JP2000310575A - Pressure sensor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the layout configuration of a sensor element part that does not require any alignment for the introduction path of a case in a pressure sensor where sensor element parts for detection pressure are arranged at a case with the introduction path where a pressure medium can be circulated. SOLUTION: At a case 2 made of resin with a recess 2a, a through hole 2b as an introduction path is formed so that one end side is open in the recessed part 2a and the other end side is open at the outside. In the recess 2a of the case 2, a plate 1 that is a porous member with a breathing property such as porous ceramic or porous resin is subjected to insert molding so that an opening at one end side of the through hole 2b can be covered, and a sensor element part 6 where a pressure sensor element 4 is fixed to a glass pedestal 5 is glued onto the plate 1 via an adhesive 7. The sensor element part 6 can be placed at an arbitrary position on the plate 1 or may receive an external pressure from the through hole 2b via the plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a case having an introduction passage through which a pressure medium can flow, and a sensor element for detecting pressure provided in the case, and the pressure medium is supplied to the sensor element through the introduction passage. The present invention relates to a pressure sensor to be introduced into a part and a method of manufacturing the same, and more particularly, to an arrangement structure and an arrangement method of a sensor element part in an introduction path.

[0002]

2. Description of the Related Art A pressure sensor of this type is disclosed in
Japanese Unexamined Patent Publication No. 261837 proposes a method.
As shown in FIG. 6, a pressure introduction hole (introduction path) J2 on the case J1 side and a pedestal J4 for fixing the sensor chip J3 are provided.
In order to ensure good communication with the pressure introduction hole (introduction path) J5 on the side, in order to accurately position both pressure introduction holes J2 and J5, projections J6 are provided at four places on the inner wall of the case J1.
The displacement is limited.

[0003]

However, in the above-mentioned conventional pressure sensor, as shown in FIG. 7, when the sensor element portion composed of the sensor chip J3 and the pedestal J4 is inserted into the case J1 and attached, the pedestal is not mounted. A problem occurs in that the bottom portion of J4 rides on the protrusion J6 and tilts.

Here, the present inventors have paid attention to the fact that the above-mentioned problem is caused by forcibly restricting the displacement of the sensor element portion (pedestal) by the projection, and rather than devising a positioning means. Even if the sensor element portion is arranged at an arbitrary position, it is considered that the positioning itself may be unnecessary by making it possible to ventilate the introduction path on the case side.

The present invention has been made in view of the above problems, and in a pressure sensor in which a sensor element for detecting pressure is provided in a case having an introduction path through which a pressure medium can flow, there is no need to position the case with respect to the introduction path. It is an object of the present invention to provide an arrangement configuration of a sensor element portion as described above, and to provide a method of manufacturing a pressure sensor that does not require alignment with a case introduction path.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a case (2) having an introduction path (2b) for introducing external pressure, and a pressure chamber provided in the case are provided. A pressure sensor having a sensor element for detection (6), wherein the pressure medium is introduced into the sensor element from the introduction path. Mounting the sensor element portion on the porous member so as to cover the opening on the sensor element portion side in the introduction path, mounting the sensor element portion on the porous member, and interposing the sensor element portion and the introduction path through the porous member. It is characterized by ensuring air permeability (ventilation) between it and.

According to the present invention, since air permeability is ensured by the porous member between the sensor element and the introduction path,
Since the pressure from the introduction path of the case is introduced into the sensor element via the porous member, in mounting the sensor element to the case, it is only necessary to fix the sensor element to an arbitrary position on the porous member. good. Therefore, it is possible to provide an arrangement configuration of the sensor element portion that does not require the positioning of the case with respect to the introduction path.

According to the second aspect of the present invention, the concave portion (2
(a), an introduction path (2b) provided in the case such that one end side opens into the recess and the other end opens to the outside, and the introduction path in the recess of the case. The sensor comprises: a porous member (1) having air permeability (ventilation) provided so as to cover an opening at one end side of a road; and a sensor element portion (6) mounted on the porous member. The element section receives external pressure from the introduction path via the porous member.

According to the pressure sensor of the present invention, claim 1 is also provided.
As with the pressure sensor of the above, since air permeability (ventilation) is ensured by a porous member between the sensor element portion and the introduction path, it is only necessary to fix the sensor element portion at an arbitrary position of the porous member. It is possible to provide an arrangement configuration of the sensor element portion that does not require positioning of the case with respect to the introduction path.

