tip of the connector terminal 5a and the resin molding member 7 are removed. The appearance of the pressure detection device 1 is shown. In FIG. 5, the left side view is a front view of the pressure detection device 1, and the right side view is a plan view.

As shown in the hatched portion on the right side of FIG. 5, in the pressure detecting device 1 of the present embodiment, a flat plate-shaped region parallel to the base member 6 is formed between the bonding portion 8a and the connector contact portion 8b in the metal-plated wiring 8. The parallel plate region 8c is formed. The parallel plate region 8c is formed as wide as possible and is arranged as close as possible to the base member 6. As a result, a parallel plate capacitor is formed by the metal-plated wiring 8 and the metal housing, and a parasitic capacitance Ct acting as a noise path is positively generated.

Although not shown in FIG. 5, in the portion where the parallel plate capacitor is formed, an adhesive composed of an insulator such as resin is provided between the metal-plated wiring 8 and the metal housing (base member 6). 9 is arranged. Therefore, the parasitic capacitance Ct can be increased by the amount corresponding to the relative permittivity of the insulator as compared with the case of air. As a result, as described above, the capacitance value of the parasitic capacitance Ct can be made larger than that of the parasitic capacitance Cic, and the noise immunity of the sensor element 2 can be ensured.

In the prior art, a chip capacitor is generally used as a capacitor for the noise pass. On the other hand, in the pressure detection device 1 of the present embodiment, the lower surface of the parallel plate region 8c of the metal-plated wiring 8, that is, the surface on the base member 6 side and the upper surface of the base member 6 in the metal housing are Adhesives 9 are sandwiched between them and arranged so as to face each other at predetermined intervals. As a result, a parallel plate capacitor is formed between the metal-plated wiring 8 and the metal housing, and the parasitic capacitance Ct of this parallel plate capacitor is used as a capacitor for the noise path. Therefore, since it is not necessary to use a chip capacitor, it is possible to realize the pressure detection device 1 having excellent noise resistance with a small number of parts.

Next, the distance between the metal-plated wiring 8 and the metal housing will be described. In order to increase the capacitance value of the parasitic capacitance Ct, as described above, the parallel plate region 8c of the metal-plated wiring 8 may be as close to the metal housing as possible. However, even when a surge voltage having a magnitude of several hundred [V] is input, a certain distance is maintained so as to secure insulation between the metal-plated wiring 8 and the metal housing and prevent the state of conduction. There is a need.

It is generally known that dielectric breakdown of air occurs when the potential gradient E [V / m] is 3 [MV / m] or more. If there is a defect such as a void in the insulator, if dielectric breakdown occurs, the surrounding resin will be carbonized, which may lead to problems such as conduction between the metal-plated wiring 8 and the metal housing, and must be avoided. Here, the value of the surge voltage generally assumed in the surge test is about 300 [V]. Therefore, from these values, the minimum distance between the metal-plated wiring 8 and the metal housing is calculated to be 0.1 [mm].

Further, as a result of conducting an EMC test using the pressure detection device 1 of the present embodiment, it was confirmed that the expected noise immunity is not exhibited when the parasitic capacitance Ct is less than 9 [pF]. Here, the parallel plate capacitor capacity C [F] is expressed by the following equation, where the area of the plates is A [m ² ], the distance between the plates is d [m], and the dielectric constant is ε [F / m]. It is represented by 3).
C = (εA) / d ... (3)

In the above equation (3), when the values corresponding to the pressure detection device 1 are substituted for A and ε, respectively, and the distance d between the plates when C = 9 [pF] is calculated, d = 0.9 [mm]. Is calculated. Therefore, the maximum distance between the metal-plated wiring 8 and the metal housing is required to be 0.9 [mm].

As described above, it is desirable that the distance between the metal-plated wiring 8 and the metal housing in the pressure detection device 1 is set in the range of 0.1 [mm] to 0.9 [mm]. However, for the maximum distance of 0.9 [mm], the area of the parallel flat plate region 8c of the metal-plated wiring 8 and the permittivity of the adhesive 9 sandwiched between the metal-plated wiring 8 and the metal housing. This does not apply because it changes according to.

Further, in order to improve the noise immunity of the pressure detection device 1, it is effective to decrease the capacitance value of the parasitic capacitance Cc instead of increasing the capacitance value of the parasitic capacitance Ct. Specifically, for example, by thickening the bonding agent 4 that joins the sensor element 2 to the pressure port 3, the capacitance value of the parasitic capacitance Cic can be reduced. That is, from the above equation (3), it can be seen that the parallel plate capacitor capacity C decreases as the distance d between the plates increases. Therefore, by thickening the bonding agent 4 within a range that does not affect the strain detection performance of the sensor element 2 and increasing the distance between the sensor element 2 and the pressure port 3, the capacitance value of the parasitic capacitance CiC is reduced. It is possible to improve the noise immunity of the pressure detection device 1.

