JP3991798B2 - Pressure sensor - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a pressure sensor that measures pressure with a pressure-sensitive element.
[0002]
[Prior art]
The pressure sensor is a sensor using a pressure sensitive element having a strain gauge formed on a silicon substrate and a pressure detecting diaphragm formed by precisely etching the silicon substrate. The pressure sensor measures the pressure by measuring the amount of strain of the diaphragm due to the pressure using the strain gauge.
[0003]
The pressure sensor is configured to measure the pressure by causing the pressure-receiving surface on which the pressure-sensitive element is disposed to face the pressure chamber into which the fluid to be pressure-measured flows. The pressure chamber in the pressure sensor needs to have a sufficiently high pressure resistance with respect to the pressure measurement range of the pressure sensor and have a sufficient sealing property against the fluid in the pressure chamber.
[0004]
[Problems to be solved]
However, the conventional pressure sensor has the following problems.
That is, it is necessary to expose a terminal pin or the like electrically connected to the pressure sensitive element on the pressure receiving surface where the pressure sensitive element for detecting pressure is arranged in the pressure sensor. On the other hand, the connector housing constituting the pressure receiving surface is generally made of synthetic resin, and the terminal pins are integrally disposed in the connector housing made of synthetic resin.
[0005]
The gap formed at the boundary between the connector housing and the terminal pin is sealed with, for example, a silicone adhesive.
However, the sealing structure using the silicone adhesive cannot always maintain sufficient pressure resistance and sealing performance. Therefore, the development of a pressure sensor that can realize a more reliable seal structure has been desired.
[0006]
The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a pressure sensor having a seal structure with higher reliability than the conventional one.
[0007]
[Means for solving problems]
The present invention includes a connector housing having a pressure-sensitive element and a terminal pin, a sensor housing into which the connector housing is inserted, and a pressure chamber formed between the sensor housing and the connector housing. In the pressure sensor containing the pressure sensitive element,
The connector housing has an insertion part to be inserted into the sensor housing, and has a ceramic block made of ceramics at the tip of the insertion part,
The ceramic block, as well are arranged the pressure sensing element on its end face, it has a through hole for inserted the terminal pin, the inner peripheral surface of the through hole was formed by metallized coatings The terminal pin is brazed via
The seal part in the pressure chamber at the tip of the insertion part of the connector housing is all in contact with the ceramic block,
In the pressure sensor, a gap between the connector housing and the sensor housing is sealed by a seal member disposed at an outer peripheral portion or a front end portion of the ceramic block.
[0008]
In the pressure sensor of the present invention, as described above, the ceramic ceramic block is provided at the tip of the insertion portion of the connector housing. And the seal structure in which all the seal parts in the said pressure chamber become a part which touches the said ceramic block is employ | adopted.
[0009]
And the seal | sticker between the said terminal pin and the said ceramic block can employ | adopt the process which brazes after performing a metallization process using the characteristic as a ceramic of this ceramic block effectively. For this reason, the sealing performance around the terminal pin is more reliable than the conventional adhesive.
[0010]
Further, the connector housing and the sensor housing are sealed with a seal member disposed on the outer peripheral portion or the tip portion of the ceramic block. Here, the ceramic block is made of ceramic as described above, and has excellent pressure resistance and little deformation. Therefore, the sealing performance between the connector housing and the sensor housing is as high as that of the prior art. Is obtained.
[0011]
Therefore, the pressure sensor of the present invention is excellent in sealing performance, pressure resistance, etc. in the pressure chamber, and has high reliability capable of maintaining excellent pressure measurement performance for a long time.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, it is preferable that the ceramic block is integrally disposed in the connector housing made of synthetic resin by insert molding.
In this case, the ceramic block can be easily and accurately disposed on the connector housing.
[0013]
Preferably, the sensor housing has a seal diaphragm, the pressure chamber is sealed by the seal diaphragm, and the pressure chamber is filled with a pressure transmission medium ( Claim 3).
In this case, since the pressure chamber is required to have higher pressure resistance and stable sealing performance, the effect of the present invention is particularly effective.
[0014]
The pressure-sensitive element is preferably joined to the terminal pin exposed from the ceramic block via an electrically conductive bump material.