Here, in the pressure sensor according to the second aspect of the present invention, the portion of the porous member (1) other than the mounting portion of the sensor element (6) is sealed. Then, the adhesive (8) is applied to the concave portion (2a) of the case (2).
In this case, a pressure path from the introduction path (2b) of the case to the sensor element can be more reliably secured.

Further, as the porous member (1), a member made of a porous ceramic or a porous resin can be adopted as in the invention of the fourth aspect. According to the fifth and sixth aspects of the present invention, there is provided a method of manufacturing a pressure sensor which does not require positioning of the case with respect to the introduction path for the same reason as the operation of the first aspect of the present invention. Can be.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. 1A and 1B show a configuration of a pressure sensor 100 according to an embodiment of the present invention. FIG. 1A is a schematic plan view, and FIG. 1B is a cross-sectional view taken along line AA in FIG. In FIG. 1A, a cap 9 described later is omitted. Although not particularly limited, the pressure sensor 100 is applicable as a sensor for detecting a fuel pressure of an automobile fuel tank, an intake pressure of an engine, and the like.

Reference numeral 1 denotes a plate (corresponding to the porous member of the present invention) made of a gas-permeable material such as porous ceramic or porous resin, for example, a resin such as PBT (polybutylene terephthalate) or PPS (polyphenylene sulfide). And a lead 3 connected to an external circuit or the like.
And is insert molded. On the bottom surface of the plate 1, a concave mold fixing portion 1a for fixing to a molding die during insert molding is formed.

The case 2 has a concave portion 2a for accommodating the sensor element portion 6, and a through hole for introducing an external pressure formed so that one end side is opened inside the concave portion 2a and the other end side is opened outside the case 2. And a hole (corresponding to the introduction path of the present invention) 2b. The plate 1 is located in the recess 2a so that the bottom surface of the plate 1 covers the opening of the through hole 2b on the side of the recess 2a (the sensor element 6 side).

The pressure sensor element (pressure sensing element) 4 is made of a semiconductor such as silicon having a strain gauge (not shown) of diffusion resistance and a concave diaphragm 4a in the center,
It is joined to one end of a hollow glass pedestal 5 having a pressure introducing hole 5a by means such as anodic joining. In the present embodiment, the pressure sensor element 4 and the glass pedestal 5 constitute a sensor element section 6.

The other end of the glass pedestal 5 is bonded and fixed to the upper surface of the plate 1 by a thermosetting adhesive (joining member) 7 made of silicone, epoxy, or the like. As described above, since the sensor element portion 6 mounted on the plate 1 in the concave portion 2a has air permeability (ventilation) between the sensor element portion 6 and the through hole 2b via the plate 1 which is a porous member. A pressure (such as the fuel pressure or the intake pressure) from the object to be detected can be received from outside through the plate 1.

Here, in the concave portion 2a of the case 2, a gap between the inner wall of the concave portion 2a and the glass pedestal 5 is filled with a thermosetting or room temperature curable adhesive (joining member) 8 made of silicon or epoxy. Have been. The adhesive 8 covers and seals the entire upper surface of the plate 1 except for the portion where the sensor element portion 6 is mounted, so as not to be exposed, and the through-hole 2b on the bottom surface (lower surface) of the plate 1
Is introduced into the pressure introducing hole 5a of the glass pedestal 5 through the plate 1.

The pad 4 of the pressure sensor element 4
The lead 3 (see FIG. 1A) and the lead 3 are bonded to each other by a gold or aluminum wire 9 and are electrically connected. Here, the pad 4b is for extracting an output from the strain gauge in the pressure sensor element 4. In addition, a cap (for example, made of resin) 10 having a pressure introduction port 10a for introducing a reference pressure such as the atmospheric pressure from the outside covers the recess 2a.
It is hermetically bonded to the case 2.

In such a configuration, the pressure (measurement pressure) from the object to be detected passes through the through hole 2b, the plate 1, the pressure introducing hole 5a of the glass pedestal 5, and the pressure sensor element 4
Is transmitted to the back surface of the diaphragm 4a. On the other hand, since the reference pressure is introduced into the recess 2a from the pressure introduction port 10 of the cap 10, this reference pressure is applied to the surface of the diaphragm 4a (the surface on the cap 10 side).