The position where the parasitic capacitance Ct is generated in the pressure detection device 1 is as close as possible to the vicinity of the entrance of the circuit shown in FIG. 4, that is, the connector of the resin molding member 7 rather than the mounting portion 7a on which electronic components such as chip capacitors are mounted. It is desirable that the position is closer to the insertion portion 7c connected to the terminal 5a. In this case, the connection order as seen from the sensor element 2 is the order of the wire 11, the bonding portion 8a of the metal-plated wiring 8, the electronic component, and the parasitic capacitance Ct. That is, in the metal-plated wiring 8, the electronic component mounted on the mounting portion 7a is connected on the electric path between the bonding portion 8a and the parallel flat plate region 8c. As a result, the input noise can be effectively flowed from the parasitic capacitance Ct to the metal housing, so that the noise immunity can be further improved.

FIG. 6 is a diagram showing an example of EMC test results for the pressure detection device 1 of the present embodiment. FIG. 6A shows an example of the EMC test result when the structure for noise suppression described above is not provided, and FIG. 6B shows the EMC test result when the structure for noise suppression is provided. An example of is shown. Comparing FIGS. 6 (a) and 6 (b), it can be seen that the noise suppression structure of the present embodiment provides good noise immunity over a wide frequency range.

According to the first embodiment of the present invention described above, the following effects are exhibited.

(1) The pressure detection device 1 includes a deformed portion that is deformed by the pressure received from the pressure medium, that is, a metal housing having a diaphragm 3a, a sensor element 2 that detects pressure by detecting deformation of the deformed portion, and a sensor element. A resin molding member 7 on which a metal-plated wiring 8 for electrically connecting the 2 and the connector terminal 5a is formed is provided. The first surface of the metal-plated wiring 8, that is, the surface of the parallel flat plate region 8c on the metal housing side, and the second surface of the metal housing, that is, the upper surface of the base member 6, are adhesives 9 which are insulators. Are arranged to face each other at predetermined intervals with a. As described above, it is possible to provide the pressure detection device 1 which is a pressure sensor having excellent noise resistance with a small number of parts by generating a parasitic capacitance Ct between the metal-plated wiring 8 and the metal housing.

(2) The capacitance between the first surface and the second surface, that is, the capacitance of the parasitic capacitance Ct is the capacitance between the sensor element 2 and the metal housing, that is, the parasitic capacitance Cic. It is preferably larger than the capacitance. By doing so, the amount of noise flowing through the sensor element 2 can be reduced, and malfunction of the sensor element 2 due to noise can be prevented.

(3) The resin molded member 7 is formed with an insertion portion 7c for inserting the connector terminal 5a in order to electrically connect the sensor element 2 and the connector terminal 5a. A metal-plated wiring 8 is formed on the inner wall of the insertion portion 7c, and the connector terminal 5a inserted into the insertion portion 7c is electrically connected to the metal-plated wiring 8 via the conductive paste. Since this is done, it is possible to secure an electrical connection between the connector terminal 5a and the metal-plated wiring 8.

(4) The resin molding member 7 is formed with a guide portion for positioning when the connector terminal 5a is inserted into the insertion portion 7c, that is, an insertion guide 7b. Since this is done, the position and orientation of the connector terminal 5a can be prevented from shifting, and the connector terminal 5a can be reliably brought into contact with the metal-plated wiring 8.

(5) The resin molding member 7 is joined to the metal housing by an insulating adhesive 9. The adhesive 9 serves as an insulator on the first surface of the metal-plated wiring 8, that is, the surface on the metal housing side in the parallel flat plate region 8c, and the second surface of the metal housing, that is, the upper surface of the base member 6. It is placed between. Since this is done, by controlling the amount of the adhesive 9 and adjusting the thickness of the adhesive layer, it is possible to obtain a desired capacitance with respect to the parasitic capacitance Ct.

(6) The metal-plated wiring 8 has a connecting portion, that is, a bonding portion 8a, which is connected to the sensor element 2 by wire bonding, and is located on the first surface of the bonding portion 8a and the metal-plated wiring 8, that is, the parallel flat plate region 8c. Electronic components are connected on the electrical path between the surface on the metal housing side. Since this is done, the noise immunity can be further improved.

(7) The predetermined distance between the first surface of the metal-plated wiring 8, that is, the surface of the parallel flat plate region 8c on the metal housing side and the second surface of the metal housing, that is, the upper surface of the base member 6. , 0.1 mm or more is preferable. By doing so, it is possible to avoid conduction between the metal-plated wiring 8 and the metal housing due to dielectric breakdown.

(8) The metal housing includes a pressure port 3 that introduces a pressure medium into the deformed portion, and a base member 6 that is joined to the resin molding member 7. Since this is done, the pressure detection device 1 having high noise resistance can be configured.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In this embodiment, an example of fixing the connector terminal 5a to the insertion portion 7c of the resin molding member 7 will be described by a method different from that of the pressure detection device 1 described in the first embodiment.

FIG. 7 is a vertical cross-sectional view showing the configuration of the pressure detecting device 1A according to the second embodiment of the present invention. The pressure detection device 1A of the present embodiment has a different structure of the tip of the connector terminal 5a from the pressure detection device 1 of FIG. 1 described in the first embodiment. Specifically, the connector terminal 5a in the present embodiment is a press-fit terminal having a springy tip.