[0015]
In this case, by bonding the pressure sensitive element by bump bonding, electrical bonding to the terminal pin and physical bonding to the ceramic block can be realized simultaneously, which is efficient.
Furthermore, the pressure sensitive element and the terminal pin can be more efficiently arranged with respect to the ceramic block. That is, the pressure-sensitive element and the terminal pin can be arranged in an overlapping manner, and the degree of freedom of the arrangement is high.
[0016]
【Example】
Example 1
A pressure sensor 1 according to an embodiment of the present invention will be described with reference to FIGS.
The pressure sensor 1 of this example includes a connector housing 30 having a pressure-sensitive element 20 and terminal pins 10, and a sensor housing 40 into which the connector housing 30 is inserted. Further, a pressure chamber 42 is formed between the sensor housing 40 and the connector housing 30, and the pressure sensitive element 20 is accommodated in the pressure chamber 42.
[0017]
The connector housing 30 has an insertion portion 35 to be inserted into the sensor housing 40 and has a ceramic block 80 made of ceramics at the tip of the insertion portion 35. This ceramic block 80 has a through hole 82 into which the terminal pin 10 is inserted, and the terminal pin 10 is brazed to the inner peripheral surface of the through hole 82 through a film formed by metallization processing. It is.
Further, the connector housing 30 and the sensor housing 40 are sealed with a seal member 50 disposed on the outer peripheral portion of the ceramic block 80.
This will be described in detail below.
[0018]
As shown in FIGS. 1 and 2, the pressure sensor 1 of this example is assembled by inserting a connector housing 30 having terminal pins 10 and pressure-sensitive elements 20 into a sensor housing 40 having a seal diaphragm 43.
That is, the pressure sensor 1 is sealed by a seal diaphragm 43 and has a pressure chamber 42 that is isolated from a fluid that is a pressure measurement target. The pressure sensor 1 is configured so that the pressure of the fluid acting on the seal diaphragm 43 can be detected by the pressure-sensitive element 20 through a pressure transmission medium sealed in the pressure chamber 42.
[0019]
The seal diaphragm 43 is firmly fixed to the sensor housing 40 by providing a welded portion 435 that reaches the sensor housing 40 by laser welding from the surface of the seal ring 431 laminated on the outer periphery thereof.
In addition, the pressure sensitive element 20 is a sensor diaphragm formed by processing a silicon layer to form a strain gauge and precisely etching a silicon substrate.
[0020]
As shown in FIGS. 1 and 2, the connector housing 30 is a component made of PPS resin in which a ceramic block 80 is insert-molded. The connector housing 30 includes an insertion portion 35 to be inserted into the sensor housing 40 and a socket portion 300 for electrically connecting a connector (not shown) of an external device.
[0021]
As shown in FIGS. 1 and 2, the ceramic block 80 has a cylindrical shape made of alumina, zirconia, silicon nitride, or the like, and penetrates three terminal pins 10 for power supply, ground, and signal output. A through hole 82 is provided. A coating film (not shown) is formed on the inner peripheral surface of the through hole 82 by a metallization process such as Mo / Mn metallization or W metallization. The terminal pin 10 is brazed and joined to the inner peripheral surface of the through hole 82 using a brazing material such as Ag, AgCu, AuCu, or AuNi with the coating interposed therebetween.
Further, on the outer peripheral surface of the ceramic block 80, a groove portion 81 for biting the PPS resin constituting the connector housing 30 is disposed so as to be firmly coupled into the connector housing 30.
[0022]
As shown in FIG. 1, the insertion portion 35 of the connector housing 30 includes an insertion base portion 353 having a substantially cylindrical shape centering on an axis parallel to the insertion direction, and a substantially cylindrical shape having a smaller diameter than the insertion base portion 353. And an insertion tip 351. The insertion tip 351 is constituted by the ceramic block 80. A connector taper surface 352 is provided between the insertion tip 351 and the insertion base 353.
[0023]
As shown in FIG. 2, the terminal pin 10 and the pressure sensitive element 20 are arranged on the pressure receiving surface 32 which is the end surface of the ceramic block 80. Each terminal pin 10 is electrically connected to each other by a pressure-sensitive element 20 and a bonding wire 34 as shown in FIG.