The diaphragm 4a is distorted by the pressure difference between the measured pressure and the reference pressure. The strain is converted into an electric signal by the strain gauge, and the electric signal is used as a detection signal from the pad 4b to the wire 9, the lead 3 and the like. It is designed to be taken out to the outside via. In the pressure sensor 100 performing such an operation, the air permeability of the plate 1 is
It is determined by the pressure change amount used and the required pressure response time with respect to the internal volume formed by the pressure introducing hole 5a of the glass pedestal 5 and the concave portion forming the diaphragm 4a in the pressure sensor element 4. For example, when the response time is 100 seconds or less for a pressure change of 1 atm, the plate 1 having air permeability of 0.01 cc / atm · sec · cm ² or more may be used.

Next, a method of manufacturing the pressure sensor 100 will be described with reference to FIG. FIG. 2 shows this manufacturing method in the order of steps (a) to (d), and shows a cross section corresponding to the cross section of FIG. 1 (b). First, FIG.
In the step shown in the figure, after the plate 1 is fixed in the molding die by the mold fixing part 1a and the lead 3 is fixed,
By injecting and curing the constituent resin of the case 2, the case 2 to which the plate 1 and the leads 3 are attached is mounted.
Are formed by integral molding (molding) of these members 1 to 3 (porous member mounting step).

Next, in the step shown in FIG. 2B, the sensor element 6 is fixed to the upper surface of the plate 1 via the adhesive 7 in the recess 2a of the case 1 (element part attaching step).
Then, as shown in FIG. 2C, an adhesive 8 is injected into the concave portion 2a, cured, and wire-bonded to form a wire 9. Thereafter, the pressure sensor 100 is completed by bonding the cap 10 to the case 2 using an adhesive or the like.

Here, it is desirable that the adhesive 7 has a viscosity before curing of 2.5 Pa · s or more in order to suppress penetration into the plate 1. At the time of bonding, care should be taken not to block the pressure introducing hole 5a of the glass pedestal 5. The adhesive 8
Also, like the adhesive 7, it is desirable that the viscosity before curing is 2.5 Pa · s or more in order to suppress penetration into the plate 1.

As described above, according to the present pressure sensor 100, since air permeability is ensured by the plate (porous member) 1 between the pressure sensor 100 and the introduction path 2 b of the sensor element 6, the pressure from the introduction path 2 b of the case 2 is maintained. Is introduced into the sensor element section 6 through the plate 1, so that the case 2 of the sensor element section 6
In mounting the sensor element 6, the sensor element section 6 only needs to be fixed at an arbitrary position on the upper surface of the plate 2. Therefore,
The arrangement configuration of the sensor element portion that does not require the positioning of the case with respect to the introduction path can be achieved.

Since the adhesive 8 is filled in the concave portion 2a of the case 2 so as to seal the portion of the plate 1 other than the mounting portion of the sensor element 6, the introduction passage 2b of the case 2 is formed. The path of the pressure from the sensor element section 6 to the sensor element section 6 can be secured more reliably. Here, in order to ensure the airtightness of the upper surface of the plate 1, it is necessary to ensure that the adhesive 8 penetrates into the gap between the inner wall of the case 2 and the glass pedestal 5. Therefore, when the thickness of the adhesive 8 (the thickness in the vertical direction in FIG. 1) is about 1 mm, it is necessary to secure this gap to, for example, 0.2 mm or more.

According to the manufacturing method shown in FIG. 2, the plate 1 can be integrally mounted on the case 2 by insert molding, which is efficient. Plate 1
Since the air permeability is ensured by the
In mounting the (glass pedestal 5), it is only necessary to adhere to an arbitrary position on the upper surface of the plate 1, and a manufacturing method that does not require alignment of the sensor element portion 6 with the through hole 2b can be achieved. (Other Embodiments) In the above embodiment, the plate 1
Was fixed to the case 2 by insert molding, but as in a first modification shown in FIG. 3, after the case 2 was separately formed (including the leads 3), the plate was formed using an adhesive 11 such as a thermosetting resin. 1 may be bonded and fixed. In this case, the plate 1 does not have to have the above-mentioned mold fixing portion.