In the present embodiment, the connector terminal 5a inserted into the insertion portion 7c of the resin molding member 7 is fixed in the insertion portion 7c by the springiness of the press-fit terminal, and the metal-plated wiring 8 formed on the inner wall of the insertion portion 7c. Contact the connector contact portion 8b of. Therefore, the electrical connection between the connector terminal 5a and the metal-plated wiring 8 can be ensured without using the conductive paste 5b of FIG.

According to the second embodiment of the present invention described above, the connector terminal 5a is a press-fit terminal having a springy tip. The connector terminal 5a inserted into the insertion portion 7c is electrically connected to the metal-plated wiring 8 due to the springiness of the press-fit terminal. Since this is done, it is possible to further eliminate the need for the conductive paste while exhibiting the same effects as those described in the first embodiment.

In the embodiment described above, the one-chip type sensor element 2 in which the strain detection element and the processing circuit are integrated has been described as an example, but the sensor element other than the one-chip type, that is, the strain gauge and the processing circuit is used. The present invention can be similarly applied to sensor elements formed on separate substrates.

Further, the pressure detection devices 1 and 1A described in the embodiment have been described as being mounted on an automobile and detecting the pressure of a pressure medium such as hydraulic oil or liquid fuel, but the pressure detection devices used in other applications have been described. Similarly, the present invention can be applied. As long as the sensor elements are arranged close to the metal housing in an insulated state and the metal housing has a GND potential, the improvement of noise immunity according to the present invention is effective for various pressure detection devices. Can act. For example, in a sensor that detects a load as strain, a large force is applied to the sensor, so that resin or the like cannot be used for the pressure receiving portion. In addition, the pedestal of the sensor element also needs to be firmly configured. Therefore, the housing of such a sensor is inevitably made of metal, and has a structure similar to that of the pressure detection devices 1 and 1A described in the embodiment. Therefore, by applying the present invention in the same manner, noise immunity can be achieved. It can be improved.

As described above, the sensor element used in the sensor may be a one-chip type sensor element in which the strain detection element and the processing circuit are integrated, or these are formed on separate substrates. You may be. In any case, the same effects as described in the embodiment can be obtained.

As described above, the noise pass capacitor can be formed by applying the present invention to the pressure detection device. Since this is a configuration that does not use a chip capacitor, it can be expected to improve connection reliability, reduce costs, and save space.

The embodiments and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired. Moreover, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

1,1A Pressure detector 2 Sensor element 3 Pressure port 3a Diaphragm 3b Pedestal surface 4 Adhesive 5 Connector subassembly 5a Connector terminal 5b Conductive paste 6 Base member 7 Resin molding member 7a Mounting part 7b Insertion guide 7c Insertion part 8 Metal plating Wiring 8a Bonding part 8b Connector contact part 8c Parallel flat plate area 9 Adhesive 10 Cover 11 Wire 12 Silicone gel

Claims (8)

A metal housing having a deformed part that is deformed by the pressure received from the pressure medium,
A detection element that detects the pressure by detecting the deformation of the deformed portion, and
A resin molded member having a metal-plated wiring for electrically connecting the detection element and the connector terminal is provided.
A pressure detecting device in which a first surface of the metal-plated wiring and a second surface of the metal housing are arranged so as to face each other at predetermined intervals with an insulator sandwiched between them. In the pressure detection device according to claim 1,
A pressure detection device in which the capacitance between the first surface and the second surface is larger than the capacitance between the detection element and the metal housing. In the pressure detection device according to claim 1 or 2.
The resin molded member is formed with an insertion portion for inserting the connector terminal in order to electrically connect the detection element and the connector terminal.
The metal-plated wiring is formed on the inner wall of the insertion portion.
The connector terminal inserted into the insertion portion is a pressure detection device that is electrically connected to the metal-plated wiring via a conductive paste. In the pressure detection device according to claim 1 or 2.
The resin molded member is formed with an insertion portion for inserting the connector terminal in order to electrically connect the detection element and the connector terminal.
The metal-plated wiring is formed on the inner wall of the insertion portion.
The connector terminal is a press-fit terminal having a springy tip.
The connector terminal inserted into the insertion portion is a pressure detecting device that is electrically connected to the metal-plated wiring due to the springiness of the press-fit terminal. In the pressure detection device according to any one of claims 1 to 4.
The resin molded member is joined to the metal housing by an insulating adhesive.
A pressure detection device in which the adhesive is arranged as the insulator between the first surface and the second surface. In the pressure detection device according to any one of claims 1 to 5.
The metal-plated wiring has a connection portion connected to the detection element by wire bonding.
A pressure detecting device in which an electronic component is connected on an electric path between the connecting portion and the first surface. In the pressure detection device according to any one of claims 1 to 6.
A pressure detector having a predetermined interval of 0.1 mm or more. In the pressure detection device according to any one of claims 1 to 7.
The metal housing is a pressure detecting device including a pressure port for introducing the pressure medium into the deformed portion and a base member joined to the resin molding member.

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