The outer peripheral surface of the ceramic block 80 is configured to function as a ring groove for arranging the O-ring 50 and the backup ring 51 as seal materials.
[0024]
The sensor housing 40 is made of stainless steel. As shown in FIG. 1, the sensor housing 40 has a concave portion 45 for inserting the insertion portion 35 and an insertion portion 35 accommodated in the concave portion 45 on the connector housing 30 side of the seal diaphragm 43. And a crimping portion 41 to be joined.
[0025]
As shown in the figure, the recess 45 includes a first recess 453 having a large diameter into which the insertion base 353 of the connector housing 30 is inserted, and a second recess 452 into which the insertion tip 351 having a smaller diameter than the first recess 453 is inserted. , And a sensor taper surface 452 disposed therebetween.
Further, the sensor housing 40 has a pressure introduction hole 441 for introducing a fluid as a pressure measurement target and a screw portion 442 for attachment on the seal diaphragm 43 side.
[0026]
As shown in FIGS. 1 and 2, the connector housing 30 and the sensor housing 40 are arranged such that a backup ring 51 and an O-ring as a sealing material 50 are disposed on the outer peripheral portion of the ceramic block 80, and this is used as a recess in the sensor housing 40. The connector taper surface 352 and the sensor taper surface 452 are brought into contact with each other and combined. Then, the caulking portion 41 of the sensor housing 40 is deformed in the inner diameter direction and engaged with the insertion portion 35 so that both are fixed.
[0027]
Next, the effect of this example will be described.
In the pressure sensor 1 of the present example, the ceramic block 80 made of the ceramic is provided at the distal end of the insertion portion 35 of the connector housing 30 as described above. A seal structure is adopted in which the seal portion in the pressure chamber 42 is a portion in contact with the ceramic block 80.
[0028]
As described above, the seal between the terminal pin 10 and the ceramic block 80 employs a process of brazing after performing a metallization process by effectively utilizing the ceramic characteristics of the ceramic block 80. is there. Therefore, the sealing performance around the terminal pin 10 is more reliable than when a conventional adhesive is used.
[0029]
Further, the connector housing 30 and the sensor housing 40 are sealed with a seal member (O-ring) 50 disposed on the outer peripheral portion of the ceramic block 80. Therefore, this seal portion also has a high reliability equal to or higher than that of the prior art due to the excellent characteristics of the ceramic block 80 made of ceramics having excellent pressure resistance and little deformation.
Therefore, the pressure sensor 1 of this example is excellent in sealing performance, pressure resistance, etc. in the pressure chamber 42, and has high reliability capable of maintaining excellent pressure measurement performance for a long time.
[0030]
In place of the pressure chamber 42 isolated from the outside in the pressure sensor 1 of this example, the seal diaphragm 43 may be eliminated and the pressure chamber 42 opened to the measurement environment side may be used. In this case, the fluid as the pressure measurement target directly acts on the sensor diaphragm of the pressure sensitive element 20.
[0031]
(Example 2)
In this example, as shown in FIG. 3, the joining method of the pressure sensitive element 20 is changed based on the pressure sensor 1 in the first embodiment.
In the pressure sensor 1 of this example, the pressure-sensitive element 20 is bump-bonded to the surface of the ceramic block 80 using a bump material 22 as shown in FIG. Here, bump bonding is generally a bump material such as a solder ball disposed between an electrode exposed on the surface of a circuit board or the like and an external electrode of a semiconductor chip such as a pressure sensitive element. This is a bonding technique for bonding a semiconductor chip onto a circuit board by melting, etc.
[0032]
In the pressure sensor 1 of this example, the pressure-sensitive element 20 is arranged with the element surface on which the external electrode (not shown) is arranged facing the ceramic block 80 as shown in FIG. Further, the terminal pin 10 is arranged on the surface of the ceramic block 80 so as to coincide with the pattern of the external electrode of the pressure sensitive element 20.
[0033]
A bump material 22 made of Au, solder, or the like is disposed between the terminal pin 10 and the external electrode of the pressure sensitive element 20, and the terminal pin 10 and the pressure sensitive element 20 are electrically connected by the bump material 22. In this state, the pressure sensitive element 20 is bonded to the ceramic block 80.
[0034]
Thus, since the pressure sensor 1 of this example has joined the pressure sensitive element 20 by bump joining, the joining is strong and its durability is high, and the reliability in electrical connection with the terminal pin 10 is high. high. Also in this example, as in the first embodiment, the sealing structure of the pressure chamber 42 is a structure that seals the portion in contact with the ceramic block 80. Therefore, the pressure sensor 1 of this example is excellent in durability and can maintain its excellent initial performance over a long period of time.
Other configurations and operational effects are the same as those in the first embodiment.
[0035]
(Example 3)
In this example, as shown in FIG. 4, the ceramic block 80 is separately prepared and assembled without being insert-molded in the connector housing 30 based on the pressure sensor in the first embodiment.
That is, the connector portion 301 of this example is a component in which the connector pins 19 are integrally formed of PPS resin. As shown in FIG. 4, the connector portion 301 has a storage recess 38 configured to store the end of the ceramic block 80 on the connector portion 301 side.
[0036]
As shown in FIG. 4, the connector pin 19 is exposed in the storage recess 38 in the connector portion 301. The connector pin 19 has a connecting portion 191 at the tip so as to be in electrical contact with the terminal pin 10 of the ceramic block 80 housed in the housing recess 38.
Further, the overall shape of the connector housing 30 in which the ceramic block 80 and the connector portion 301 are combined is configured to be substantially the same as that of the connector housing integrally formed with the ceramic block in the first embodiment.
[0037]
As described above, the pressure sensor 1 of this example applies the connector housing 30 in which the ceramic block 80 and the connector part 301 which are separate parts are combined, and realizes the same effect as the pressure sensor in the first embodiment. ing.
Other configurations and operational effects are the same as those in the first embodiment.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structure of a pressure sensor according to a first embodiment.
FIG. 2 is an explanatory diagram showing a structure in the vicinity of a pressure chamber of a pressure sensor in the first embodiment.
3 is an enlarged explanatory view showing a structure in the vicinity of a pressure chamber of a pressure sensor in Embodiment 2. FIG.
4 is a cross-sectional view showing a structure of a pressure sensor in Embodiment 3. FIG.
[Explanation of symbols]
1. . . Pressure sensor,
10. . . Terminal pin,
19. . . Connector pins,
20. . . Pressure sensitive element,
30. . . Connector housing,
32. . . Pressure-receiving surface,
35. . . Insertion part,
40. . . Sensor housing,
42. . . Pressure chamber,
43. . . Seal diaphragm,
45. . . Recess,
50. . . O-ring,
51. . . Backup ring,
80. . . Ceramic block,
81. . . Groove,
82. . . Through hole,

Claims (4)

A connector housing having a pressure-sensitive element and a terminal pin; a sensor housing into which the connector housing is inserted; and a pressure chamber formed between the sensor housing and the connector housing. In the pressure sensor containing the element,
The connector housing has an insertion part to be inserted into the sensor housing, and has a ceramic block made of ceramics at the tip of the insertion part,
The ceramic block, as well are arranged the pressure sensing element on its end face, it has a through hole for inserted the terminal pin, the inner peripheral surface of the through hole was formed by metallized coatings The terminal pin is brazed via
The seal part in the pressure chamber at the tip of the insertion part of the connector housing is all in contact with the ceramic block,
The pressure sensor is characterized in that a gap between the connector housing and the sensor housing is sealed by a seal member disposed at an outer peripheral portion or a tip portion of the ceramic block.   2. The pressure sensor according to claim 1, wherein the ceramic block is disposed integrally with the connector housing made of synthetic resin by insert molding.   3. The sensor housing according to claim 1, wherein the sensor housing has a seal diaphragm, the pressure chamber is sealed by the seal diaphragm, and the pressure chamber is filled with a pressure transmission medium. A pressure sensor.   4. The pressure sensor according to claim 1, wherein the pressure sensitive element is joined to the terminal pin exposed from the ceramic block via an electrically conductive bump material. 5.

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