In the above-described embodiment, the cap 10 is provided with the pressure introduction port 10a which protrudes outward in a cylindrical shape. However, as in the second modification shown in FIG. And projecting in a cylindrical shape toward the
The pressure introduction port 10a may be a simple hole. Further, as in the third modification shown in FIG. 5, both the through-hole 2b of the case 2 and the pressure introducing port 10a of the cap 10 may have a shape that projects outward in a cylindrical shape.

Further, the reference pressure may be introduced from the through hole 2b of the case 2 and the pressure (measured pressure) from the object to be detected may be introduced from the pressure introduction port 10a of the cap 10. Further, the sensor element section 6 does not have the glass pedestal 5, and may be configured to directly adhere the pressure sensor element 4 to the plate 1.

The sensor element section 6 may be, for example, a type that detects a capacitance that changes according to an applied pressure, in addition to the one using a strain gauge. In addition to the above conventional technology, for example, there is a means for aligning a sensor element portion (pedestal) and an introduction path in a pressure sensor as disclosed in Japanese Patent Application Laid-Open Nos. 5-52686 and 9-236501. Although disclosed, these require positioning of the sensor element portion and the introduction path, whereas the present invention provides a surface of the porous member attached to the case so as to cover the introduction path portion. The sensor element may be attached to any position in the above, and the alignment itself between the sensor element (pedestal) and the introduction path is unnecessary,
This is different from the conventional pressure sensor.

[Brief description of the drawings]

FIGS. 1A and 1B show a configuration of a pressure sensor according to an embodiment of the present invention. FIG. 1A is a schematic plan view, and FIG.
It is A sectional drawing.

FIG. 2 is a process chart showing a method for manufacturing the pressure sensor shown in FIG.

FIG. 3 is a schematic sectional view showing a first modification of the present invention.

FIG. 4 is a schematic sectional view showing a second modification of the present invention.

FIG. 5 is a schematic sectional view showing a third modification of the present invention.

6A and 6B show a conventional pressure sensor, in which FIG. 6A is a sectional view and FIG. 6B is a perspective view.

FIG. 7 is a cross-sectional view illustrating a problem in the conventional pressure sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plate, 2 ... Case, 2a ... concave part, 2b ... Through-hole, 6 ... Sensor element part, 7, 8 ... Adhesive.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F055 AA22 AA39 BB05 CC02 DD05 EE14 FF43 GG01 GG14 GG25 HH05 4M112 AA01 BA01 CA15 DA18 DA20 EA14 GA01

Claims (6)

[Claims] 1. A pressure sensor comprising: a case (2) having an introduction path (2b) for introducing pressure from outside; and a sensor element (6) for detecting pressure provided in the case. Pressure sensor is introduced from the introduction path into the sensor element portion, wherein the porous member (1) having air permeability covers the case so as to cover the opening on the sensor element portion side in the introduction path. A pressure sensor, wherein the sensor element is mounted on the porous member, and air permeability is secured between the sensor element and the introduction path via the porous member. 2. A case (2) having a concave portion (2a); an introduction path (2b) provided in the case such that one end side opens into the concave portion and the other end side opens outside; A porous member having air permeability provided so as to cover an opening at one end of the introduction path in the concave portion, and a pressure detection mounted on the porous member in the concave portion of the case. And a sensor element for receiving an external pressure from the introduction path through the porous member. 3. An adhesive (3) in the concave portion (2a) of the case (2) so as to seal a portion of the porous member (1) other than a mounting portion of the sensor element portion (6). The pressure sensor according to claim 2, wherein 8) is filled. 4. The pressure sensor according to claim 1, wherein the porous member is made of a porous ceramic or a porous resin. 5. A case (2) having an introduction path (2b) for introducing pressure from the outside, and a sensor element (6) for detecting pressure provided in the case, the pressure being controlled by the case. A method for manufacturing a pressure sensor, wherein the pressure sensor is assembled in a form that can be introduced into the sensor element section from the introduction path, wherein a porous member (1) having air permeability is provided on the sensor element section side in the introduction path. Attaching a porous member to the case so as to cover the portion, and attaching the sensor element portion to the portion of the porous member opposite to the attachment portion to the case using an adhesive (7). A method for manufacturing a pressure sensor, comprising a mounting step. 6. The case (2) is formed by resin molding, and in the porous member attaching step, the porous member (1) and the case are integrally molded. The method for manufacturing a pressure sensor according to claim 5, wherein: